Post HG install - results, problems and comments.
09-19-2007, 10:09 PM
#1
Instructor
Thread Starter
Post HG install - results, problems and comments.
So i just finished my headgasket install this weekend.
The car runs pretty well, with the exception of a possible vac/boost leak. One big difference since the install - the rpms drop very quickly when i let off the throttle, as opposed to before, when they would just hang and drop slowly.
Let me just say two things -
1. Why did porsche design then thrermal switch/cycling valve bracket like that? what a mess. I ended up bypassing the cycling valve, because im doing an MBC/tial 38 next weekend.
2. I dont know how some of you guys can do a HG in like 8 hours. it took me like 20.
now onto the main problem. When i start the car, it shudders, vibrates, and almost stalls. vac starts at 10 mg of merc., drops down to 2, then after about 5 seconds it settles at 10 (autometer gauge). before the HG, it would be around 16. Also, once the car is warm, it reads 15mg at idle, and 18 while driving, no throttle. could this be a vac leak?
Finally,i can only boost 9psi. is this due to no cycling valve? was i supposed to do anything with the wires when bypassing the cycling valve?
The car runs pretty well, with the exception of a possible vac/boost leak. One big difference since the install - the rpms drop very quickly when i let off the throttle, as opposed to before, when they would just hang and drop slowly.
Let me just say two things -
1. Why did porsche design then thrermal switch/cycling valve bracket like that? what a mess. I ended up bypassing the cycling valve, because im doing an MBC/tial 38 next weekend.
2. I dont know how some of you guys can do a HG in like 8 hours. it took me like 20.
now onto the main problem. When i start the car, it shudders, vibrates, and almost stalls. vac starts at 10 mg of merc., drops down to 2, then after about 5 seconds it settles at 10 (autometer gauge). before the HG, it would be around 16. Also, once the car is warm, it reads 15mg at idle, and 18 while driving, no throttle. could this be a vac leak?
Finally,i can only boost 9psi. is this due to no cycling valve? was i supposed to do anything with the wires when bypassing the cycling valve?
09-19-2007, 11:24 PM
#4
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do you have anything hooked up to your wastegate or is it all just unhooked. If you want to be safe just run a line from the IC pipe to the wastegate directly and plug the hole in the J boot and then you can't boost much (don't remeber the psi) but you wont over boost until you can install the MBC
09-19-2007, 11:39 PM
#5
Instructor
Thread Starter
the j boot is plugged, but the wastegate is still stock. I just ran the line from intercooler pipe/ LBE straight past the cv, and into the wastegate. i thought this was how to bypass it.
09-19-2007, 11:47 PM
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