1,8 GTI hesistates.......

hello everyone, Ive been very busy with my GTI lately!
I took the cilinderhead off and everything was replaced incl. 8 new valves( by a very wel known company), all the gaskets are new, all the coolant hoses, radiator, expansion tank, new sparkplug wires, dizzy cap and rotor(all BERU), new injectors. I also fitted new engine mounts, and an supersprint spaghetti exhaust manifold and a new exhaust. all the filters etc etc.
I fitted everything en it looks like new now, and the engine sounds&runs very good and starts perfectly aswell. Timing is spot on 6 degrees and the CO percentage is 1,2% with the ventilation pipe disconnected.

The problem is that the car hesistates when Im driving at an constant speed, very annoying. When the revs are rising its keeps sputtering, also when I suddenly accelerate. I can accelerate easily up to 6000rpm!!
Who nows whats wrong, I checked all the vaccuum pipes and gaskets bij spraying brake cleaner on them with the engine running and no faults were found…….

any help would be very much appreciated, as this project has cost a lot of money en work, and I want it perfect(technically)
greets yal

fuel filler neck

filler cap

crud in the tank

 8O

thanks for your reply,
fuel filler neck is as good as new, filler is brand new, but crud in the tank is a possibility although the tank has been removed in the past!
Ill have a go and drain the tank.
Sometime ago I read here something about a mesh filter near the fuelpump, could someone tell me where to find it??

greets yal

The filter on the pump is in the intake side, definately worth checking that out

you will need to disconnedt the inlet to  the pump and inside the inlet on the pump is a small gauze filter  :wink:

my tank is still full, so I guess Ill have to wait until its empty to avoid spilling to much! Or doesnt it make a difference? How do I remove this filter from the pump then??

greets yal

hello, I just took the fuel pump off but there is NO mesh filter on the inlet of the pump!!! I have an 1983 1,8 DX so maybe things changed over the years

greets yal

today I changed my "non return valve" which is screwed in the fuelpump.
Still no difference, under load the car hesistates and Ive noticed when accelerating on low rpm the problem is worse(between 2000 and 4000rpm). Over 4000rpm till around 6000rpm it pulls better.

greetz yal

get it crypton tuned sounds like it could be over fueling

Silly question but i take it you did the timing before doing the mixture?
Either that or maybe weak fuel pump?

Check for wear on the dizzy shaft.

Yal "Timing is spot on 6 degrees " You sure you set this at 6??

O deg TDC me thinks!

Haynes and thsi site says the same for cam timing
"To get the flywheel in the spot you need it in, remove the green plug as shown, and put the car in 5th gear, and roll the car forward by hand until the marks roll around and the pointer is pointing at the 0-degree dot on the flywheel.
"

http://www.thediygroup.com/ignition_timing.htm

1.6 EG=0 degrees (with vac pipe connected)
1.8 DX=6 degrees BTDC (vac pipe disconnected)

ahhh, ignition timing. Me was on the cam timing lines. sozzzzz

thanks for the replies so far!
Today I drained the fuel tank, but no crud came out, not at all!! I also fitted a brand new bosch fuel pump, expensive :twisted: .. Than I tested the car, checked the timing which was 1 degree out and set the mixture.
With the vaccuum hose off the advance mechanism I see NO difference when I put it back on. I tried sucking the vaccuum pipe and the advance mechanism does move a bit, but dont know how much it should move..
I also noticed that when I drove at a constant speed the car hesitates aswell, drove at 4500rpm (150km/h) on the highway and the problem was still the same.
There is no play on the dizzy shaft, also the car has only done 125 000km.
btw, I use bosch triple electrode sparkplugs, but dont suppose these cause the trouble….Starting to run out of options :cry:

greets yal

I know you said that you've put new plug leads on but could 1 or more be faulty? Its a possibility and the hesitation you describe was similar to mine and that was just down to the leads.. try swapping those again?

Dan

Might be worth cleaning the throttle body out.?
Another thought ignition module??

hi, thanks for  the replies so far! :wink:

I have cleaned the fuel distributor out again, still no difference.. I than cleaned out the fuel tank again,  and when I took out the fuel sender I discovered another filter, and below this filter was tonnes of desintegrated rubber.  
After cleaning this out the car still sputtered when driving at a constant speed, then I closed the mixture a bit, to make it run leaner!
Now CO percentage is 0,7% / 0,8% with the crankcase breather disconnected, when I reconnect its around 1% which I think is too low, but it runs much better now :mrgreen: (and before the value was 1,1 /1,2%)
Wouldnt it harm the engine do drive around with a lean mixture?? It does NOT pink, and I only use 98 octane fuel. I find it strange that it runs much better now, and before it didnt smoke at all, and the sparkplugs looked fine aswell

greets yal

did you refit new injector seals or refit the old ones?. i had this on one of mine,  can you hear any air leaks.  try using a length of windscreen washer hose like a stetphoscope (spelling ?)  to listen around injecters/ air pipes.   ?8 from vw, or ?2.40 from gfs.  ps don't let neighbours see you with tubes hanging out your ears. ops:

mk 1 jim, thanks for your reply.  Fitted new injectors with new seals, I also replaced nearly all the hoses. I checked airleaks by spraying brake cleaner on the connections while the engine is running, when leaking the rpms change and the engine runs a bit rough.

greetz yal