Getting pissed off!!! (video added)
Getting pissed off!!! (video added) So i thought i had this issue fixed a while back but it seems like it came back..
Everynow and then my car will have an extremly bad hesitation, sometimes it right when it starts up (cold) sometimes it takes a little while to start doing it. Today on the way home from work, i got about 1/2mile down the road before it started, the car would sputter while accelerating, when i let off the gas it would backfire, and i could smell gas, kind of seemed like it wasn't running on all cylinder, maybe half the cylinders. I got out, opened the hood, messed with the coil pack harness connectors and started down the road, it ran fine for about 3 miles then started up again..
I am getting no ses lights at all. I am to the point where it is just pissing me off and making me want to get rid of the car. I was thinking about replacing the entire engine bay wiring harness because of how the previous owner did the wiring when he replaced the motor. He replaced it with another motor from a 98 trans am.
any input would be greatly appriciated because i am stumped and just don't know what to do anymore...
Everynow and then my car will have an extremly bad hesitation, sometimes it right when it starts up (cold) sometimes it takes a little while to start doing it. Today on the way home from work, i got about 1/2mile down the road before it started, the car would sputter while accelerating, when i let off the gas it would backfire, and i could smell gas, kind of seemed like it wasn't running on all cylinder, maybe half the cylinders. I got out, opened the hood, messed with the coil pack harness connectors and started down the road, it ran fine for about 3 miles then started up again..
I am getting no ses lights at all. I am to the point where it is just pissing me off and making me want to get rid of the car. I was thinking about replacing the entire engine bay wiring harness because of how the previous owner did the wiring when he replaced the motor. He replaced it with another motor from a 98 trans am.
any input would be greatly appriciated because i am stumped and just don't know what to do anymore...
Last edited by Tx98Formula; May 3, 2010 at 07:01 PM.
Staging Lane
Joined: Mar 2010
Posts: 94
Likes: 0
From: Temecula, CA
I would remove and replace all the spark plugs. While your at it pickup a set of plug wires. Run a good fuel injector cleaner through it as well. If your still having the problem it may be a problem with the PCM. Was the PCM used during the motor swap the same one that was in the original car or is it the one that was original in your car.
I just replaced the plugs a week ago, made no difference, at that time i also ran seafoam through the intake and in the gas tank. I have not tried changing the plug wires yet i guess i could give that a shot, but if one or more of the wires were bad wouldn't i get a ses light?
as far as the pcm i am not sure, honestly the guy i bought the car from couldn't tell me much about it, it was actually the guy before him that swapped the motor. The guy i bought it from could only tell me the motor was bought from LKQ, it had all the mods in my sig besides the ls6 intake. He couldn't tell me what gears were in the rear end or and real details at all.. As far as i know it is the PCM that was originally in the car, which i did send off to Solomon at LT1performance tuning. But the car was acting like this before it was tuned also.
as far as the pcm i am not sure, honestly the guy i bought the car from couldn't tell me much about it, it was actually the guy before him that swapped the motor. The guy i bought it from could only tell me the motor was bought from LKQ, it had all the mods in my sig besides the ls6 intake. He couldn't tell me what gears were in the rear end or and real details at all.. As far as i know it is the PCM that was originally in the car, which i did send off to Solomon at LT1performance tuning. But the car was acting like this before it was tuned also.
i have not checked all the plugs for spark just because i figured it one or more wasn't getting spark that it would throw a code..
plus it is completly random, sometimes it does it as soon as i start the car, sometimes after it warms up a little bit, and sometimes it doesn't do it at all and runs great all day long...
plus it is completly random, sometimes it does it as soon as i start the car, sometimes after it warms up a little bit, and sometimes it doesn't do it at all and runs great all day long...
nope.. msd wires, but they are the stock coils..
it would be alright if it was throwing some codes out so i had somewhere to start but i'm getting nothing...
i was told that there are supposed to be 3 grounds on the motor itself, can anyone tell me where all they are supposed to be grounded to? some pictures would be awesome too.. One on the front passenger side of the motor was cut, i noticed it when i put on the ls6 intake, the only part left was on the coolant line on the front passenger side of the motor, where is that supposed to go? i'll post up some pictures later of the wiring on this thing.. that is why i think its a wiring issue somewhere in the engine bay harness..
it would be alright if it was throwing some codes out so i had somewhere to start but i'm getting nothing...
i was told that there are supposed to be 3 grounds on the motor itself, can anyone tell me where all they are supposed to be grounded to? some pictures would be awesome too.. One on the front passenger side of the motor was cut, i noticed it when i put on the ls6 intake, the only part left was on the coolant line on the front passenger side of the motor, where is that supposed to go? i'll post up some pictures later of the wiring on this thing.. that is why i think its a wiring issue somewhere in the engine bay harness..
Trending Topics
main thing with the wiring is the grounds, he had spliced into both coil pack harnesses and ran his own ground, both of the front O2 sensors weren't getting a ground so i had to run my own for that, i have found 2 ground wires that are not hooked up, the one i just described in the previous post and the other one is attatched to the front driver side of the motor right behind the altenator..
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo i also forgot to mention.. when i'm driving it, while i'm giving it part throttle, just easy on the gas, it stumbles really bad then it will kick in and and run normal for 1-2 seconds, then start sumbling again, it does this constantly off and on. Then when i let off the gas it will backfire..
All symptoms sound like mis-fires on some or all of the cylinders.
It's possible you might have forgotten to plug in one side of the coils when installing the intake.
Other than that, you might have a problem with the wiring and the splicing of wires and grounds you were talking about a few posts up. Maybe look into re-doing all those splices yourself, so you know they are dont right - and of course, yes, be sure all those grounds are connected!
It's possible you might have forgotten to plug in one side of the coils when installing the intake.
Other than that, you might have a problem with the wiring and the splicing of wires and grounds you were talking about a few posts up. Maybe look into re-doing all those splices yourself, so you know they are dont right - and of course, yes, be sure all those grounds are connected!
i am uploading a video right now.. my main problem seems to be the driver side coil pack harness... I was only able to pull the #1 & plug wires to check for spark since the damn AIR system is in the way but they are definatly getting spark. Its when i move around the actual connector from the coil pack harness to engine bay harness that the car starts idling very rough! as soon as the video is done uploading i'll post it
is there anyway you can get some pictures of where all of the ground are supposed to be hooked up? i already ran my own ground for the driver side coil pack harness, i know its a good ground which is why this makes no sense to me
is there anyway you can get some pictures of where all of the ground are supposed to be hooked up? i already ran my own ground for the driver side coil pack harness, i know its a good ground which is why this makes no sense to me
Staging Lane
Joined: Mar 2010
Posts: 94
Likes: 0
From: Temecula, CA
The main engine ground is infront of the starter on the engine block. The harness ground is attached to the back of the drivers side head if I'm not mistaken. Check those but by the video I am guessing that a wire in that harness connecter has wiggled loose. Keep us updated.
I am thinking about just finding a used engine bay harness and possibly a new pcm (i've heard bad things about the 98 pcm) and just rewiring the entire motor, depending on how much the new harness will cost..
Check the ground on the back of the pass side cylinder head. Very over looked when doing installs. Also, just because the ses light isn't on, doesnt mean you dont have any stored codes. Hook it up to a scan tool and check the history. Then let it run and see if you can get it to act up again. This way you can verify if it truly is random or maybe narrow it down to specific bank or cylinders. The plug wires could also cause this, but seems to random. They would act up more consistently I would think.
i have hooked up my scanner and still nothing, i don't have a super expensive scanner, its just a code reader only but it should tell me all the stored codes and everything..
I will definatly go over all the motor grounds, i am sure they aren't hooked up..
it seems like whoever put the motor in just didn't care, things are basically just throwin in there and wires are spliced (mainly grounds which are pretty improtant).. I've been seeing used wire harness going for around $150-$200, so if i can find one i'll just change the whole thing out, have it look much better under the hood and hopefully fix my issues..
I will definatly go over all the motor grounds, i am sure they aren't hooked up..
it seems like whoever put the motor in just didn't care, things are basically just throwin in there and wires are spliced (mainly grounds which are pretty improtant).. I've been seeing used wire harness going for around $150-$200, so if i can find one i'll just change the whole thing out, have it look much better under the hood and hopefully fix my issues..
well i decided to just bypass that connector and see if that would work, i spliced in some wires running past the connector.... still no help, the car still stumbled and idled like complete garbage, so i am guessing that one of the wires is messed up further back in the harness, or i don't know..
So i started pulling all of the wires, i have pretty much everything disconnected so far, i am going to finish pulling the harness tomorrow, i need to pull the intake manifold off so i can figure out where the wires go back behind there, it was just to hot and the kids were getting on my nervous a little to much to finish it today. But i figured while i am doing this i can go ahead and delete the AIR system while i'm at it and maybe do a couple other things to clean up the engine bay, now i just have to find a engine bay harness for the right price...
So i started pulling all of the wires, i have pretty much everything disconnected so far, i am going to finish pulling the harness tomorrow, i need to pull the intake manifold off so i can figure out where the wires go back behind there, it was just to hot and the kids were getting on my nervous a little to much to finish it today. But i figured while i am doing this i can go ahead and delete the AIR system while i'm at it and maybe do a couple other things to clean up the engine bay, now i just have to find a engine bay harness for the right price...
the O2 sensors don't even have 100miles on them... also if you watch the video, everytime i mess with that one harness connector the motor will drop down to about 2-300 rpms and as soon as i let go it will go back to 900-1000 rpms.. Plus with how all the wiring looks under the hood i would feel a lot more conforatable putting in a new harness, things are so spliced together and about a million different grounds ran through there.. i don't know what the guy did to this thing but it wasn't right..
the O2 sensors don't even have 100miles on them... also if you watch the video, everytime i mess with that one harness connector the motor will drop down to about 2-300 rpms and as soon as i let go it will go back to 900-1000 rpms.. Plus with how all the wiring looks under the hood i would feel a lot more conforatable putting in a new harness, things are so spliced together and about a million different grounds ran through there.. i don't know what the guy did to this thing but it wasn't right..
thats the only thing i can figure is there is a wire that is messed up somewhere in that harness, like i said both of the O2 sensors were replaced not that long ago, i have put a completly different coil pack harness on there, it has new plugs, i have tried new plugs wires... nothing has helped.