1.6T 8v problems

[mikec123]

Hi im Mike im running a 1.6T 8v on DTA i am having a few problems with my car when i get to about 3800rpm in every gear it jerks and backfires, i can drive through this and its fine after 4000rpm, when i ease of it gets to 4000rpm and my revs drop to 3800rpm i have changed my plugs and fitted a cav turbo fuel pump but its still happening. Any help would be apprieciated! cheers:p

[Welsh Dan]

Overfuelling?

[Stuart]

has it only just stated happening or has it always done it?

[brucer]

when my gte did this i changed a few things on the ignition side of things.still didnt cure it.found out it was the fuel pump relay that was duff.and when the car was moving around would cause the part inside the relay to judder an stop the fuel pump.

try wiggling it when the engines running.its located on the bulkhead and see if the engine dies down.

the new relay was 24pound from vauxhall.

hope this helps

[craig green]

Sounds like its underfuelling to me.

Change / check the relay & get a gauge on it to check the fuel pressure.

Have you had the injectors cleaned recently? (has it been left unused at all)?

[mikec123]

It hasn't always happened it ran fine!It does sit around because i dont use it alot! I took it to Stealth Motorsport and they said it was fueling ok! I will check the fuel pump relay though cheers!:D

[Stuart]

highly unlikely to be a fault with the relay... it either works or dosent work.
had it been stood a while and have you NOT put fresh fuel in?

[Philsutton]

highly unlikely to be a fault with the relay... it either works or dosent work.
had it been stood a while and have you NOT put fresh fuel in?

depends on the xe's / lets the fuel relay supplies power to the ecu as well an if the voltage is down on this it can throw up so many random fault codes (that dont exist) and is very hard to trace.

[scott.parker]

Guys it's not had stale fuel in it, and im not 100% sure what it could be either, it's quite a strange one, the plugs have been done, a let pump has been added etc, so im stating to think the way the revs dip and then it kicks/pops/backfires that there is some sort of lack off fuel then a surge, could this be caused by some sort of sensor/switch??

Scott

[brucer]

[quote=Stuart]highly unlikely to be a fault with the relay... it either works or dosent work.


thats a lie.because mine would work fine most the time.going over bumps would jingle the insides of it and stop it workin.so saying it would either not work or work is wrong. :D

[therealnovaboy]

if you have a fuel filter then see if it is dirty ?

mabee an injector is blocked?

[therealnovaboy]

a relay could just work then not work, its realy either on or off. its unlikely to go wrong espesualy at the revs stated, then to do it at the same rpm again.

[Mike]

It could be, for some reason, losing fuel pressure at XXX RPM, then the pressure is coming back in and causing its surges .

If you can get your hands on a feul pressure gauge, an inline type, plumb it in and watch the pressure rise/fall. Could be worth a shot?

[brucer]

my relay switched th pump on/off mainly through accelaration. 3-4500prm.so can kinda say its at a constant revs.just my experience with it.could be many things.

[Rickyb]

my mate had the same sort of prob on 1.7T r5and it was down to it need to draw more air in from behind the AFM worth a try

[Philsutton]

If its on DTA it shouldnt be running a AFM anyway, stupid question but check the gaps on the spark plugs a fwe of the last few turbo cars I worked on that had simliarish problems where down to having gaps the size of the british channel.

[scott.parker]

If its on DTA it shouldnt be running a AFM anyway, stupid question but check the gaps on the spark plugs a fwe of the last few turbo cars I worked on that had simliarish problems where down to having gaps the size of the british channel.

We did that mate after i asked the first time on mikes behalf.

Scott