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GTR engine problem

dairyboy

By dairyboy,
in Engines & Forced Induction

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dairyboy Collaborator

dairyboy

Posted
Posted

I think I might have some idea what's wrong with it...but it doesn't hurt to ask :)

So far it's all stock stuff on it but the car doesn't seem to wanna start. It takes about 2-3 cranks before I'll be able to boot it up and even if it's up idle is lumpy/rough as if it's got a lumpy cams in there (but I think it's the stock cams right now..might have to check) the car doesn't seem to wanna boost up either and doesn't really wanna rev past 5k.

Any ideas fellas? I think the O2 sensor isn't working properly as well so are these problems related to that? Probably will do a leak down test/compression to see how unhealthy the engine is first.

Actually, do you guys think it might be a chipped ECU issue? The ECU looks like a stockie but I haven't actually pulled the cover off to see whether it's been chipped or not.

Thanks ;)

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meshmesh Mentor

meshmesh

Posted
Posted

dairyboy, It's really a hard call to determin your problem over the net. Ultimately, your best bet is to take it to a workshop.

I'm thinking it could be so many things:

1. You have a After Market ECU, and they've pulled out all the mods returning it to stock, before delivering it to you?

2. They stuck the original ECU back in, and left some after market mods?

3. Idiling, could be an injector issue?

4. Cranking, cold be a battery issue, have you checked the battery? and what size is it? After I did my mods to my GTR, the thing was very hard to start & idling was sometimes an issue.. Found out I had a 280cc battery that was good for a suzuki swift, upgraded it to a 450cc no problems. Idiling, was a tune issue related to my 700cc injectors.

5. Boost past 5000??? Like cameron said - "What happens when you hit 5000rpm?"

dairyboy Collaborator

dairyboy

Posted
  • Author
Posted

From my short drive, it doesn't seems like it will rev past 5000rpm. I didn't really push it all that hard.

As for the injectors, previously it's 550cc but now replaced with the stock injectors. It's also got the Z32 AFM but now the stock unit. The exact mods will gonna be a bit of a mystery until I pull the damn thing apart but so far I know everything should be reverted back to stock, with exception to the fuel pump. Maybe it does have a pair of lumpier cams.

I know it's going to be difficult to get an exact answer on the net but I am just trying to get as much leads to start tracking down the exact problem.

This is my plan of action -

* Check what cams its got

* Reset ECU

* Confirm the exact type of ECU..

Anything else I should add to that list?

Thanks everyone for their constructive input so far :)

blind_elk Grand Master

blind_elk

Posted
Posted

Was the car already owned by someone here when you bought it, or did you buy it as an import?

I'd have some money on the battery. As the battery starts to die, the ECU starts sensing poor voltage and starts trimming all the performance out of the engine.

As a test, after you've taken the car out for a warmup, stop the engine, then restart and see if the performance returns.

BoOsTeD_RB26 Experienced

BoOsTeD_RB26

Posted
Posted

The starting problem and the idling problem may well be caused by a rooted inlet manifold gasket. Mine has got progressively worse, now mine takes 2-3 cranks before it will start. Broken inlet manifold gaskets can cause it to sound verrry lumpy.

Dont know about this 5,000rpm revving problem your having though.

Good luck fixing it :)

meshmesh Mentor

meshmesh

Posted
Posted
Blocked cat?

Just made me think of something?? Those Apexi~[jap brand] exhaust thingo's that you pull a lever from the inside of the car and they either keep the car quiet, or pull the lever and it goes back to loud again, have an effect that can stop the car from revving. Eg: If the flange is closed 3/4 of the way, the car will be quiet, but will be hard to rev & not rev past a certain rpm.

I'd say it could also be an "exhaust" related issue. May check to see if you have one of these units, or a block somewhere.

dairyboy Collaborator

dairyboy

Posted
  • Author
Posted

Got a stock exhaust replaced the HKS one and a new cat so the exhaust shouldn't be an issue? It's definitely been looked at that's for sure. It doesn't only sound lumpy but the car is lumpy, the damn thing wanna shake itself apart.

Will definitely investigate further with the inlet gasket..but that looks like a major operation if that's really rooted.

Anymore ideas guys? At least I've got some areas to check..

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