2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Engine runs perfect last night, today it won't WOT & bucks all over the place?

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Old Oct 20, 2008 | 06:48 PM
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From: Texas BABY!
Engine runs perfect last night, today it won't WOT & bucks all over the place?

Ok, so I have a new problem with my engine. It has been running perfect for the last few months, though I have only got to drive it maybe 50 miles.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
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Then the other day I thought I flooded it due to not letting it warm up before turning it off. Turned out it was just a lose wire at the fuel pump relay but before I found that I had already pulled the plugs and put oil in there.<o:p></o:p>
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So after I got it running naturally it smoked and I knew the plugs would be dirty. So I decided to clean the engine with the water treatment yesterday, ran a gallon of water through it and it seemed to run a little better once it got it out of it’s system. I then noticed I had a can of seafoam, so I ran that later yesterday while I was giving the car a bath. That really did seem to help. I also finally got my Atmospheric pressure sensor hooked up again, the connector was hiding behind some other wires.<o:p></o:p>
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I then drove the car a little and it ran great, first time to drive it with it fully together and all the major things done.<o:p></o:p>
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I picked up some plugs to install today. So today I went out and changed the plugs and then started it and let it warm up while I did some other stuff. It started and idled perfect. After a little bit I went for a drive and noticed it didn’t feel right. I then stepped on it and it will NOT rev at WOT, if I give it a little gas it will rev but still runs into problems. Bucking, power loss, ect.<o:p></o:p>
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Overall it seems it is either getting too much or too little fuel. I am willing to bet it is too little. My question is what could be causing this and happen literally overnight.<o:p></o:p>
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Only thing that changed between today and yesterday is the plugs. I HIGHLY doubt I got the wires mixed up as I did them one at a time, but maybe I didn’t get a wire on quite right? Could/would that cause this kind of problem? Wouldn’t it not run at all if the wires were not on all the way?<o:p></o:p>
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I also have some 3800rpm lag when it is running right, could that be part of the problem? I already re-ground virtually everything a few weeks back but it didn’t help. But I will worry about that after I get the engine running right again.<o:p></o:p>
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So any ideas as to what could be causing this?<o:p></o:p>
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Old Oct 20, 2008 | 07:04 PM
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From: SUmner, WA
fuel filter is prolly done due to using the cleaning agents which most likley broke down alot of crap in your fuel tank and sent it through your fuel filter
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Old Oct 20, 2008 | 07:23 PM
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From: Texas BABY!
Originally Posted by rrw
fuel filter is prolly done due to using the cleaning agents which most likley broke down alot of crap in your fuel tank and sent it through your fuel filter
Nope, i am 99% sure that is not the problem, it is brand new for one thing. And the other is that i didn't put anything through the tank, it was put into the intake.
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Old Oct 20, 2008 | 08:14 PM
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From: SUmner, WA
how about the fuel sock on the fuel pump what does it look like. i only say this because i have ran into this problem and it was all due to a rusty tank because it sat for so long
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Old Oct 20, 2008 | 08:28 PM
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From: Texas BABY!
Originally Posted by rrw
how about the fuel sock on the fuel pump what does it look like. i only say this because i have ran into this problem and it was all due to a rusty tank because it sat for so long
As have I, I actually have a whole new fuel system, including the tank. My old one WAS rusty but those problems have been behind me for some time.

the fuel system is all new, so i highly doubt it is anything behind the fuel rail, and i just had the injectors cleaned and they were working fine yesterday so i doubt that is the problem.

This is why i am so stumped, i can't figure out what could have happened between yesterday and today.
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Old Oct 20, 2008 | 08:59 PM
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then this leaves me to say the usual
check tps
check boost sensor
maybe a secondary injector clip shook its way off it was broken before.
you know the same answers you thought about to yourself when it happend
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Old Oct 20, 2008 | 09:03 PM
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From: Texas BABY!
Originally Posted by rrw
then this leaves me to say the usual
check tps
check boost sensor
maybe a secondary injector clip shook its way off it was broken before.
you know the same answers you thought about to yourself when it happend
Yeah, i have thought the same things.

I will unplug the TPS and see if that does anything (it assumes WOT when it is not plugged in).

Boost sensor will be checked and/or swaped with my parts car sensor. will see what happened. I am really woundering if i didn't get a plug wire on right seeing as that is the only thing that changed between today and yesterday. But it seems it would either work or not work if that was the case.

And i did use good NGK plugs before anyone askes.
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Old Oct 21, 2008 | 08:03 PM
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From: Texas BABY!
Well i figured this one out finally. Turned out to be a cuple of small things.

My leading rear plug wire was not on quite right.

My TPS was a tad out of adjustment

My timing was a tad retarded

And my gas tank was low (not empty, just low)

Fixed all of the above and it is back to normal! runs better now as well!
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