[B_I_G_B_O_Y]

Apologies if this topic has come up in the past, but I have searched the forum and cant find anything that is close enough to my problem.

My '91 R32 GTR is very erratic at the moment, and the problem is now getting more and more frequent.

What happens is she will sometimes (condition is always from cold startup) idle at around 2000rpm, I'll drive a bit further, the idle revs will drop to 1200rpm, drive again and the idle revs are back up to 2000rpm. Once she's warmed up revs will be normal (around 1000rpm). And there's more...!

Whether cold or warm/hot/hard driving/switched off for an hour/driven again, she sometimes acts like she's choking and needs the heimlich manoeuvre to sort her out!! What happens is I'll accelerate up to just before 3000rpm and the engine will behave like I'm hitting a rev limiter. It will just not go over and bring second turbo in, the action is like on off on off on off, needle bouncing under 3000rpm, with pedal down/midway/easing on power-doesn't matter.

After alot of p*ssing about and looking a pr*ck (about 2 mins or so) she'll clear the problem and act as if nothing has happened!!!

Any help and info greatly appreciated as always....

Ian

 

[leggus]

It will just not go over and bring second turbo in

Turbo's on a GTR run together, there's no one turbo out, next one comes in, they run parallel.

 

[Mookistar]

few posts recently with similar probs. could be throttle position sensor, afms, spark plugs, few other things

best get it to a specialst imho

mook

 

[B_I_G_B_O_Y]

Ok cheers. Where would be the easiest and cheapest places to look/test/exchange first? I know my way round engines no probs, but know nothing about skylines and their ancillary costs.

Oh, and can spark plugs really affect a skyline like this? Never had spark plugs do this kind of thing to any of my previous cars. (been driving for nearly 20 years :chuckle: )

 

[langerdan]

borrow some good afms try em out first thing id do

 

[mava_rules]

yep would check afms first.

 

[B_I_G_B_O_Y]

Had an M5 before this, and the way I checked the afm's was to disconnect them, drive the car and see if there was a difference/improvement. Surely it would be the same... Yes/no?

 

[bazgtr]

AFM can play up and give a loss of power feeling. When driving can you you here the air intakes trying to suck air in??? When the problem is around, Like the car is being strangled through one air flow.

What is the idle on when starting up in the morning without moving when cold?

If it's high then can you tell me one thing for me.

Has the plenium been off for any reason before the problem?

 

[B_I_G_B_O_Y]

Baz, yes it does sort of feel like its being 'choked' and there is (what I think) an excessive amount of suction going on when turbo's are exhausting, but I just thought/think that is because they are aftermarket filters on the turbo's. I believe they are M's-whatever they are??!!??

Idle speed is 1400 when started from cold, this stays steady although it sounds like it is GENTLY creeping up-not sure-spose I didnt run it long enough to be sure.

As for the plenum, I have no idea if it has been removed/or played about with.
Why?

Ian

 

[B_I_G_B_O_Y]

Just read that-it cant be sucking if its exhausting can it-TW*T!!

 

[B_I_G_B_O_Y]

Oh, and Baz, there isnt a loss of power feeling. Basically she WILL NOT go over 3000 rpm and hit BIG boost. The needle bounces up and down under 3k, which is how the engine is behaving. It REALLY IS LIKE A REV LIMITER. And this is NOT ALL THE TIME. Some days it wont happen at all, another day or two and it will????????????????????
Cheers,
Ian