Idle/misfire, Caused By Head Gasket?

[RipNGrip]

Hey guys,

I have been trying to troubleshot my engine problem for a long time now and its finally getting down to a diagnosis and i would love if all u guys/girls could enter your input and effective form of action. PLEASE i am getting annoyed and having WITHDRAWS from lack of turbocharged power. My daily driver. (1.5 n/a just isn't the same)

Details:

93 r32 gts4-t (RB20DET)

2 x bov (stock and aftermarket) - aftermarket disabled

walbro 500+ fuel pump

turbosmart boost Tee

front mount Intercooler

stock internals

stock turbo

auto to man conversion - GT-r gearbox, exedy clutch etc...............

splitfire coilpacks

The problem:

Starts with heistating lead to complication after complications and replacing lots of stuff.

Currently, car cold starts fine revs fine............... then as it gets warmer (not hot but warmer) starts to stutter ( like a half miss) then it starts to miss (sounding like a rexy) missing through the stumbles through the rev range. it gets worse as it warms! I am over fueling, i think

Performed actions in an attempt to solve:

1. swapped coils > SP coilpacks

2. swapped afm with one from a wrecker

3. arm resoldered old one

4. changed fuel filter, installed new fuel pump (walbro)

5. swapped ignitor pack with working rb20det

6. new coilpack loom

7. cleaned aac valve

8. checked and solved vacuum leaks

9. all 6 injectors are clicking - used screw driver to listen for mechanical operation

10. cleaned O2 sensor with carby cleaner

11. changed and regapped spark plugs

12. ECU diag returns two codes> 54 auto trans disconnected (FINE) code 12 AFM voltage over 0.5 volts at idle or greater than 2 volts with idle engine or stalled engine

HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Could it be a fried ecu when installing an amp?

Small leak in the head gasket which gets larger as the car warms and causing the misfiring and broad minded persontering

fuel regulator?

[RipNGrip]

how do i confirm head gasket?

and if it is a head gasket should i buy a NEWER RB20DET from a gts-t (mine has had a 220,XXX kms life) and swap the sump with my gts4-t would this work? (i am guessing the only difference to be the front diff and 4wd sump?? anything else)

or should i RECON head, and new head gasket etc which would be a stronger and more money wise

[rob82]

Sounds more like a clogged injector.

[RipNGrip]

Clogged injector?

should i use an injector cleaner? which one?

or

Do u send it to a shop?

[RipNGrip]

There is a little white smoke at the start when cold.... then it passes! oil doesn't look throthy, but might seem a little less viscose, and the radiator seems to have a little trace or chemicals/oil on the top but it isn't milky.

[Risking]

Blocked injectors are not going to cause this issue.

You havent tried a cam angle sensor but I doubt that will be your problem either.

Instead of trying to diagnosis a problem and having it drag out forever invest the 80-100 bucks a workshop will charge and let them find the problem.

At least this way the problem is diagnosised your not wasting time or money guessing and you have a repair estimate etc from the shop that you choose.

[RipNGrip]

Yeh that is a good idea... it is hard to pick a workshop that won't bone me for all i am worth and that can fine the problem easily and quickly.

any recommendations?? in brisbane CDB/brisbane

GT auto - it already been there

mercury motor sport

STZ automotve

opition1garage

[Risking]

Sorry im in sydney so cant really comment on them.

Anywhere with a TK tester and some knowledge should be able to diagnosis it for you though

[RipNGrip]

i am sending it to mercury motorsport in newmarket.... hopefully they can figure it out for me! without charging me an arm / leg

[blind_elk]

Yeh that is a good idea... it is hard to pick a workshop that won't bone me for all i am worth and that can fine the problem easily and quickly.

any recommendations?? in brisbane CDB/brisbane

GT auto - it already been there

mercury motor sport

STZ automotve

opition1garage

How about your local Nissan dealer, who can hook up the Consult module.

Have you tried a new temp sensor?

[RipNGrip]

Ummm..... actually ihaven't tried that! apparently nercury specialize in rb20s soo hopefully! i will look into it

[GTR32GUS]

How about your local Nissan dealer, who can hook up the Consult module.

Have you tried a new temp sensor?

Yeah try that sensor

U can just turn the that screw on the standard ECU and it will flash codes at u 5 long and 5 short flashs means everything is OK

[RipNGrip]

I have done the self-diag and the ECU returns......

54 = auto trans d/c > auto to man conversion

12 = AFM

but i have changed the afm and it still returns a code 12 only reason i think it is a heady..... just little specks of black stuff from the exhaust it feels wet but its not wet to touch!

Edited May 4, 2007 by RipNGrip

[l0r0de0]

This sounds pretty much identical to the problems i'm having with my rb20det in my rodeo minitruck.

Im getting error code #54 as well.

It's got the skyline manual box as well, so i'm assuming that I must have an ecu out of an automatic car.

Be good to see if you fix it so I can fix mine too.

[nisskid]

try playing around with ur igniter module, play with the plugs etc and see if it makes a difference when its missing. better yet if uve got a mate with a RB chuck theres in and see if it makes a difference.

[RipNGrip]

Nisskid: i have swapped the ignitor pack before with no improvement and i should try and pull out some of the coils when idling to see if it makes a different but i been lazy and it revs fine when its completely cold! first turn over so its weird!

loloror: or whatever ur name is . I will post a solution! if they find it.

QUESTION: would a stuffed temp sensor cause these symptoms and won't it come up as a ecu selfdiag code?

[nisskid]

my bad, i only saw that ud changed the coilpacks, not the igniter.

[RipNGrip]

YEh its a good suggestion for plp who encounter it next time!

[RipNGrip]

Well update: I sent the car to mercury motorsport in wilston on newmarket rd. Fixed the problem within two hours, so while it was there i brought a sliding performance high flow turbo, dump pile, fuel pressure reg, and asked them to tune and remap ecu. HEHEHE couldn't help it i have been missing my boost! Apparently, cracked spark plugs which is disappointing idiriums didn't even go 100 kms. Hopefully, i can pick up my car on wed/thur and go for a strap!! wonder how she will go.................................. thinking about injectors now!

p.s compression test was done 165 tpo 175 across the board! and she was running lean! lol

Edited May 21, 2007 by RipNGrip