Thumper Posted December 10, 2004 Share Posted December 10, 2004 I just finished installing an intercooler into my car. Now the car is running like crap. I have 2" piping but tight 90 degree turns. Before I installed the intercooler I was boosting 10-10.5 psi. Now it will go to about 6-7psi and then drop to 4psi. Right when it hits 6psi it starts to run rough. It does the exact same thing in all the gears. I lowered the spark plug gap to .030" but it didn't help. It is now back to .045". I have rechecked and rechecked all of my connections. I have done the carb cleaner at idle leak test and no leaks. Does this sound like an air leak or ignition problem? I'm leaning towards air leak because it ran perfect b4 I did the install. Any suggestions on how to test for a leak? TIA Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 10, 2004 Author Share Posted December 10, 2004 Also my DIY MBC is hooked up in the stock location and I just cleaned it. TIA Quote Link to comment Share on other sites More sharing options...
slownrusty Posted December 10, 2004 Share Posted December 10, 2004 Go to Walgreens and buy their $5 stethescope - thats what I did....can't beat it!! Sounds like an air leak for sure. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted December 10, 2004 Share Posted December 10, 2004 I agree. it sounds like a boost leak..it may not be leaking at idle but when under boost it is leaking.. a good way to test this is to pressureize the system with a compressor or something.. When doing this you can use dry ice and you will see where it is leaking out.. that sucks though.. good luck Quote Link to comment Share on other sites More sharing options...
mjfawke Posted December 10, 2004 Share Posted December 10, 2004 Possibly a leak, but how about moving the boost gauge to before the IC to check that it isn't a blocked core. Wouldn't be the first time a rag has been left in an end tank... Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 10, 2004 Author Share Posted December 10, 2004 Thanks for your replys. I do not think it is a clogged intercooler or pipe because the the boost goes to 7psi and then slowly drops. Also the car runs rough while it does this. So the air getting measured at the afm is not reaching the combustion chamber. If it was just a clogged intercooler then the car would run like it was at 4psi but not rough. I will be getting a stethescope today and checking for leaks. Also I am going to redo some of my pipe connections. I'll keep you guys posted. Thanks. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted December 10, 2004 Share Posted December 10, 2004 It could be either a boost leak, as mentioned already, or it could be that your intake pipe is collapsing from the suction of the turbo intake. What are you using for an air filter and intake pipe to the turbo inlet? If you are using the stock 280ZX Turbo boot, is the steel spring still in it? When I did my intercooler, I took out the spring and I could only hold boost up to about 9 psi for about 3 seconds and it would drop to vacuum and the car would coast down untill the boot opened up again! It drove me nuts for a couple of days. Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 10, 2004 Author Share Posted December 10, 2004 I'm using the stock turbo boot with a metal aftermarket intake pipe. The ring is still there and it is still very firm. I am pretty sure it is not collapseing. Thanks anywayz. I'm on the way out too put it back together. I just finished redoing some of the connections. Hopefully it will do the trick. Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 11, 2004 Author Share Posted December 11, 2004 Well good new bad news situation. I fixed the big problem it will now boost 14psi spike then drop down to 10-11 psi (i'll explain in a bit). Plus the power is as smooth as before the intercooler, but with alittle less power on the the topend,. The problem I had eariler was not a boost leak but an electrical problem. It was my ecu connections. Basically the wires are so worn that their center metal wire is showing and if you move it one way it runs crappy and if you move it another it runs normal. So I have to go the junkyard and try to find some nice ecu connections. My problem I have now with the boost is if I floor it first and go through all the gears 1-4 it will read 10-11psi. If I nail it in second it will read 10-11psi. But if I floor it in 3rd or 4th gear it will go up to 14psi and the drop down to 11-12psi by 4k. I unhooked my boost controller once and it when to 18psi b4 I shut it down:twisted: . I have also used two different boost controllers and both are doing the same thing. The boost gauge flucuates at 10-11 while i'm driving. UPDATE!!! I am 99% sure I found the problem. On one of my runs my bov recirculation tube blew off. After that while at full throttle I would here the blow-off vavle. So what was happening is the my blow-off valve is not holding the higher boost. And yes I have crushed the top of my bov very far might even be too far. I am not 100% sure that its the blow-off valve because I don't have time or money to weld a plate too seal the blow-off valve hole. My friend has order a welder and should get it on wednesday so I guess I will just have to borrow his brand new toy. Well time for me to invest in a new bov. I thinking the hks ssqv. Anybody have a bov that they want to get rid of, like real cheap, like free. Ted Quote Link to comment Share on other sites More sharing options...
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