Damn.... its just too bad
Damn.... its just too bad So i put together a spec'ed combo with my 346. AFR 205 heads and custom cam.
Everything was running fine after install. went to go and tune the car so i could dyno this past weekend. Tuned the car.... made #1 and #2 wot wideband verification passes and it pulled pretty good. Made appropriate corrections after each. Made the 3rd WOT pass and the motor shuts off at 120mph. Pulled off the road. Thinking fuel pump? Try and turn it over and it cranks just no fire. try for 6 seconds and it fires up. I start to realize that under normal driving i get some oil smoke out of the back on decel and also when doing work.
I guess i damaged some rings with the motor losing fuel. The car never smoked like it does now. It might of had a small puff of oil smoke on decel prior to the new H/C but noting that was constant and only happened on decel after a hard run.
I did a compression test...
#1 = 170
#2 = 210
#3 = 180
#4 = 210
#5 = 45
#6 = 210
#7 = 60
#8 = 210
Checked the leak down on 5&7 after pulling the valve cover and loosening the rocker arms and the only place i could hear air was from the oil fill tube on both cylinders. It was not blowing out of the hole though. I could only hear it.
Sucks regardless.... I wonder why the fuel pump would do that and still work perfectly every time i have started it since.
Everything was running fine after install. went to go and tune the car so i could dyno this past weekend. Tuned the car.... made #1 and #2 wot wideband verification passes and it pulled pretty good. Made appropriate corrections after each. Made the 3rd WOT pass and the motor shuts off at 120mph. Pulled off the road. Thinking fuel pump? Try and turn it over and it cranks just no fire. try for 6 seconds and it fires up. I start to realize that under normal driving i get some oil smoke out of the back on decel and also when doing work.
I guess i damaged some rings with the motor losing fuel. The car never smoked like it does now. It might of had a small puff of oil smoke on decel prior to the new H/C but noting that was constant and only happened on decel after a hard run.
I did a compression test...
#1 = 170
#2 = 210
#3 = 180
#4 = 210
#5 = 45
#6 = 210
#7 = 60
#8 = 210
Checked the leak down on 5&7 after pulling the valve cover and loosening the rocker arms and the only place i could hear air was from the oil fill tube on both cylinders. It was not blowing out of the hole though. I could only hear it.
Sucks regardless.... I wonder why the fuel pump would do that and still work perfectly every time i have started it since.
Thats shitty man.
Sounds like it needs rings since its leaking into the crankcase.
Probably from too long of a WOT pull with it being lean is my guess, but im not a FI tuner.
Killer looking car though, BTW.
Sounds like it needs rings since its leaking into the crankcase.
Probably from too long of a WOT pull with it being lean is my guess, but im not a FI tuner.
Killer looking car though, BTW.
It would be amazing if my problem was just the head gasket. Not really wanting to spend $3000 on a newer better bottom end.
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Joined: Sep 2006
Posts: 447
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From: Houston
My lq9 was running lean. Then not that long ago the truck started running like ****. I did a comp test then a leakdown. I got air through the tb and down into the crankcase. Running it hard and/or lean must have cause the valves seals and rings to take a dump on me. My compression was not as high or as low as yours and the leaks sounded really bad. My highest was 175 and lowest was around 80. This definitely does not sound like head gaskets at all tho.
My lq9 was running lean. Then not that long ago the truck started running like ****. I did a comp test then a leakdown. I got air through the tb and down into the crankcase. Running it hard and/or lean must have cause the valves seals and rings to take a dump on me. My compression was not as high or as low as yours and the leaks sounded really bad. My highest was 175 and lowest was around 80. This definitely does not sound like head gaskets at all tho.
Hopefully it is just one or the other, not both. I don't have a puller or stand so it's a real pita to do it in car. On the bright side, if you do, you don't have to worry about dropping a front differential to do it all 
Check the coolant and see if its low. If it is it could be a head gasket but I doubt it.
Also, you can take a squirt bottle of water and set it on stream. With the motor running spray each header tube and find the one/ones that the water burns away the slowest and thats where the problem(s) are.
Seeing as how you already did a compression test that probably wont help much, but worth a shot if the coolant is low.
Also, you can take a squirt bottle of water and set it on stream. With the motor running spray each header tube and find the one/ones that the water burns away the slowest and thats where the problem(s) are.
Seeing as how you already did a compression test that probably wont help much, but worth a shot if the coolant is low.
Yes car was running fine before and right after install so it seemed. Dynoed 430hp and 405tq. No smoke after install until we were finishing up the tuning. Tune was good. Wideband read 12.4-12.5 afr as the car shut down. flippin weird man.
