stallone

All the question is in the subject.

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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

The ODB

Absolutely.

you can use a 0-10,000 ohm potenciometer (from radio shack) wired inline with your coolant temp sensor on the front of your intake (assuming you have TPI).
I suggest running two 5-prong relays in line with the two wires going to the coolant sensor... and a toggle switch to allow you to switch between stock ECM control, and the potenciometer control.

Turning the potenciometer will add resistance to the resistance of your coolant temp sensor. A higher resistance indicates a cooler temperature and causes the ECM to add more fuel based on coolant-temp enrichment (this can be as much as 20%+ extra fuel over the base fuel map).
Adding fuel is easy by doing this, however leaning the fuel will require you to wire the relays a little bit differently. I got my best power results by leaning the fuel down several percent.
If you're interested in this method and have any questions just let me know.

good luck


------------------
*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, .462/.470 lift @1.5:1 ratio. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch.
N/A runs 10.9 @124,
Crack-runs 10.3 @135
haven't run at track since Oct-99

[This message has been edited by The ODB (edited February 05, 2001).]

stallone

to lean the fuel mixture, what do i have to do?

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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

The ODB

To lean the mixture you must fool the ECM by lowering the resistance of the coolant temp sensor (physically impossible to do directly).
You can do this by wiring the relays so that when triggered (via toggle switch) the relays take the coolant temp sensor completely out of the circut. This leaves the ECM seeing only the resistance of the potenciometer... which can be manually adjusted (via control ****) to any resistance value between 0 and 10,000 ohms.

you must use two (5-prong) relays for this trick.

theformula

The proper way to adjust your air/fuel ratio would be

A: Custom chip
B: Bolt ons

You can adjust the air fuel ratio with an adjustable fuel pressure regulator. Or, air intake mods (K&N, cold air, ported plenum, runners, etc..)

C: You can increase/decrease the TPS sensor

To lean out your engine, do some intake mods and custom tuning.

------------------
91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN93, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL, Holley 9mm wires, fastchip, Bosch O2sensor, Bosch in-line pump(w/stock pump), SLP headers & catback,short shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

F22Raptor

Formula, you don't adjust the A/F mixture by adding bolt ons like a cold air or K&N. Whoever told you that, tell him to give you your money back. A chip or ECM work is the way to adjust A/F in Fuel Injection. Bolt ons alter the A/F mixture (most of the time they lean the mixture). An AFPR does adjust the mixture, but it does without regards to rpm and other conditions like air temp. etc, it just gives you a lot more fuel over the entire rpm band. Please, make sure you know what you are saying before you speak.

Guest

I dont understand why we are messing with pots and CTS's here...
You can adjust the A/F mix to your liking at WOT with a chip or by adjusting the fuel pressure. At WOT the computer reads right off the fuel map table and ignores everything else. Raising or lowering fuel pressure at this point has complete control over the A/F ratio.
Part throttle is a different story. Once you hit closed loop the computer takes over reading off the TPS, MAF or MAP and various other things like the CTS. The main adjustments made to keep the A/F at where it wants it is done by the readings coming off the o2. If you really wanted to adjust part throttle by lying to the computer, the o2 is the place to play, not the CTS.

The ODB

madmax,
my way costs about $15 and gives you complete control on the fly regaurdless of open or closed loop. This is very handy when doing test n tune runs for max power.

just another alternative to choose from. Everyone has their different preferences.

theformula

F22Raptor, ...so what you're saying is a ported plenum, bigger runners, doesnt affect your a/f ratio? Of course it does. I changed my air/fuel ratio when I put on my blower. I was running VERY lean. Of course, mods like a blower don't have to be that extreme to change it.

I remember when I had stock fuel pressure, and all of my intake mods. K&N cold air setup, air foil, ported plenum. Timing was at 6*btdc. I was running LEAN. I could here knock@WOT! Before all my intake mods this was not happening.

The only way to ADJUST air/fuel ratio would be to lower fuel pressure. But in this case..the guy already has stock fuel pressure. He said he wanted to LEAN his car out. Why do you think I told him to do the bolt ons. There is only one way he can lean his car out now (without custom programming of course). MORE AIR. And more air can be attained from..yes...intake mods.

Guest

No, in closed loop at part throttle you cannot have complete control by adjusting the CTS. Reason is, the block learn and integrator take over and do their level best to adjust the A/F ratio to 14.7:1. Worse yet, if it sees a high temp from the CTS reading, it eventually richens the mix thinking the car is running lean. If you look into the prom code its readily visible what effect the CTS has on the fuel mix. The leanest point involving the CTS at WOT is actually at 132F on the base bin I use, which is from a 1988 350. It varies little across the different chips.

Grim Reaper

Madmax is absolutely correct about the fact that during closed loop, all these "kludges" will be negated by the ecm maintaining 14.7.

In fact, it will introduce driveability problems as the calculated injector pulse width may be further away from what the what is truly needed to maintain 14.7. This is what I have found introduces "stumble and hesitation"; the calculated injector pulse width based on the sensor inputs and various tables will be too far away from the real value.

Worst, while you MAY get the "right combo" for WOT, there are many other places where the ecm goes into open loop and this probably will not be correct for this.

Bottom line, GM put those sensors there for a good reason and to make the ecm to work properly, its the eprom where you have to make the necessary adjustments; not "kluding" the system by introducing "false readings" to fake out the ecm.

Lastly, bumping up your fuel pressure DOES NOT result in increased fuel flow at a constant level throughout the load range; only larger injectors will do that. Bumping up fuel pressure will have its greatest effect at the high loads (low vacuum) and its least effect at low loads (high vacuum). I have done a lot of testing on this and collaborates my findings by check the fuel pressure with the vacuum line disconnected (high load/low vacuum) and connected (low load/high vacuum). This is why you measure fuel pressure with the vacuum line disconnected; to simulate high load and obtain its highest reading.

The ODB

I'm sorry and don't mean to **** anyone off but madmax is wrong. If your car maintained a 14.7 A/F ratio with a 40F degree coolant/engine temperature it simply would not run. The ideal A/F ratio changes based on the reading from the CTS, and that's why my method works. There is no debate whatsoever that it works period. I have done it many times and my friends have also done it.. verified by diacom readings and also by DFI pulse-width readings.
You are right about the very high coolant temps causing it to go richer though. That's why you can only lower the resistance down so much on the POT to reach the leanest setting.
If you run so rich that the POT cannot lean you down enough then your injectors are too big, or you run too high fuel pressure.

The ODB

I'm sorry and don't mean to **** anyone off but madmax is wrong. If your car maintained a 14.7 A/F ratio with a 40F degree coolant/engine temperature it simply would not run. The ideal A/F ratio changes based on the reading from the CTS, and that's why my method works. There is no debate whatsoever that it works period. I have done it many times and my friends have also done it.. verified by diacom readings and also by DFI pulse-width readings.
You are right about the very high coolant temps causing it to go richer though. That's why you can only lower the resistance down so much on the POT to reach the leanest setting.
If you run so rich that the POT cannot lean you down enough then your injectors are too big, or you run too high fuel pressure.

Guest

Where do you come up with 40F?
Read my post first, then comment. The engine will not go into closed loop and set the A/F at 14.7:1 or thereabouts until engine temp hits at least 106F+/- a few depending on the exact chip. Funny that I just went to the dyno today with a wideband o2 stuck in the pipe and watched the A/F readings from cold to operating temp and verified this.
You are right that the CTS changes the A/F but only at WOT. There is a multiplier table that relates coolant temp to a % increase in A/F ratio. Without knowing the actual numbers of increase and decrease through the temperature range (and it varies alot) then you are wasting time trying to pick the 'ideal' temperature for what you want.

Before you try to say I am wrong, learn how to read the information in the actual prom. Ive read the whole damn thing for the 7165 ECM, all 272 pages worth. If you'd like the .pdf file I'll send it to you.

Grim Reaper

Again, I have to back Madmax on this; given my own working knowledge of writing eproms and interpreting Diacom readings. I must add that without knowing what EXACTLY is happening inside the eprom, these Diacom (or any other scan tool) can be misleading. Its only part of the picture.

First, until you hit the "magic CTS temperature" set in the eprom to enable closed loop; you will remain in open loop. Generally, most eproms are between 105-120*F; my L98 is about 115*F (actually 45*C)on the stock eprom, though this is changeable.

In open loop, when you first start an engine, it will remain in open loop and then alter the A/F ratios; initially starting quite rich if the engine is quite cold and slow increase the AF ratio to 15.2 until the car hits the "magic CTS number" in the eprom.

The thing to always remember is that these AF ratios are based SOLELY ON TABLES. Thus, if you tables are off due to modification, it MAY SAY 15.2, but you could be at anything...it is strictly a calculated number based on the tables. That is why the eprom and the tables are so important if you REALLY want the correct AF ratio that the eprom is trying to derive.

You say "There is no debate whatsoever that it works period". That's a pretty narrow minded statement IMO. Yes, you can KLUDGE it so it will work under limited applications. But its a KLUDGE...that is a fact, and it is very limited and dangerous thing to do. You can KLUDGE other sensor too to obtain affects to the injector pulse width, the MAT is will work quite nicely also.

But these are just band-aid solutions (and poor ones at that). You are not addressing the REAL problem ... the eprom itself.

Also, given that the original "poster" has a SD TPI car, it is even more critical to get at the heart of the problem; the eprom and forget all these "hack-saw" methods that often cause more harm than good.

Grim Reaper

I should add that another problem with "faking" the ecm through the CTS is that affects a lot of other things. Your idle speed for one, your spark advance based on coolant temperature for another, the locking of your TCC if you have a locking automatic, the enabling of highway mode, the operation of the EGR and Purge Canister, your fans, the activation of Power Enrichment, start-up enrichment based on coolant; just to name a few. Get the picture? This is a BAD MOD and it causes a whole raft of problems that have people wondering "why is my car running so poorly or getting such horrible gas mileage".

Anyone that attempts this modification is looking for trouble.

The ODB

you guys crack me up, and you both just told on yourselves.
keep reading books ok.

The ODB

you're right I only could run high elevens and get 29mpg highway.
now that I think about it, that does really suk.

forget I mentioned it

Grim Reaper

No flame intended OBD, but I guess since you are such an expert on TPI, that is the reason you went to carb?

Sorry bubb, continue BS'ing your high school buddies. If you cannot read and discuss facts in an open and logical manner without throwing some jibe in, then go to another board.

The bottom line is, you know nothing about the inner working of the ecm and can only "hay-wire" stuff together. Based on what you are saying, the only way I can see you getting the 1/4 mile times you are quoting is by pushing your car off a 1,320 foot cliff.

I did notice that you only posted ets to 1 digit and mph to no digits. Care to post those timeslips? Oh, I know, you lost them.

Don't try BS'ing people and talking about ill conceived "hay-wire" solutions AND when people try to discuss it LOGICALLY AND HONESTLY with you; get "flamatory".

Good day, jerk.

Grim Reaper

[This message has been edited by Glenn91L98GTA (edited February 06, 2001).]

Guest

High 11's?

I thought it was 11.5 on the 305 and 10.9 on the 383. Doesnt look like high elevens to me, where did that come from? Lose track of those numbers?

F22Raptor

Formula, I tell once again: You don't know what you are talking about.
You don't adjust the fuel mixture with a supercharger or runners or by porting the plenum. This mods DO alter fuel ratio (they lean the mix most of the times), but the are not a tool for adjusting or fine tuning the A/F mix.
So, what do you do if you want to trim the fuel flow on an engine? add a supercharger or runners or maybe port the plenum??? To say that shows you don't know what you are saying. You would have to go to the ECM or jetting in a carburated engine or raise or lower fuel pressure in FI; however, raising the pressure will affect WOT for the MOST part.
Glenn, you seem to know more about tunning that most of us. Am I right?

F22Raptor

MadMax, can you send me that .pdf file?
2064_1@msn.com
Thanks, Rick

Grim Reaper

F22Raptor and Formula; I can see where you are both coming from. If a car was excessively rich; then you could add mods that increase airflow to help lean out the mixture...to a point. But you still have to check the BLM/INT and preferrably a Wide Band O2 to ensure that you got your mixture right. The problem is that the increased air flow cannot be controlled "finely". It may lean out at some parts and richen others. Kind of like leading a dog by it's tail.

The better choice is what F22Raptor is suggesting; use the eprom to adjust the VE Tables so you maintain the correct AF ratio (actually injector pulse width to obtain 128/128 perfection) to match the modification of the engine; throughout the rpm and load ranges.

And if you are too lean, then adding mods (except increasing fuel pressure, which only helps @ WOT, does little for lower load ranges) is the last thing you need.

This is what I interpret F22Raptor's post to imply and I agree with it as being the preferred method of tuning.

JoelOl75

I've heard about the 600 ohm resistor trick in the CTS when you want to experiment with a slightly richer mix to see if it helps your ET. Then it could easily be removed. This is just for a guesstimate to see if it works because a rich car is no faster than a lean one and usually TPIs run rich at WOT anyway, but this will improve the part-throttle at the expense of MPG's.

I agree the true and proper ways are fuel pressure, fuel inj size, and custom PROMS. GM did a pretty good job and these cheap tricks usually do nothing except waste gas and make it seem faster because of the part-throttle "snap" but in reality it runs the same or slower.

stallone

Hi guys,

finally, i have checked my o2 sensor, and it work correctly: .2 to .9 mv. So the problem is somewhere else to explain why the fuel mixture is too rich!!! Is it possible that a bad egr valve can explain it?

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trans-am 91 3.08 posi 5.0 lb9 5 speed stock

Grim Reaper

After re-reading the original question "To lean my mixture, what do I have to do?" by stallone (I don't do the quote thing). Formula's answer about using bolt-ons is with merit if the person was planning on modifying their vehicle anyways.

If they had the stock intake and were planning on replacing it, then this would make sense to do first since it moves them in the right direction (leaner) and any additional tweaking should be done after, or you'll do it/pay for it twice.

F22Raptor

Exactly Glenn. IF and only IF you had other mods in the future, then yes, bolt ons do lean the mixture. I said it on my 2 previous posts, however, THEY ARE NOT a tool for fine tunning A/F mixture. AFPR and EPROM are.

442guy

wouldnt moving the intake air temp sensor to a colder area richen the mixture? and vise versa?

Grim Reaper

Yes, but the ecm does not do the calculation correctly especially if the temperature falls below +5*C (44*F). The EGR will kick out and the ecm will over compensate on the lower MAT readings. This is a concern for people with a relocated MAT (or a TB Bypass) in colder climates in winter.

I found decreasing the EGR enabling temperatrue to a much lower number will avoid this overcompensation and give a more accurate calculation with colder MAT readings.

The ODB

madmax, where did you see me post 11.5 ? I have no idea what you're talking about there.

and Glenn, you guys in canada are way too smart for me. That's why I got rid of my TPI and went to carb.
So Glenn, how fast does your car really go? just wondering how all that book knowledge helps you out at the track. How fast could I have gone with my TPI back in 1993 if I'd read the same stuff that you have? Where exactly were you in 1993? were you driving a TPI car back then? just curious.

nah actually I don't really care,
I'm 35 years old and have no plans to ever own any more TPI junk again. I was just offering some alternate possiblities based on my past experiences.. So if people don't like my hay-wire tuning methods, or if people that think they know everything can't run as fast as someone with a haywire mod, and gets upset, well they don't have to ruin their own cars with it.
I figured out the POT trick back in 1993. Are you guys upset now because you never tried it?
I'm just wondering how exactly I got the TPI experts so upset in the first place by offering new info.
If you think I'm really B.S.ing you then call my bluff. Someone from Ill or Mo come around and ask about my white 305 Iroc between 1993 & 1996. See what answers you get.
And when my car comes back out this year with that same 305 with a carburetor + some haywire, come by and check out how slow it is.
I'm serious, you are all welcome to check out all my supposed b.s.

no problems..

Grumpy

Yep, 6 years ago that's how I did it. but times have changed a little since then. Used to beat the dome in on EGR valves to disable them too, years ago. Heck even 160dF thermostats are used by some folks, even to this day. But, why?. The tools are here for doing things right, and rather cheaply. Dial the CTS down and your also changing timing. So which helped the timing or the fuel?. Or would just changing the timing be enough or would more less fuel with more timing?. Far easier to do it right.

The ODB

I used a non CC distributor.
Doing it right costs far too much and runs way to slow for my tastes,
but that's just me.
do what ya like.

Grim Reaper

OBD, I'm 46 and I'm the original owner of my car. Yes, I was tinking with TPI back in 1993 to and yes I tried most of the "tricks" to fake the ecm. Some appeared to give results and others did not.

But, because of inconsistencies I got Diacom so I could see what my engine was really telling me. The results indicated that I was running rich, even at the stock settings and all those "tricks" where hurting me not helping me. So the solution was simple, dive into the eprom so I could have FULL CONTROL over the functioning of my engine.

OBD, I don't necessarily disbelief you with your performance claims. Tuning IS a major factor as to why one car with a lot of modifications doesn't seem perform half way near where it should, while another car with surprisingly few mods gets phenomenal performance. The key is tuning.

With carb and non-computer controlled cars the tuning is easy and obvious to many of us old timers; hence why many of us will die clutching our carbs in our cold dying hands that will have to be pried off with a crow-bar. For some reason with EFI, people have chosen to think of the ecm as a "mysterious black box" that is best left to a few "beady eyed computer geeks wearing thick glasses and half a dozen pens in their front pocket".

If you had a leaning problem with your carb, would you change the jets or "choke off" some air? Change the jets of course; choking off the air would be dumb. But those "fake sensor" readings are effectively the same thing as "choking off" the air to your carb to eliminate a lean condition.

A "carb guy" could explain to the other person that the solution is really, re-jetting the carb, but if they chose to continue to "choke off" the air, that's their business. But if the other person then promotes this as the proper fix, they better expect a "carb guy" to explain to others the problems this solution may cause.

In this case, you can just swap "carb guy" for "efi guy" and the "other person" for yourself; I'm just explaining the proper way to do it and the problems "faking" the CTS may cause.

Lastly, it appears you get a little nasty and defensive when people disagree with your suggestion. If you would like to be a respected member of this web site I suggest that you reconsider your responses. Grumpy (aka Bruce Plecan) is probably the brightest person around when it comes to engines and efi. He has been inside the ecm much earlier than yourself and was trying to give you his "expert opinion" (and he's the only person in EFI on this board that I would truly call an expert) yet your responded rather rudely to him.

You might wish to re-consider the attitude you are presenting in your posts. I've been reading a few of your posts on the other boards and I would say that you are not a "wannabe"; there is definite experience in many of your answers. I agree with fair number of your replies and disagree with a few others. Not a big deal.

Not everyone agrees with my posts and sometimes, after further analysis and "tweaking" of my eprom, I discover that what I originally thought to be a good modification actually has turned out to be a bad modification or has other consequences that people should be aware of. But I share my findings so others can be aware of it and possible test it to see if they find the same thing. The name of the game here is to share information; not get nasty when someone disagrees with it or points out limiting factors with a suggestion.

I think if you act a little "politer" in your responses you'll get a lot more respect than you might otherwise. It would be ashame to have people completely discount your answers only because they don't like your attitude because I think you have a lot of useful experience to share with the others. Just don't get your nose bent out of shape if someone points out a fault with it. It's going to happen more often than you think...even when you ARE CORRECT and your suggestion is EXACTLY what should be done.

Grim Reaper

OBD, on the otherhand, you certainly have "livened" up the board in general; which isn't a bad thing.

And to others, let's give OBD a chance too. Yes, he's made an interesting "introduction" and has gotten noticed quite quickly. Maybe because of some of the responses he has already gotten from others has made him a little "curter" in his replies. I think if we give his answers the respect it deserves (even if we disagree) OBD will respond in a more open and fair discussion.

The CTS trick (also a similar thing could be done with the MAT too) could be useful if you were at the track and trying to determine if you need more fuel and/or timing. It could also be a useful "quick" fix or for limited application such as the track. I would still disagree with it as a "long term/overall" solution, but that is just my opinion. Nothing to start a major "flame war" over.

So let's give OBD a chance too!

Grim Reaper

My bad...it should be ODB not OBD as I've been typing. Guess I think "ecm" too much.

The ODB

Fair enough to me.
Did you really think I disrespected Grumpy in my reply? I don't see that I did and certainly didn't mean to.

oh and a bit more info. My findings are that the MAT has a little effect on the base fuel map, but nowhere near the amount the CTS has.
The factory TPI ECM may have been considered 'smart' back in it's day, but it's nothing compared to the newer systems GM uses now.
The old TPI was effected by a lot of variables that tended to make TPI racers very inconsistent at the drags. Part of my solution was to eleminate as many variables as possible. Keeping the car in open loop during the run was one way. Using a non CC distributor was another. Using fixed resistors on the sensors was another. The POT was a great way to match the tune with the current mods (which changed pretty often). I could get the car dialed in right in less than 20 minutes and without a laptop. I had a huge advantage over the other TPI racers.
Oh and lastly, I used an alternator cutout to improve consistency. Trouble is the ECM was never happy with low voltage, so my solution was the Jacobs Accuvolt regulator that supplied a solid 14v to my fuelpump, ignition, and ECM.. also allowing me to run an alternator cutout.
Not only was the car pretty fast but also dead on consistent. If I had not had such great results with those mods, then I definately would not offer them up here without a warning.
The way I explained the POT was that you can bring it into the circuit via a toggle switch while testing or racing, and then return to normal ECM operation when you're done.
If you know of an adverse effect of running the POT on the CTS circuit, then please explain for everyones benefit. To this day I know of no downsides myself.

thanks for the reply.
ODB

Ed Maher

OK, now that everyone is being civil...as it turns out this whole fight was over nothing. I have to agree with the ODB. His low buck solution w/ pots and Rs would give you an element of consistency and tunability at the track.
However, this wouldn't really help anybody on a day to day basis, which is the market we tend to gear our answers towards here. Fooling sensors and driving around will lead to a flurry of posts like "why do i get such $hitty gas mileage" "Why do i keep burning trannies up" Why did i fail emmisions" Why does my car run like $hit", etc, all of which would be consequences of running a cold CTS.
So the correct way to deal with this in the low buck side would be an AFPR, which can be constructed for a little change and a gasket set. For only a few dollars more you can burn your own chips (which a whole set-up is <$200 these days) and be in ultimate contraol of everything.

So no more fighting, you're both right. You just weren't taking into account the reasoning behind both of your answers (by both i mean the 2 schools, kludge vs. burn)
...ed

The ODB

you're right about that. Not everyone would automatically know how to avoid those problems you mentioned. I did forget to say that I run an RPM switch to control my TC lockup feature while doing runs. When not racing a pressure switch in my tranny takes care of the lockup. During normal driving I would let the ECM go closed and keep it's own A/F ratio.
Sorry I left so much out, but that would've been a huge post.

thanks

Grim Reaper

ODB, is that with MAF or SD TPI? I could see the MAF system not relying or relying on the MAT very little as the MAF is the key sensor relied upon by the ecm. I don't know enough about MAF as I have an SD car so my knowledge is more specialized in that area.

With SD cars, the MAT does play a more important role in the ultimate calculation of the injector pulse width. More so, if the MAT temperature falls low enough to disable the EGR. By altering this constant to keep the EGR working at very low temperatures, I find the MAT results in a much more accurate reading. Too many "inter-relationsips" within the eprom that leaves your scratching your head when you make an eprom change and it behaves differently than what you expected ... usually turns out to be something else in the "hack" that is also affected.

And YES, the CTS has a lot more effects on the ecm than the MAT. The CTS is almost "god like" after the MAF (or MAP for SD) and O2.

Take care.

Guest

Actually, like I said, its better to use the o2. Why? I started messing with TPI outside the computer in 1986. If you did it in 93, you are 7 years behind me. I never said your method did not work at WOT, I said it was not the right sensor to adjust.

[This message has been edited by madmax (edited February 07, 2001).]

The ODB

my bad, I am slipping again forgive me. Since I had an 86 it was originally a MAF car. After a short time I thought MAF's were junk so I converted to SD via DFI.
Seriously that was a while back, and I consciously try not to think of it so much to cut down on my nightmares. Every time I lift my hood and see that carburetor sitting there I get the nicest warm feeling inside. Much less stress.
Maybe my feelings toward TPI would be different if I got into it today, but back then I was pretty much on my own and had to figure everything the hard/expensive way. Hardly anyone really knew anything and the few that did were just out to rip you for a buck.
So hopefully that explains my viewpoint a little of why I scrapped the whole mess.

check you later,
ODB

JoelOl75

Check your vacuum line from the fpr. Is it leaking? Is there a fuel coming out of it when you disconnect it with the car running? If so the diaphram is ruptured. Also since you converted over to SD did you ditch and plug the cold start injector? Otherwise I would look into leaking FI's, lazy O2 sensor (Just because you get good readings doesn't mean it's switching over the correct counts fast enough)

These are some things to look at, albeit right up to the leaking FI's it would be better to borrow a scanner than rip into the motor.