OK, I think I may have a blown turbo, it blows white smoke only when I back off the throttle, and its poors out, won't idle properly, and is really flutterly like its got a miss, when I try to hit boost, at 5000rpm its only running like 2pound boost instead of 16-18 psi, back off the throttle and has a massive back fire ....
It's lost so much power, I can't even drive it to get in on the car trailer

Any thoughts would be appreciated

 

Year/model?

Compression test. Serious loss of power in vacuum is most likely due to internal seal failure. A very large vacuum leak could also cause some similar issues at idle/low RPM, but should clear up at high RPM.

 

How can I test for a vacuum leak ?
It's a 91 model bridge port,
Could it also be ignition problems ? like coils ?

 

It couldnt be ignition problems. Smoke = seal failure as mentioned above. White smoke indicates coolant entering the combustion process. A compression test should be your next move.

 

Will the compression be different or vary from different size ports ?
What should the compression pressure be ?

 

See 2nd gen FAQ: https://www.rx7club.com/showthread.p...55#post5131155

The second one from the top is compression testing. Porting does not change compression.

 

So what would be my next step if compression is all good ?