Kidformula

I'm new here and need some help.
I have an 89 Formula with 305 TPI. I have had the car for about 5 months. The previous owner was an acquaintance and replaced a lot of stuff getting it to run right, but never got there.
It has New plugs, wires, cap and rotor, ignition coil, fuel pump, pressure regulator, ECM. All those replaced by the previous owner. Since I bought it I've replaced the injectors (Bosch 3 from Southbay), fuel filter, IAC, MAF, O2 sensor, and I cleaned the EGR to make sure it seats. I also replaced the CTS and IAT sensor.
The fuel pressure is around 47 KOEO and drops to 43 or so when idling. It stays there while driving around town and cruising at around 55mph. The timing is set at 6 degrees in drive with in bypass mode as directed by the emissions label under the hood.

I have a couple of problems first when I try to start it first thing in the morning it cranks for 6 to 7 seconds before it even pops or anything. Usually I can try it again and it will start right up. Yes the fuel pump primes for 2 seconds or so when I first turn the key. After the car has been run it seems to start right up if still somewhat warm or only cranks 2 to 3 seconds before it starts.

My second problem which likely related is that my BLM shoots right up to 160ish. That tells me that I am very lean. I don't get any crosscounts until the INT hits the 160 mark.

I have used two cans of carb cleaner trying to find vacuum leaks spraying around gasket areas and vacuum lines with no luck

Where do I go from here?
Any help is much appreciated.

camaro1185

Vats, ign. control module? Also check to make sure your oil pressure thing is not faulty. It sounds like the ecm may not be seeing oil pressure for a couple of seconds, then once it does it fires up. Im not sure how to test that, but worth a try.

Here is something I used a lot when working out the bugs of my car when I got it. I know its for a L98 but it can possibly help out (was from a vette site)

L-98 Engine Start Sequence

When you start an L-98 engine Corvette, a series of events take place that causes the engine to run.
Knowing the sequence will help you troubleshoot no start conditions.

Fuel Rail Pressurization:

When you first turn the key to the “on” position, the fuel pump will run for 2 seconds pressurizing
the fuel rails. There is a Shraeder valve on the passenger side fuel rail near the rear of the
engine and if you measure the pressure there after the pump runs, you should see between 40-42 pounds
of pressure. The reading will go to 38-40 pounds nominal once the engine is running.

Initial Crank Action:

If you then rotate the key to the start position (assuming the anti-theft system has not disabled the
starter), the engine will rotate.

Once the oil pressure has reached 4 PSI, the oil pressure switch will close allowing the fuel pump to
run. (Note that you should have a black oil pressure switch/sender. It is mounted behind the
distributor on the driver’s side and if it is not black, it is suspect due to a run of bad units
that stayed in the GM parts pipeline for some time).

The distributor will send a string of pulses to the ECM (Engine Control Module) in response to the
engine being rotated by the starter. These pulses continue as long as the engine turns (both
starting and running) and if they are not present, the engine will not run.

ECM Reaction:

If the ECM sees oil pressure greater than 4 PSI and the reference pulses from the distributor, it
will energize the injector drivers which will begin pulsing the injectors on for 4 ms (milliseconds)
periods. (In the L98, all injectors on one side of the engine fire at the same time followed by all
injectors on the other side firing at the same time. On the LT-1, the injectors are fired
individually at the appropriate time).

The ECM will also pull in the fuel pump relay in effect paralleling it electrically with the oil
pressure switch. (If the fuel pump relay fails, you can still normally get the car to start and
run unless you can’t make at least 4 PSI oil pressure. This is a “limp home mode” feature put in
place to allow for a fuel pump relay failure).

The ECM also monitors the TPS (Throttle Position Sensor mounted on the throttle body assembly) and
wants to see .54 volts at this time. If it sees appreciably more than 0.54 volts, it will assume
the engine is flooded and the driver has pressed the accelerator to the floor to clear the flooded
condition and restrict the fuel flow as a result. (.54 volts during start and at idle from the TPS
is very important to both starting and run performance.)

Assuming the ignition module is good (meaning there is a spark of sufficient intensity to ignite the
fuel), the engine will “catch”.

Engine "Catches":

When the engine catches, the MAF (Mass Air Flow sensor mounted just ahead of the throttle body) sends
a signal to the ECM advising that air is flowing and also just how much air is being pulled through
to the intake manifold. The ECM takes note of the amount of air being consumed and adjusts the
injector pulse width to around 2.2 ms nominally so as to attain a proper air/fuel mixture to insure
combustion. (This is how the 1985 through 1989 L-98 works. For information on the 1990 and 1991 L-98
variant, see the Note below).

The engine should show an initial idle speed of around 900-1100 RPM and then slowly diminish to
600-700 RPM unless the air conditioner is on in which case it will run at around 800 RPM.

If this does not happen, the Idle Air Mixture valve (located on the throttle body) may be misadjusted.
Alternatively, there may be a leak in the intake manifold or another vacuum leak may be present.
Listen for hissing sounds---there should be none.

ECM Mode:

The engine will now be in Open Loop mode meaning that the ECM is controlling the air/fuel mixture by
referencing values stored in memory.

Once the Oxygen sensor (mounted on the exhaust pipe) reaches operating temperature of several
hundred degrees, the Manifold Air Temperature (MAT) sensor shows an intake air temperature of more
than 140 degrees and the Engine Coolant Temperature (ECT) has reached 160 degrees, the computer will
switch to closed loop mode meaning the Oxygen sensor’s output is examined along with the MAT and ECT
outputs and the ECM adjusts the injector pulse widths (more “on time” or less “on time”) to constantly
strive for a 14.7:1 air/fuel mixture which is the best mixture to hold down pollution.

Note that prolonged idling can force the computer back into open loop mode.

Note: In 1990, the MAF was eliminated from the engine in favor of a speed/density system. This
system uses a sensor called the MAP sensor which measures the Manifold Absolute Pressure (hence the
name MAP) and compares it with the atmospheric pressure outside the intake manifold. This
information, coupled with the Manifold Air Temperature, Engine Coolant Temperature and Engine RPM
is used by the ECM to determine the amount of air entering the cylinders. It is a different way of
reaching the desired 14.7:1 air-fuel mixture ratio but functionally is like the MAF system in that
the ECM uses the feedback to control the "on time" for the injectors.

Corvette used this approach in the 1990 and 1991 L-98 engines and in the 1992 and 1993 LT-1 engines. With the 1994 model C4, they went back to the MAF system. Note that MAF based systems are far more accurate since they measure air flow directly whereas the MAP system infers air flow indirectly. A multitude of things can throw the calculation off and Corvette returned to the MAF system beginning with the 1994 C4 (with a MAP backup). From a troubleshooting standpoint, the MAP operation comes into the sequence the same place that the MAF does.

Summary:

If you have a no start condition or if the L-98 starts and then dies, check the above items in
sequence to see if all the events are occurring as required.

A Scan Tool makes this job much easier and is a highly recommended troubleshooting aid for these
sorts of problems.

camaronewbie

That article is incorrect. The ECM does NOT ever see oil pressure - the ECM is not programmed to read oil pressure, and there is no sensor connected to the ECM that senses oil pressure.

The oil pressure sending unit (OPSU) circuit that feeds the fuel pump is a backup circuit ONLY - it only works if the ECM and thus the fuel pump relay circuit are not functioning. The OP stated that his car primes, so his ECM and fuel pump relay are working fine. There is no "switching" between circuits on the running of the fuel pump, as the ECM has no control what-so-ever over the fuel pump circuit that is fed by the OPSU.

You might have an issue with your ignition module, your pickup coil, maybe the cold start injector, or something else. But it sounds like your ECM, fuel pump relay, and fuel pump are all doing their job as they are supposed to.

Besides, if it were an fuel pump relay issue, it would take longer than 6 seconds for the OPSU to recognize oil pressure and run the fuel pump long enough to pressurize the fuel rail with enough gas to start the car. I had this issue when I first went carbed - had to wait for the OPSU to power up the fuel pump after the starter turned motor and built up oil pressure - it takes much longer than 6-7 seconds - more like 20 - 30+ seconds for the OPSU to power up the pump and get the fuel up to the injectors.

Kidformula

Thanks for your responses, I have wondered about the pickup coil in the distributor but I don't know how to test it, and currently don't have the money to go buy a new distributor. I have read a couple of guys have had similar intermittent problems that were fixed by changing the distributor.

Would that also cause a lean running condition or would that be something else fuel related? The injectors are supposed to be the 19 lb Bosch 3, would it make a difference having a K&N cone filter and 3" exhaust?

camaronewbie

Might be a way to test that little pick up coil, I don't know - do a on here for "pickup coil" and see. The ignition module is testable at most local parts stores, but I never tested one, just replaced since it's a $30 part. Pickup coil ought to be like a $10 part.

ASE doc

The pick up coil requires disassembly of the distributor, including removal of the shaft, to replace it. testing is fairly simple. Use a DVOM to test the coil's resistance. Should be between 800 and 1000 ohms. Also, check for looseness of the pole piece and timing core on the shaft/base of the distributor. These pieces break.

ASE doc

High BLM and/or Integrator points to a lean condition. The system is adding fuel to compensate. Check plugs to see if the engine is actually rich. This would indicate a faulty O2 sensor or incorrect PROM. What does INT and Block learn do at idle? Does Integrator drop low at idle when BLM is at 160? If so, this means that it is not caused by a manifold air leak but is somewhere in either the fuel supply or fuel metering, (clogged injectors, wrong PROM, faulty CTS, or MAF). If Integrator goes high at idle and then goes low under load, the problem is a manifold air leak and not fuel metering or supply.

Kidformula

I will test the pickup coil tomorrow and get the ignition module checked too. I don't remember exactly what the BLM and INT were doing at high speed but at idle the BLM pegs 160-170 and after 30 seconds or so the INT catches up. It didn't catch up before I changed the O2 sensor. I changed it just last week, it was a white color on the finned portion that sticks into the exhaust. I believe that means lean.

I read on another post that some people had problems with the Bosch 3 injectors, what are the chances that they aren't flowing right? Could that be causing a lean condition, I've only had them in since January?

ASE doc

I haven't heard of any trouble with the Bosch IIIs. Carefully check for vacuum leaks at areas away from the motor, like the brake booster, and look at Integrator and BLM under load to see if it might be a MAF problem or basic programming issue. Has the current engine and management system ever worked correctly. Or has this problem been there since the last time you did work on it? The scanner will be your best tool for finding this problem. Look at all the ususal suspects.

CTS reading, does it make since? If it says engine temp is 200 degrees 2 minutes after startup, it's probably lying. MAF at idle should be about 1.4v, at WOT it should be 4.5v, KOEO it should be about .5v MAT can affect fuel delivery in extreme cases. The MAT correction map on the 3rd gens is not nearly as steep as the CTS map but it should be looked at as a possible cause. If you have access to a scanner, maybe you have access to a scope. Scope injector waveform to look for signs of a failing quad driver or poor ECM ground/injector power supply.

Kidformula

First off thanks for the help

I checked the pickup coil and it came in a 946 ohms. I checked again for any leaks and found that the vent on the evap canister was sucking in air pretty good. When I unplugged the solenoid on top of the canister it quit sucking air in. How is that supposed to work? I thought that it would just suck the fumes in from the gas tank not outside air. Any thoughts there?

I also looked at the distributor rotor and shaft while I had the rotor off checking the pickup coil, and it had a slight bit of movement (I would say less than 1/16") side to side. Is that normal?

I didn't check the ignition module because as I was out there I realized that when I had set the timing before I had unhooked the wrong wire. The tan and black wire wasn't even "close" to the distributor it was by the fan for the heater and the A/C. The grease was all dry and hard on the bottom of the module so I did wipe it off and put new dielectric grease on it.

I had to go over to my buddies who has a timing light and once I unhooked the correct wire I found the my timing was way off. I set it where it should be then unhooked the battery to clear the code 44 that I got for the EST error and then drove the car home. I now have to wait until it cools down enough to see if that cures my problem.

On the way home though I noticed that the INT and BLM were still all over the place, but I might need to drive it some more for everything to relearn.

86T/A_Ram_Air

if base timing was "way off" that could very well be a big part of your issue

ASE doc

BLM and INT don't relearn. They are secondary fuel correction and they are windows into what's going on in the system. BLM compensates for fueling issues. Did you watch BLM and INT as you drove? As I said before, this will tell you if the problem is just at idle or in the fuel supply or management system itself. Timing being off will not affect BLM or INT to any measurable degree, not before it causes the engine to stop running. If this engine is running lean, you need to fix it before you do alot of driving. Otherwise you will severely damage it.

Kidformula

I did try to watch the BLM and INT as I was driving. As you said changing the timing didn't seem to change the BLM the INT seemed to be ranging all over from 128 to 170. It did seem to hang on the rich side a bit more than what it used to though.

As far as the lean condition goes, should the vent on the EVAP canister be sucking air like it was?

86T/A_Ram_Air

i don't think so

ASE doc

The EVAP sonenoid is a vent type. When not commanded on, it vents vacuum to the atmosphere. Remember, high BLM is lean, low BLM is rich. Integrator is short term fuel trim and will range all over as you drive. BLM is long term and should stay neutral at 128. If BLM goes high as you drive, that means that the enguine running lean.

Kidformula

I just went and started it and drove around for about 5 minutes. Starting temp was around 45 degrees. It started with about a 3 second count. So that seems better. As it started to warm up it was switching rich to lean sort of hanging on rich until it hit about 62 degrees and then it wanted to stay lean. I checked the EVAP canister vent to see if it was sucking air in and it was. I unplugged it to see if that would make a difference on the cross counts it didn't seem to. The BLM was sitting at 154 the INT didn't seem to go above 145.
As I drove it around the BLM went right up to 160 and the INT went as high as 175, but it was all over depending on engine load, which I imagine it should be, although it shouldn't normally be that high. It was hard to find a flat place that had a long straight path to be able to cruise at the same speed for very long. When I got back home the BLM was right at 160 and the INT was ranging from 128 to 145. As soon as it would reach 145 the IAC would move and then the INT would reset to 128. The O2 reading was about .10-.14. This was with the EVAP unplugged.

Kidformula

ASE DOC does that mean under normal operating conditions the EVAP canister vent should be sucking air in until the solenoid kicks on the clear out the vapors from the tank?

ASE doc

Yes, the EVAP solenoid will suck air until it is switched by the ECM to draw vapors from the canister. It should have a vent filter, little peice of foam rubber attached to it. Most EGR solenoids are the same way. The high BLM when driving indicates a basic fuel delivery deficiency. It may be that MAF is inaccurate, it could be injectors or low fuel pressure. It is not likely a vacuum leak. Vacuum leaks will cause lean idle but when the throttle is opened. The vacuum leak has less affect on AFR. Look for any air leaks between the MAF and throttle body. Is your PCV system intact? What is MAF reading at idle? At WOT? Are you reading coolant temp in degrees F or degrees C? You may have a CTS problem.

Kidformula

I'm reading in degrees F the CTS and MAT are both new and seem to be within a degree or two of my thermometer outside when the engine was cold.
The PCV system is intact I haven't replace the PCV valve yet, and I haven't seen any rips in the elbow between the MAF and the throttle body.

I did just replace the MAF a reman from Autozone(I know it could still be inaccurate) but I did it based on how it ran with the MAF unhooked. When the old one was unhooked the car seemed to run better and if I remember right the O2 sensor reading seemed to fluctuate a lot more. When I unhooked the new one a couple of weeks ago it seemed to have more of a hesitation than when the sensor was hooked up. I don't remember it doing that so bad as compared with the old one.

At idle the MAF was reading 5-6 grams per second. At WOT it went up to about 129 gps at no load sitting in the drive way. I did only let it get up to about 4000 rpms before I let off though. I know what you were looking for was volts by my OTC monitor 4000E won't tell me that. I have access to a snap-on brick I will try to get it before the end of the day and will let you know what I get if it will tell me the volts for the MAF.

I have checked fuel pressure several times since I replaced the injectors and it is fairly consistent between 47-50 KOEO and 42-43 at idle it goes up under acceleration like it should. It's not adjustable so I can't play with it to see what it does that way.

Kidformula

I tried using the snap-on mt2500 but it didn't give MAF voltage either. Is there another way to test for it? Or is the gm/s reading good enough? It was the about the same between the two scan tools, about 5 gm/s at idle and up to 100ish at wot on a snap throttle.

ASE doc

Go to Trouble Shooter in the MT2500's menu and look for "data scan normal values" this will tell you what to expect. I honestly dont remember. I'll look at my Helm's manual for the 87 today, which should be the same, and see if it gives the normal range.

Kidformula

The troubleshooter said to compare the MAF reading with the AIRFLOW reading. The MAF is the actual the AIRFLOW is a calculated reading based on the other sensors. It then said that the reading should be within 2 of each other. The readings were right on with each other. The AIRFLOW might have been a second or so behind at different throttle positions but it did catch right up to match the MAF reading.

ASE doc

Then you do not have a MAF problem. look at injector pulse width and compare it to "data scan normal values". If it's not right, suspect PROM or ECM failure. This would be highly unusual.

Recheck fuel pressure, this time while driving the car. When Block learn goes high, does fuel pressure drop? Be sure that your okay with the CTS reading, and that there is absolutely no unmetered air getting into the motor. If all checks out okay, replace your injectors. Again.

Kidformula

You keep on mentioning the prom is there a way to test it, other than replacing it? How would I know if I have the wrong prom. According to the scan tool I have a 8161 prom. Should that tell me anything? If I do have to replace my injectors, again, should I go with 22 lb injectors or stick with the 19 lb injectors?

ASE doc

The stock 305 takes 19lb injectors. Larger injectors will only cause overfueling. The PROM number is useful for referrence. You can check the number to see if it matches your engine configuration. The only way to test the ECM or PROM is in the car. If the injector pulse width is not in line with normal values, you have to suspect faulty programming. As I said, this would be highly unusual. ECM's just don't lose their basic program and continue working without setting a trouble code. Aside from CTS or fuel pressure, I really can't think of anything aside from the injectors themselves that would cause under fueling when the MAF is working properly.

Kidformula

Doc thanks for all your help. I really appreciate it. I guess I'm looking for some new injectors. That stinks. I guess I can try to see if the guys at Southbay can help me out with testing and replacement. They were "supposed" to be flow checked and balanced.

ASE doc

I didn't know you used South Bay. Those are some great guys. Send the injectors in and they'll check them for you. If they check okay, we have a problem somewhere else.

Kidformula

Well I just talked with Frank from Southbay and he got my injectors and tested them, they were spot on at 19lbs. He wondered if there might be something wrong with the prom. Other than finding one that works to try it is there any way of testing the prom?

ASE doc

the only method available for testing the PROM is in a known good ECM. the only way for testing the ECM is on a known good engine. I think we're missing something here. We've overlooked something stupidly simple. And I'm afraid that if you jump on the PROM or ECM you'll be disappointed and with alot less money in your pocket. Viewing data when the key is tuned on, before you try to start the car may show you something. I really believe that there is something missing that is affecting engine crank fuel. The ignition switch sends a crank signal to the ECM to tell the ECM that the engine is being started and the ECM responds by adding extra fuel for start up depending on the air and coolant temps reported by the temp sensors.

On cars so equipped, the cold start injector also helps add fuel. Did I have you check the CRK fuse? Did we confirm, if you have it, that the cold start injector is working?

Kidformula

I don't have a cold start injector and until I get my injectors back from Southbay I can't test too much.

The kid I got the car from told me that this was not the original engine. He said that the person he got it from told him that it was a 350. From what I found on the block behind the drives side head it is a 5.0l LB9, the car came with the 5.0l LB9
If it got bored out a little bit during a rebuild could that be part of my problem?
I know that I am just guessing here but I don't know where else to go.
The "boss" is telling me that if I can't get something figured out then it has to go away. The back yard isn't big enough to hide it and I don't have enough money tell come up with to say I sold it(while its hidden in the back yard).

I know that the 22lb injectors are too big for my car, but if I was working on a dirt bike that was running too lean I would just change the jet. Yes I know that there are a lot of sensors and such involved here but is it possible that bigger injectors even if they normally would over fuel the engine might give the correct amount of fuel given the situation?

86T/A_Ram_Air

if the PROM has the file for 19LB injectors than it should run ok....it will be a touch lean though if it really is a 350.

Kidformula

Would there be any numbers on the prom itself to identify it as to what it actually is, if it is aftermarket or stock or is there some other way to identify it?

ASE doc

For questions regarding PROM id, go to the DIY PROM forum.

Kidformula

Well I think that I may have found a problem, just like you said Doc it is probably something simple that was over looked. I went down to the garage, where I have the car while the injectors are out, and pulled the computer out. I pulled the prom and it is a Delco ABWN 8656. I did a Google search for it and to see if I could find what it should be and I brought up another post here on Third Gen that somebody else had the same prom in a 89 irocz with a 5.0 tpi automatic. Sounds familiar right. The Camaro version of my car. He was having the same lank crank to start problem. Someone posted that the prom he had, and I have is for an 87 5.7 tpi.

That makes a lot of sense. The 87 would have a cold start injector that mine doesn't, it would have 22lb injectors that mine doesn't, that would explain the long crank time and would also explain the lean running condition across the rpm range.

Now I just need to find where to buy the correct prom for my car.
I'll get my injectors back from Southbay and reinstall them and see what happens.

Any good ideas on where to get a stock prom for my car? I'm guessing the dealer.

Thanks so much for all of your help.

I hope that with a fix in mind it will help me be able to keep the car and keep my "boss" off my back about it.

ASE doc

The dealer may be a no go. They pretty much drop support for any vehicle more than 15 years old. Especially specialty parts that aren't in high demand. The problem you face was common among ODB1 vehicles even when they were current. Just look sometime at a GM PROM cross referrence guide and see how many different PROMs were made to solve various drivability complaints. Thank god for the EEPROM.

To find your PROM, or at least a solution, post a thread on the DIY PROM forum. Or just PM RBob. You'll find him over on DIY PROM. He seems to be the resident guru of that area.

fireburdluvr85

now u have explained whats happening to me except mine wont even rev past 1200 rpm. i was driving fine then it just lost all throttle and everything. now the difference is i had my modis hooked up and the only code i get is 44. i spent 5 hours trying to get home. i always keep a spare maf, icm, and ecm on hand. 41 lbs when running. no difference in pressure when trying to go. my blm and int bout up near 160. o2 14mv. 5 g/s on maf at idle. dont understand why itd run great then **** the bed. btw this is a 91 tbi swapped to 89 tpi. its run great for 2 weeks. has new bosch 3s.... gonna keep an eye on this thread

ASE doc

Check your MAF at full throttle. Does it respond to throttle changes? You are not getting fuel.
I suspect your MAF or MAF circuit. Try unplugging the MAF sensor before starting the car. See if it runs better this way. If so, it's in the MAF circuit.

fireburdluvr85

glad you answered there sir, i did try unplugging the maf and no change, still refused to rev past 1200, had to have it towed last night. 17 miles from home it wouldnt even limp. 5mph is pretty hard to drive. lol. i tried unplugging each sensor each different start and got no changes. i kept my modis plugged in and it for once told me not much useful. everything looked good to me. now if i let it "cool" down for awhile it would start and run fine for a few. changed out my icm with a known good and it ran for about 25 mins ok till i started going then just lost everything again. it would go nice and smooth plenty of go then just like someone unhooked my throttle cable. i just cleaned out my iac ports and replaced my iac the other day. it is opening and closing. verified that on the side of the road yesterday. just set my tps to .54v. idle speed set to 450. timing at 6*. i bought this swap as a running drivetrain. i drove the car for awhile before we pulled it so i know it did run great. ran great for me before yesterday. i am going to do the carb cleaner trick just to verify that there is no vacuum leaks.

Apeiron

No, but it does see fuel pump voltage, and some versions of the code apparently will insist on seeing the fuel pump voltage powered by the OPSU with the fuel pump relay off during cranking.

ASE doc

On 89 and up vehicles, the OP cutoff switch did cut off the fuel pump relay if oil pressure dropped low enough for the switch to open. I don't believe that this is the OP's problem since he is running very lean once started.

Apeiron

Not on any of the thirdgens.

ASE doc

I misstated my point. To the best of my knowledge, the relay opens once the car is running and the oil pressure switch powers the pump as long as pressure is high enough to keep it closed(5psi). I'm actually not sure because I've never tested it. Have you? I can't on my car because it's nothing like stock.

I've never heard of the FP relay staying open when cranking. I haven't seen it on any car. I wish I knew for certain.

Apeiron

The ECM powers the pump relay any time it sees distributor reference pulses, and for two seconds after the last one. That's where the 2 second prime and the 2 second run-on after stalling come from. You could yank the OPSU out completely and the car would continue to run just fine.

fireburdluvr85

you ever check the ecm main power at the ecm? itll show up on a scanner as an occasional loss of communication. just a thought if you got a few mins to check it out. our cars are getting older and the wiring is starting to lose integrity.....

ASE doc

So, are you saying you found your problem?

fireburdluvr85

nada. still messing up but not as predictable. i gotta break out the old multi meter and start tracing wires. had an under dash fire from a mis routed main harness during my dash swap. burned up my ecm bat power and ign signal. died on my way to work after running great all day. i do believe i will start a thread on mine tho and leave this ones to the op. i actually posted that up in hopes that it would maybe help them.

ASE doc

You have the Modis. Use it to monitor data looking for changes in any of the PIDs coinciding with the problem. There must be changes in BLM or Integrator as the problem shows up. Use the Vantage function to scope EST circuits as well as power and ground circuits. The damage to the harness may have affected any number of data circuits. Yeah, your own thread is a good idea. Even though your symptoms sound similar, the cause(s) may vary widely.

Look closely at the four circuits between the ECM and ICM. You may be losing crank referrence pulses ot at least they're getting so weak that the ECM can't see them clearly.

Kidformula

Hey guys I know it took me some time to get back on here but here is my update. I got my injectors back and installed them, (Big thanks Southbay) and got my new prom from the dealer and installed it, and the car won't start. I am guessing that it is a vats issue because I have no injector pulse while cranking. Just for kicks and giggles I installed the old prom again and it started. The old prom is from an 87 Camaro or firebird with a 5.7 tpi. From what I have read that means no vats (for the 87). I read how to bypass the key with a resistor and I tried the 15 different values (twice just to make sure) with no luck. Yes I did wait the 4 minutes in between, no I don't know what the original resistance was because the key that I have has never had the pellet in it, but the car has always had a signal to the injectors before swapping the prom.

Any ideas on what to do next?

Some have said to get a prom with the vats disabled I don't even know where to begin to get that done.

Any help is much appreciated. Thanks

86T/A_Ram_Air

any tuner should be able to do that....like pcm4less or places like that