I have a 93 R1 that runs perfectly except.... When I run through the gears at WOT, the car will bog slightly immediately after I shift, before boost kicks in. At partial or light throttle it maintains full boost whenever I want it. When it happens, it feels like it has too much fuel, or (not quite) lag - I just know that it shouldn't.

My mods are:

M2 ECU, Intercooler, catback, intake
SR High flow cat
RP Fuel pump
4.33 R&P
Profec B

Any suggestions?

Thanks
MCF

 

My 94 was bogging down around 3000-3500 rpm's, then I read about a grounding issue that may/may not take care of the problem. Pettit Racing sells one, but I manufactured one from a ground battery cable and two ends. Hooked it up to the negative post on the battery and sanded a little on my wheel well inside the engine bay then bolted it down. There is a perfect threaded hole there for a (what else) 10 mm bolt.

Total cost from Autozone about $6.00

Haven't had a problem with it since.

 

Thanks for your input - I actually have checked all the grounds & have the Pettit kit installed.

Also, I can be anywhere from 3,500rpm and up - usually higher when it happens - so I don't think it is a ground issue. This happens consistently, in all gears, but only under WOT.

 

You might want to think about installing a fuel pressure gauge and see whats going on..

There have been a number of threads recently of people with aftermarket fuel pumps having this problem.. However, each problem seems to have their own unique fix.

 

I think you may be right... If it is a fuel pressure issue (too much I assume) would it also explain a rich idle? Also, what could be a potential fix? Thanks for all your insights.

MCF

 

You might want to check for a sticking injector(s), too. At WOT's longer duty cycles an injector that is sticking might tend to hang open causing a very rich condition, even though it might not (yet) be noticable at light loads.

I'd go ahead an install a fuel pressure gauge. It pretty easy and can be a temporary setup. Check fuel pressure at WOT, then watch for a 'rapid' loss of pressure after you shut off the engine.

 

Not that this thread will help, but it seems like a similar problem:

https://www.rx7club.com/forum/showth...=new+fuel+pump