random missfire and sputtering

[HePiL]

hey all,

Ive got a 89 vr4 with a rs engine in it, now i keep getting a random missfire and sputtering at times, mostly when its hot. it will happen at high revs, low revs in and off boost and any gear.

i have changed plugs, leads, put a set of evo coils in it, checked all earths, checked battery and its still doing it.

my thoughts are now directing more towartds fuel problem, maybe it has a dogey fuel pump and its not producing enough fuel and vaporising or dirty filter, but im leaning more towards pump coz if it was a dirty filter it would have worked it's self out by now or at least do it more often.

like i said it happens at random times, i will be on the highway doing 100 sitting on bout 2800 revs in fifth and it will all of a sudden start to sputter, after abou 10 seconds it will be right, then do it again 30 mins later. Or taking off from the lights it will sputter and miss. Im at wits end and its starting to really **** me to tears.

any help would be greatly appreciated.

cheers
nev.

 

[rob323]

It could be alot of things, first thing to try is to unplug and then reconnect all the plugs in the engine bay wiring harness to check for loose or bad connections.
Check battery terminal connections, check earth strap connections.

What ecu are you using and have the caps been redplaced?

 

[JAP63]

yep.
My thoughts the same..look towards the loom/ecu...something as simple as a loose battery terminal can cause that though..but itd be a disconnecting type thing..does it just misfire or turn the ignition off for a split second..your not getting the red lights come up on the dash when it happens are you?

 

[HePiL]

What ecu are you using and have the caps been redplaced?

im pretty sure its running the rs comp witch has been chipped and socketed.

your not getting the red lights come up on the dash when it happens are you?

no warning lights come up, its like it will die and run on 3 cyl for 10 sec then run fine, then do it again like 30 mins later.


all earths have been taken off, sanded and put back on.

 

[Entaran]

i'm heading for ECU issue or somethign that's telling the ECU where the timing is.

 

[rob323]

Loose spark plug, loose spark plug lead?

 

[HePiL]

negatory, dane would kick me in the head if it was a loose lead i sure.

could i have a leak in one of my vac hoses that could cause it to start to sputter once it heats up? is that possible?

 

[VR-4Squid]

check the fault codes, instructions can be found at www.vfaq.com

 

[3zercrowd]

AFR's are being checked tonight.

 

[HePiL]

right then,

checked the afr's everything is alright, changed ignitor, changed fuel filter as some suggested, problem still there, may be looking into fuel pump as might have dodgey ebay walbro jobbie.

 

[CLuTZ]

A mate had a similar sounding missfire, only when his car was warmed up, and it turned out to be his ECU that was faulty.

 

[Jonson]

Ive also had an ECU problem before that was causing very random missing and surging once heated up.

Got a spare ECU laying around you can try?