92 3vze rough cold idle :(
09-07-2010, 08:16 PM
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92 3vze rough cold idle :(
alright...gonna try yet another forum for a possible answer, its getting worse. 
I have googled for a possibility til my fingers are numb, and still havent found anything, but i really doubt i am the only person that has had this problem.
92 pickup, 3vze, 5spd, stock engine and trans. all starts with a cold engine. starts just fine with no hesitation. as soon as it turns over when cold, it just idles like crap. rough idle, hesitation, no power when trying to accelerate. after either letting the truck warm up in the driveway, or driving it for a while, it just suddenly gets better...like it flipped a switch and went back to running like it has since i have had it. i really dont know what may have caused it, but it started after i changed the valve cover gaskets/intake plenum gasket. when i had it all taken apart, i put some seafoam in the intake chamber. it started up just fine afterwards, just like a normal seafoam job, it pissed off the neighbors for a while, then all was fine. the next morning it just started to run like crap when its cold. i really dont know what else to do. i got new cap, rotor, plugs, wires, cold start injector, temp sensor, pcv valve. anyone have any other ideas at all that i could try to test that wont cost me a large sum of money? any ideas are welcome guys...gotta get this thing runnin right so i can drive it to school. thanks for looking!!!
I have googled for a possibility til my fingers are numb, and still havent found anything, but i really doubt i am the only person that has had this problem. 92 pickup, 3vze, 5spd, stock engine and trans. all starts with a cold engine. starts just fine with no hesitation. as soon as it turns over when cold, it just idles like crap. rough idle, hesitation, no power when trying to accelerate. after either letting the truck warm up in the driveway, or driving it for a while, it just suddenly gets better...like it flipped a switch and went back to running like it has since i have had it. i really dont know what may have caused it, but it started after i changed the valve cover gaskets/intake plenum gasket. when i had it all taken apart, i put some seafoam in the intake chamber. it started up just fine afterwards, just like a normal seafoam job, it pissed off the neighbors for a while, then all was fine. the next morning it just started to run like crap when its cold. i really dont know what else to do. i got new cap, rotor, plugs, wires, cold start injector, temp sensor, pcv valve. anyone have any other ideas at all that i could try to test that wont cost me a large sum of money? any ideas are welcome guys...gotta get this thing runnin right so i can drive it to school. thanks for looking!!!
09-07-2010, 09:21 PM
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Check for vacuum leaks all around the intake & vacuum hoses - try spraying starting ether or unlit propane torch and listen for an increase in engine speed.
Check for cracks in the rubber bends of the air hose between the air meter and throttle body.
Check the tps - maybe the IDL terminal is not grounding to E2 when the throttle is closed (idle position).
Perhaps the cold idle-up passage in the throttle body is clogged with gunk. You could try cleaning it with a throttle body cleaner but be sure to not get any solvent on or in the tps, 'cause that would kill it.
Is the warm idle set somewhere between 800 (spec) and 900?
Injectors could be dirty and clogged. Run a bottle of a cleaner containing polyether amine through the tank. Only two prods that I know of that still have it are Red Line SI-1 Complete Fuel System Cleaner and CRC's "Guaranteed to Pass Emissions Test Formula"
Check for cracks in the rubber bends of the air hose between the air meter and throttle body.
Check the tps - maybe the IDL terminal is not grounding to E2 when the throttle is closed (idle position).
Perhaps the cold idle-up passage in the throttle body is clogged with gunk. You could try cleaning it with a throttle body cleaner but be sure to not get any solvent on or in the tps, 'cause that would kill it.
Is the warm idle set somewhere between 800 (spec) and 900?
Injectors could be dirty and clogged. Run a bottle of a cleaner containing polyether amine through the tank. Only two prods that I know of that still have it are Red Line SI-1 Complete Fuel System Cleaner and CRC's "Guaranteed to Pass Emissions Test Formula"
09-08-2010, 07:03 AM
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Cold start injector? If it is not working and thus not spraying fuel during warm up, you could have a rough idle that smoothes out once the engine reaches operating temp.
09-08-2010, 07:16 AM
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But the CSI I think only sprays for maybe 5-10 seconds at the most, so if it's still idling rough after, say, 30 seconds, it's probably not the CSI. Just sayin.
09-11-2010, 08:33 AM
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Check for vacuum leaks all around the intake & vacuum hoses - try spraying starting ether or unlit propane torch and listen for an increase in engine speed.
Check for cracks in the rubber bends of the air hose between the air meter and throttle body.
Check the tps - maybe the IDL terminal is not grounding to E2 when the throttle is closed (idle position).
Perhaps the cold idle-up passage in the throttle body is clogged with gunk. You could try cleaning it with a throttle body cleaner but be sure to not get any solvent on or in the tps, 'cause that would kill it.
Is the warm idle set somewhere between 800 (spec) and 900?
Injectors could be dirty and clogged. Run a bottle of a cleaner containing polyether amine through the tank. Only two prods that I know of that still have it are Red Line SI-1 Complete Fuel System Cleaner and CRC's "Guaranteed to Pass Emissions Test Formula"
Check for cracks in the rubber bends of the air hose between the air meter and throttle body.
Check the tps - maybe the IDL terminal is not grounding to E2 when the throttle is closed (idle position).
Perhaps the cold idle-up passage in the throttle body is clogged with gunk. You could try cleaning it with a throttle body cleaner but be sure to not get any solvent on or in the tps, 'cause that would kill it.
Is the warm idle set somewhere between 800 (spec) and 900?
Injectors could be dirty and clogged. Run a bottle of a cleaner containing polyether amine through the tank. Only two prods that I know of that still have it are Red Line SI-1 Complete Fuel System Cleaner and CRC's "Guaranteed to Pass Emissions Test Formula"
checked for vac leaks previously, but tried it again with the propane idea...still no change in anything.
checked the intake tube that i have for leaks/cracks, nothing there.
shot a crap load of throttle body cleaner to clean out the little tube in there, made the idle a little smoother when warm, but no change to the way it acts when cold.
warm idle is set just a hair over 800 when warm.
i got some of the CRC stuff you mentioned and slapped that in the tank, which is just about at 1/4 tank, so its time to fill 'er up again.
in the end, i tried all the thoughts mentioned above, and it still is acting the exact same way except that it is starting to act up without sitting as long. possibly due to the fact that its starting to get cooler up here? im thinking about possibly makin a video or something so you guys can actually hear the damned thing. thanks a lot for your suggestions!
01-16-2012, 09:33 PM
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I've been gone for a while, but I'm baaaackk.
I did finally get it running right...after almost a year of just dealing with the morning ritual of letting it warm up, and then dealing with the horrible fuel mileage while driving it. Actually drove it for about 2k miles over the year and it was alright after it warmed up, and just had bad mileage.
Anyways, here is what I did. Hopefully it can help someone else.
Changed the intake plenum gasket again, just to make sure that wasn't my problem. Old plenum looked okay, but it was a cheap gasket to begin with, so i replaced it with a higher quality one. I again checked and/or replaced the sensors on the back of the intake. I then went through the all too familiar hell of disconnecting all of the vacuum lines on the plenum, and got as many pictures from other vehicles as a reference. It ran a little bit better after that, but just barely. After getting all of it together and letting it run for a minute I decided to check out everything visually. Found out that I had an injector wire broken at the plug.
I took care of that situation real quick and tried it again. Started up and ran like a champ. Runs smoother and better than it ever has. Does a lot better on gas, and doesn't foul out the #1 plug all the time anymore. Maybe I should have taken the fouled #1 into consideration earlier. Oh well.
Anyways, I would suggest running through the same things the guys above said, which is pretty much what I did. The guys on here are a great help. If you take that intake plenum off, check all your injector connections. A plug that is fouled more than the others might give you a good indication.
Good luck, man. I hope you can get it going right. Lemme know if there's any way I can help.
I did finally get it running right...after almost a year of just dealing with the morning ritual of letting it warm up, and then dealing with the horrible fuel mileage while driving it. Actually drove it for about 2k miles over the year and it was alright after it warmed up, and just had bad mileage.
Anyways, here is what I did. Hopefully it can help someone else.
Changed the intake plenum gasket again, just to make sure that wasn't my problem. Old plenum looked okay, but it was a cheap gasket to begin with, so i replaced it with a higher quality one. I again checked and/or replaced the sensors on the back of the intake. I then went through the all too familiar hell of disconnecting all of the vacuum lines on the plenum, and got as many pictures from other vehicles as a reference. It ran a little bit better after that, but just barely. After getting all of it together and letting it run for a minute I decided to check out everything visually. Found out that I had an injector wire broken at the plug.
I took care of that situation real quick and tried it again. Started up and ran like a champ. Runs smoother and better than it ever has. Does a lot better on gas, and doesn't foul out the #1 plug all the time anymore. Maybe I should have taken the fouled #1 into consideration earlier. Oh well. Anyways, I would suggest running through the same things the guys above said, which is pretty much what I did. The guys on here are a great help. If you take that intake plenum off, check all your injector connections. A plug that is fouled more than the others might give you a good indication.
Good luck, man. I hope you can get it going right. Lemme know if there's any way I can help.
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