Sputtering Under Load (RESOLVED! See Post #67)
05-03-2013, 04:21 PM
#62
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I'll take a new video shortly. It runs a LOT better than it did in that video I posted, mainly 'cause I disconnected the MAF. Weird.
05-05-2013, 10:28 AM
#63
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So Steve83ta has been super generous and took a look at the car for me yesterday. After a couple hours of messing with different things on the car there's something to think about related to fuel:
On his '98 TA pressure is 60 psi at start, stays at 60 when revving, drops to 50 when turned off, stays at 50 for several hours.
On my '98 TA pressure is 52 psi at start, stays at 52 when revving, drops to 0 within 1-2 seconds when turned off.
We checked the injectors, they are not leaking. He thinks it could be the fuel pump causing the immediate drop in psi when the motor is turned off. We're going to do the filter today (I haven't changed it while I've owned the car), check the fuel pump amperage draw, etc. If the amps are not within spec (And maybe even if they are) I'll be looking at purchasing a new fuel pump next week.
On his '98 TA pressure is 60 psi at start, stays at 60 when revving, drops to 50 when turned off, stays at 50 for several hours.
On my '98 TA pressure is 52 psi at start, stays at 52 when revving, drops to 0 within 1-2 seconds when turned off.
We checked the injectors, they are not leaking. He thinks it could be the fuel pump causing the immediate drop in psi when the motor is turned off. We're going to do the filter today (I haven't changed it while I've owned the car), check the fuel pump amperage draw, etc. If the amps are not within spec (And maybe even if they are) I'll be looking at purchasing a new fuel pump next week.
05-06-2013, 09:35 AM
#65
Have you tried spraying carb cleaner around the intake to see if idle changes? If you have a bad enough leak it can cause the misfires. Although you should get a "system too lean" code.
Also, I think you mentioned the car runs better with the MAF unplugged? Have you tried replacing it with a good one?
Also, I think you mentioned the car runs better with the MAF unplugged? Have you tried replacing it with a good one?
05-06-2013, 10:01 AM
#66
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We have run 4 different MAF's (all confirmed working) through the car. No change. I used carb cleaner and it ignited. Never seen that happen before, but it did. Brake clean didn't cause any change as Steve had it hooked up to his scan tool with the graphing program open to look for changes.
He tested the fuel pump. Amps are around 7.5, which is just about what his '98 is at. Also, volume of fuel is a bit more than his is flowing, so the fuel pump isn't the main issue. Changed the fuel filter, no change in drive-ability.
Checked vacuum. -15 or so, and bouncing all over the place. Goes up to around 15-20 when on the gas, but again it's bouncing and not consistent. Per his tech book it's stating this could be a burnt valve, broken valve spring, etc. We're going to do a compression check again (this time on the passenger side cylinders) and possibly rip apart the top end this week I think.
He tested the fuel pump. Amps are around 7.5, which is just about what his '98 is at. Also, volume of fuel is a bit more than his is flowing, so the fuel pump isn't the main issue. Changed the fuel filter, no change in drive-ability.
Checked vacuum. -15 or so, and bouncing all over the place. Goes up to around 15-20 when on the gas, but again it's bouncing and not consistent. Per his tech book it's stating this could be a burnt valve, broken valve spring, etc. We're going to do a compression check again (this time on the passenger side cylinders) and possibly rip apart the top end this week I think.
05-09-2013, 08:03 PM
#67
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PROBLEM FOUND! Check the photos for the work done today... All are cell photos so the quality sucks:
Went to do a compression check:
Then decided to pull the valve covers - passenger side:
A little closer:
Time to rip the top end apart:
Steve has his old LS1 with 55k miles on it (He has his LS6 now) so we're using his heads, springs, rockers, etc:
We're hoping to have the heads and everything swapped over by Saturday or Sunday at the latest. We ordered all the gaskets needed from GM today. Should be here tomorrow or Saturday. I can't wait to get this thing back on the road!
Went to do a compression check:
Then decided to pull the valve covers - passenger side:
A little closer:
Time to rip the top end apart:
Steve has his old LS1 with 55k miles on it (He has his LS6 now) so we're using his heads, springs, rockers, etc:
We're hoping to have the heads and everything swapped over by Saturday or Sunday at the latest. We ordered all the gaskets needed from GM today. Should be here tomorrow or Saturday. I can't wait to get this thing back on the road!
05-10-2013, 12:25 AM
#68
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Nice thread update Rick. I tried to update the other Ls1 thread but it kept screwing with my pic sizes.
I hope thats answers a lot of peoples questions. Like I said on another thread, the guys who had that in the back of your mind give yourself a good pat on the back. For the others, well its a learning experence and we we're greatfull for all kinds of ideas, there is never a dumb one, that can often lead to the eureka moment, getting the job done. Now back together, and a FUN BURNOUT!!
Steve
I hope thats answers a lot of peoples questions. Like I said on another thread, the guys who had that in the back of your mind give yourself a good pat on the back. For the others, well its a learning experence and we we're greatfull for all kinds of ideas, there is never a dumb one, that can often lead to the eureka moment, getting the job done. Now back together, and a FUN BURNOUT!!
Steve
05-10-2013, 10:22 AM
#69
PROBLEM FOUND! Check the photos for the work done today... All are cell photos so the quality sucks:
Went to do a compression check:
Then decided to pull the valve covers - passenger side:
A little closer:
Time to rip the top end apart:
Steve has his old LS1 with 55k miles on it (He has his LS6 now) so we're using his heads, springs, rockers, etc:
We're hoping to have the heads and everything swapped over by Saturday or Sunday at the latest. We ordered all the gaskets needed from GM today. Should be here tomorrow or Saturday. I can't wait to get this thing back on the road!
Went to do a compression check:
Then decided to pull the valve covers - passenger side:
A little closer:
Time to rip the top end apart:
Steve has his old LS1 with 55k miles on it (He has his LS6 now) so we're using his heads, springs, rockers, etc:
We're hoping to have the heads and everything swapped over by Saturday or Sunday at the latest. We ordered all the gaskets needed from GM today. Should be here tomorrow or Saturday. I can't wait to get this thing back on the road!
Glad you found the issue but pretty sure myself and a couple others posted to check the valvetrain on the first or second page of this thread...?
Anyways, hope everything works out as you've been having this issue for quite some time.
05-10-2013, 10:53 PM
#71
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You made me stop and doubt myself thinking I was also blind. I went out and checked. It has to be a refection from the LED flashlight and camera flash because it isn't cracked. There is a casting step there.... Unless Im still blind. You can't happen to tell me what cylinder that was on the passenger side can you?
05-10-2013, 11:06 PM
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If you had that in the back of your mind or mentioned it eairler in the thread impressive since it was a "web Diag".
Again thanks for eveyones input. In the future if someone ever has the same kind of symptoms they have this thread to refer to.
Small Update
Lt1pwr1 I went back and reread the whole thread, I had only skimed it before I got involved. And saw you said pull the covers way back in Feb, then again in March. Along with offering to take the headache off his hands. Sounds like you know at least as much as me
Ill know more tomorrow, but one odd thing about this was the amount of missfires on 5-7 and the plugs are completly fouled out after a couple thousand miles. Some of this could be becuase of the broken spring, but that spring is on the pasenger side, cylinder #8 intake spring. One of the first things I noticed when I hooked up my scan tool was the LTFT was at 126% as you are prob well aware that is WAY WAY OUT RICH! Some plugs did okay and looked perfect with this way extra fuel so the car didn't lean itself out and burn up, cylinders 5 & 7 did not! Like I said completly fouled. Im hoping this was becuase of the extra fuel but most of me doesn't buy it, also the MAF was unplugged for an extend time so that didn't help either. Thats why Rick and I are doing both heads. Just in case.
Last edited by Steve83ta; 05-11-2013 at 12:00 AM. Reason: Update
05-10-2013, 11:54 PM
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Rick did a great job with the pics and the step by step so I let this tread run a little bit, but this the other info I posted on LS1.com on Thursday.
05/9/13
"I don't want to threadjack Rick's thread but I figured I would give you a guys an update as we said answers would be today. And for everyone who agreed and said "Broken Valve spring, or burned valve" give yourself a good pat of the back as you were right. Broken Valve spring and pics to follow. And for everyone else thanks for all of your ideas. Also on a side note. Some one has been inside this engine, how do I know, the driver side valve springs, retainers and keepers are stock, the passengers however are not, see if you can tell in the photos I post. Rick might have some better ones. This is also a BIG NO NO!! That is getting corrected also.
05/9/13
"I don't want to threadjack Rick's thread but I figured I would give you a guys an update as we said answers would be today. And for everyone who agreed and said "Broken Valve spring, or burned valve" give yourself a good pat of the back as you were right. Broken Valve spring and pics to follow. And for everyone else thanks for all of your ideas. Also on a side note. Some one has been inside this engine, how do I know, the driver side valve springs, retainers and keepers are stock, the passengers however are not, see if you can tell in the photos I post. Rick might have some better ones. This is also a BIG NO NO!! That is getting corrected also.
Last edited by Steve83ta; 05-11-2013 at 12:08 AM.
05-11-2013, 10:12 PM
#74
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Another huge shout out to Steve for all the help today! The rocker is not cracked. Strange optical illusion I guess. More progress today. Heads are off, everything is cleaned, getting ready to put the new heads on... Photos from today:
Oh haiii... Found 2 of these - of course we didn't verify which cylinder(s) they were from:
Looks like aftermarket springs, retainers... Possibly a head off of a newer Trans Am, Corvette, etc.?
Heads are going back on tomorrow or during the week (depending on family plans).
Oh haiii... Found 2 of these - of course we didn't verify which cylinder(s) they were from:
Looks like aftermarket springs, retainers... Possibly a head off of a newer Trans Am, Corvette, etc.?
Heads are going back on tomorrow or during the week (depending on family plans).
05-19-2013, 09:10 AM
#77
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SHE RUNS!!
Video here:
Some more progress (cell phone) shots from yesterday:
Bolting the exhaust back together:
We still need to add some coolant and a coolant temp. sensor.
Video here:
Some more progress (cell phone) shots from yesterday:
Bolting the exhaust back together:
We still need to add some coolant and a coolant temp. sensor.
05-20-2013, 12:59 AM
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Last edited by Steve83ta; 05-20-2013 at 01:15 AM.