I have recently rebuilt the my EA82T.

But when i accelerate at WOT, my car surges at around 5k so much to the point that i cant rev past 5k, its almost like a fuel cut or rev limiter. I sometimes feel a single surge a bit above 3k too.

I can rev past 5k if i dont WOT it.

 

I also had a problem of running rough at idle and it would shudder at medium load under 3k rpm, so i decreased my plug gap to .6mm and it made an inprovement

 

Im at a loss. I cant hear any pinging, i havent seen any codes. Surely my fuel pump should be able to supply enough fuel at 5k.

 

New KGK BP6R11's, almost new leads. MSD blaster2 coil.

 

The engine is completly stock, except for 2" exhaust after the stock downpipe.

 

Any ideas are welcome

Start with vacuum and timing<

Tps?

Timing is on 20 deg.

I cant see how a vac leak will affect my motor while it is pushing boost.

 

If i was running out of fuel, i would know about it wouldnt i, it would be pinging/knocking and such?

 

I was thinking i might give my airflow meter a clean. Spray it with some pure alcohol or the like.

 

Gannon

I was thinking TPS as well...

 

Regarding the MAF, there is a CRC QD (quick dry) electronics cleaner that works well, there is a MAF specific product, alcohol should do fine, WD 40 I bet would work great, brake cleaner probably.. just make sure the thing is OFF and not hot (cant take long to cool off) and if you use something that doesnt evaporate quickly, blow as much off as possible before plugging it in and turning it on.

Ive already cleaned the maf with some contact cleaner.

No difference.

 

It seems odd that it will give a single surge at about 3k, and then several surges at 5k

Could i have a hole in my fuel or ignition map?

Cos thats what it feels like

 

I accelerate in any gear and it has heaps of power, but as i pass 3k rpm, there is a single surge and then all is good until 5k, then it wont rev much past there.

 

Any ideas?

I think you have either a boost leak (which is actually different than a vaccum leak) or serious fuell issues, did you properly hone your cylinders, and did you properly break it in, or did you drive like a batouttahell right out of the garage.

Did you do anyhting to the valvetrain? and what does it fell like when you get to5grand, no power at all, kinda like a revlimmiter?

have you checked the TPS??

 

 

That is for my SPFI TPS, but the principles are the same.. You may have a three prong TPS without an idle sensor switch (I think you do, since it is a turbo car) and in that case, pretend that Terminal A is not there, and perform only the "Throttle Opening Signal" test. The TPS will be located on the throttle body, probably directly opposite the throttle drum (the bit that the cable attaches to) just like it is on the SPFI throttle body; it is just in a different location.

 

There is a possibility that the actual resistance values that are "correct" for the turbo are not the same as the SPFI unit, and there is a chance that "C" and "D" are swapped. However, the important part is where it mentions continuous increase and decrease as the throttle opens and closes. Measure while operating the throttle as slowly as possible, and watch your meter for a "blip."

 

The TPS is a potentiometer, essentially a "volume knob." Everyone has had stereos with "crackly" volume knobs, right? You are looking for a "crackle" in your "volume knob."

Bottom end was professionally redone. Heads were reconditioned but valvtrain didnt need attention.

 

As for a break-in, i didnt 'flog' it but i didnt baby it either. Did as much varied driving as possiable.

 

I noticed thisarvo that it gave a bit of a surge just before 4k too.

 

When i get to 5k, it seems to run out of power. Kinda like as if i eased up off the accelerator pedal then reapply it slighty, repeated. Not a violent surge like rev limiter. It is still showing 7psi of boost at this point also

 

I want to get a fuel pressure gauge and test fuel pressures.