i have a major problem between 2500 rpms until my turbo spools up. like under 2500 it runs perfect no problems no misses. then the hesitation then the turbo spools up and doesnt miss a beat. its a 1987 rx7 with a turbo 2 conversion. the only thing i changed when switching cars is i got a rtek 1.7 ecu and a safc. turbo etc. at first i thought it was a boost leak but the car is pulling 15 lbs when spooled and is fine. even if im not going into boost like 1/4 throttle past 2500 it just misses like crazy. it makes me so mad. anything i can try to do to fix it?

 

I believe this is due to the way the RX7 ECU switches from primary fuel injectors to your secondary during these RPM's, causing a hesitation. If you search for 3800 RPM hesitation or just hesitation (search titles only) you will find alot of information on this.

First place I would start would be to check your grounds, especially the ECU ground located under the intake manifold. A member here (Aaron Cake) has a nice write-up for your grounds:

http://www.aaroncake.net/RX-7/grounding.htm

Next, I would check the fuel filter, and the fuel pump sock (located in the fuel tank).

Besides this if you search what I showed you, you can probably find more helpful information. Hope this helps.

 

i have checked all my grounds. i even added some. and for the 3800 rpm hesitation threads, mine is different it seems. they all seem to hit a wall. mine does it for a thousand rpms and then fires fine once in boost. the secondaries have to be kicking in. if not i would have blown this thing sky high already running 15 pounds of boost just on the stock primaries. should i try to take the safc off the car? i tried this once and couldnt get the car to start at all. and like i said even at 1/4 throttle not under that much load it still does it.

 

what kind of AFRs are you getting??

 

Dusting of this thread - I have identical symptoms on my 88 S4...Rebuilt motor with street ports, stock turbo, Rtek 1.7 with 550cc / 720cc. 3 inch exhaust, approx 12 psi boost...Car is perfect below 2500 and above 4000 but bogs terribly between...Any suggestions on where to look? I've started the ground everything procedure but haven't had any luck.