15psi boom-boom

[kelvinb]

**TESTING ON OPEN ROAD BY MYSELF***

35mph I did a 2nd gear pull till about 6500rpm and shifted, Everything is good. 47mph I did a 3rd gear pull, about 5500rpm my car went BOOM but doesnt die. Still running. Try 3rd again.... BOOM, but still running. Tried it one more time and POP again. I say #### it and shift into 4th and go again and BOOM intercooler pipe blows off . The clamp flew off somewhere so I went home and called it a night. What I don't understand is why it was popping.

Fuel cut?
I rewired the pump with a relay awhile ago and it never did this before, even when it creeped to 20psi.

Pulling timing?
Supra SMIC so I don't think it is that.

Boost leak?
I just installed a new silicone hose but it is possible it was leaking since that is where the intercooler pipe popped off.

me=confused.

 

[spoolup]

take it your still on a 14b? and take it you have no fuel control correct?

If its fuel cut, you will know its fuel cut. it does not just pop or boom it leterally tries to stop the car. your body WILL make a movement towards the windshield.

you say pulling timing? what are you logging with? atleast borrow a freinds pocketlogger, that will verify that.

chances are you are running into detonation. check your spark plugs and replace if questionable (a set of 4 should cast about $8 at NAPA). more than likely you are on a higher timing map and due to the age of the plugs and condition of the plugs (maybe the lack of fuel or too much timing) your car is detonating at that boost level in the higher gears. If you just replace the plugs the problem will more than likely go away. But I would still pressure test the intake path since its easy to do and can prevent all sorts of problems.

 

[project_tsi]

Sounds like boost leak/ fuel cut.

 

[kelvinb]

I will pressure test it tonight and see what I come up with. I am running 92 octane and 15psi. I have no datalogging, I was just trying to think why it would be doing this. Thanks for the info

 

[Michael Z.]

Sounds like boost leak/ fuel cut.

I would have to agree. You never mentioned how much boost you are running. Could you be overdoing it with your boost vs. fuel?

For future troubleshooting, when the car goes BOOM the first time, you probably shouldn't make it go BOOM again until you know what's going on with the car.

 

[kelvinb]

I didn't list the boost in the first post, but the 2nd its listed. I was running 15psi. I have ran 18psi before and never had it pop like this before. I am assuming it was a boost leak and it just couldn't take it anymore and blew off. 2nd gear I was on it full throttle for maybe 3-4 seconds. In 3rd I was on it for about 5 and it would pop.