A couple weeks ago my car started to stop boosting between 1-3 gear. When it hit 4-5 gear it'll boost 1-2 psi only. Normally, it'll boost 8-10 with a manual boost controller. I've test for leaks on all my charge pipes and intercooler, none was found. Try it w/o manual boost controller, no change. Turbo spools fine and bov blows loud, but it's not pulling like it was turbo charge anymore.

Did a compression test and come to find out that piston 1 was 160, piston 2 was 135, pistom 3 was 145 and piston 4 was 160. Could this be causing me not to boost correctly?
D16a6
Mazda MX6 IHI turbo

 

your compression sounds fine. You might want to check the turbo and see if your leaking air out of the compressor. This happened to me because somehow the snap ring that connects the compresor to the middle wasnt hooked on right. Make sure your snap ring is right. If thats not the problem check your wastegate. Plenty of things that it could be but those two are the most probablt besides a leak in the charge pipes.

 

Is that compression fine?
hmmmm mine was a lot higher than that they were all at 190psi

 

The compression isnt great but it isnt horrible either. Not bad enough to were you would lose that much boost at least.

 

a local turbo rebuild told me that he saw in alot of cases that if the cars ignition coil is bad or going bad no boast til you changed it. not sure if true of false but thats a thought if you got a spare coil laying around.

 

Ok, so far I've try unplugging the line from wastegate and still no boost. I'll be replacing the wastegate to see if it's the problem.....will let everyone know this weekend..



http://home.earthlink.net/~freemanmoua

 

Dont go and replace the gate yet. Disconnect it and try a spring or something else to keep the flapper closed and drive really softly and see if you make boost. If you still dont get boost your wastegate isnt the problem and you can save yourself the hassle of getting a new one.

 

Compression is a little low (depending on c/r) but the main concern is the inconsistency... as i always knew it you wanted to be within ~10 psi of one another... variations indicate wear and upcoming issues.

 

also low compression wont make your boost gauge read lower..