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Strange Problem With Gtr

PhilGTR

By PhilGTR,
in Engines & Forced Induction

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PhilGTR Rising Star

PhilGTR

Posted
Posted

I have this little problem with my 33 gtr where i get intermittent loss of power. Its stock standard not even an exhaust.

This is what i have discovered so far,

When i first start the car in the morning when its cold, it seems to be lacking a bit of response, but i dont push it, it just feels that way down at the low revs. Maybe thats what its meant to be.

Once the water temp gauge goes up to where it should be, the car feels good! the response and power is how it should be. But SOMETIMES after driving for a while like 30 mins plus, sitting in traffic here and there and when the oil temps are up to about 80C it feels like it is a bit hesitant to go at lower revs and it feels slower through the rev range too. Almost feels like it doesnt want to go for a second or so and then slowly the power comes on.

But then when i turn the car off for a while, come back after 20 mins drive it again and it feels like normal again, pulls hard and all. WHat the hell is going on?????? Can sometime tell me what it could be? Ignition timing hasnt been touched, plugs are correct too.

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PhilGTR Rising Star

PhilGTR

Posted
  • Author
Posted

Its running the stock air box with a hks panel filter.

And the boost seems to be normal, it just doesnt want to pull as hard. Under say half throttle in 2nd gear around 2-4krpm it feels flat and laggy. But then i stop to get petrol, start it up a few mins later, its feels much better again.

My mech plugged it into a diagnostics thing and reckons ignition timing is ok. he also reckons the coils and sparkies are fine and he reckons the afm is ok too. He is kinda stumped too, but I havent realy been able to show him the problem properly as it is intermittent. He reckons it drives fine because he hasnt experienced the changes in performance.

He was suggesting a possible fuel pump problem?? could it be possible?

enilyks33r Enthusiast

enilyks33r

Posted
Posted

It sound like the ecu is seeing knock and then using the low octane ignition map to protect the engine. Turning off and on allows the hi octane map to be used.

I had a similiar problem on GTSt, it was detecting knock just off idle when at operating temp, try retarding the timing 2-3 degrees at the CAS.

  • 2 weeks later...
URAS_33 Contributor

URAS_33

Posted
Posted

I have a similar problem except mine's in a 32 Gtst with a RB26 convertion. At low rev's specialy in 1st and 2nd gear.

I go to take off and its like the turbos are straved or something, it will slowly boost up then drop out.

But if I take off on high revs, its fine.

Can't think of what the hell it could be.

VSPEC-33 Community Regular

VSPEC-33

Posted
Posted

My car has the same problem from the sounds of it. I'm running 1 bar boost (restrictor removed from standard setup) and all your standard mods. For me, the car drives perfectly for the first 10 mins or so, making 14psi or so. Then it hesitates for half a sec, becomes sluggish and will only boost to 7 psi, but it feels flatter than when the car was running that boost standard.

I can then turn off the car, restart it instantly and its nice and responsive again, making 1 bar again. It clearly electrical but i get no warning light on the dash to say somethings wrong and i cant figure it out. I figured either afm's or my boost solenoid? Sounds very similar to your dramas, probably the same item giving us greif.

d-d Mentor

d-d

Posted
Posted

Not sure what's going on there Phil.

I have never experienced that problem in mine.

In regards to driving it first thing in the morning when its cold, mine is very spluttery if it goes over 3k rpm. But as soon as its mildly warm its fine for the rest of the run (whether its a 5min or 5hr drive).

Hope you can find the problem, fix it and let us know for future reference!!

- Dave.

rb180 Collaborator

rb180

Posted
Posted
Not sure what's going on there Phil.

I have never experienced that problem in mine.

In regards to driving it first thing in the morning when its cold, mine is very spluttery if it goes over 3k rpm. But as soon as its mildly warm its fine for the rest of the run (whether its a 5min or 5hr drive).

Hope you can find the problem, fix it and let us know for future reference!!

- Dave.

Exactly the same things happens to mine when its cold. As soon as you hit abit of positive pressure it starts to splutter but when its up2 normal driving temp its fine.

ferni Grand Master

ferni

Posted
Posted

That's normal for the stock ECU, mine used to be like that when it was cold in the morning, as soon as the water temp hits (can't remember) it switches from open to closed (or is it the other way around) mode... and it runs good/normal. When i switched to a PFC i don't have this anymore - but not like i fang it when cold anyway, so it makes no difference.

As for driving it for 30mins and then it dropping boost from 14 to 7, there is something wrong there.

  • 2 weeks later...
PhilGTR Rising Star

PhilGTR

Posted
  • Author
Posted
That's normal for the stock ECU, mine used to be like that when it was cold in the morning, as soon as the water temp hits (can't remember) it switches from open to closed (or is it the other way around) mode... and it runs good/normal. When i switched to a PFC i don't have this anymore - but not like i fang it when cold anyway, so it makes no difference.

As for driving it for 30mins and then it dropping boost from 14 to 7, there is something wrong there.

Recently in the colder temps i noticed it is happening more often like in the mornings and nights when its like 5 degrees or so. Warmer days seem to be ok asnd doesnt happen as much.

Strange thing is, it doesnt do it when i thrash it, it seems to happen under low revs and low boost etc, low throttle. Sometimes I give it the fang up to 14psi and its fine still. I also disconnected the boost solenoid so it runs 7psi but still does it. So its not a high boost issue. Something to do with too much air flow, but why? grrr

I have a PFC coming to im going to throw it on the dyno to see whats going on and hopefully fix it or at leats know what to fix.

  • 5 months later...
GTAAAH Mentor

GTAAAH

Posted
Posted

I recently replaced my r32 gtr afm's with r 33 gtr afm's and since then it has been messing up at low rev's as well, same business, unless i give it to it (which i won't because it's cold) it feels damn slow and damn laggy.

Once it heats up it's all fine though

I regapped my plugs from 1.0 to .8 at the same time i put the new afm in, im gonna try re-gap my plugs to 1.0 again tonight and see if it makes a diff

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