Still Got Running Problems Under Load

[Obey_R 23]

Well after having the 205 off the road for almost 2 months, it was time to fire her up for the first time today. I've had the same problem for a while now, it will idle perfectly, no signs of any problems at all. But at low revs under load it will be very hesitant and jerky, like it's kangerooing but much more sudden. I had my next door neighbour take it out, who is part time mechanic, he says it seems like an ignition faul rather than fueling because of how on/off the jerking is, rather than lack of fuel pressure etc.

 

Since I've started having the problems I've changed the following...

 

HT Leads

Spark Plugs

Dizzy Cap

Rotor Arm

Ingition Coil

Ignition amp

Fuel filter

Injectors

Refurbed head, so new gaskets etc

 

 

I really cannot think of anything else it could be. Even if it's not ignition related, what else could make it be like this? Are there any really obvious things that could have come unplugged to cause these kind of problems? Eg, that white wire near the ignition amp, is that meant to be plugged into anything?

 

I'm getting really fed up with this one, I've spend the last 2 months and the best part of £450 on parts only to have the same problems!

 

Ross.

 

Oh and it's a standard 1.6 gti

 

Oh another thing, if you boot it in the lower gears it is amost 100%, sometimes the odd blip, but certainly much better. Whereas if it's already stuttering and you give it some, it bogs down.

Edited July 25, 2011 by Obey_R

[Tom Fenton 1,542]

Sounds like classic knackered air flow meter to me, and you've ruled out a lot of other things.

[Obey_R 23]

Yup that's one thing I'm yet to try as I can't find anyone nearby with a known working good one to try! I might take a trip down to Baz one evening after work...

[M@tt 77]

have you tried retracking it? ie bend the contact arm slightly with some needle nosed pliers so that it sweeps over a fresh contact area

[kilauea 7]

Have you got a multi-meter? I'd try testing as per haynes before messing about with it. I've got the same afm on a different motor (vw) and was convinced it was the problem, but testing revealed it was fine.

Turned out to be an hidden vacuum leak elsewhere.

[dino20vt 3]

So the only parts you've not tried are:

 

Dizzy lead

Fuel pump

TPS

 

Might be worth trying these just to eliminate them from the equation.

[Obey_R 23]

Took the AFM off for a clean etc today. Got the old school multimeter out with a needle, connected a 9v battery as per the guide to tset AFMs. The results showed it jerky when you opened the flap, with a sudden drop immdietly in the voltage, it was then nice and smooth from about 1/4 open.

 

Cleaned it with a bit of solvent, nothing changed so retracked the arm and it seemed a bit better so left it like that.

 

Now on the way home it hasn't changed, apart from now even at high revs it will loose all power for a few seconds then a nice BANG out of the exhaust and it would give me power again.

 

I'm still trying to get hold of another 1.6 AFM, does it sound like it could be the throttle position sensor? If so I'll change that tomorrow.

 

All help is greatly appriciated as I'm tearing my hair out.

[DamirGTI 342]

jerky when you opened the flap, with a sudden drop immdietly in the voltage

 

This needs to be smooth voltage build up as soon as you crack open the flap up to fully open .. so , yours is deffo worn out ... try to retrack it one more time , and retest with the multimeter (analogue one is best .. with an needle , if you have one use it rather than dig. one ...) until you get smooth voltage while opening/closing the flap - if you can't get it right , scrap the AFM and get a second hand one (a known good unit ..)

 

Other than this , check the ignition timing , and timing belt alignment .. TP sensor would make it kangarooing , but nothing else to add on it based from your problem description it's not a TP sensor (can unplug it and the engine works without it .. it's for the fuel cut off on overrun , and signal to the ECU for fully open to add a little bit more fuel ..)

 

Damir

 

one more thing : check the dizzy signal cable (the back one with 3pin yellow plug in the middle ..) , start the engine and wiggle it a bit ...

Edited July 26, 2011 by DamirGTI

[Obey_R 23]

I did use an analogue multimeter before and tried tracking it 3 times both north and south with no gain.

 

I'll give the dizzy connection a wiggle but I've had that disconnect when I did the head gasket and the problen was the same before and after.

 

The white female spade connector near the coil isn't meant to be plugged into anything is it?

[DamirGTI 342]

It'll be the AFM then ..

 

No , the single spade connector near the coil is unused on Jetronic management .. it's for knock sensor , or something like that , can't remember ..

 

Damir

[Tom Fenton 1,542]

I've previously tried re tracking an 8v AFM and it didn't work for me. Sadly the only options are either the second hand lottery, or a lottery win needed to buy a brand new one.

[Obey_R 23]

Thanks gents, ill hopefully pop and see Carl Chambers tomorrow and try a good afm. I'll report back soon!

[205_sunderland 4]

mine is similar to this at very low revs ie pulling along ding no effort at all at say 1500rpm i get a tiny (nothing like this) cough and as it missfires for a secound but only does it at low revs and low throttle.

 

how much do the tps cost?

[smithy 1]

Look in for sale section someone was selling a load of parts and fairly sure there were TPS there.

 

But you can test them and set up first details in Haynes.

[smithy 1]

Took the AFM off for a clean etc today. Got the old school multimeter out with a needle, connected a 9v battery as per the guide to tset AFMs. The results showed it jerky when you opened the flap, with a sudden drop immdietly in the voltage, it was then nice and smooth from about 1/4 open.

 

Cleaned it with a bit of solvent, nothing changed so retracked the arm and it seemed a bit better so left it like that.

Now on the way home it hasn't changed, apart from now even at high revs it will loose all power for a few seconds then a nice BANG out of the exhaust and it would give me

power again.

 

I'm still trying to get hold of another 1.6 AFM, does it sound

like it could be the throttle position sensor? If so I'll change that tomorrow.

 

All help is greatly appriciated as I'm tearing my hair out.

 

 

Out of curiosity where do you put 9v battery and what pins do you put meter on when testing this way?

I have only done it as per Haynes which just measures ohms.

[DamirGTI 342]

http://www.the944.com/afm.htm

 

Damir

[smithy 1]

http://www.the944.com/afm.htm

 

Damir

 

 

thanks for the link damir.

[Obey_R 23]

Things have gotten even worse today. On the way home I couldn't really get above 30mph it just wouldn't respond to any input. Kepy coughing and popping, backfiring and missing. Stopped just before home and wound in the mixture screw on the throttle body and it made it quite a bit better, but certainly hasn't cured it.

 

Hopefully the new AFM will arrive tomorrow and I can see if it's that causing the problems - if not, there will be a for sale thread!

[welshpug 1,657]

that's not a mixture screw, its just an air bypass screw for the throttle body

 

the mixture screw is on the afm.

 

 

this sounds precisely like when my AFM died.

[Obey_R 23]

My mistake. Either way it managed to get me home! Glad it still sounds like an AFM fault, hopefully it will arrive tomorrow and I'll see!

[kkronja 0]

It could be also the fuel pump in the process of dying-have you checked the pressure it makes?

[Rob_the_Sparky 9]

So the only parts you've not tried are:

 

Dizzy lead

Fuel pump

TPS

 

Might be worth trying these just to eliminate them from the equation.

 

No not really, also could be (in most likely first):

 

ECU temperature sensor - if broken can make the ECU heavily over fuel

Air leak - but these normally make it run like crap with little throttle but are fine with lots of throttle

Fuel pressure regulator - not sure what that would do when bust. If hose to it from the plenium is bust then it would over fuel on all but full throttle, if the actual regulator breaks then not sure. However, never heard of one breaking.

[Obey_R 23]

I have changed the Ecu temp sensor recently so that's not the problem. Not checked fuel pressure but ive recently swapped over for a set of 40 carbs, so as soon as I've finished fitting those we will see of that cures the problem!

[Obey_R 23]

Still got the same duxkimg problem even after ditching the whole induction system and fitting carbs!

[Anthony 1,003]

That's annoying!

 

I assume that it's exactly the same symptoms/severity as before? If so, you can rule out just about everything fuelling related.

 

Is there anyone with another 205/309 GTi near you that would be willing to either let you swap parts off their car, or try parts from your car on theirs to rule them out? It sounds like you've replaced just about everything, but worth double-checking the usual suspects against known working ones as it's not unheard of to have two faulty parts with the same issue.

 

My gut feeling with stuttering under load is the HT side of the ignition system breaking down (coil, dizzy/arm, HT leads) so would be worth double-checking all them against a known good set.