I'm trying to help a buddy out with his Civic. Its a 93 EX coupe with a turbocharged D16z6 in it. T3 Turbocharger, Intercooled, 2.5" downpipe, custom mapped P28 ECU, walbro 255lph fuel pump. Stock injectors, stock fuel rail. 2.5" full exhaust.

The car runs fine when tooling around town and when doing lower RPM pulls and normal driving. But when doing High RPM pulls Redline to Redline, the car seems to start cutting out at around 5.5-6k rpm. I can run the car up to redline under light acceleration letting the rpms build gradually to redline. Under FULL THROTTLE acceleration its a different story. Depending on what gear you are in and how much load is on the engine, it starts to cut out at around 5500 rpm. Not quite like its hitting a rev limiter, but more like it just starts to lose spark or fuel.

At idle the fuel pressure is around 35 psi, with the vacuum line off the FPR its at about 42 psi. Its hard to monitor fuel pressure while driving.

I had a turbo'd z6 hatch several years ago and I never had any problems like this at all.

We have tried SEVERAL different things. We've changed plugs, fuel filter, dist cap and rotor, reset timing, installed a new MLS head gasket, and a few other things. NOTHING has seemed to help this problem.

It really seems like its just losing something under heavy load. Spark? Fuel? Under very light load, the engine freely revs up to redline, but not under heavy load.

The air filter is not the issue as it does not run one!

Any ideas????

 

I would think it was spark. Are you running a colder plug? And have you tried closing the gap on the plug? Only other thing I could think of besides plugs would be maybe you have a boost leak somewhere.

 

My first thought was spark also, Running some NGK BKR7E-11's in it right now, that are 2 heat ranges colder than stock. I put some colder denso iridiums in it also and that did not make a difference. I closed the gap on the BKR7's to 40 and it didnt really seem to help a whole lot.

I thought about a boost leak but all the intercooler piping is tight and all the boots are sealed well.

 

If its not the plug gap...I'm saying bad dizzy. (Assuming the car has been tuned properly on a dyno)

 

Im assuming the car isnt tuned at all.

 

.040 ?.?. . . try .020 and see if that fixes your problem.

 

We'll give it a shot. Never thought about gapping them down that far

As far as the car being properly tuned, its probably not. The existence of a competent import dyno tuner around here is nil.

 

Gap around .030" should solve your problems. Stock gap just gets blown out with higher boost

 

2 heat range colder? What kind of power you putting down? Try the gap at .30 like Shifty says, may have to close it up a bit more, but that's a good place to start.

 

I was thinking stock injectors just can't keep up with the fuel demand. And if the ecu ain't chipped or tuned as soon as the map sees positive pressure your car will start to do some funny things


Kev

 

OK, tried regapping the plugs at .30 and still no change. The ECU is chipped too. It is a Turbo program but I'm unsure of exactly what kind of tuning was done to it. He purchased the car from another guy who had done all the work on it.

Kinda blind on this, not sure what has all been done to the ecu.

 

Tuning plays a huge role in how a car will run.

 

In that case I say have someone re-tune or at least see if it has the right map sensor setting on what ever program it's using.

 

I hate to re-open an old thread but I am having the same issue. (Same issue, but with a Miata engine)

OP, what did you eventually find out was the fix?

Thanks,
Mike

 

Uh, this is Honda Tech, not Miata Tech. Maybe you should try miata.net. Also, you just bumped a 4 year old thread. Don't be that guy. No one likes that guy.

 

Um yea 4 year old thread, didn't have a resolution.

we don't do miatas, nor can we help you with a vague post that has 0 information.

 

Hello my dear friend!It seems strange but I'm having the same problem on an Accord, has anyone figured something out?It starts to get close to the rev limit and stops accelerating as if it were running out of fuel. But everything is perfect. It doesn't like dandandandan, it just holds the rotation just before the limit and doesn't