ownor

iTrader: (5)

Hi guys,

i'm having a hard time figuring that one out so i thought i'll post up here as i've always received good help on this board

anyways i had problems dialing in the tune on my L03 Formula after doing a full exhaust and some other minor mods. i had also installed a tpi pump prior to that.
during an extended VE learn session, it came to me that there was a lot of correction like +12 on a specific VE cell during one run, then on the next run it would pull out a bigger amount again, and my WB readings ended up being somewhat all over the place as well. i also experienced a maxxed out duty cycle during higher MAP and RPMs, so i was sure it was about time i installed my aeromotive afpr. furthermore i had an issue when i would get on it with the tank being low (like in the 1/4 range, sometimes even when slightly under 1/2) with the car seeming sluggish and even cutting out and stalling. i have had that issue after installing a new ac delco TPI pump, strainer, and in-tank hoses & clamps. i thought i had choked the filter a bit too much when emptying the tank before dropping it for the pump swap.

it all lead me to the conclusion that there had to be something in the wrong with my fuel system. i installed the schrader valve from my actron TBI fpr kit into the feed line (that is the right place, aint it?) where it goes from the frame to the engine fuel lines. with my tank about 1/4 full, i had 8 psi fuel pressure during idle i began wondering why that thing was even running as good as that!
so i got my tools out and got ready to take a bath in fuel.. after the new fuel filter was on it, i thought, well you sucker, let me see some good pressure now. i still had 8 psi of fuel pressure! so with even less than 1/4 tank left after the filter change, i barely made it to a nearby gas station (it died two times on me during that 5 minutes city drive). 30 euros later i had refilled the tank between 1/2 and 3/4. it stopped dying and ran before (not too well, but anyways..), i measured fuel pressure again - same 8 psi.

what's going on here? did i get a bad pump? before the swap, i put 12V quickly to it to make sure it was running at all, but of course didn't measure the pressure outside of the tank.
or could it also be my fuel pressure regulator going bad? i once swapped out my injector pod because i broke something on it.

if it's not the fuel lines or the FPR, it looks like i have to drop the tank again

sorry for the long story. thanks in advance for any hints and comments!
greetz
ownor

RBob

iTrader: (1)

If you block off the return line the pressure should go to about 60 psi. If not, then time to check the connections then drop the tank. It could be a bad pump, bad wiring/connections, or the fuel line between the pump and outlet tube split.

Low voltage to the pump can be an issue. Try to measure the voltage at the connector to the pump. This needs to be done with the pump connected as a load.

RBob.

thomas1976

I can feel your pain, good luck.

ownor

iTrader: (5)

I guess the best way to do this would be to get a 14x1.5mm plug for the return line coming out of the TBI?

Just checking if i got that right:
If this doesn't work out to say at least 45-50 psi (i'm guestimating that would be the minimum acceptable pressure for a TPI pump?), it's either the feed line itself or an in-tank problem (as was mentioned: pump, electrical connections, pressure line from pump to outlet tube).
Could the problem be a ripped or clogged strainer as well?
Any way to check the fuel pressure regulator? I guess these normally don't go bad, but you never know..

Thanks for the input, Bob.
Thanks for your condolences, Thomas

thomas1976

Stock TPI use around 47psi, 45 would be a week pump.

A ripped strainer could allow large debris to clog the pump.

Make sure theres no air in the FP gauge hose.

RBob

iTrader: (1)

That can be done. Or at the line from the engine to fame connection. With stock rubber lines, some say to carefully pinch the return line.

One item I forgot is the fuel filter. It may be clogged.

RBob.

ownor

iTrader: (5)

unfortunately i did already replace the filter. i will try to get ahold of a plug like that to test fuel pressure without a return. btw, do i jump the fuel pump relay for that test?

thomas1976

Could already try engine off, key on, the fuel pump turns for about 3 seconds. Like wen setting fuel pressure with a AFPR.

ownor

iTrader: (5)

i tried measuring fuel pressure last time, with KOEO. the pump primed for about 2 seconds, but iirc the gauge didn't display anything.. could be because there was unbled air left in the gauge line though.
i'll let you guys know what's going on with the pump 'burst' pressure once i get the appropriate plug. thanks for the input so far!

RFmaster

You can manually force fuel pump to operate by supplying +12 V to Pin G on the ALDL connector. Use 10Amp inline fuse for safe operation. Fuel Pump will operate regardless of the ignition key position. Measure Fuel pressure but keep in mind that you only have 11.5 to 12 volts vs. normal 13.8 to 14.3 Vdc with engine running. Fuel pressure will be slightly lower.

//RF

ownor

iTrader: (5)

okay just did some measuring today. with the return line plugged off completely at the TBI, it came up to about 40+ psi at the feed line after multiple priming, and about 55-60psi with 12V put to pin G.
i then held the bypass switch on my actron fuel press gauge (to put the fuel system under load, so to speak) and again put 12V to pin G, which gave me constistent fuel flow and pressure (about 25 psi). as RFmaster noted, that is with about 12V, so it might be reading lower than compared with values taken with the engine/alternator running (about 14V).

does that sound about right? if so, i'm guessing next thing should be replacing the fuel pressure regulator/swapping over to my external VAFPR (ofc disabling the old internal regulator).

btw, just for further reference: the ALDL connector's pins are numbered like this, i wasn't 100% sure myself so i looked it up quickly before putting 12v to the wrong pin:
FEDCBA
GHIJKLM

ownor

iTrader: (5)

anyone??

RFmaster

Since dead head check (12 volt to term G) produced 40+ pSI it appears that pump can provide pressure. However, fuel system must be capable of delivering both pressure and volume of fuel to feed engine requirements over a wide range of operating conditions. I would consider by-passing internal fuel pressure regulator in favor of external VFPR (13301). I am very close to firing a setup like that on my latest project. I am speculating , but it is possible that internal FP regulator is weak (change in tension over temperature) or broken. Worth a look just to eliminate that possibility. I know that getting TBI service parts in your neck of the woods can be a PITA!

and another though - in your original post you've stated that a full exhaust system has been installed. I'm sure it is well constructed, but is it anywhere close to fuel lines????? However remote - make sure that there is adequate separation between fuel lines and exhaust. In old carb days hot fuel - dropped fuel pressure and created vapor lock.

In my set up I run Autogage 2239 fuel pressure sensor (0 to 30 PSI) which is datalogged with EBL. Any fuel pressure deviation from the norm can be easily captured, play-backed and analyzed without taking an expensive petrol shower ($7/G or 1.35 Euro/L?).

//RF

ownor

iTrader: (5)

Thanks for the input! Come to think of it, i myself also had the idea that the pressure is actually breaking down over time, as in, during engine warm up. Couple of things to consider before i post my exact thoughts: I have a ZT-2 wideband with their LCD Display in the car. I once had the engine overheat real bad recently because my fan relay didn't kick on the fan (turned out to be a loose connection at the relay connector ). I was thinking maybe that hurt the spring in the internal fuel pressure regulator?

Anyways, FWIW, here goes: on cold-start and afterwards, the AFR is as expected, a bit rich after start-up maybe, but nothing to worry about. Then, as it gets warmer, the AFR will jump around in closed loop from anywhere between 12.5 and 16 or 17 I was thinking it could also be an exhaust leak though, i haven't got a chance to compare those readings with narrow band readings or INT/BLM yet. If the WB readings are somewhat correct, the fuel pressure could be the culprit - either being too low or bouncing around like the AFR as well.
I did have that issue before the engine overheating on me, but to a smaller extent. I was thinking it was a problem of it not being tuned properly and/or a clogged fuel filter (which i changed without any effect).

Might be best for me to change over to the external unit real soon! I did a short mockup again last weekend and hopefully will get some/the right fittings and lines shortly to get the job done. As far as getting parts over here, i get almost everything i need from the States.. never been a big hassle though, it only sucks if you need a part real quick. Furthermore i have another TBI assembly kicking around the garage somewhere, i might even try that just for kicks (IF i find it ).

An electric fuel pressure sensor to use with the EBL would really be a nice addition, even more so with a VAFPR. I don't really mind the occasional squirt from the schrader valve, but the fuel filter change are always ending up in a mess for me! Maybe i'm doing something wrong here though... Btw, the petrol shower is a somewhat expensive pleasure indeed the liter goes for a slightly cheaper rate of about 1.20 Euro right now, i'd think that would relate to $6/Gal. or thereabouts.

The cat-back i have is a 3" Hooker Aerochamber system. I highly doubt i'd be the first to notice fuel pressure woes with that somewhat common exhaust setup, and i'm pretty sure it's not close to any fuel lines, but thanks for the pointer all the same.

RFmaster

These gen 2 SBC can take a beating but overheating can take a toll on the heads. I have seen this too many times as people jump to conclusions based on preconceptions. It takes a certain amount of discipline to stick to troubleshooting process - performing checks and verify actual performance.
In your last post you've stated that you have a bouncy AFR once in CL. I agree that possible culprits could be flaky fuel pressure and exhaust leaks. In all my SBC powered cars and trucks I've systematically experienced what I thought header leaks (hooker, headman, etc)! The problem was especially problematic on my towing rig - which run hot at times (pulling trailers up hill did not help it any). In this instance the problem was traced down to a cracked head (very tiny leak that would open up at higher temps) that systematically would dump a tiny amount of antifreeze into combustion chamber. O2 sensors do not like antifreeze at all (it kills them) - check O2s for white like glaze. This leak also caused weird surges while in CL (as AFR was bouncing all the place). You may be lucky and could be just an exhaust leak or a weak fuel pressure regulator spring.

//RF

ownor

iTrader: (5)

Ok guys, 2 years later and I found my own thread when looking for "fuel pressure problems"..... yeah, dumbass. guess there was a lot of other stuff keeping me busy and forgetting things like that in the meanwhile.

Anyways, same problem. I recently cranked up my fuel pressure to 16-ish psi by modifying the stock FPR tho. I still have the stock spring in it though.
It was running really nice after i dialed it in and it had been running quite consistent for about 5 mild to wild and somewhat extended drives so i thought everything was fine.
Took it to work this week and at some point my WBO2 showed 20-21:1 AFR without any lean pops.. only slight cutouts and of course a real loss of power, barely being able to keep a 100kph cruise.
Had this condition for about a minute, then went away again. Came again later.. I thought it's a "switched" vac leak or something because it cycled in a strange matter.. I changed to a closed loop bin on the way and it really nicely compensated for it (BLMs were @172), but i know that it's actually not running right..

Found out that it's my fuel pressure though!!! I still have the same FPR (though modified for adjustability), TPI fuel pump, filter, lines, injectors etc in there.

So at times it will run somewhere around 9 psi, and then again at the ~16psi i set the AFPR at. I can also see this reflected in the BLM readings.. It will max out at 172 with low pressure whereas with the high pressure reading it's backing off to getting close to 128.

There's no thermal influence to this. It barely started today when cold and fuel pressure was about 9 psi, 5 minutes later it was running at 16 psi, but i already had it happen the other way round.

The fact that it's changing from minute to minute between these two conditions lead me to the conclusion that it's likely not a mechanical or "hydraulic" (fluiddynamic?) issue, but i might be wrong. I thought about the pump harness, relay where it would be an intermittent wiring problem. However, the EBL WUD shows PMP voltage is always like 13.5 or something in that region so that shouldn't be the big problem either i guess.

I'm really lost on this. It was, and still is, running nicely when the pressure is fine like i set it...
Any input is appreciated!
Thanks!

oh btw, also it seems there's something flaky with my WBO2 readings since at ~20-ish AFRs i really don't know how that thing can even still run! But let's that one out for now!

RFmaster

ownor

Has it been two years already???

The ECM gets PUMP voltage input signal right at the oil pressure switch. The rest of the wiring between engine bay and fuel pump is not monitored. In other words you may have a flaky connection at the tank due to corrosion which (may) result in a pump dropping RPM - lower fuel volume & pressure. To validate this I would put a voltage probe right at the tank (if possible).

How about pinched fuel line???

//RF

ownor

iTrader: (5)

RFmaster, yep has been almost two years and a lot has happened not so much concerning the car though.. also the Bird is just driven every now and then in sunny summertime.

good pointer on the PMP voltage! i didn't know that was taken at the oil press sw...
think it could be quite troublesome to find the causes of such an intermittent problem. is there a way to access the pump connector without dropping the tank anyways??

also about the fuel line.. think that would lead to a more consistent low pressure condition, no?

thanks!

ownor

iTrader: (5)

ok, i have an update... did a log on the way back from work when it happened and i just did a playback analysis. unfortunately i dont have a fuel pressure transducer for logging.. instead i'm going off the BLM, which also seems to be just fine for indicating way lean condition: 172 BLM -> concluding the ~9 psi FP, and 125-130 BLM as being just fine ~16 psi FP.

so with those indicators i was looking at the log. for some parts it seems i'm only seeing these low pressure readings when i'm at low rpms, or after some period at lower rpms.

i'm having some problems with my battery. i had to jump start it a lot so i keep a good one in the trunk for jump starting lol. i have yet to get a new one but euro-cars have other battery poles so i have to go order one at a battery vendor which i wanna before the weekend.

so i was thinking with the battery broken down like that.. IGN/PMP voltages are normally reading in the 13.5-14.0V range when cruising @1500+ rpm. but when having more idling/stops/low speed driving it seems the pressure - along with the voltage - takes a dump! i have a 140amp alternator that i had rebuilt about 3 years ago. at idle rpm it's about 13.0V actually, and won't rise much until like 1300-1500 rpms.

i'm attaching a log file, maybe someone can take a quick look at it for me would be great. for now BLM, RPM and IGN/PMP are the signals of interest
https://rapidshare.com/files/2308955155/cl_bla.dat

thanks again!

Jeffs82TA

iTrader: (1)

owner

I once had a kinda the same condition on a TBI camaro fuel pressure would drop to 8-9psi. I would get a lean trouble code on the ECM, from catalytic converter to the muffler almost the exhaust would turn orange. The car would have trouble accelerating felt like it was pulling a boat, would try and die at idle.

Later found to be that small hose between the fuel pump and the metal line inside the fuel tank had a small cut in it and it just kept getting larger.

I never checked for pump voltage though so may not be the same problem.

ownor

iTrader: (5)

Jeff, was that an intermittent condition, like changing back and forth between normal pressure and that low pressure reading?

I also had a bad idle surge because of the lean mixtures, and as you say feels like pulling a boat (truck-boat-truck comes to mind).

Thanks on the pointer on that hose inside the tank. Might need to drop the tank anyways

Anyone on the voltage issue and my dead battery?

I did a plot of RPM vs. BLMs using the log from EBL. I doesn't have info for IGN/PMP voltage though..
Note that i scaled the BLMs, so BLM 128 = 3000, indicating normal fuel pressure, and BLM 172 = 4000, indicating the low fuel pressure.
To me it seems that every time the RPMs are @2k or lower for some time, fuel pressure seems to take a dump as the voltage would go down because of charging the battery and lower alternator output at these engine speeds.

roughly speaking:
normal fuel pressure = normal BLMs = rpms > ~2k = generator output & voltage is okay
low fuel pressure = BLMs maxing out = rpms < ~2k for some time / idling = generator output & voltage too low



plot link for better resolution

Anyone else?

RFmaster

ownor

I dumped you drive log into excel and found one anomaly that does not make sense.

Here is the brief summary - at any time your tps% is below 5% I observed periodic injector pulse drop out from values one would expect given operating condition to 0!!!
For example see data log 0:10:11 to 0:10:12
time |tps% aPW DC%
0:10:11 5 | 1.89 15
0:10:11 5 | 0 0
0:10:11 5 | 0 0
0:10:11 5 |1.86 14
0:10:11 5 | 0 0
0:10:11 4 | 0 0
0:10:11 2 | 1.74 13

This is not suppose to happen!!! I would ask Rbob to take a close look at your data log and bin file....

//RF

RFmaster

Further to my previous post - the sky high BLM (engine is lean) does not appear to be fuel pressure related, but instead the culprit may be with the ECM systematically failing to command fuel delivery when required.

//RF

Ronny

iTrader: (1)

I experienced a lean condition one day out of the blue. Turned out to be a MAP sensor. No CE light. Turned out so bad car would barely run so I did not datalog. MAP was 26 years old so I guessed right. I did coolant sensor same time but I hear that adds fuel when bad.

ownor

iTrader: (5)

hmm, on that injector pulse drop out you are mentioning RFmaster, I'm actually using a "workaround" to run TBI since i had my EBL modified for PortMod, but with the driver mode still being saturated (or was it PnH, i always forget)... the driver mode needed for TBI injectors anyways. rbob made a jumper connection and cut it so i could still run TBI. since the PFI actually also changed the injector firing rate/timing, i had to use ASYNC mode though, which will trigger injectors not based on DRP or something like this but on timer interval (every 12.5ms).
could that maybe contribute to the "drop out" condition you see at idle, RFmaster?

my idle was good the last 5-10 cruise or drives i did. i always did them in open loop since i was tuning with the wbo2, so i know that it never ran that lean before. also it's not only in idle.
note that when analyzing the plot i did, you'd also have to account for DE/AE/PE flags locking the BLMs at 128 (at least i think so).

thanks for the input so far, but i want to stress again that this is not a lean issue by itself. the lean issue is a consequence of the fuel pressure dropping. that is the issue i'm trying to troubleshoot.

RFmaster

Ok - did not know about the hardware modification done to your EBL! So please disregard "the sky is falling" statements posted earlier!

To narrow the possibilities I would bite the bullet and get Autometer 2239 fuel pressure sending unitwith Pico 5643PT pigtail for fuel pressure data logging purposes and inline T. I have used this (2239) sensor (0 to 30 PSI) in TBI system and for PFI 2246 (0 to 100 PSI) should do the trick for you.

I have never seen fuel pressure drop like you are describing, but then again gremlins always find new and inventive ways to offend one man's ride.
As for fuel pump access - I have seen people remove their back seat and hack an access panel in the sheet metal. It is rather dangerous with gas tank in place since fuel lines are near proximity to the body shell.

//RF

RFmaster

Found something very interesting while looking for Autometer 2246 sending unit - AC-Delco 13500744, for about $20, fuel pressure sending unit used to measure fuel pressure in LH8 - ENGINE GAS, 8 CYL, 5.3L, SFI, ALUM, HO, GM; LH9 - ENGINE GAS, 8 CYL, 5.3L, SFI , E85 MAX, ALUM, GM; Z71 - "OFF ROAD" CHASSIS.

AC-Delco sensor is a lot less expensive than a +$100 from Autometer! The question is what are its attributes...... (pressure range, output voltage, etc)

//RF

RBob

iTrader: (1)

I looked at the log for ignition & pump voltage versus BLM. I didn't see a correlation. What Jeffs82TA mentioned is a possibility. Both the level of fuel in the tank and the flexibility of the line between the pump and output affect this.

Higher temperature the more flexible the hose is, so if split the higher the pressure/volume loss is.

RBob.

ownor

iTrader: (5)

RF, thanks for the pointer on the delco fp sensor, but as you said i wasn't able to find any data for it. I'm pretty sure it would be 0-5V or 0.5-4.5V but dunno what the pressure range is.
I know that fuel tank access door hack is rather convenient, but I guess I'd still prefer not hacking up my chassis for that

FWIW i swapped in a known good battery after buying some clamp-to-side-pole adapters. we'll see if that changes anything, i'll probably take a cruise on the weekend.

RBob, what's an acceptable range for voltage readings for IGN/PMP at idle anyways?
And if there's no correlation to voltage, what else could it be
I'm pretty sure it's not a thermal issue. I started it 2 times from cold (like, first start on that day at 25°C ambients) and it barely wanted to start and when it did, i saw fuel pressure was low again.. On one of the two occurrences, after 2 minutes of city/urban driving it was fine again, on the other one 10 minutes of extra-urban drive wouldn't change anything.
On another occurrence, it was all fine when started from cold.

RBob

iTrader: (1)

Good possibility that the wiring connections are intermittent. This could be at the bulk head connector or inside of the tank.

The other thing to check is the FPR. There may be something in it that is getting under the seat, BTDT. Although in my case I had to open it and remove the object in order to get fuel pressure back.

> RBob, what's an acceptable range for voltage readings for IGN/PMP at idle anyways?

While running, in the 13 to 14.8 volt range. Usually higher when cold out.

RBob.

LastC3

The battery issue could be the culprate ...... noting the issue occurs at low rpms ..... ??

I know on our C5s, any battery issue will cause the computer to whack out a bit .....?????

just a thought

RBob

iTrader: (1)

Rock Auto lists this as a gas tank pressure switch. While a china supplier site lists it as an oil pressure switch. Not sure, but it would be great if is was truly a decent range fuel pressure switch.

RBob.

RFmaster

Rbob

I am going to source this sensor. The biggest hindrance is going to be finding a matching PED plug. According to this assembly drawing:
http://parts.nalleygmc.com/showAssem...ssembly=392112

Item #13 is 13500744 SENSOR,FUEL PRESS(PART OF FUEL LINE ASM 25813125 LBLD 3125,25949801 LBLD 9801)(03.682)(ACDelco #13500744). Required: 01 Alternative part number 213-4422; 2134422
It looks like this sensor screws into fuel line.

Let the fun begin.

//RF

RBob

iTrader: (1)

At that price I'd solder right to the terminals...

RBob.

RFmaster

Indeed, but once I get this sensor I'll try to find a corresponding plug - my guess it is going to be of the three wire variety with Pin A being a ground terminal, Pin B sensor output, Pin C +5 volt reference.

//RF

ownor

iTrader: (5)

Alright guys, i have an update.

Swapped in another known good battery after buying some pole adapters last week (US-style side-bolt to EU-style top-clamp posts). On the weekend i did a 150km autobahn trip, then today 150km of practically roadracing and another 150km autobahn back home (i went through like 1.5 tank fillings btw )

Results: 2 occurences of the low fuel pressure issue.
1) After close to an hour of autobahn, i stopped at a fuel station to look at the log for VE and knocks. Had the ignition on, engine off for about 15 minutes while doing some VE and SA tuning. When i restarted after flashing i could immediately tell that the FPR was low again since it was idling really rough at 19 AFR.. Checked the gauge and yes, 9 psi again. tried to drive it for like 100m in the parking lot there, then parked again to rev it 3 or 4 times to 2.5k rpms... Then it was all fine again.

2) After some hours of very spirited driving and some SA tuning, i found myself going uphill and after climbing about 2-300m of altitude through several curves, it wanted to die on me after a right curve. First thought okay something`s reeally broken now It had completely lost power at about 3 krpm. Noticed that AFR was again 20+. Shifted to N, tried multiple throttle positions then let it go down to idle and rolled out. Idle had a bad surge and it almost wouldn`t move from idle speed when touching the throttle and the condition didn`t vanish.
Got ready to park it on the road with hazard flashers.. but before that, tried the good ol`e "lets give it a restart" approach -- and everything was fine once again!

Feeling a bit lost on this. It seems there`s some slightly loose/intermittent and/or corroded connection somewhere in the pump wiring?

RFmaster

It would appear that have an intermittent - the question is it internal to the fuel tank or is related to feed through (harness) plug. After helping many of my third gen friends with various fuel pressure related problems I can not recall one that did not relate to the harness. Here in SoCal we have very dry conditions and absence of moisture and winter road salt keeps under bodies in virtually factory like conditions minus dirt and road grime. An east coast car stands like punk rocker in a middle of a Sunday service!

I would drop the tank - inspect wiring harness, plugs for a frayed contacts.

Side note.
A while back I was reading a diagnostic recommendation - using oscilloscope to observe current pulses induced by the fuel pump onto voltage supply line. When pumps looses back pressure it begins to spin faster (less back pressure) vs. when back pressure is normal. This would indicate a rapture in the in tank fuel hose between FP outlet and feed through port.

When all said and done it may lead to dropping that tank.

I have yet to see a single broken FPR spring.

//RF

ownor

iTrader: (5)

Thanks again RF and Rbob for your input.

The thing that strikes me as funny is that it was gone after a restart in the 2nd occurrance.. But maybe it doesn't have to do as much with the restarting as with the fact that there was not a whole lot of fuel left around the pump pickup after those twisties i was going up

Since the car has never been driven in winter the under body is as clean as i would imagine a sunbelt car to be. But moisture could still put a small toll on connectors and stuff like this i guess.

For measurements either with a multimeter or an osci, i guess i'd have to drop the tank anyways as it seems, to access the pump connector?

On the osci diag: what backpressure are you talking about, like backpressure in the fuel feed line to the engine/FPR, or specifically in the in-tank fuel hose?

Oh well... while i'm at it i might as well replace it with a stronger pump so i don't have to get in there again at some later point for more power I was looking at the Racetronix stuff and their FP wiring harness upgrades - anyone on that?

RBob

iTrader: (1)

The Racetronix hot wire kits are good to use. Although I don't run them under the car, but through the interior. It gets too hot under the car and it takes a toll on the wire's insulation.

As for the on/off and restart of the fuel pump. With an intermittent connection the connecting point can get arc welded together. This is caused by the current at that point. Then that itty-bitty arc weld can break causing the low fuel pressure. Do a key off and a key on and it gets welded again and have fuel pressure again.

RBob.

RFmaster

Probably need to start a new thread regarding this AC-Delco 13500744 fuel pressure sensor. Here it is in its full glory:

In shipping package


Front view


Top View (into connector body):


Bottom view (into inlet port)


Back View



Initial observations:
Plug - unknown at this time but definitely larger than common 150 series PED plugs used on TPS, CTS applications. No Pin markings what so ever - argggg.
Brass body, 5/8" hex. while interior threads measure 8.97x13mm - would appear as metric thread to me! It would nice if some one with all data access could look-up wiring details on the following vehicles where this sensor is used:

Part#: 13500744
Manufacturer:
Total number of applications: 116
BUICK(1)2009-2009
ENCLAVE(1)2009-2009
CADILLAC(3)2008-2009
ESCALADE(3)2008-2009
CHEVROLET(49)2007-2009
AVALANCHE(8)2008-2009
COLORADO(3)2009-2009
SILVERADO 1500(17)2007-2009
SUBURBAN 1500(8)2008-2009
TAHOE(10)2008-2009
TRAVERSE(1)2009-2009
VAN G1500 1/2TON EXPRESS(2)2008-2009
GMC(47)2007-2009
ACADIA(1)2009-2009
CANYON(3)2009-2009
SIERRA 1500(17)2007-2009
SIERRA DENALI(3)2007-2009
VAN G1500 1/2 TON SAVANA(2)2008-2009
YUKON(11)2008-2009
YUKON XL 1500(10)2008-2009
HUMMER(6)2008-2009
H2(2)2008-2009
H3(2)2009-2009
H3T(2)2009-2009
SATURN(10)2008-2009
OUTLOOK(1)2009-2009
VUE(9)2008-2009



//RF

RBob

iTrader: (1)

Got someone to look it up for a '07 Silverado, 2WD, 5.3l engine. The sensor is located behind the ABS unit in the fuel line. It also shows it located under the truck in the fuel line where it runs along the chassis.

It uses an o-ring seal. It interfaces to the fuel pump control unit. So far, so good.

1 - purple, signal
2 - gray, ground
3 - brown, +5 volts

RBob.

RFmaster

I pulled Delphi Catalog. It looks like 13519047 plug body mates into 13519049 (150 GT series) but there are differences. It looks like a variant of 150 GT series plug body.

Need to find actual plug number used in that 07 Silverado...

Female pins are 12191819 Female GT 150 Tin Plated Terminal, Cable Range 1.00 - 0.75 mm2, Cable Insulation Range 2.25 - 1.70 mm

//RF

RFmaster

ACDelco PT2391 (OE# 19168035) should be matching plug!

A trip to a dealer proved to be useless waist of time - local Chevy parts counter clerk tried several different searches that yielded nothing. A tip from experienced parts guy help me id the correct plug. Let how it turns out!




Again, my apologize @ownor for hijacking this thread.

//RF

morgsie

iTrader: (1)

Gah! wish I would have known about this before I spent $100 on the electric autometer sensor... That is pending the PSI range. RF, definitely start a new thread on this once you find it's pressure range. Very cool find.

RFmaster

Update

Almost a month later the PT2391 (19168035) plug finally showed up. It works with the 13500744 fuel pressure sensor - mates very nicely. Plug has position numbers so I'll assume that they are correct (sensor does not have pin number indications). Next week I'll start testing with compressed air.








//RF

Westech

ttt anyone?

Ronny

iTrader: (1)

Thread is 6 months old? what is your question?

RFmaster

Just been very busy - changing jobs also made things a bit more difficult.

//RF

Rocket-Doc

iTrader: (11)

Did you ever get anywhere on that FPS?

RFmaster

Still sits in my box of projects to get to. Sorry.