'89 running/idleing rough
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Pro
Joined: Nov 1999
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From: Woodland Ca
'89 running/idleing rough
I finally got my car smogged and licenced after a year of it being parked and not ran. It seemed to run fine for a week. A few days ago it runs fine until it warms up and then it just runs rough. Now it runs rough, will top off at 70-74 mph, and when I put the petle to the floor, it actually deacselerates(slows down).
No service engine soon light is on.
Any ideas?
Thanks!
No service engine soon light is on.
Any ideas?
Thanks!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
First check to see if any codes have been set. After you have dealt with them, assuming the problem remains, take a ride with a fuel pressure gauge hooked up where you can read it while driving.
RACE ON!!!
RACE ON!!!
Thread Starter
Pro
Joined: Nov 1999
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From: Woodland Ca
Thanks for the responces. The wife is getting ancy. Whats her conmute car back! I had a simular porblem and it turned out to be the computer.
When you say "cat", do you mean a clogged pre-cat?
When you say "cat", do you mean a clogged pre-cat?
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Is there year old fuel still in the Tank? that does sound like what I experienced in a truck with a clogged cat-how was it running b4 storage? never heard of a cat going bad just sitting, fuel on the other hand-yeah.
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Joined: Nov 1999
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From: Woodland Ca
Yea, new 91 octane gas with injector cleaner 2 weeks ago. I have already filled again with new tank of 91 octane gas.
I had the pre-cat checked before storage and they checked fine. There was a little bit of loose material in it though. It kind of makes me want to do the screw driver method!
I had the pre-cat checked before storage and they checked fine. There was a little bit of loose material in it though. It kind of makes me want to do the screw driver method!
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Did you check timing? Once the bypass is disconnected, the 42 will stay in History until cleared.
What did you have to do to get it through smog? If it was an air pump problem and it was dumping fuel, suspect the CATS. You can remove the O2, jury rig an adaptor, and then thread in a pressure gage. Anything more than 3 lbs points to a blocked up system.
What did you have to do to get it through smog? If it was an air pump problem and it was dumping fuel, suspect the CATS. You can remove the O2, jury rig an adaptor, and then thread in a pressure gage. Anything more than 3 lbs points to a blocked up system.
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From: Woodland Ca
Thanks SunCr! I will clear the code and try again. I had to time it, replace the fuel cap and by-pass the tach fillter. The idiot not only disconecteded while testing the first time, but on the recheck. I ended up by passing the filter(hooking up the wires together), because he said that it was arcing on the valve cover and could start a fire. Could this be an issue? I am planning on ordering an filter through Mid America soon.
I did have a code 42 problem before know that I think about it. It turned out to be the ECM. It was replaced with a reman. and it seemed to fix the problem. Prior to that I bought a Ignition Control Module but this did not fix it.
I did have a code 42 problem before know that I think about it. It turned out to be the ECM. It was replaced with a reman. and it seemed to fix the problem. Prior to that I bought a Ignition Control Module but this did not fix it.
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From: Woodland Ca
I cleared the code. Now I have an intermitent Service engine soon light with no codes.
Also, I noticed one of the radiator fans is on with the vehicle cold and not runnung. This isn't normal is it?
Also, I noticed one of the radiator fans is on with the vehicle cold and not runnung. This isn't normal is it?
Le Mans Master
Joined: May 2000
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Originally Posted by BIG K
I cleared the code. Now I have an intermitent Service engine soon light with no codes.
Also, I noticed one of the radiator fans is on with the vehicle cold and not runnung. This isn't normal is it?
Also, I noticed one of the radiator fans is on with the vehicle cold and not runnung. This isn't normal is it?
Is your AC on now that you disconnected that battery? Do you have your ALDL terminal grounded?
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Fan will run if a Code is current or with the diagnostic link grounded. It also runs if the ECM sees a Coolant Temp Signal at 226 or higher (a/c off). Some of us had that problem about a year ago with our '89's. Mine was toggling well over that number and though it would eventually start, there was no fast idle and the fan was on. Troubleshooting the sensor and the circuit proved that ECM was bad. Easiest to see with a scanner.
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
I use an Auto XRay that I bought from a Discounter for about a Hundred and a Half. I then forked over a few more Bucks for the Computer App and USB cable that allows me to download and graph whatever I've captured. It's a little slow for data logging, meaning it isn't the best for an intermittent, but it will give you enough info to troubleshoot basic ECM/Sensor problems.
A scanner isn't going to help you with the 42. Assuming the Bypass isn't open or grounded and especially since you swapped out the ECM, make sure the Mem Cal is fully seated.
My experience with the Pre Cats is that they fall apart (mine failed under warranty) and make one heck of a racket once they do. I didn't bother with any performance issues as the noise was enough for me to have it towed to the Dealer. If you think they're plugged up, you can always disconnect it at the Headers, but if they've never been off, that might be a bigger challenge than just jury rigging a fitting into the O2 bung to check back pressure.
A scanner isn't going to help you with the 42. Assuming the Bypass isn't open or grounded and especially since you swapped out the ECM, make sure the Mem Cal is fully seated.
My experience with the Pre Cats is that they fall apart (mine failed under warranty) and make one heck of a racket once they do. I didn't bother with any performance issues as the noise was enough for me to have it towed to the Dealer. If you think they're plugged up, you can always disconnect it at the Headers, but if they've never been off, that might be a bigger challenge than just jury rigging a fitting into the O2 bung to check back pressure.
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From: Woodland Ca
Thanks again for the help. Is it posible to have a wire grounding out in the distribitor to cause this? I remember that there was a plastic holder/spacer that some wires pass through, that was crumbling. I think that this insulates the wires as they pass through the distribitor.
But what's kind of weird to me is that the engine seems to run better cold. When it has been running at highway speeds for a while it get's worse.
1slyder1, do you understand what a clogged pre-cat is from what SunCr has posted?
But what's kind of weird to me is that the engine seems to run better cold. When it has been running at highway speeds for a while it get's worse.
1slyder1, do you understand what a clogged pre-cat is from what SunCr has posted?