'R' Mis-firing I Think!

[Matt Evans]

I know this topic has been covered countless times, but after trawling through loads of threads, I can't seem to find one with the exact same problem as mine.

Basically, when I start the car and rev it, its fine. When I pull off its fine, until I try and giv it a bit of welly, then instead of revving like it should it just kinda goes 'BRRRRRRRRRRRRRR' like a burbling sort of sound. When I hold off the throttle it seems to go until I try to floor it again.

It also seems to get worse when the car warms up. It starts to burble and hold back with even less throttle. It boosts fine, but I don't think its over boosting because half the time the boost gauge isn't even reading half way. Plus after the car has warmed up it burbles a bit when I rev it in nuetral too.

Any ideas folks?

Oh yeah! I've run it through my laptop with Nissan Datascan software and checked the Datalog graphs, but tbh I don't really know what to look for.

Also, the car is fitted with NGK Iridium plugs, Magnecor leads, a Warlbro pump, plus the dizzy cap and rotor arm. All these parts are about a year to 18 months old, as I changed them all to cure a similar problem before.

 

[Matt Evans]

O.k. I just checked the plugs and No.1 plug chamber had water in it. I cleaned the plug, lead, chamber etc. and just tried the car again, but its the same. If I accelerate softy, about 30% throttle, it'll boost and rev perfectly through the rev range, but as soon as I give it about 35 to 40% throttle or above, it still boosts o.k. but just isn't revving properly.

Does anyone have any idea what it might be?

 

[ki_saj_ng]

possibly fueling issues?

do you have much fuel in the tank? how long ago was walbro fitted? who did it?

 

[Matt Evans]

Right, I fitted the pump myself, about a year or so ago. Plenty of fuel in tank. Running super unleaded plus octane booster. But its been running fine ever since. Only lately its played up. :?

 

[nismoboy]

sounds like an air leak! check all your intercooler pipes/vaccum pipes etc.
also check your inlet pipe for unmetered air.

 

[Fast Guy]

When I pull off its fine, until I try and giv it a bit of welly, then instead of revving like it should it just kinda goes 'BRRRRRRRRRRRRRR' like a burbling sort of sound.

If you're doing it within a couple of minutes of start up, it's probably telling you it's cold :lol:

If it's similar to a Subaru sound, then you're probably dropping 1 cylinder. Chances are it's number 1. I have seen people have the water problem and needed to change the leads as the water seemed to knacker them.
It might be worth looking at the dizzy cap and rotor arm as well as these can also cause problems.

 

[ki_saj_ng]

When I pull off its fine, until I try and giv it a bit of welly, then instead of revving like it should it just kinda goes 'BRRRRRRRRRRRRRR' like a burbling sort of sound.

If you're doing it within a couple of minutes of start up, it's probably telling you it's cold :lol:

If it's similar to a Subaru sound, then you're probably dropping 1 cylinder. Chances are it's number 1. I have seen people have the water problem and needed to change the leads as the water seemed to knacker them.
It might be worth looking at the dizzy cap and rotor arm as well as these can also cause problems.

the subaru sound will be at idle tho aswell, im talking from experience and i think this is also possible from a fooked H/G...

is your oil clear? no water mixed in?

as for air leaks, you will see black smoke (burnt fuel) out the exhaust but you havent said this so i think thats out the picture?

 

[Matt Evans]

Nah, I try not to boot it from cold, for obvious reasons. If anything, its worse when it warms up though. I'll try putting an old lead on No.1 tomorrow and see if that helps. I hope it does. Yeah, it idles fine. It happens when the car is in gear and moving, but when its at its worst, it'l do it when revved out of gear and stationary, But idle seems always to be fine. :?

 

[ki_saj_ng]

how bout a new fuel filter?

 

[Matt Evans]

I replaced it when I did the leads/plugs etc. The thing is, the problem is there all the time, but it sometimes gets worse, then gets slightly better again. I suppose, if the filter was blocked then the problem would be the same all the time. I think, but could be wrong.

 

[ki_saj_ng]

I replaced it when I did the leads/plugs etc. The thing is, the problem is there all the time, but it sometimes gets worse, then gets slightly better again. I suppose, if the filter was blocked then the problem would be the same all the time. I think, but could be wrong.

true, but what i meant is when the need for fuel is really low, your ok but when you floor it, you need more fuel and maybe fuel filter is not allowing enough to pass?

i dunno, just a thought...

 

[GTIR-LOZ]

if possible pull of a plug lead while its misfiring (make sure you use a proper insulated ht lead puller otherwise you will badly shock yourself :evil: ) if it stays the same you know its that cylinder playing up, if it gets worse that cylinder is ok

its prob water in number 1 thats caused it, may need properly drying out

 

[SickBoy]

I had ethis problem to #

Checked all the plugs looked ok but turned out 1 was knackered put new set in and problem solved

Lee

 

[Matt Evans]

All sorted now :!:

It was No.1 lead. Even though I'd cleaned the water out of the plug chamber and cleaned the plug, the water had obviously killed the lead. Changed the lead today and it goes like hell now! :twisted:

So anyone who gets this prob in future, with water in plug chamber, should definitely check the leads too. Could save a lot of head scratching.

Thanks for the help everyone. 8)

 

[geetee]

would have got the same result putting no.1 plug and lead in a very low oven for a couple of hours - just wet

 

[Mark_GTiR]

I had this problem too a while back, water had got in plug chambers 1 & 2 - ran like a dog.

Properly dried them all out and siliconed the leads on - sound as a pound.

Glad to hear you got it sorted!

 

[soin]

me too i also had the same prob , recently cured by new leads .. one of my leads was shorting out on the metal plate that screws onto the rocker cover under the intercooler ... there was a black spot of sooty looking dust right where the lead had been contacting .... thinking about putting a carbon or perspex cover there insead