02 LS1 in 81 Trans Am. Car is skipping - HELP!
09-06-2013, 12:01 PM
#1
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02 LS1 in 81 Trans Am. Car is skipping - HELP! We did an LS1 swap in my 81 Trans Am. It has a skip, or a hesitation going on. Feels like it is flooding itself or something. It seems to do it when letting off the throttle, then easing back into it. It will also do it as you slowly start off. Seems to do it between 1000 - 1500 RPMs. It will hesitate, then usually start running fine, sometimes it will skip 2 or 3 times in a row. I had my buddy hook up a scan tool to it and it did not throw any error codes, no misfires, nothing. I had my mechanic check for vacuum leaks & put a fuel pressure gauge on it. It was showing 58 pounds of pressure. He had the car in neutral and slowly revved the engine...he thought around 2500 RPM or so the fuel pressure jumped up and the car would skip. That is all I know. ANY THOUGHTS? HELP!
Here is what we did to the car.
2002 - LS1 out of a Camaro SS from a junkyard. Assuming it is stock. Running stock exhaust manifolds
2004 - 4L60E tranny
Stock 4th gen F-body fuel pump
Pump to tank fuel seal kit etc. - http://www.vetteworksonline.com/cata...roducts_id=178
Brand new gas tank
Brand new stainless fuel line front to back
Had the PCM done by Hi Tech Tuning, taking out items not needed
4th gen electric fans
Lokar throttle cable
Lokar Tranny dipstick
etc.
Thank you in advance.
Here is what we did to the car.
2002 - LS1 out of a Camaro SS from a junkyard. Assuming it is stock. Running stock exhaust manifolds
2004 - 4L60E tranny
Stock 4th gen F-body fuel pump
Pump to tank fuel seal kit etc. - http://www.vetteworksonline.com/cata...roducts_id=178
Brand new gas tank
Brand new stainless fuel line front to back
Had the PCM done by Hi Tech Tuning, taking out items not needed
4th gen electric fans
Lokar throttle cable
Lokar Tranny dipstick
etc.
Thank you in advance.
Last edited by 81TtopTA; 09-17-2013 at 10:30 AM.
09-17-2013, 11:15 AM
#6
When I did the vetteworks 4th gen bucket mod...I chose to buy a new GM pump for piece of mind. It could be the pump like bczee said. I am re-using the fuel regulator in my bucket.
you put new fuel lines in ...what diameter?
I'd think you'd see a code thrown for low fuel pressure...not sure though..
you put new fuel lines in ...what diameter?
I'd think you'd see a code thrown for low fuel pressure...not sure though..
09-17-2013, 12:34 PM
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I used new 3/8" braided stainless from front to back. I used the Vetteworks kit
http://www.vetteworksonline.net/cata...roducts_id=123
and their inline fuel filter & fuel pump to 2nd gen tank kit.
It is a used fuel pump. It was showing 58 pounds of pressure and when he slowly idled it up in neutral, there was an increase in fuel pressure when the motor hesitated.
I see you are from Painted Post, NY. We should connect sometime with the T/As. I am from Canton, PA, just south of Elmira, NY. Do you know anyone in the area that might be able to help diagnose this issue?
http://www.vetteworksonline.net/cata...roducts_id=123
and their inline fuel filter & fuel pump to 2nd gen tank kit.
It is a used fuel pump. It was showing 58 pounds of pressure and when he slowly idled it up in neutral, there was an increase in fuel pressure when the motor hesitated.
I see you are from Painted Post, NY. We should connect sometime with the T/As. I am from Canton, PA, just south of Elmira, NY. Do you know anyone in the area that might be able to help diagnose this issue?
When I did the vetteworks 4th gen bucket mod...I chose to buy a new GM pump for piece of mind. It could be the pump like bczee said. I am re-using the fuel regulator in my bucket.
you put new fuel lines in ...what diameter?
I'd think you'd see a code thrown for low fuel pressure...not sure though..
you put new fuel lines in ...what diameter?
I'd think you'd see a code thrown for low fuel pressure...not sure though..
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09-17-2013, 01:46 PM
#8
I think your lines are fine. Are all your gauges connected? I ask because I remember having a stutter myself prior to connecting tach and speedo. Hopefully the problem is in your GM fuel bucket ( regulator or pump). I hate throwing parts at the problem... But you should be able to pick up a new pump bucket on eBay cheap ( I got mine from seller named fparts , in Philly). I do not know of anyone local who tunes or diagnose issues..... I've heard that some good repair shops hook up an oscilloscope to the pump wiring...run it and can diagnose issues with the pump.. Just a thought.
Yeah, we should get together sometime....since we are close by.
Yeah, we should get together sometime....since we are close by.
09-17-2013, 01:52 PM
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The tach is hooked up, the speedometer is not. The fuel gauge is connected to the old school gauge and does not register correctly. The temperature gauge is also hooked up.
I think your lines are fine. Are all your gauges connected? I ask because I remember having a stutter myself prior to connecting tach and speedo. Hopefully the problem is in your GM fuel bucket ( regulator or pump). I hate throwing parts at the problem... But you should be able to pick up a new pump bucket on eBay cheap ( I got mine from seller named fparts , in Philly). I do not know of anyone local who tunes or diagnose issues..... I've heard that some good repair shops hook up an oscilloscope to the pump wiring...run it and can diagnose issues with the pump.. Just a thought.
Yeah, we should get together sometime....since we are close by.
Yeah, we should get together sometime....since we are close by.
09-17-2013, 02:34 PM
#10
Hook your speedo up....the PCM may be looking for it to be connected. Before you throw any new $parts$ at it...try it. Doesn't seem like it would cause an issue... but you may be surprised.
Did the fuel gauge work before the swap? If so, you need adjust the float with the 4th gen bucket.... Same thing happen to me.
Off topic....Could you design some custom TA decals for me? I think I recognize your username from another forum.
Did the fuel gauge work before the swap? If so, you need adjust the float with the 4th gen bucket.... Same thing happen to me.
Off topic....Could you design some custom TA decals for me? I think I recognize your username from another forum.
09-18-2013, 06:40 AM
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Hook your speedo up....the PCM may be looking for it to be connected. Before you throw any new $parts$ at it...try it. Doesn't seem like it would cause an issue... but you may be surprised.
Did the fuel gauge work before the swap? If so, you need adjust the float with the 4th gen bucket.... Same thing happen to me.
Off topic....Could you design some custom TA decals for me? I think I recognize your username from another forum.
Did the fuel gauge work before the swap? If so, you need adjust the float with the 4th gen bucket.... Same thing happen to me.
Off topic....Could you design some custom TA decals for me? I think I recognize your username from another forum.
09-18-2013, 07:13 AM
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There are 4 custom brackets made that the shaker bolts too. The bottom of the shaker was removed. If you look close around the rim of the shaker, you can see the heads of the 4 bolts. They have a very large flat head on them. I will try to remember to get some photos the next time I have it off. The shaker has a dodge durango air box lid fastened to it, then it just clamps to the base and the hose hooks on. pretty simple setup...the main thing is, its functional. That was my goal. I also put a screen in the backside of the shaker to keep leaves etc out & help try to shed a LITTLE water out. We also installed a K&N air filter to help keep moisture out.
09-18-2013, 08:35 AM
#14
I'm wondering about the following:
Vaccuum leak
Loose Tach connection (had a similar problem with mine back when I had a holley EFI)
Loose alternator connections
I'm also interested in pics of your air box setup, as I want to keep mine functional too. I plan to switch to the stock GM efi this winter.
Vaccuum leak
Loose Tach connection (had a similar problem with mine back when I had a holley EFI)
Loose alternator connections
I'm also interested in pics of your air box setup, as I want to keep mine functional too. I plan to switch to the stock GM efi this winter.
09-18-2013, 09:15 AM
#15
Kevin,
How did you mount the vetteworks kit? I recessed mine so I didn't have to cut the trunk. If you dont have access via the trunk, you are going to need to drop the tank and bend the 2nd gen fuel float away from the 4th gen fuel bucket. I had to do the same thing when I did the fuel bucket swap.
Before you do this, I'd connect the speedometer to the PCM. Let's eliminate that possibility first. Do you have a new speedometer?
When I changed the pump in the fuel bucket, I found that it is tough to reuse the fuel line...and in order to remove it, I had to cut it with razor blade.
Thanks for helping me with my decals.. I started to work with a local shop here in painted post... but I can't get them to finish it. I'll gladly pay you for the design and decal work. PM me your email and I'll fwd you the request.
Leon
How did you mount the vetteworks kit? I recessed mine so I didn't have to cut the trunk. If you dont have access via the trunk, you are going to need to drop the tank and bend the 2nd gen fuel float away from the 4th gen fuel bucket. I had to do the same thing when I did the fuel bucket swap.
Before you do this, I'd connect the speedometer to the PCM. Let's eliminate that possibility first. Do you have a new speedometer?
When I changed the pump in the fuel bucket, I found that it is tough to reuse the fuel line...and in order to remove it, I had to cut it with razor blade.
Thanks for helping me with my decals.. I started to work with a local shop here in painted post... but I can't get them to finish it. I'll gladly pay you for the design and decal work. PM me your email and I'll fwd you the request.
Leon
09-18-2013, 09:19 AM
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Purchased a brand new gas tank and cut it out, recessed the stock 4th gen fuel pump using the vetteworks kit(s). I used brand new stainless braided fuel line all the way to the front. I do not have a new speedometer.
Ill PM you my email
Ill PM you my email
Kevin,
How did you mount the vetteworks kit? I recessed mine so I didn't have to cut the trunk. If you dont have access via the trunk, you are going to need to drop the tank and bend the 2nd gen fuel float away from the 4th gen fuel bucket. I had to do the same thing when I did the fuel bucket swap.
Before you do this, I'd connect the speedometer to the PCM. Let's eliminate that possibility first. Do you have a new speedometer?
When I changed the pump in the fuel bucket, I found that it is tough to reuse the fuel line...and in order to remove it, I had to cut it with razor blade.
Thanks for helping me with my decals.. I started to work with a local shop here in painted post... but I can't get them to finish it. I'll gladly pay you for the design and decal work. PM me your email and I'll fwd you the request.
Leon
How did you mount the vetteworks kit? I recessed mine so I didn't have to cut the trunk. If you dont have access via the trunk, you are going to need to drop the tank and bend the 2nd gen fuel float away from the 4th gen fuel bucket. I had to do the same thing when I did the fuel bucket swap.
Before you do this, I'd connect the speedometer to the PCM. Let's eliminate that possibility first. Do you have a new speedometer?
When I changed the pump in the fuel bucket, I found that it is tough to reuse the fuel line...and in order to remove it, I had to cut it with razor blade.
Thanks for helping me with my decals.. I started to work with a local shop here in painted post... but I can't get them to finish it. I'll gladly pay you for the design and decal work. PM me your email and I'll fwd you the request.
Leon
09-23-2013, 09:40 AM
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UPDATE!
I had a friend check the car out yesterday. He unhooked the MAF while the car was running, we revved it up and no more hesitation. Looks like the MAF might be the issue.
I had a friend check the car out yesterday. He unhooked the MAF while the car was running, we revved it up and no more hesitation. Looks like the MAF might be the issue.
