Serious Accellaration Problems!!!!.....HELP....

[ericherm1]

(spell check off)..hehe

Ok, I got my 1991 GTR back from the tuning shop and they said that the #1 turbo is bad (HKSGT2530's) the bearing is going out.

He said that the #2 turbo will suck the air but the #1 turbo blows

it out????? Will a bad bearing cause this?? Also under full accelleration the car runs great but under lets say 1/2 load or 1/4 load (load being pedal position from off to the floor) the car runs really bad, sputtering allot, sounding like a choking chicken..lol!

Please HELP!!!!!!!!!

[rev210]

check the base timing.

Could be a problem with the AFM/s..any problems at idle?

[EnricoPalazzo]

Dude if ur car is the same one as ur avatar, that is pure Horn!

Good luck with the problem.

[ericherm1]

I had the AFM's ran through nissans diagnosic machine (they are Z32 AFM's by the way) and they responded great so they told me they were ok.

Another guy said that it could be fuel dillivery??

Yes my car is the same one as in my avitar!

<---------

[EnricoPalazzo]

Wanna swap?

[rev210]

its not fuel delivery (ie: pump) unless the issue occurs under load.

The plugs can cause this issue if too cold a heat range with too small a plug gap.

Try reset on the ecu?

Does the ecu give any faults in diagnostic mode?

Perhaps the camshaft timing if adjustable gears are fitted, recently happened to a mate of mine.

[ericherm1]

No codes are registering from the ecu. I just replaced the plugs with NISMO platinum plugs, and no difference.

I think that maybe the exahust cam is positioned wrong???

But, tuning the exahust cam would be very hard due to the #1 turbo being bad right??

My freind is looking for a replacement HKS GT2530 for me and if that falls through then I have to take both off and send them down to HKS tokyo and have them rebuilt!!

Do you guys think that because one of the turbos are bad that could be the reason why it can't be tuned properly right now?

(dumb question but i have to ask)....

Eric

[rev210]

If you have a bad turbo you usually know about it when the thing is full throttle as opposed to losing midrange and low end power.

Is the problem only when boost is present or does it do it when cruising at higher rpms and light throttle?

If it does this on cruise then its not a turbo.

Turbo bearing failure produces noise, if all other avenues are blank then just pop the turbo's off and have a look. Don't just assume its broken.

[adam 32]

just pull the intake pipe off and see if theres any shaft movement. if it moves more than 1-2mm then its bad news, and you cant rebuild BB turbos unfortunately

[ericherm1]

The turbo problem was diagnosed at the Nissan dealership! They said the the rear turbo is in excellent shape but the front

one is "sticky".

They said that is why the car runs like crap at normal speeds and low load. Under full throttle or full boost the car runs strong but

not as strong as it should. When I turn it off you can hear the rear turbo spinning but the front is not .

(kinda like a frozen caliper on a disk brake-it works badly while you drive but when you slow down it wants to skid the tire..)

I have a couple of freinds looking for factory used turbos so that I can use those temporarally.

We called HKS Japan and they said that only a handfull of shops

are cretified with them to rebuild their BB turbos. And its going to

cost me around 70,000Yen for both. I guess some really special tools are needed??

Here is an updated picture ................

OH and the oil catch tank is temp. disconnected till we get it tuned

properly...lol