Fuel issue, not sure where else to turn
 

To start off, please bear with me, I have read a ton of stuff off the site, and found lots of informative things. However, I am not sure what else to search/read.

Car is a 88 Turbo2, has 550 primaries, 750 RC secondaries, 3" turboback, large FMIC, but otherwise stock.

The car was always getting too much fuel, it had a RTEK 1.7 in it when I bought it, we think the ECU was toast, not sure what happened, because after switching to a stock ecu car ran better. Put in a FD fuel pump, car ran a little better. So we kept trying to think what else it could be.

Can't seem to diagnose the issue, under the recomendation of a local RX7 guy, we put in a aftermarket FPR. The regulator can't seem to get the pressure down to where it needs to be, its always at 3 bar or higher.

Once the car warms up, it will run decent, but stutters if im just cruising at a constant rpm. It stutters if I go to accelerate hard, but once it seems to clear itself out, it hauls ass.

Is it just getting too much fuel? This car has been an absolute frickin nightmare since I bought it, I used to be a Supra guy, and am not used to all these quirks this car seems to have.

Is there literally anything else it could be? I do understand the pressure is an issue, but is it really that big of an issue? Should I just put the stock FPR back in?

Does the car stutter hard at all rpm's or just within a tight range, and if so. what is it? Also, the stock ECU does not have a way of controlling your larger than stock secondaries.

If I am cruising along at a constant rpm, lets just for example say 1/4 throttle, 40MPH in 3rd gear, it has a miss/stutter like the spark is no good/too much fuel.

If I floor it, the car seems to stutter briefly as though clearing its throat and then hauls ass.

Under just normal driving, like accelerating normally from a stop while in traffic etc, I can accelerate normally thru the gears, with no issue. It is only while maintaining a speed, or under HEAVY acceleration, that it seems to do this problem.

If I watch the pressure on the guage on the FPR, it can get up to like 5 bar just while free revving it, but no stumbles free revving, it is smooth and fast

first you need to stop flooring it until you figure this issue out

I have only actually put the pedal down a small amount of times while trying to diagnose, the car is not my daily driver and I have only put on maybe 100 miles in the 2 years I have owned it because of the gremlins it seems to have.

Normal fuel pressure should be close to 35psi. If you are above 40psi then that is too much especially since you have large secondary injectors. For the most part, free reving and keeping the car under 3800 rpm while driving should keep the secondary injectors from engaging and this could explain some of your problems.

I am trying to get my hands on the stock FPR, or I will purchase a good aftermarket one instead of the junker that was put into it.

Also, how does the car perform when it is cold. Is it night and day or do some of the same driving when warm problems still exist?

The car performs worse when cold, the stutter is more often and noticeable.

Have you verified proper operation of the injectors? If there is debris or a slight clog in the injectors, the fuel pressure behind it is going to be increased. I'd recommend having them flow tested, or at the very least verify proper resistance on them.

Just wanted to update:

Took the injectors out, had them cleaned and flow tested, they turned out to be high impedance injectors (FAIL). Replaced with low impedance that I had cleaned and tested, installed aeromotive FPR, car runs like a dream now. Thanks guys!

Good for you.