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Discussion Starter · #1 ·
Morning all,

Had a bit of a mishap yesterday evening - was out giving the Stagea a quick run, at about 4500rpm in 3rd on full boost (0.85bar) there was a pop/crack from the exhaust and I lost all power. Engine now reluctantly revs to around 2000rpm and then drops off, very lumpy idle. Strong fuel smell in exhaust.
I'm hoping this might be coilpack or CAS related rather than anything internal (pistons or the like) - symptomatically what would be the most likely fault based on the above? I'll test the CAS and check the coilpacks/plugs when I get a free minute, but would be nice (or maybe not!) to know what I'm potentially up against.....

Cheers
 

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Have you checked that all intercooler hoses are connected/intact? Might just have popped one.
 

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Happened to me about 2wks ago in the 200...at 3am on an unlit backroad. Tried to limp home but decided it wasn't worth it (at the tme thought it might have been something more terminal). Got towed and problem fixed in 10mins the next day. Broken jubilee clip.
 

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Discussion Starter · #5 ·
Right, went home last night and checked the hoses - all look to be in good shape, and all sealed nice and tight with the jubilee clips. Started the car up - came to life straight away and settled at idle for about 5 secs, then immediately started bogging down and cut out. Lots of fuel smoke/soot out the back. Any attempt to restart the car after this was futile, it would maybe fire up for a second at most and then die again.
I've taken off all the inlet bits and checked the plugs - all six are black and wet with fuel (these were changed a couple of weeks ago and up until this incident the car was running great). So it appears that the engine is massively over-fuelling, and it doesn't appear to be isolated to any one cylinder. Presumably I can rule out the coil packs (would all six go at the same time?).
I guess the next step is to do a compression test on each cylinder maybe? Seeing as I can't get the engine up to temp, what's the best way to do this on a cold engine?
 

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Discussion Starter · #8 ·
I'll give that a go once I've put it all back together - would unplugging the AFM not still give issues though? Or is the premise for this that getting no signal from the AFM is better than maybe getting a duff signal instead?

Cheers!
 

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The idea with the MAF is that by removing it the ecu will use a stock/set value with no variable. Thus the ecu will fuel to a set value rather than use any results it seems from the MAF sensor.

If the above doesn't help...
Sounds like it was quite sudden, so whilst you've checked the IC hoses, I'd suggest getting a can of carb cleaner, run the car up and start spraying around the whole area of the intercooler and all hoses etc. This should highlight any holes/splits in hoses and even the intercooler (though IMO sounds like a hose)
 

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Yes, unplug the AFM and see how/if she runs in limp mode.
I'd also pull off the fuel reg signal hose and check it's not pouring fuel into the plenum.
 

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Discussion Starter · #11 ·
Cheers chaps, that gives me plenty of avenues to explore this weekend :bowdown1:

Interesting point about the fuel pressure regulator - I presume having an uprated fuel pump (believe mine's a Walbro 340) would put additional strain on the diaphragm so could cause failure; any idea what pressure the standard regulator can handle?
Apologies if the above is way off the mark, I'm no expert by any means :chuckle:
 

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Discussion Starter · #12 ·
Aaaaand...... it's the AFM! Starts and idles fine with the AFM unplugged (although starts missing if I give it a little throttle once it reaches 2.5k revs). Soon as it's plugged back in and restarted it just bogs down and cuts out.

Soooo.... what's involved in replacing with a Z32, and where best to pick one up? :chuckle:

Massive thanks to all, I was tearing my hair out before!
 

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Unless you are remapping (as far as I'm aware) the Z32 will hinder your setup as it will affect the readings back to the ecu, thus the fueling again.
You are better of using some carb cleaner and seeing if it's just dirty.
 

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Discussion Starter · #14 ·
Yeah realised this not long after asking - z32 plus fitting bits plus another remap and suddenly the cost starts adding up!
Mind you would I need to get the map checked anyway with an original replacement, or should they all operate within a pretty slim range anyway?
 

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Discussion Starter · #15 ·
Right hoping to get this sorted in the next couple of days. If I plug the laptop into the car and check on Datascan, what AFM reading should I be getting at idle or thereabouts? Just want to double check it's definitely the AFM at fault before I go ordering a new one.

Cheers
 

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Discussion Starter · #16 ·
OK MAF voltage is 0.17v with ignition on but no engine running, goes up to 2.6v at idle (until it stalls). Bit of reasearch suggests this should be nearer 1.1 to 1.2v, so looks like AFM/MAF is definitely the culprit!
 

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Discussion Starter · #17 ·
OK, bit of a setback - just fitted the new MAF and still getting the same issues keeping the engine running? Will have to plug the laptop in again tomorrow and have a look, but assuming the MAF is fine what else would be causing the high voltage reading?
 

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Discussion Starter · #18 ·
AARGH! Same readings both from Datascan and on the multimeter: voltage from MAF is 0.2v at IGN on but engine off, but shoots up to 2.2v at idle.

Running the car at idle without the MAF connected gives an injector time reading of around 2, as soon as the MAF is connected it goes up to 10-11.

I also checked the fuel pressure regulator - no fuel coming out of the vacuum pipe so looks to be ok.

The replacement MAF was from JDM Garage and should be tested as working according to their site - have I just been unlucky and gotten a duff replacement as well? Is there anything else that could cause the MAF to give out a high voltage, or that would cause the engine to start overfuelling as soon as it's plugged in?

Sorry for rambling on, I'm starting to run out of ideas now! All advice gratefully received!
 

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AARGH! Same readings both from Datascan and on the multimeter: voltage from MAF is 0.2v at IGN on but engine off, but shoots up to 2.2v at idle.

Running the car at idle without the MAF connected gives an injector time reading of around 2, as soon as the MAF is connected it goes up to 10-11.

I also checked the fuel pressure regulator - no fuel coming out of the vacuum pipe so looks to be ok.

The replacement MAF was from JDM Garage and should be tested as working according to their site - have I just been unlucky and gotten a duff replacement as well? Is there anything else that could cause the MAF to give out a high voltage, or that would cause the engine to start overfuelling as soon as it's plugged in?

Sorry for rambling on, I'm starting to run out of ideas now! All advice gratefully received!
what was the ending result to this problem? what was the problem? how did it get resolved?
 

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Discussion Starter · #20 ·
Ended up being some sort of fault/short in the loom somewhere, I took the opportunity to upgrade to a Haltech ECU with MAP sensor and wideband controller :)
 
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