[looby]

Hi all, i put a post on last week explaining about my gtst which has started stalling randomly and hessitating. I have been told it could be the coil pack, lambma sensor, or overboosting. I have tried cleaning the injectors, the air filter (K&N) and the aac valve. Does anyone know which i should try next, the lambma sensor, coil pack or is the overboosting?. The problem by the way has started as soon as i put on a straight through exhaust ON (decatted). I don't have the old exhaust so i can't put the cat back on.
PLEASE HELP..........

 

[HKP]

it's just a processe of elimination, try a new lambda sensor, you could also try the AFM (air flow meter)

it would be over fueling not boosting

 

[DAZMAN]

Hi mate,when your engine is playing up,unplug 1 of your coilpacks and see if engine gets worse,if engine gets worse when 1 is unplugged ,then that 1 is ok.Do this until you have been through all 6 coilpacks.If engine doesnt get worse when 1 is unplugged then you know that 1 is the bad coilpack and you can solve the problem.Will only take you half hr to check.This will eliminate coilpacks or solve your problem.

 

[looby]

Thanks for the advice lads, as far as checking the coil packs i was going to do something similar but i can't get one of the screws out of the cover due to some big metal thing in the way, so it would take some time to do this test and on top of that the car can run perfect one day and be awefull the next.
As far as the lambna sensor i can get a universal sensor gor £38 if it is the wright one would this be O.K to use?

 

[DAZMAN]

I think so, my mate just replaced his with a universal about same cost and it cured his problem.Just thought it would be easier to check coilpacks 1st.Re-place lamba sensor 1st then(located near turbo elbow) then go from there.

 

[looby]

Excellent thanks for that have you any idea why the sensor would go wrong just because of the exhaust?

 

[HKP]

as long as it has three wires the two wires the same colour are to heat the sensor and the single odd colour sends the signal to the ECU (one black and two white oem) i think it is ok to use a universal sensor

 

[HKP]

Excellent thanks for that have you any idea why the sensor would go wrong just because of the exhaust?

they may have knocked it and damaged it whilst fitting your new exhaust

 

[looby]

Thanks very much i will try this as soon as i get time. I'm of now to watch the rest of rocky 4.

 

[DAZMAN]

From what i gather,it can be quite common.Taking the cat of seems to emphasise the problem.Would not jump to any assumptions though,seen though you have bought it now,fit it and go from there.If its not that then check your coilpacks next.By the way have you put new plugs in?

 

[looby]

I have only had the car a couple of months, and i have reciept from a full service last year and they put iridium plugs in whatever they are

 

[DAZMAN]

I would still change them next as this is your cheapest option.Garages(a few unscupulous 1s)may say they re-placed them, when they havnt. Make sure they are the correct 1s.

 

[looby]

Will do cheers, i still can't get my head around the fact that the problem has only occured since the day the exhaust was done. If i check the coils by unplugging them 1 at a time won't i get misfires?

 

[DAZMAN]

Not misfires,you will hear the engine drop if ya know what i mean,but you will only have to leave it on tick over in the drive or rev it a bit to find out.

 

[looby]

Sorry to be a pest just 1 more question. The stalls and hesitation are very intermitent. If it was the coils or lambna would it not occur all the time? And also i read somewhere that the skyline has variable valve timing now i have just sold an R6 and that had the same and you had to turn the ignition on and let the valves set otherwise it would not start or run like a bag of sh$t i sometimes i do this when i start the car but i know the wife does'nt and she gets a lot more stalls than i do. Is this anything to do with it?

 

[DAZMAN]

Neh mate i never do.Coilpacks,plugs,lambda sensor and afms can all cause intermitent problems.My money is on coilpacks though.

 

[looby]

Cheers mate i will test them first, is it normal to take something off the top before removing the cover there is 1 screw i could not get to

 

[DAZMAN]

Cant remember my gtst to well im afraid,Gtr slightly different.Not sure if a pipe goes over,but yeh seems normal to remove something,from what i remember.Not a strut brace is it?

 

[looby]

No a strut brace its small and round i think 3/4 of the way up on the right side. Thanks for your help i have to go now i live in a pub got to go and lock it up.

 

[HKP]

there is a screw under here but you should be able to get to it with an alan key without removeing the inlet pipe above