intermitant holding back

[cojack]

Hi guy's i have this strange holding back issue thats been bugging me for a couple of week's now. I really need to sort this problem as i am planning on turning up the boost but don't want anymore damage to happen just rebuilt the bloody thing :lol:

Sometime's when you hit full throttle there is a surge of powerloss which comes and goes it sort of feels like heatsoak like when i had the tmic. Also the exhurst note deepens slighlty. Hope this makes sense as it's a bit difficult to explain. :doh:

I have rebuilt the engine replaced dizzycap and rota arm plug's 1 grade colder and plug leads set the timing. plug's and leads made it better but i still feel it's not right. Boost is ok every time your at full throttle the boost gauge is just about touching 7.

Whilst i was out last night this problem accured again and when this is happening i tend to lay off the gas incase off it will cause damage to the engine. noticed my fuel was getting low well it was getting close to a quarter and was a few miles out of town.

About ten miles down the road pop's a shell garage so i swing in there and stick £20 in. Pulled out the petrol station and the problem has gone pulling nicely all the way up the rev range. And for the rest of the journey. Got back in the car today to go do some work on my mates car and it's back still plenty of fuel in around half a tank.

So i was thinking about it some more today no fault's in the ecu memory btw we can see this fault is either ignition of fuel related. Had a few item's changed on the ignition side now i'm looking at the fuel side a bit.

I have a walbro pump thats done about 2-3k in the car. But because the fault went after i had put more fuel in maybe the fuel pump filter has come off and is restricting the fuel pump from doing it's job as more fuel the pump filter will float higher away from the pump and not be able to get sucked up by the pump.

Or i could be taking shit and it could be some thing to do with the ignition side.

Any help would be great guy's starting to do my sweed in a bit now want to get the thing quicker.;-)

 

[houghy_1]

No your not talking $hit mate cos ive got exactly the same symptoms and we've the rolloing road day next week:? :evil:

Its when your pulling on boost and will make a sudden loss of power then i dip the clutch and change gear and chill hoping ive not done any damage!!!

I went to see another R owner and did some launching and spirited driving and it was fine,pulled hard in every gear.

But its now doing it again,
its when you put more than 75% throttle on(watching it on the Apexi S-AFC)

I also have a Walbro fitted and also a w4nk bleed valve :doh:
The Apexi has also been set to provide more fuel to keep the fuel mixture rich enough across the revs.

Help anyone???

Matt

 

[CHRIS_2010]

i had a similar fault..turned out the oil seperater bottle was of its brackets witched kinked the hoses coming off.making the oil pressure gauge go of the gauge then it would cut the ignition back

 

[Fusion Ed]

Needs some diagnostics. Need to check the AFR under the conditions this happens. Basically datalog the events.

 

[mattygti-r]

i had the same on my GTI-R when i owned it, turned out to be fuel filter needed replacing

 

[cojack]

houghy_1 my fault doesn't just creep up on your when you floor it. It is always there untill it decide's to go. Also noticed last night there is a flat spot when on light throttle going to full throttle only when it is faulting otherwise it is fine.:doh:

Needs some diagnostics. Need to check the AFR under the conditions this happens. Basically datalog the events.

Any east way to check this as i am using standard ecu and standard boost thinking of taking it up to hiteg to see what they make of it.


Matty don't think it will be the fuel filter as it was replaced just before i rebuilt the motor but i am changing it on sat anyway when i change the oil.

 

[campbellju]

Are you saying its just losing power rather than misfiring then?

Have you checked what your plugs look like. This can give an indication of operation at least though its far from perfect. What plug gaps are you running? Over gapped plugs can cause some funny symptoms.

Jim

 

[Cambridge_pulsar]

Check there's no movement of the rotor arm on the shaft of the distributor as this was the case on mine which was just a loose screw, although I think the dizzy was knackered too...

 

[cojack]

Are you saying its just losing power rather than misfiring then?

Have you checked what your plugs look like. This can give an indication of operation at least though its far from perfect. What plug gaps are you running? Over gapped plugs can cause some funny symptoms.

Jim

Yes jim it's just losing power not as much power loss as if 1 of the cylinder's had gone down compleatly but the power does fell very week.

I regapped the plug's to 0.65 about a month ago when i replaced the lead's dizzy cap on rota arm. The gap was a little wide but the colouring of the plug's looked normal.:roll:

 

[campbellju]

Igntion sounds fine then. That leaves fuelling and leaks. I've got a meter you can borrow to check fuel pressure if you want? My guess would be leaks though under boost. Too much fuel is not normally a fault with the fuel system and too little fuel would cause det.

Of course it could be some random electrical gremlin

 

[cojack]

Igntion sounds fine then. That leaves fuelling and leaks. I've got a meter you can borrow to check fuel pressure if you want? My guess would be leaks though under boost. Too much fuel is not normally a fault with the fuel system and too little fuel would cause det.

Of course it could be some random electrical gremlin

I'm pretty sure there's no leaks as all the vac hose's and air pipe has been replaced with samco vac hose's. The boost alway's goes just under 7 all the time.;-)

What is this meter you have mate any info to it.? Is this not just a fuel pressure gauge?

Really hope there is no gremlin in there as i was out after 12 last night and it was raining :lol:

 

[campbellju]

Yep just a fuel pressure guage really with a few hoses

 

[houghy_1]

houghy_1 my fault doesn't just creep up on your when you floor it. It is always there untill it decide's to go. Also noticed last night there is a flat spot when on light throttle going to full throttle only when it is faulting otherwise it is fine.

OK,hope it gets sorted fella.

Matt

 

[cojack]

Me to got a few thing's look at this weekend so i will hopefully find out what it is:doh:

 

[Bart GTI-R]

Hi there , Iv had this trouble with my R for a while, exactly what you describe in your first paragraph

So Far Iv ruled out
Fuel Filter (new)
Dizzy (new)
Leads (new)
Plugs (Standard, new and gapped properly)
Vacuum Leaks (although not checked behind the Plenum)
Power Transistor (although when cleaned up ran really sweat for a while)
Coil (second hand)

It feels like its trying to boost more thinking that it is the wastegate sticking, therefore causing it to retard the timing and chuck more fuel in, & when you go to the petrol station you turn the car off then back on after a while so It will be ok till it measures it overboosting again.

Well thats my sort of guess maybe totally wrong, would be interested to know what Hi-teq say mate

 

[another sunny]

I had a similar fault only when it wasnt performing well i lasted , same exhaust note change etc, mine turned out to be a knock sensor(bad connection or something) anyway all fixed now

 

[cojack]

Hi there , Iv had this trouble with my R for a while, exactly what you describe in your first paragraph

So Far Iv ruled out
Fuel Filter (new)
Dizzy (new)
Leads (new)
Plugs (Standard, new and gapped properly)
Vacuum Leaks (although not checked behind the Plenum)
Power Transistor (although when cleaned up ran really sweat for a while)
Coil (second hand)

It feels like its trying to boost more thinking that it is the wastegate sticking, therefore causing it to retard the timing and chuck more fuel in, & when you go to the petrol station you turn the car off then back on after a while so It will be ok till it measures it overboosting again.

well thats my sort of guess maybe totally wrong, would be interested to know what Hi-teq say mate

So i take you still have this problem??:roll:
I don't think it is over boosting as the boost gauge goes up to about 7 if it was over boosting the gauge would go past 7 if you know what i mean.

When you say you have rule out the power transistor thingy did you replace it or just clean it up. As you say there it ran ok maybe thats where your problem is
;-)

I also think if the det sensor was playing up it would bring up a fault code which is 55 when runing ok or 55 if running badly.:doh:


Keep them coming guy's ;-)

 

[Bart GTI-R]

Yeah its intermittant though and because the Power Transistor is under the t.m cant really do much when it plays up. It seems like the boost gauge spikes when its playin up Iv got an Apexi as well as standard and its more accurate.

The Clutch is slippin now so havnt really been boostin much lately, I dont have any fault codes in the memory either. I met a chap up Sutton Park in the summer and he had the same problem too.

 

[Braveheart]

In responce to antgtir issue regarding "Hesitation between 3k to 4.5k rpm + Fueling issues??" I had a similar problem.
I picked up a GTIR last month and felt it was running a bit funky. It seemed to pick up ok at low revs but stuttered and hesitated badly between 4.5 - 5k rpm. When I layed off the gas the damned thing wanted to go. Not good when you are entering a corner looking for engine breaking. It was also idling high (1100rpm) and just felt a bit unwell.
The car it's self is bulk standard except for a mongoose exhaust (without cat) and sump guard but with a poor service history (jap 18k service). I bought it off a farmer who had owned it for 4 years and done 2k miles in that time. It has 60k on the clock, it was imported in 2002.
Anyway, given the service history and poor performance, I booked it in for the full boona.
Falkland performace changed all the fluids, plugs, point, air filter (now K&N) front disks and pads and rear pads. (disks and pads were well shot.... it was grinding along)
I was full of hope but the car was still running poorly.
It turned out to be the knock sensor (error code 34) This sensor they explained was there to pick up pinking etc and when triggered would retard the ignition timming by 6deg. It's meant to reset it's self but did not and I thing I will source a new sensor.
They reset the ECU and the error was gone. The car is now running fine. Much smoother, pulls all the way through the rev band and thankfully enters engine breaking now when I gas off. I did refrain from taking it out on the track at knock hill last sunday however as I have a sneaky suspition the problem would return plus I did not want to buy another set of brake pads so soon.

Hope this information helps and I may post it in a couple of other places on this web site.

Lang may your lumb reek... all the best Braveheat (Scott)

 

[Bart GTI-R]

Hi Cojak, did you ever sort the problem mate