I have a 90 Turbo II that has rough/no idle and hesitation at approx 1300-2000 RPM. Other wise the car runs strong. Here is what I have done.

First, no emissions.........

TPS checks, replaced with another good TPS and no change in problem

All sensors check, double/triple checked them with a Fluke 88AN Multimeter.

All connectors cleaned

Continuity between sensors and main harness plugs are good

Throttle body removed and all settings adjusted and reset to factory specs

If I retard the timing as far as adjustment allows, the problem gets better. During a rebuild, can the person somehow put back components 180 off? I know the pulley with the timing marks on it only fit one way.

The crank angle sensors is within specs

I wonder if someone removed the gear on the sensor and replaced it backwards.

Any thoughts?

 

Sounds more like a vacuum leak or misrouted hoses if it runs strong at higher rpms. Use the propane method to see if the idle improves. If so, use the propane to pinpoint the leak. Look for a cracked turbo inlet hose. They can split open when installing it and suck in unmetered air. Read this:

https://www.rx7club.com/showthread.p...propane+method

Have you checked timing with a timing light?....if the marks line up then the cas should be installed ok. If it were off more than a couple teeth it likely wouldn't run.