91 GTA cut out at highway speed!
05-08-2020, 03:36 PM
#1
91 GTA cut out at highway speed!
after spending most of last summer trying to figure out why the car wudn't start.. it was determined the pcm was faulty. I bought a new reman from rockauto and its seemed to fix the problem.. today i took it on the highway for the first time in about 18 months or so.. and as soon as i hit 100km/hr ( 60mph ) the check engine light flashed once or twice and the car stalled and won't start since. I changed the injectors last summer as well.
05-08-2020, 04:16 PM
#2
Re: 91 GTA cut out at highway speed!
after spending most of last summer trying to figure out why the car wudn't start.. it was determined the pcm was faulty. I bought a new reman from rockauto and its seemed to fix the problem.. today i took it on the highway for the first time in about 18 months or so.. and as soon as i hit 100km/hr ( 60mph ) the check engine light flashed once or twice and the car stalled and won't start since. I changed the injectors last summer as well.
Paperclip code check
check for proper spark
fuel pressure check
Then report back your results ...
05-08-2020, 04:52 PM
#3
Re: 91 GTA cut out at highway speed!
Flat out won't start is usually "punch in the head obvious" once you get into the troubleshooting , it's very most likely totally lost either spark or fuel . You say the check engine light came on , did you do the "paperclip" trick yet to check the codes ? If not (and if you never heard of the paperclip trick) just search the word paperclip here and literally dozens of threads will turn up describing it . So , in this order , do the ;
Paperclip code check
check for proper spark
fuel pressure check
Then report back your results ...
Paperclip code check
check for proper spark
fuel pressure check
Then report back your results ...
currently broke down on the highway... it may be the coil which is one of the only things I didn't change.. goin to do the coil bypass now see if it will fire up
05-08-2020, 06:06 PM
#4
Re: 91 GTA cut out at highway speed!
Flat out won't start is usually "punch in the head obvious" once you get into the troubleshooting , it's very most likely totally lost either spark or fuel . You say the check engine light came on , did you do the "paperclip" trick yet to check the codes ? If not (and if you never heard of the paperclip trick) just search the word paperclip here and literally dozens of threads will turn up describing it . So , in this order , do the ;
Paperclip code check
check for proper spark
fuel pressure check
Then report back your results ...
Paperclip code check
check for proper spark
fuel pressure check
Then report back your results ...
Last edited by goalieforlife; 05-08-2020 at 09:27 PM.
05-09-2020, 09:15 AM
#7
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Re: 91 GTA cut out at highway speed!
Plugs are only a couple years old... injectors new last summer.
Compression, air/fuel, spark. The 3 Magic Ingredients. That's all it takes for an engine to run. A die-while-driving-down-the-road-and-won't-start-back-up clearly means one of the Magic 3 has gone missing. Your task now is not to argue about what you've replaced over the last couple of years, but to determine which one disappeared TODAY, and why. If you want us to help, that is. If all you want to do is argue about it, then we don't have to be bothered.
Now that we've gotten past that mental block...
Shoot some starting fluid into the TB. Try to start it. If it hits a few licks and then dies, and doesn't even do that until you squirt some more starting fluid in it, you have a fuel problem.
Congratulations. You just checked off #1 of The 3 Magic Ingredients. If that didn't make it start, keep going.
Compression doesn't usually "go away" suddenly on its own to the point that the motor instantly stops running while driving happily down the highway, except for ONE cause. That being, a timing set failure. If your engine still has the type of cam sprocket with the phenolic teeth molded over chinesium gums, then as the chain wears, it puts stress on the teeth, trying to pull them apart as the space between the links of the chain grows. Eventually the teeth can't stand it any more and they strip off. Eeeeeezy enough to troubleshoot for this; take off the dist cap, unplug the pink & white wire connectors at the coil, unplug the injector harnesses, and have your assistant hold the throttle wide open and whirl the engine over. If the dist doesn't move, or moves in small jerks, or otherwise isn't moving the same as the engine is spinning, or if the engine sounds like it has no compression or seems to be forcefully pushing air into either the intake manifold or the exhaust, you need a timing set. Get either yerbasic stock replacement one, or a GOOD QUALITY roller; NOT a cheeeeep "truck roller" set. While you've got the dist cap off, pull the rotor and LOOK REAL CAREFULLY at everything down inside there, especially the reluctor (star wheel) which unfortunately is hard to see because it usually has a sort of shield over it. But look closely anyway because ... you're already there anyway.
You just checked off #2 of the Big 3.
If both of those check out, you have a spark problem. At this point, since the whole engine failed all at once and not just one cylinder, chances are something that affects all 8 cylinders broke. Probably not the spark plugs; all 8 of them probably didn't fail completely hard all at exactly the same instant with no warning whatsoever. Could have, but I'd guess that the probability probably has AT LEAST 30 zeroes to the right of the decimal point before a non-zero number is reached... IOW, it has NEVER happened in the history of The Car, and it will take about 100 trillion years before the probability reaches 50% that it happens to ONE car. We can safely rule that out I think; ELIMINATE park plugs from all further conversation. Probably not the coil although it could be. Far more likely it's something inside the distributor. See this post for further enlightenment. https://www.thirdgen.org/forums/tech...off-while.html In case the title sounds familiar, maybe it should, and maybe there's something you could learn from this guy's experience. After all, that's the beauty of the Interwebz... Algore gave us all the ability to profit from EVERYBODY ELSE'S MISTAKES!!! All we have to do is quit arguing, pay attention, and LEARN.
Come back and let us know what you found when you get it running. Or, if it turns out to be a fuel problem, how to quickly troubleshoot that without a bunch of "maybe it's this maybe it's that" kind of stuff.
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05-09-2020, 10:36 AM
#8
Re: 91 GTA cut out at highway speed!
Doesn't matter if they were new this morning. If the car doesn't run, the car doesn't run.
Compression, air/fuel, spark. The 3 Magic Ingredients. That's all it takes for an engine to run. A die-while-driving-down-the-road-and-won't-start-back-up clearly means one of the Magic 3 has gone missing. Your task now is not to argue about what you've replaced over the last couple of years, but to determine which one disappeared TODAY, and why. If you want us to help, that is. If all you want to do is argue about it, then we don't have to be bothered.
Now that we've gotten past that mental block...
Shoot some starting fluid into the TB. Try to start it. If it hits a few licks and then dies, and doesn't even do that until you squirt some more starting fluid in it, you have a fuel problem.
Congratulations. You just checked off #1 of The 3 Magic Ingredients. If that didn't make it start, keep going.
Compression doesn't usually "go away" suddenly on its own to the point that the motor instantly stops running while driving happily down the highway, except for ONE cause. That being, a timing set failure. If your engine still has the type of cam sprocket with the phenolic teeth molded over chinesium gums, then as the chain wears, it puts stress on the teeth, trying to pull them apart as the space between the links of the chain grows. Eventually the teeth can't stand it any more and they strip off. Eeeeeezy enough to troubleshoot for this; take off the dist cap, unplug the pink & white wire connectors at the coil, unplug the injector harnesses, and have your assistant hold the throttle wide open and whirl the engine over. If the dist doesn't move, or moves in small jerks, or otherwise isn't moving the same as the engine is spinning, or if the engine sounds like it has no compression or seems to be forcefully pushing air into either the intake manifold or the exhaust, you need a timing set. Get either yerbasic stock replacement one, or a GOOD QUALITY roller; NOT a cheeeeep "truck roller" set. While you've got the dist cap off, pull the rotor and LOOK REAL CAREFULLY at everything down inside there, especially the reluctor (star wheel) which unfortunately is hard to see because it usually has a sort of shield over it. But look closely anyway because ... you're already there anyway.
You just checked off #2 of the Big 3.
If both of those check out, you have a spark problem. At this point, since the whole engine failed all at once and not just one cylinder, chances are something that affects all 8 cylinders broke. Probably not the spark plugs; all 8 of them probably didn't fail completely hard all at exactly the same instant with no warning whatsoever. Could have, but I'd guess that the probability probably has AT LEAST 30 zeroes to the right of the decimal point before a non-zero number is reached... IOW, it has NEVER happened in the history of The Car, and it will take about 100 trillion years before the probability reaches 50% that it happens to ONE car. We can safely rule that out I think; ELIMINATE park plugs from all further conversation. Probably not the coil although it could be. Far more likely it's something inside the distributor. See this post for further enlightenment. https://www.thirdgen.org/forums/tech...off-while.html In case the title sounds familiar, maybe it should, and maybe there's something you could learn from this guy's experience. After all, that's the beauty of the Interwebz... Algore gave us all the ability to profit from EVERYBODY ELSE'S MISTAKES!!! All we have to do is quit arguing, pay attention, and LEARN.
Come back and let us know what you found when you get it running. Or, if it turns out to be a fuel problem, how to quickly troubleshoot that without a bunch of "maybe it's this maybe it's that" kind of stuff.
Compression, air/fuel, spark. The 3 Magic Ingredients. That's all it takes for an engine to run. A die-while-driving-down-the-road-and-won't-start-back-up clearly means one of the Magic 3 has gone missing. Your task now is not to argue about what you've replaced over the last couple of years, but to determine which one disappeared TODAY, and why. If you want us to help, that is. If all you want to do is argue about it, then we don't have to be bothered.
Now that we've gotten past that mental block...
Shoot some starting fluid into the TB. Try to start it. If it hits a few licks and then dies, and doesn't even do that until you squirt some more starting fluid in it, you have a fuel problem.
Congratulations. You just checked off #1 of The 3 Magic Ingredients. If that didn't make it start, keep going.
Compression doesn't usually "go away" suddenly on its own to the point that the motor instantly stops running while driving happily down the highway, except for ONE cause. That being, a timing set failure. If your engine still has the type of cam sprocket with the phenolic teeth molded over chinesium gums, then as the chain wears, it puts stress on the teeth, trying to pull them apart as the space between the links of the chain grows. Eventually the teeth can't stand it any more and they strip off. Eeeeeezy enough to troubleshoot for this; take off the dist cap, unplug the pink & white wire connectors at the coil, unplug the injector harnesses, and have your assistant hold the throttle wide open and whirl the engine over. If the dist doesn't move, or moves in small jerks, or otherwise isn't moving the same as the engine is spinning, or if the engine sounds like it has no compression or seems to be forcefully pushing air into either the intake manifold or the exhaust, you need a timing set. Get either yerbasic stock replacement one, or a GOOD QUALITY roller; NOT a cheeeeep "truck roller" set. While you've got the dist cap off, pull the rotor and LOOK REAL CAREFULLY at everything down inside there, especially the reluctor (star wheel) which unfortunately is hard to see because it usually has a sort of shield over it. But look closely anyway because ... you're already there anyway.
You just checked off #2 of the Big 3.
If both of those check out, you have a spark problem. At this point, since the whole engine failed all at once and not just one cylinder, chances are something that affects all 8 cylinders broke. Probably not the spark plugs; all 8 of them probably didn't fail completely hard all at exactly the same instant with no warning whatsoever. Could have, but I'd guess that the probability probably has AT LEAST 30 zeroes to the right of the decimal point before a non-zero number is reached... IOW, it has NEVER happened in the history of The Car, and it will take about 100 trillion years before the probability reaches 50% that it happens to ONE car. We can safely rule that out I think; ELIMINATE park plugs from all further conversation. Probably not the coil although it could be. Far more likely it's something inside the distributor. See this post for further enlightenment. https://www.thirdgen.org/forums/tech...off-while.html In case the title sounds familiar, maybe it should, and maybe there's something you could learn from this guy's experience. After all, that's the beauty of the Interwebz... Algore gave us all the ability to profit from EVERYBODY ELSE'S MISTAKES!!! All we have to do is quit arguing, pay attention, and LEARN.
Come back and let us know what you found when you get it running. Or, if it turns out to be a fuel problem, how to quickly troubleshoot that without a bunch of "maybe it's this maybe it's that" kind of stuff.
Alot of good info here.. Thanks. I've changed most of the suspected parts u listed except the distributor itself and the ignition coil.
But as stated just bc it was changed doesn't mean it hasn't failed so I will go over this again.. thanks so much and I will keep you all posted.
05-09-2020, 10:42 AM
#9
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Re: 91 GTA cut out at highway speed!
The coil itself hardly ever goes bad; not saying it can't, or hasn't, just, it's not the most likely suspect. If it turns out to be a no-spark, odds are very high it's inside the distributor. Also, there's no real way to "bypass" it, except with another coil. Which of course, if you have access to one, they're SOOOOPER EEEEZY to swap, you just have to unplug and replug it, don't even have to mount it or anything. If you can do that, and it still doesn't start, and has 12V on the pink wire, it's probably not the coil.
I should also mention, it's POSSIBLE, though again HIGHLY UNLIKELY, that something in the tach circuit can cause this; typically a short either in the wiring or the noise filter. I can't recall how your setup is wired in that area, but if you follow the white wire away from the coil back toward the firewall and you come to a little metal can that you can unplug, that's the noise filter; if it still doesn't start with it unplugged then at that point you know the fault is in the dist.
I should also mention, it's POSSIBLE, though again HIGHLY UNLIKELY, that something in the tach circuit can cause this; typically a short either in the wiring or the noise filter. I can't recall how your setup is wired in that area, but if you follow the white wire away from the coil back toward the firewall and you come to a little metal can that you can unplug, that's the noise filter; if it still doesn't start with it unplugged then at that point you know the fault is in the dist.
05-09-2020, 11:14 AM
#10
Re: 91 GTA cut out at highway speed!
The coil itself hardly ever goes bad; not saying it can't, or hasn't, just, it's not the most likely suspect. If it turns out to be a no-spark, odds are very high it's inside the distributor. Also, there's no real way to "bypass" it, except with another coil. Which of course, if you have access to one, they're SOOOOPER EEEEZY to swap, you just have to unplug and replug it, don't even have to mount it or anything. If you can do that, and it still doesn't start, and has 12V on the pink wire, it's probably not the coil.
I should also mention, it's POSSIBLE, though again HIGHLY UNLIKELY, that something in the tach circuit can cause this; typically a short either in the wiring or the noise filter. I can't recall how your setup is wired in that area, but if you follow the white wire away from the coil back toward the firewall and you come to a little metal can that you can unplug, that's the noise filter; if it still doesn't start with it unplugged then at that point you know the fault is in the dist.
I should also mention, it's POSSIBLE, though again HIGHLY UNLIKELY, that something in the tach circuit can cause this; typically a short either in the wiring or the noise filter. I can't recall how your setup is wired in that area, but if you follow the white wire away from the coil back toward the firewall and you come to a little metal can that you can unplug, that's the noise filter; if it still doesn't start with it unplugged then at that point you know the fault is in the dist.
upon inspection my current coil color is yellow so i must of changed it out with an accel ignition coil. | will try to get another coil just incase it did fail. with regards to the tach i have never heard of that before so that and the stuff mentioned above is worth looking into. Switching from a TBI to a TPI has not been fun so far. i sold my base bird and " upgraded " to the GTA.
Thank for all your help guys I got no plans to give up.
05-09-2020, 11:26 AM
#11
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Re: 91 GTA cut out at highway speed!
Switching from a TBI to a TPI
Yes I would agree that an aftermarket coil is probably more likely to fail than OE. Also more likely to stress out the module, esp if the heat sink compound is less effective or it otherwise gets hotter than usual for whatever reason.
05-10-2020, 03:00 PM
#12
Re: 91 GTA cut out at highway speed!
At least the ignition systems are, for all practical purposes, the same. Same dist, same coil, etc. Anything you learned or own in the way of spare parts for the one, applies to the other.
Yes I would agree that an aftermarket coil is probably more likely to fail than OE. Also more likely to stress out the module, esp if the heat sink compound is less effective or it otherwise gets hotter than usual for whatever reason.
Yes I would agree that an aftermarket coil is probably more likely to fail than OE. Also more likely to stress out the module, esp if the heat sink compound is less effective or it otherwise gets hotter than usual for whatever reason.
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