I have a 89 trans am, it will start and idle most times, but when you put it in gear and start to go down the road it will die, doesnt matter if you are going 10mph or 70 it just dies, it will start back up and run again for a few minutes then die again in the middle of the road, the security light stays on when it dies like that, so most say its the VATS thing i need to bypass, but the thing is, it doesnt die in a few seconds after starting, it stays running almost all the time without dieing, its just when your going down the road that it will stall out and die, i have replaced the fuel filter and still didnt help. what else could it be? ignition module in the dist cap?
the steering column ignition was changed out, it does NOT have the coded key it has a regular key.

 

have your ignition control module checked...


Posted from Thirdgen.org App for Android

 

Thanks my3rd, can the auto parts places check the module? or how can i check it at home? i also changed the PCV valve and still didnt help, just trying to narrow it down and starting with little things first, i was told that the module thats in the dist cap is super easy to break and that i should just change out the whole cap assembly but right now i dont have the funds to do that.

 

autozone checks them for free but they do not always test bad even when they are bad. the best advice I can give is to buy the one with the limited lifetime warranty because...Well you will need one atsomeoneagain...we just replaced my roommates again and his was less than 2 years old.

 

Repeated failure of the ICM can be caused by low primary resistance of the ignition coil. Also, be sure to apply heat transfer grease to the bottom of the ICM when installing. Dielectric tune up grease works in a pinch.

 

Thank you, didnt know about the heat transfer grease
Also someone told me i should write a detailed disc of what its doing so i will try and do that, maybe that will help, im so lost with this car haha
will start after 2 or 3 try's
stays running while its idle
security light constantly stays on when started
try to give it gas and it wants to bog down (in park)
go in drive and start to go, it will go for sometimes a block or maybe even a mile before it just dies
the oil pressure, water temp and everything is reading good according to the guages
it will start back up again after a few more try's
put it back in gear and start down the road and it dies again

im totally stumped on this one, never had a car do that
the closest thing to it i had happen was when the cat coverter was stopped up
on an old car i had, took it off and beat the crap out of it and put it back on it
worked fine after that
these are the options people have told me it could be so far
VATS
cat converter stopped up
ICM
PCV (replaced yesterday)
fuel pump going out
fuel filter stopped up (replaced a week ago)
couple wires on the tbi are missing the coating in places

 

couple of vids i made, not the best but might help i hope

 

Your symptoms sound alot like low fuel pressure. Test fuel pressure. It should be 35-40 at idle and go to 40+ when you tap the throttle. You could also have injector troubles but the behavior sounds like a fueling issue to me. The broken line in your photo is the vacuum line to the heater control valve that is also in your photo. That line breaks out of the engine harness close to the valve and comes from the HVAC control head in the dash. The broken line accounts for a small vacuum leak. On an otherwise healthy engine, it wouldn't have any noticeable effect on driveability.

EDIT: Hold on a second. Your car is TBI, not TPI. Fuel pressure should be 9-13 psi and you need a special adapter set to test it. You can watch injector spray for an indication of low pressure. The spray from the nozzles should be a cone shape and when you tap the throttle, the spray should mist a little and hit the sides of the throttle bore. It is common for the regulator spring in the throttle body to crumble from rust and cause fuel pressure to drop off.

 

Thanks Ase, i dont have a way to test the pressure but i will have to figure out a way to get it done,, sounds like fuel pressure to me too, just cant figure out from what, is it injectors, pump, lines, regulater, everyone i talk to tells me something different that they are for sure it is haha, which doesnt help at all, but im trusting my gut and staying with the fuel issue, going to try and limp it to autozone this week and see if they can test it with the computer , might take me all day to get there with it dieing every 5 minutes haha

 

my roommate car died like that the whole way home when we bought it because I thought it was fuel or something as well, turned out it was definitely a icm... now when his fuel pump went out, well it was similar but it never made progress, only got worse...

 

I detailed a basic visual method for checking fuel pressure by watching injector spray. The TBI injectors are right on top of the throttle body. You can remove the air cleaner and watch them spray fuel. Refer to post #8 for the visual pressure verification method. The ignition module is a common failure item but the symptoms are different. An engine with a heat related failure of the ICM will start and run just fine in all driving conditions until the ICM gets hot enough and the engine will shut down like you turned the key off.

VATS can prevent engine starting both by preventing starter operation and by preventing fuel injector pulse. Once the engine is running, the VATS passkey system, by design, will not stop the engine from running. If there is a VATS issue, a DTC will set in the ECM and the CEL and security lights will illuminate. If a VATS failure was causing your engine to run poorly, it would be a new one for me, and that's saying alot.

One thing that I didn't think of when I first read your symptoms is the fuel pump and /or pick up screen. The fact that your engine runs for a while, even though it won't support a load, and then shuts down after running for a short time could point to a restriction in the fuel pick up screen or a weak pump. Injector spray pattern will reveal low pump pressure and if the spray falls off when you snap the throttle, that would indicate poor flow. If the spray is weak all the time, you would want to disassemble and inspect the injector pod on the TB for a broken spring. If the spray looks good at idle and falls off on throttle snap, or if the spray deteriorates over time, you may have a restriction in the pick up screen or a failing pump. You would want to verify this with a pressure and volume test of the pump before dropping the tank. Loss of injector output can also be caused either by a failure in the ECM or by faulty injectors.

All of these things are easy to verify with fairly simple tests.

 

Sorry its taken a while to get back to everyone on this, thank you for trying to help, heres what we have done to it so far
new pcv valve
New cap and rotor
New icm module
2 new fuel filters
and rebuilt the tbi

we did all the new parts first, minus the rebuild of the tbi and the car would sit an idle just fine, as long as you needed it to, but put it in gear and went down the road and it died still
so rebuilt the tbi and put everything back together and cranked her up and holy crap
what a vacuume leak, sounds like a vacuume cleaner sucking and so loud you can hear it over the engine, the idle is SUPER HIGH and wont go down.
Im posting pics of kinda before an after, and also some more video's of after the new parts and tbi rebuild, you can hear the idle is super high and wont stop and the car is cutting out when you pop the throttle.
seriously affraid to drive it because the idle is way to high and i dont want to blow the motor or something.

 

Intermittently my 89 350 TPI would start but then quit. Check engine light scanner result showed EGR fault. Would clear then reappear...happened multiple times. Engine stopped completely on highway in traffic for a few seconds once, restarted by itself at 60 MPH. Scanner showed EGR faults every time. I did find a used replacement EGR solenoid after looking a long time. These are not easy to find. If EGR is wide open too much exhaust gas is recirculated and engine can not run.

 

Was in a super bad mood earlier then someone came to look at the car to try and figure out the problem, so...
hes standing there looking at the engine just staring.... for like 5 minutes, then grabs the tranny dip stick, pulls it out, looks at it and sticks it back in... closes the hood and proceeds to tell me that its running like that because the tranny fluid is a tad over full, and that i need to drain some out and the car will run right, O.O well hello !
you know how hard it was not to laugh?
he never looked at anything else, never started it or even turned the key at all
but its the tranny fluid being over full thats causing it to die going down the road ?
ok im a girl... excuse me... woman... and i for one know that THAT will not cause a car to run like that and die, omg seriously?
hes thinking because im a woman that i dont know **** and that hes gonna make some quick money and the cars still gonna run like crap, nope not gonna happen !
im still laughing ! i swear i should have taped it !

 

Trans fluid will be very high with the engine not running as it all drains back into the bottom of the unit without the pump turning. Do not let that guy touch your car. I'm sorry but none of what you did does anything to address low fuel pressure. The "rebuild kits" offered in the aftermarket don't include the fuel pressure regulator spring. The high idle could be an air leak. Be sure that you used the correct base gasket and that it is installed correctly. Recheck for any split hoses or other vacuum leaks.

I suspect that you have either a failing fuel pump or a restricted pick up screen in the tank. One test for this that you can do yourself with basic hand tools is the full flow test. On the TBI it is easiest to remove the throttle body and connect a length of 3/8" fuel hose to the pressure line(larger of the two lines) and clamp it in place. Insert the other end of the hose into a 5 gallon gas can and jumper the fuel pump relay so that the pump will run continuously. Let the pump run this way for 2 minutes and then look at how much fuel is coming from the hose into the can. The pump should move about 2.5 quarts of fuel in a minute but the main test is how much fuel is coming from the hose after 2 minutes. It should be a full stream that reaches atleast about 4 inches from the end of the hose. I suspect that the pump's flow will begin to drop off after a minute or so. Look at the flow right after you start the pump running and compare it to the flow after 2 minutes.

Did you check the injector spray pattern as I suggested? If the fuel pump tests okay, which will surprise me, and injector pressure is still low, you need to disassemble the TB again and this time remove the tin cover on the bottom of the regulator to check the spring.

It is still also a possibility that the pick up coil in the distributor is failing. Though your symptoms don't point that way, I wouldn't disregard it until I was sure. Test the pick up coil(green wire and white wire at the rear of the ICM) for resistance. It should read 800-1000 ohms cold. Factory service discard specs are 500-1,500 but I think that outside 800-1000 is a sign of coming failure.

 

i have to agree with ase. i have a 91 formula that would do the same thing and i replaced every part u have. no change for the most part. i even went as far as changing the head gaskets do to low compression readings. the problem ended up being that the 3/8" rubber line from the pump to the pickup tube was porous and leaking. had a great spray pattern for the most part until a load was put on the motor ie, putting into gear and driving over 5mph. the pump ran so i figured it was fine. dropped the tank and low and behold the final problem. my car was tbi and i had a pressure kit hooked inline with the tbi. read 11 lbs at idle but would drop off after 1500 rpm. worth a shot.

 

Op, have you made any progress on this issue? Any updates? Please let us know.

 

Sorry for not updating you guys, havent made much progress lately been trying to get the money up for the fuel pump and of course the cost of putting it in, its in the tank so will have to pull everything out and going to clean out the tank while its out just incase, because as you saw in the pics and vid's the fuel coming out was nastyyyy stuff, as soon as i get that done i will post pics, updates and vids and please keep your fingers crossed that that is what the problem is you guys are the best thank you for your patience and all the help, will get back with you soon i promise !

 

oh almost forgot, i changed the gasket on the tbi to another one that came with the kit and that eliminated the vaccume leak yay ! you were stop on that leak thank you for the help there its still dieing when you drive it and as you saw i pretty much changed everything that everyone suggested accept the fuel pump and pick up screen, so next job is fuel pump, screen and cleaning out the tank anyone wanna come help pull the rear end out ? hahah jk jk !

 

You don't have to remove the rear end. I have done several of these tanks. On the lift they are easy. On jack stands they are a little more work but still not bad. The hard part is the exhaust. You have to completely remove the rear section of the exhaust. On a stock system, this means detaching it at the rear of the cat and snaking it out the back. First thing you do is detach the rear brake line, above the differential, from the body so that you don't stretch the hose when you let the axle hang. Then, detach the rear shocks from the axle and let the axle hang on the trailing arms as low as it will go. Watch the springs so they don't fall on you. You'll need to be sure they go back in place on reinstall. Once the rear end is down, remove the rear exhaust and heat shield. Detach the fuel lines at the passenger side frame rail, disengage the wiring harness connector in front of the tank and remove the tank. The less fuel in the tank, the easier it will be.

 

Hi there, sorry to hear about the problems you are going through with your car. If it helps any I know how you feel. My 91' 454 Tbi, left me stranded on the side of the road multiple times the last 3 days. My symptoms were very similar to yours, my rig would Idle and rev. just fine but when you drove down the road it would die intermittently, it would always restart and drive for a while and then die again. sometimes it would restart itself while you were still driving and other times you had to pull over and restart it with the key. after replacing the cap, rotor, Icm, Computer, and coil it ended up being the pickup coil on my distributor. I replaced the distributor for $100 and my problem was solved. I was told repeatedly that it was probably my fuel pump or fuel filter I had changed my fuel filter and didn't believe that it was the pump and it wasn't. not to say that yours isn't the pump , just saying that mine was the distributor and it was much cheaper and easier to change. it was intermittently losing spark but only when under a load while driving down the street, putting stress on the pickup coil. I hope this helps and I hope you get your problem figured out best of luck. PS buy a brand new distributor, I replaced it the first time with a remanufactured one and the Remanufactured distributor failed within the first 20 miles save yourself the headache and buy new.

 

Looks like nothing's been done to your car, ever. Do some other minor things that may help. Basically a tune up. Plugs, oil and fitler, plug wires, air filter, PCV valve. These are small changes to bring your car to a base line and are fairly cheap to do as well. Then start looking at the more expensive things.

 

dnswalder just mentioned the pick up coil as a possible problem. Im disappointed with myself as I haven't mentioned this myself. A failing pick up coil can drop out under load, or the ignition coil itself can cause low KV and spark drop out under load.

We kind of jumped straight from my suggesting that you test fuel pressure to replacing the pump. Your problem most likely is the pump, but a quick test for spark drop out wouldn't hurt. You can use an inline bulb type spark tester and a long plug wire to set up so that you can see the tester bulb from the driver seat while you drive the car. Watch for the spark to drop out when you try to accelerate. Another inexpensive way to test the ignition is to use an adjustable spark KV tester that you can buy at any parts store. Set it at 40KV and look for the spark to jump the tester gap. If it doesn't, is the spark leaking out through a wire and arching on metal somewhere or is there no spark? If it's arching somewhere, replace all plug wires and the coil wire. If no spark at all, test the pick up coil with a DVOM for 800-1000 ohms. If not in this range, replace the distributor. If the pick up coil is okay, suspect the ignition coil.

It's been advised that you complete a major tune( plugs, wires, cap and rotor, PCV, fuel and air filters) you've already done part of it. If the wires are Packard brand, they are original and way past due. If not Packard wires, check them for stiffness and the terminals for corrosion. Having said that, I have had wires that looked and even ohm tested fine that were in fact no good. So if in doubt, replace them. The remaining tune items should be done if you don't know how old they are.

 

Thanks DNS and ASE you guys are a ton of help, finally got a day off and tinkered with it abit more, after taking the battery off and letting it sit thinking maybe it would reset something we cranked it, it idled so pretty and stayed that way for about 30 minutes, no stalling no dieing at all, then hubby climbed in and gave it gas, he pressed slow and steady and it picked up idle just fine with no dieing no spitting and spuddering, then he popped the gas after he let off and she started to spit and spudder, while he had it idling the pic below shows the hose that was OFF, so after reving it a few times he put the hose back on and it chugged and died right off, it did crank right back up and idled but it was sluggish, also on a long shot we folded the back seat down and pulled the back cover off and low and behold we found where they had made a hole to replace the fuel pump before, so yay no pulling the tank, or so i thought, take a look at the pics and see for yourself, thats just nasty, i mean i have seen worse but lord that was ugly to find, and added a few vids of the idle and revs to maybe better help with the discribing the problem i hope, he has a few things in mind that we are going to try tomorrow too so im sure i will be posting more, thank you guys again for all the help, couldnt do it without you ! your the best
as you can see from one of the vids she has plenty of power haha i so want to get her running right, im not scrapping her for any reason shes a classic and i love her













http://s255.photobucket.com/user/cdn...94222.mp4.html

http://s255.photobucket.com/user/cdn...94248.mp4.html

http://s255.photobucket.com/user/cdn...94551.mp4.html

http://s255.photobucket.com/user/cdn...95443.mp4.html

 

If you can manage to get it running while a hose is disconnected, don't be surprised if it runs badly when you re-connect the hose all the sudden while its still running.

Before you re-connected the hose, the ECM had made adjustments to accommodate the missing-hose condition. When you re-connect the hose, the ECM will not immediately respond with a proper adjustment.

The ECM has to do a "re-learn" if you make any changes to the system.

To accomplish a re-learn, you need to turn the car off, and let it sit for a spell. Then turn the car back on, and drive it (or at least let it sit and run) for a spell to cause the ECM to re-learn the new configuration.

 

Ok had to wait until the sun was down today it was to hot for me out there to be working on the beast today haha
But... took the EGR valve off and tested it by trying to push it in with my fingers, it was super stuck ! wouldnt budge at all, the finally with all the strength i had it gave way and i was able to push it in, i covered the connector line with my finger and the inside of the egr still moved so i know thats a bad thing, wondering if that wasnt the problem the whole time, so now waiting to get the part ordered and find out here are a few pics of the egr valve, when i took it out and set it in the sink and shook it slightly the rust fell out all into the sink, just horrible ! so wish me luck, still narrowing down small parts and praying one makes it run haha

 

The EGR valve on that car is pressure modulated so, yes you can move the pintle with the vacuum line plugged. This type of EGR valve does not test like a non modulated valve. You can apply vacuum to this valve with it on the bench and it will not open. It has to have exhaust pressure applied to operate.

An open EGR valve will cause the motor to idle poorly and even stall without throttle. It will not cause the engine to idle okay, then under load. Absolutely not.

Looking at your fuel tank mess, it's obvious what your trouble is. Personally, I'm very sad to see that someone hacked up the body like that. Dropping the tank just isn't that bad. Also, those hose and clamp connections are a future leak waiting to happen. Fortunately, your TBI is low pressure so less chance of trouble.

I do in tank fuel pumps about 15-30 per year. I kill book time on them. I hate undercar work but fuel tanks just aren't that big of a deal. The fuel system on my beasty uses two external pumps so I never need to go back in the tank for a pump failure anyway.

The change in idle from reconnecting the make up air tube of you PCV system to the air cleaner is as WEG stated. It causes a sudden change in manifold vacuum and since your engine is speed density controlled, the engine responds to the change. It shouldn't have stalled though. Check you PCV valve for being restricted or for damage and while you have it out, replace it with a new one because it's cheap and can cause issues. Remember also distributor and a full ignition tune for best performance and reliability.

 

Thanks you guys, yea the fuel tank is a big mess from the looks of it, i almost cried when i pulled that cover back and saw the hack job they did on the trap door, that was just sickning really have to wait till payday to get the egr valve but it looks so bad i want to replace it just incase, and i do still need to drop the tank and clean it or replace it all together , i did replace the pcv valve about 2 weeks ago i think now, my first thought was that that was what it was, but it didnt help
so i think hopefully this week will be the egr valve and maybe the fuel pump replaced see how that go's and go from there, if it doesnt help then i will start on the distributer, wires, plugs, and the rest of the stuff you mentioned.
Wasnt looking forward to dropping the tank but after seeing the hack job on the make shift door i think anything i had to go through to pull the tank would have been better than seeing that

 

Sorry. I don't mean to beat you up. I see that the PCV valve is on your list of replaced parts early on. I missed that. Fuel tanks are available, new and used, post an add on the "Parts Wanted" section of the Classified forum and see what's out there. There is also a proven method of tank repair available. I know of one shop in Portland that does it. They blast the tank clean and coat it with a fuel resistant resin. I've seen good results with this and it's often less expensive than a new tank.

 

not a problem ASE thank you so much for all the help, most of it now depends on money and waiting to get paid, pay check to pay check hurts these days, but i will get right on the ads and see what i can find you guys are amazing with help and suggestions, couldnt have come this far without you ! keep up the great work and i will try and keep everyone updated as soon as we do a part or if by chance someone comes to fix it i will post updates and pics and vids

 

Ok got time to replace the EGR valve and guess what ? she started just fine, put her in gear and took off, went around the block just fine.. no dieing, so took her out on the road to get her some gas and she didnt die spit or spudder so far, just got home
Now.......that hopefully fixed the dieing problem, but now she runs rough, she has a little shake to her on idle and driving, the idle is high also
the idle will fluctuate but will not drop below 1000 rpm at idle
i have no idea how to change the idle on this thing, can someone post a pic of what i need to look for and what to do please
im so close lol but yea looks so far like the egr valve fixed the dieing or at least i pray it did, it did fine on the open road, she really hauled *** and didnt die at all not even tried to die, was so happy i was yelling haha

 

So you're saying that the EGR valve itself fixed the problem? What have you done with the fuel tank? I just can't believe that the EGR valve would cause your symptoms. If it did, that's a new one for me.

The high, surging idle is a lean condition. Look very carefully for vacuum leaks.

 

Yea spoke to soon, after i posted that we took it for a test drive, drove all over town an it ran fine but still had the high idle , then this morning same thing, drove all over town an ran didnt die, but idle was still high, sooo hubby takes it to work an it ran fine, then on the way home it died twice an there is a strong smell of gas inside the car
All we did to the tank was put the pump back in so we could test if it was the egr valve, so it still has the old pump for now and hubby is at the end of his rope with the car, we have tried everything almost an dont have the money to keep buying guess parts
would an exhaust leak cause the bad idle like that ? cause it has a horrible exhaust leak
someone said it might be the cat converter stopped up

 

So not sure what to do next, about at the end of my rope with this thing !
so far we have replaced ::
New Dist cap and rotor
New Icm module
New fuel filter
New pcv valve
New EGR valve

I really dont have the time or money to keep fixing maybe parts *sigh*
i refuse to scrap her because she runs and just needs more time and
attention than i can give her i guess
anyone want to buy her an fix her? haha

 

A restricted cat will not affect idle unless it's completely plugged and then the engine may not start at all. I deal with about 5-10 restricted cats per year and they only cause a loss of power under load with increased engine speed. It's like the engine has a governor and it can't pull above a certain rpm. The worse the cat is, the lower the speed that the engine chokes at. Things that cause high idle are, as I said, vacuum leaks. A vacuum leak is unmetered air, or air that gets into the intake around the throttle body. It will cause the engine to idle high because it can. The idle will also be unstable because, while the engine is getting added air, it is not getting enough added fuel to go with it so it runs lean. Another cause of high idle is timing too advanced. Then there is the IAC valve and control circuits. I don't recommend replacing the IAC unless you know how to first test it to verify that it's bad. To test the IAC, you at least need a scan tool to monitor IAC command. I also use a lab scope to watch command voltage to the coil. You can introduce additional air by creating a large air leak(disconnect the PCV hose or the brake booster hose), disconnect the IAC valve and test to see if air is passing through the IAC ports. Then, reconnect the IAC and use your hand over the throttle body to pull the idle down below 600 rpm. This should force the IAC to open and you'll hear the idle try to increase. Then remove your hand from the throttle and listen for the idle to stabilize. By this method, and using a scan tool to watch IAC counts, I can be pretty sure whether an IAC is working or not. One issue that comes up is throttle shaft bore wear. The throttle shaft rides in bores machined into the aluminum TB. Over many years and miles the aluminum wears, along with the shaft itself in some cases, and the shaft develops runout, or side to side movement in the bores. This is most prevalent on the cable side of the TB as this is where most side load is placed on the shaft. When the wear gets bad enough, it can cause the throttle shaft to run out of place and affect idle quality. On most TBIs Ive seen, it will generally cause a sticky gas pedal. That's why I didn't mention it as a possible cause earlier. But it is something to look at. Especially if the base throttle setting might have been changed to compensate for worn throttle shaft bores. Try moving the throttle shaft up and down while holding the throttle slightly off the closed position. You should not be able to feel or see it move anyway but rotation.

The fuel smell is most likely a leak at one of the scabbed together hoses on the fuel tank. I am still very certain that your original issue( idles okay then stalls after you drive it for a minute) was caused by the conditions in that fuel tank. I have never seen an EGR valve cause an issue like that and I've diagnosed alot of bad EGR valves.

My number one mission in my work is to never replace any part without first verifying its failure. I do quite well at this. Granted, I do this 10 hours a day everyday and have done it for many years. I have most every piece of test equipment you can dream of and alot of experience using them. Still, if we are careful and take the time to test, we can avoid throwing parts at a problem. This said, you have really replaced any part that isn't a common failure item on that car. Therefore, I can't say that you've really gone off track on this. I feel your frustration, but it's an old car and you just have to work through it. The key to long term success is make every repair the absolute best it can be. That way, you don't end up going back and refixing things you already fixed.