What havn't I done!

[Bigslick]

My car just wont keep boost. What will it feel like if it is a vaccume leak? Thats my only other option, I have changed a bunch of things ecu, HEP, CTS, etc. once my car hits over 9-10 psi it bogs down but the turbo gage keeps climbing up to more psi and the rpms are around 4500 to 5000. When the gage says 15 psi it sure doesnt feel like it. Sometimes it will buck and other times my turbo doesnt seem to be on the same page with the engine, it will spool up to 15+ psi no problem but it doesnt give me boost like it should. Some days are worse then others. But when i stay in the rage from 0-9 psi i normally have no problem. I dont think it has anything to do with fuel pump, filter etc. The thing that has me stumped is that when the car just starts up and is cool it will run pretty smooth at high psi ranges through all gears. What do you guys think because i have had this problem for almost a year and it holds me back from showing people what my 87 Daytona Shelby can really do. ThX

[HOOPTYBOOST]

You have double checked your timing correct?

[minimopar]

+1 on the cam and ignition timing.

[Bigslick]

well a little more then a year ago I had my timing belt replaced with a new one by a mechanic that i know and he set the timing. When i got my car back from him there was no boost problem until a couple months after so do you think it could have changed?

[minimopar]

Certainly. It's not hard to check yourself:

http://minimopar.knizefamily.net/enginetiming.html

[Bigslick]

Cool ill check thx.

Before i go all out in checking my timing are you guys pretty positive that this is my problem?

[big_P]

I had a problem that sounds similar

It was timing

+1

[Bigslick]

So do i add +1 to the timing or what?
I know its a stupid question but i must make sure.

[turbovanman]

Quote:

Originally Posted by Bigslick So do i add +1 to the timing or what? I know its a stupid question but i must make sure.

Hes saying that he agrees with timing, +1=one more person who agrees! lol!

[Bigslick]

Thanks now that i feel like a complete IDIOT......LOL

[turbovanman]

Hahhaaha, no worries, this will cheer you up,

[whistlin']

Probably getting pre-ignition and knock sensor is retarding the timing.

[Bigslick]

wouldn't that throw a code?

[jonnyb]

It does sound like it might be a timing belt issue, but reading your first post, you said that it seems fine when it's cold and that it "bogs" down when it's hot.

I know you said you don't think it's a fuel issue, but those symptoms sound like it could be that your fuel pump is on its way out. Sometimes when a fuel pump is getting ready to go, it will run fine when the car is first started, but then as it runs for a while and the fuel pump heats up it will start to perform like crap. This would cause your car to run fine in the lower boost range because the dying fuel pump can keep up with the needed fuel, but as the computer asks for more fuel in the upper boost/rpm ranges the dying pump just can't keep up.

The net effect - lean condition, computer pulls timing, car bogs down and feels sluggish.

Checking the timing belt is easy so do that first and if it looks correct, then put a fuel pressure guage on it and run the car around so that it gets hot and see what you've got for fuel pressure under high boost.

Good luck!

[glhsken]

+1^^^ hehehe couldn't resist