Guys, I'm stumped. I'm trying to breathe life into a '94 truck I have with a 22RE. The engine was blown so I swapped a low mileage one in from an '89 and swapped all of the components. When I first started it, it ran great...I set the timing and it ran super smooth and idled well. When I took it for the first test drive, I got about 100 yards down the road and then it started missing and started idling really low and really rough. The weird part is when I tried to adjust the idle with the screw on the TPS, it had no effect whatsoever. That makes me wonder if something is up with the TPS. At this time, it's not showing any codes. Thoughts?
rough erratic idle/low idle/miss
- Thread starter seray76
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Check all the connections in the engine bay. A bad connection will cause all sorts of weird stuff...
check the ground strap at the back of the head and the ground that is on your intake.
- Thread starter
- #4
You know, I had the feeling I might have forgotten a ground. I should also add that when I do the jumper wire to set the base timing, the idle and timing doesn't change...which is another indicator of the TPS malfunctioning from what I've read. I know the one to the intake is good...I checked it last night. However, I don't even remember hooking one up to the back of the head. I went through it last night and didn't find any loose wires, but it obviously could be hiding from me
. Where on the back of the head should it hook...maybe it will help me find it. Thanks much...I think that might be it!!!
it goes from the fire wall to the rear lifting hook.
it could be the tps mine was bad and did not throw a code until i drove the truck a while.
- Thread starter
- #7
I checked the ground and that's not the problem. I am, however, convinced the TPS isn't working because the idle doesn't change when I do the jumper wire to try and set the base timing. Is there another way to check and see if it's working or not. Also, would it also affect the cold idle as well when I first start it? It barely idles even when it's cold.
Thanks
Thanks
you need to check a FSM!
it will tell you how to check the tps with an ohm meter, and answer your other question about the cold start injector.
it will tell you how to check the tps with an ohm meter, and answer your other question about the cold start injector.
also if you search on here there is a thread about the injector wiring harnes, and a bad conection inside all that plastic sheathing, it could be in faq but i am not sure.
would the injector wiring cause problems with the TPS and the test pot when setting the timing though?
when i rebuilt the 86 with blown head gasket, i set the timing with a bad tps, when the code finally showed up, 2 days later and i replaced it, it ran like s***, i jumped it to check the timing and it was off.
oh sorry! if the computer is not receiving good signals it will fawk up every thing.
did you figure out what was wrong yet?
- Thread starter
- #14
OK, I tested the TPS and found out it was indeed not working...so I bought one, replaced the old one, and it did fix part of the problem. The jumper wire now works so I was able to correctly set the timing...and it will actually stay running now. BUT, the cold start idle doesn't work..i.e. when I first start it it barely idles around 800 rpms, and in addition, the idle is still kind of all over the place...and there is a definite miss. In fact, when I re-set the timing, it be dead on for a second or two, and then the timing mark would completely disappear when the miss was there, and then it would come back. I've seen a miss move the mark a little, but it completely disappears.
Any ideas? Before I swapped the engine, everthing worked just fine....except the motor was blown lol...but all this other stuff wasn't an issue.
EGR?
Vacuum leak?
Distributor?
Coil?
I'm kind of at a loss...
Any ideas? Before I swapped the engine, everthing worked just fine....except the motor was blown lol...but all this other stuff wasn't an issue.
EGR?
Vacuum leak?
Distributor?
Coil?
I'm kind of at a loss...
- Thread starter
- #15
AND, I should also add that when I turn it off, it shuts off really rough...kind of like it's going to start dieseling, but it doesn't actually...it just takes a second or two longer than it used to with the old engine and it's super rough...
Could be nothing, but maybe it's also a symptom of something...
Could be nothing, but maybe it's also a symptom of something...
check for cracks in the rubber connectors on each side of the crossover tube from the AFM to the TB.
check the cross over tube too!
post up some pics, close ups of the intake side of the engine.
post up some pics, close ups of the intake side of the engine.
- Thread starter
- #18
OK,
I checked crossover tube...seems to be ok. To describe the idle a little better, it's actually "surging". It also seems to be running a little rich, by the smell anyway. That with the cold start idle not working, hopefully it's not more than one thing. Here are some pictures of the intake side.
I checked crossover tube...seems to be ok. To describe the idle a little better, it's actually "surging". It also seems to be running a little rich, by the smell anyway. That with the cold start idle not working, hopefully it's not more than one thing. Here are some pictures of the intake side.
i wold make sure that those connectors are making good connection.
have you checked the computer for codes, my 84 has an 87 FI system and the O2 sensor would turn the check engine light on for a few seconds then it would go out but the system still stored the code.
also on the front of the intake are 2 sensors they are in the water jacket one of those controls the cold start injector.
i will have to dig out my FSM and see witch one.
have you checked the computer for codes, my 84 has an 87 FI system and the O2 sensor would turn the check engine light on for a few seconds then it would go out but the system still stored the code.
also on the front of the intake are 2 sensors they are in the water jacket one of those controls the cold start injector.
i will have to dig out my FSM and see witch one.