nikom1

Hello Everyone!
I need help with this car. It is an 87 TA with the 5.7L. Here we go. I bought this car 2 years ago and it needed an engine. SO I INstalled a remanufactured 350 and from day 1 it gets 10mpg and lacks power I have searched everything on the car and replaced everything twice. All I can see is that the BLM's go over 150 when you apply throttle. At Idle it is around the 128 and maybe lower once heated up. The car is all stock other than the exhaust from front to back. It has the headers with a heated O2 sensor connected. Please help me!! I gave up on this but the car is immaculate for its age other than this problem. I did everything over not just the engine. suspension, brakes, etc.
Ask me any question that you have and I will answer as soon as possible.


Thanks ahead of time to anyone who can help me.

Nick

88 350 tpi formula

iTrader: (9)

whats everything?

not trying to sound funny but it helps to know what was done.

nikom1

Hey thanks for responding!

As is the engine is the 5.7L , from the beginning I put the new motor in and did not want anything old in it so I replaced everything. Distributor, cap, rotor , wires, Ect sensor for the guage and the one for the ECM. It has the heated O2 sensor, Computer changed twice,knock sensor, throttle position sensor , idle control valve, injectors. fuel pressure diaphram. afpr as well even though it is all stock, put one on just in case i was going to do something to it in the future. Vacuum guage on it stays at about 19.
I had given up on it last year and had brought it to the GM dealer, and 3 other repair shops and not one person can figure it out.

ULTM8Z

Remanufactured engine... what cam is in it?

88 350 tpi formula

iTrader: (9)

it sounds like you have a scan tool since you mentioned the block learn values.

no codes?

what is your base timing set to with the est wire unplugged? and since im asking what timing cover and balancer were used on the 350?

what is the fuel pressure reading at idle and when you give it gas?

nikom1

I

nikom1

No codes whatsoever! The engine is all stock, called the company over and over to make sure of it. Fuel pressure is 38 vacuum on and 44 off
Base timing is set to 6 degrees before tdc.I now have a new thought but am trying to be sure of it. On an 87 where were the timing tabs on they pulley located, at 12 o'clock or 2 o'clock.? I am searching on line but finding pictures showing them in both areas,wtf. Possibly timing off? The tabs on the cover are in the 2 o'clock location but the pulley is from the previous engine

nikom1

Just found pics of the original engine and it had the 2 o'clock cover so then the timing is where it should be

nikom1

ULTM8Z

A MAF car is going to be very sensitive to vacuum leaks (much more so than a MAP car). Any air that the engine takes in after the MAF sensor is air that's unaccounted for by the ECM, and it'll really going to screw up the performance.

Are you absolutely sure you have no vacuum leaks anywhere? What engine vacuum do you have at idle? A factory car should have upwards of 19 inHg at idle in neutral.

You should double check all your vacuum operated emissions equipment is hooked back up correctly since you literally had the engine bay apart to get that engine replaced.

88 350 tpi formula

iTrader: (9)

Have you rechecked the timing recently? i ask because I have seen similar issues before where the timing is off and it makes a huge difference on power. obviously the original engine had someone attack it with a rattle can who knows what was correct/swapped when you got it.

there are other things to check but i do not like getting to far ahead with out rechecking the basics.

are the number 4 and 7 plug wires in the correct spots and not switched?


its interesting it sees a lean off idle condition but seems fine at idle?

I do not think you answered what the fuel pressure is when your on the gas and it is exhibiting lack of HP and BLM is adding fuel

also no misfires correct? runs smooth?

nikom1

The timing is right on the mark for 6 degrees before tic. Yes I have driven the car with a fuel pressure gauge on it and fuel pressure rises when I step on the gas as it should. I have gone over the basics as the other shops I have brought it to. It does seem to have a skip every so and so.

nikom1

So, for sure my first thought would of been a vacuum leak so I smoked the intake and found nothing, the vacuum is pretty steady with the the gauge on it. I removed very thing that is not needed in this engine as the a.i.r. System, cold start valve. But no changes what so ever. I am just thinking if the base intake manifold is leaking internally. I have done the tests with vacuum and it does not show that it is.
I have taken apart the Plenum a couple of times wants to replace the fuel injectors and again to replace the fuel pressure regulator in and tested for vacuum leaks on both times afterwards

ULTM8Z

yeah, but what is the gauge reading? In fact, what is the MAP sensor reading on the scanner when you have high BLM's?

Does the scanner output data to a PC?

Steve Mack

iTrader: (5)

Do you still have the catalytic converter on the car?If so the honey comb interior could be broken in pieces and blocking the exhuast system.I have seen this on other cars and my own once.

ULTM8Z

edit : double post...

nikom1

No map sensor on the 87'

nikom1

When I Put the new engine in I replaced everything with exhaust. So the convert it was new and now it is hollowed out

ULTM8Z

Yep forgot about that....


So then what does the vacuum gauge say?

nikom1

I have a snap on scanner that shows me pretty much all the info. Everything seems fine other than the Blm's , it goes right into close loop after warming up. The O2 readings constantly change from rich/lean. Temperature is up around 200 degrees.

nikom1

It is at 20 at idle and drops as it should in throttle. The needle does not bounce around at all

nikom1

This is what the plugs look like all around

TTOP350

iTrader: (8)

platinum????

nikom1

They are oe ac delco plugs, this is the 3rd set installed in 1400 miles on the engine.

From what it looks like it is running lean, but 10 mpg is where I am lost

TTOP350

iTrader: (8)

They look like platinum, not really needed. The cheapies work fine.

What did you do for injectors or have I missed that some place?

What rear gears are in this car and is the speedo correct with a GPS?

ULTM8Z

Yeah, changing injector flow rates can screw things up without proper recalibration. EVen the same flow rate but different injector type (i.e., original TPI to LSX style) can screw things up without proper recalibration. Ask me how I know that!

nikom1

The injectors replaced our 22 pound from one company online
I don't know what is in the rear end pretty sure the stock
The speedometer seems to be right on never noticed a problem

nikom1

And no recalibration should be needed since the engine is 100% stock

TTOP350

iTrader: (8)

Have they been flow checked to see if they are working properly?

nikom1

These were replaced to knock them off the list if what can be causing this problem. Nothing changed from replacing them, they have been tested with the ohm meter and they are not leaking at all.

ULTM8Z

Not necessarily. As TTOP350 is alluding to, if the injectors are not identical to the original ones, you can have lean/rich issues (even if the advertised flow rate is the same). Though, if they're similar enough, you can get away with it.

What injectors did you get?

Do you have the ability to export data from the scanner?

nikom1

These are what were installed

http://www.ebay.com/itm/Set-of-8-Rebuilt-4-Hole-Upgrade-1987-1988-Pontiac-Firebird-5-7L-TPI-Injectors-/252227262957?hash=item3ab9ea99ed
but again , the problem never changed. The injectors were changed just to get them off the list.

Now its air or fuel that is not correct. If it was running rich it would have black smoke and the plugs would be black. So therefore it is getting more air somehow right? For it to go 10mpg and have the plugs looking lean

nikom1

My main question now is what is keeping the injectors pumping so much fuel. Is it the intake base gaskets? And if it is wouldn't it not have more problems than just mpg and lack of power?

Valve adjustment?

nikom1

What i the differance from the '89 22lb injectors and the '87 22lbers?

Jersey89GTA

iTrader: (1)

Those are Bosch III injectors. Our car came stock with Multech injectors.

I put a set in each one of my cars, didn't have to adjust anything.

ULTM8Z

How's the ignition system? I've seen cars with bad plug wires (on the same side of the engine as the O2 sensor) generate 150+ BLM's. If one "bad "cylinder is causing the ECM is add a ton of fuel, it'll screw up the rest of the engine that's running properly...

You said you replaced everything twice... does that include ignition components?

Again, do you have the ability to export scanner data? There are a multitude of things that could be causing 150+ BLMs,,,

nikom1

Fully understandable to ask but the coil was first replaced with and aftermarket "performance" one then a brand new oe was installed cap and rotor done twice and new set of 8.8 mm wires. Wires have been swapped from bank one to bank 2 with no difference.

ButEven if one cylinder on bank one had a problem, understandable that it would make the blm's high. Making the computer dump gas , wouldn't the plugs on the rest of the cylinders be black, and possibly black smoke from the exhaust? The exhaust has a strong smell, but no smoke.

nikom1

I have the car in storage now , I will get to it this week and get the scanner data from it.

ULTM8Z

True.

I keep asking this though... does the scanner have the capability of exporting data?

An even more basic question... how do you know what chip is in the computer? Is it even the factory chip? Maybe previous owner did something with it?

nikom1

Yes , from the beginning of owning this car , the computer was first replaced and I got the numbers from the chip and double checked it with the dealer and it is the correct factory chip. part #either 8656ABWN or 8674ABWT not positive which one but i have them both down on what slip I have here with me. I know it was the correct one. for the year , make , model ,engine size and transmission

ULTM8Z

recommend you back-probe the ECM pins against this schematic and make sure all the voltages are correct.

http://chevythunder.com/fuel%20injec...%20#1227165%29

nikom1

I have a question about the scanner. Call me so I can see if you can help me with it?

nikom1

It has all been done before

88 350 tpi formula

iTrader: (9)

well this thread is a mess. it would be nice to go over the actual data and checks otherwise as i see this is just a random poke in every direction.. not the way to diag

ASE doc

Hello nikom 1. After reading through your thread, my first question is, what Snap On scan tool do you have? Does it graph data? If so, create a custom data list with just the O2 voltage, Integrator, and Block Learn and select graph display. If it is the old MT2500, just select custom data list and you'll have to look a little harder to see the data figures. By choosing just three PIDs, you'll get the fastest refresh on the selected PIDs.

Then, take a drive to recreate the fault and look at what O2 voltage is doing. I assume that it drops low under load. If so, in the service bay(your driveway if that's the case), use propane injected at a vacuum line and alternately inducing a vacuum leak to test O2 sensor response. The plugs indicate that the lean condition under load is real, and not a faulty O2 sensor reading. Still, we want to know for sure. You put a heated O2 sensor in the car that originally had a single wire O2. We want to be sure that the sensor is responding normally. Once we know that the O2 is working correctly, we can look at possible causes for the system going lean under load.

First off, I would do a quick MAF test. With the key off, disconnect the MAF sensor. Then, start the engine. This will of course set a code and the motor may not run great, but this will place the ECM in default Memcal fuel control, where it ignores the MAF sensor and operates on a sort of half a** speed density fuel map based on RPM and throttle position. You will likely not get closed loop fuel control in this state, but you will get O2 voltage. Take the car for another road test and see if the lean under load condition is corrected, according to O2 voltage. Under heavy throttle, the O2 should hit 900mV and stay there until you release the throttle. This isn't a definitive test but, it generally gives us a pretty good idea if the MAF is our culprit.

If the MAF test doesn't reveal anything, and we know that the car is definitely running lean under load, the only thing left is fuel delivery. You tested fuel pressure in the bay at idle I assume. Figure out a safe way to attach a fuel pressure gauge so that you can view it through the windshield while driving the car. Look for fuel pressure to drop when under load.

You had questions on the Snap On scan tool. What are your questions?

nikom1

Thank you for the quick response. I have a newer diagnostic tool, the snap on solus edge. I was just not sure which way to record the readings on it.
The air mass meter has been replaced 3 times and runs at 6grams at idle, on throttle I am not sure right now as the car is in storage at the moment and i do not remember.
The fuel pump was tested while driving with the gauge on it and fuel pressure was rising on throttle as needed. That is where I and everyone else who has looked at it is lost. Where is the gas going, and why is it running lean?
I will be taking it out from storage soon , I just am not sure what to do next with it. I will record it while under load and Post it for some thoughts.

ASE doc

The Solus Edge has graphing option and to record you tap the icon on the top of the screen that looks like an old school floppy disc. To up load files, you use Snap On shop stream connect. The trouble is that Snap On uses odd file extensions so that anyone who wants to view your recordings pretty much needs to have shop scream on their PC.

Also, I have noticed that, while the labscope on my Modis Ultra will record over long periods, the scan tool only seems to save one screen at a time.

If you break this problem down to its basic parts, it's alot simpler than it may seem. Either the engine is running lean under load, or the O2 sensor is lying. If we can just verify that the O2 sensor is telling the truth, that only leaves a fueling or fuel control issue. Just because you've replaced the MAF 3 times, doesn't mean that it, and its circuits are working correctly. That's why, before we continue throwing parts at this problem and assuming because it's the 3rd such new part that it must be working correctly, we need to stop and do some verification testing of the parts and circuits involved in under load fueling.

The quick MAF test I detailed is pretty much a first step whenever this type of fault occurs. It is a free test that while it doesn't specifically condemn a part, does certainly point out a problem in the MAF circuits. Did you test fuel pressure while driving under load, or just while snapping the throttle. These are two completely different things.

nikom1

The MAF was first replaced because it had a code for it when the car was purchased. It was then replaced with a Remanufactured unit which was giving a code then another one with the same problem and then the third was ok. But again where is this gas going? Running lean is a problem! As soon as i get it out I will run it and record the info and send it.

ASE doc

The question isn't so much where the fuel is going as what is preventing the system from providing sufficient fuel. Again, unless the O2 sensor is giving us bad information, the system is going lean under load. The most common cause of this is a MAF sensor or circuit fault. I specify sensor OR circuit because, especially on a 30 year old vehicle, the circuitry is just as suspect as the sensor. That's where pinpoint testing comes in. Have you completed the trouble tree for code 34? Aftermarket MAF sensors are notorious junk. Unfortunately, that's about all that's available. If you can find an AC Delco MAF sensor for your car, buy it.

Another clue to a MAF fault is the MAF voltage PID, assuming I remember correctly that MAF voltage is displayed on scan data. The MAF sensor signal operates like other 5 volt sensors between .5 volt at the low end and 4.5 volts at the high end. On a full throttle 2-3 upshift you should see at least 4 volts and closer to 4.5. I assume that you've already checked the air intake system for any leaks. Vacuum leaks have less of an effect at full load, when inlet vacuum is low. However, any place where the engine can get air besides though the restrictive MAF sensor and stock air filter housing, it will pull it in. This unmetered air will reduce measured air and cause the MAF to read low.

Your next move should be to try the MAF quick test that I detailed in my first reply to you. It will point out very quickly if this is a MAF problem.

nikom1

Hello ,
The vehicle is out of storage now so I will be copying all the export data as soon as possible here for someone to help me . Hope you are all ready for it .

Nick