Flat spot/Power Loss

[Terminal]

Ok, im having trouble with my car. it started out as just a flat spot in 2nd, but now its become a total loss of power right through the gears and into full boost. when it idles now it's like a misfire, the revs are jerky and the exhaust note is off. i ran the ECU diagnosis test, and it came up emtpy (55). i checked all the coil packs, and none of them seam faulty. i suspect it could be bodgy spark plugs or maybe a fuel pump fault, or a crank angle... im really stumped here. the car is running like poo and it only started stuffing up about 2 days ago. any help or suggestions appreciated.

Edit: It's an R33 Series 1 93 model with 130,000km on the clock

[VIPERGTSR01]

have you checked for any leaks in your plumbing

[Terminal]

Well, actually i had a squealing noise coming from somewhere whenever i hit 5000rpm, full boost, but it went away once the car was warm. i went around all my intercooler piping with a spanner and gave all the clamps a tighten, then the noise stopped. after that was when the flat spot occured.

[wreckedhead]

mechanic

[Ouch]

Check the turbo status?? cos sounds like exactly what happened to mine.... turbo died.

[Terminal]

Well the self diagnosis didn't say anything was wrong with the turbo. also, once i get into the higher revs it runs normally, i'd assume if the turbo was dying that at higher revs/boost it would run even worse.

[TTT]

3 things I can guess at..

1.) spark plug gap is too big. try re-gapping them to 0.8mm

2.) AFM is dirty and neesd cleaning or there is a leak between the afm and the throttle body. You said you already checked the cooler piping but what about the induction pipe from the afm to the turbo..?

3.) bolts on the turbo manifold have come loose causing you to loose boost through there before it gets in to the exhaust side of the turbo. If this is the case, it will soon blow the turbo gasket requiring a new one (which is about $20) but putting it on is a pain in the arse and will cost about $150 for a professional to do.

hope that helps.

TT

[Abo Bob]

I think your coil packs are on their way out. Mine was similar to this when it started happening and the people I bought the car from said they would fix it for me. They tried everything but the coilpacks even though I said that's what I thought it was.

Eventually they did it; zoom zoom.

If this is what it is they will get progressively worse over a month or two. The ECU can only see one side of the coil packs so it can be them without an error code.

Check your crank angle sensor too.

[Terminal]

Ok, i started pulling the coil packs out to replace the spark plugs, and they're wet. not wet with fuel, but wet with water?? i cleaned the engine bay the other day with a damp sponge and then splashed it with water, but i couldn't imagine water getting into the engine. this i asume is not a good thing, so ill let them dry.

i checked the coil packs, it wasn't them, they're fine. the turbo gasket thing is a possiblity. i might have a go at that next if replacing the sparkies with 0.8mm gap ones doesnt do anything.

thanks a lot for your help, really appreciate it.

[Terminal]

Ok, replacing the sparkies didn't change anything. it still has a massive flat spot when i rev it, then it's idle is really surging. is there any chance it could be the injectors are dirty?

when i rev it and there's no exhaust noise, i can hear an odd spinning sound. im assuming that's the turbo spinning without any exhaust hitting it. im stumped, but i don't want to have to resort to a mechanic

[sean01]

If your turbo manifold gasket is leaking, you will definentely hear it so I would cancel that out. Sounds like a bad AFM or fuel pump to me.

[MegaGTS4]

If you have been cleaning your engine bay lately I would be checking the electrical conectors on the AFM, O2 sensor, CAS and ignitor for damp conections.

Check for coil packs for earth leaks aswell, as the insulation on the coil packs becomes brittle from heat and breaks off causing stray discharge.

MEGA

[Abo Bob]

That surging points me away from coil packs but I'd just like to point out that my coils showed no signs deterioration or earthing and tested fine but when they were replaced the problem was fixed.

Not trying to tell you over the internet what to do, just making sure that you and anyone reading this realises that this is a possibility.

Good luck with it mate, and let us know what fixes it.

[Terminal]

i think it might be a fuel pump problem now, as it only loses power sometimes, its very random.

the fuel pump is behind the back seat right? ill pull it out and have a looksey.

[MegaGTS4]

Fuel pressure test might be better? as it would tell if the pump is stuffed, and might be easyier than removing pump.

MEGA

[Terminal]

How do i do a fuel pressure test? i'm a bit of a newbie at skylines.

also, might a power transistor fault have the same effect? a mate of mine seemed to think my dizzy was on the way out, but not knowing i don't have one.

the problem seems to have stopped getting worse. i just have a lack of power sometimes, my idle is rough and when its cold it won't rev past about 3000rpm and sounds like its running lean or not getting fuel or spark.

[VIPERGTSR01]

my sisters toyota camry used to run like sh!t randomly, after so checking over i diagnosed the fuel pump after that the car run perfect.

[Terminal]

I have another theory.

is it a common, or likely occurance that the timing gears/cam gears can come loose, or the timing get wacked out some way, maybe a tooth on the timing belt has come off or the belt has jumped a tooth? i had my head in the engine bay and there were odd noises coming from under the cam cover, and also a spinning/wooshing noise coming from the inlet manifold.

anywho, any replies are appreciated.

[red17]

Ok people have suggested that you check out your AFM but you havent replied about it anywhere. Id cover that base first before jumping to greater, more expensive conclusions.

[WLD747]

hate 2 tell ya that washing your engine bay is very bad and a costly mistake. i learnt the hard way.

First all the coils are warpped and will not fire properly.

all your plugs are damaged due to the water.

you need need all new coils and plugs to fix the problem and they are not cheap!