89 CABRIO GTI, FUEL/STARTING PROBS

FOLLOWING ON FROM PREVIOUS MESSAGE. I'VE HAD A MAN OUT (MOBILE TUNER), WHO SAID HE THOUGHT THE FUEL PUMP WAS KNACKERED, SO I CHANGED IT, ALONG WITH THE FUEL FILTER(I SUSPECT THE LATTER MAY HAVE BEEN THE MORE LIKELY CULPRIT). IT STILL WON'T START, BUT ALMOST DOES, IT'S REALLY TRYING TO FIRE UP NOW. I CONSULTED THE HAYNES MANUAL AND CHECKED THE COLD START INJECTOR/VALVE AND THIS IS NOT SQUIRTING THE CONICAL SPRAY AS SUGGESTED. IT'S MORE OF A DRIBBLE SO I WILL CHANGE THIS NEXT.   SHOULD THE FUEL ENTERING THIS VALVE BE HIGH PRESSURE OR JUST A STEADY TRICKLE AS IS THE CASE?????????
 :dontknow:

it should spray  

have you tried pouring a small amount of neat petrol into the air intake just to get it warm  :dontknow:

it worked on mine after it had been stripped and rebuilt  :wink:

Thanks for the reply. Are you saying the fuel line that connects to the cold start injector/valve should be under pressure before it gets to the valve?

With regard to neat fuel, I've tried some easy start squirted past the throttle butterflies in the throttle body, is this where you mean, or through the hole with the cold start valve removed?

Thanks

Mark W

the fuel in the line should be under pressure then when the injector gets the signal on cranking it should inject for 5 seconds.

what i did with mine was removed the circular end of the air intake (at the metering head) turnded it round through 180 (so its like a cup) tipped abit of neat fuel in there and then lifted the plate on the metering head with a magnet and then got somebody to turn the engine over whilst slowly raising the air intake pip with the fuel in. so if that gets it to run even for a few seconds  then is a fuel problem.

ive been havin loads of problems with mine to get started. if i left it for ages then tried it would start up alomost straight away but switch it of and it wouldnt start   i pulled my injectors and the were wet around the end i.e dribbling so flooding the engine.

ive just bought a new set of injectors ( ?117) but now it starts on the button  8)

have you pulled your injectors????  and checked em??

…testing them…..(Right click and 'Save Target As….')

Injector test pdf

…and a quick video (listen to them andjust about see the spray pattern)…
Injector video

Thanks for the injection test guide, Prowler.
The thing that my main concern at the minute is the lack of pressure in the fuel injector and cold start injector supply lines, so I don't want to write off my injectors just yet.  Any ideas as to what may be causing the lack of pressure?
A chap has mentioned that the timing might need to be adjusted, as the new cylinder head fitted is a TSR 102 with high lift cam(the mildest one).
 

the pressure is dnoe by the pump it could be a clogged up filter in the tank–pump or even buy the airbox or crud in the lines

or just a plane knackered pump  

Mark,

Sounds like you are describing low system pressure.  This can be caused by:

Damaged or broken pressure control valve/spring (in metering head)
Faulty fuel pump
Fuel line blockage on supply side
Blocked fuel filter

Do prowlers injector test to verify that the injectors are dribbling or whatever - this does not mean that the injectors are no good but would confirm overall low system pressurem and one of the faults above.  If the main injectors are ok then the fault is only in the CSV circuit.

Cheers

rich

hi there i was reading that one of you guys bought some fuel injectors for ?117? i cant seemed to find any for less than ?200 for the four, for my 91 gti cabrio. can any one reccomend anywhere? cheers

I got a set for ?26 +VAT from VW for my '90 cab

thats got to be a price for each one right?

yeah

cheers i ll get the phone to vw in the morning!.

They'll probably quote you ?35 each + VAT - try and talk them down  :wink:

I GSF'd for mine in the end after a bit of hunting. They turned out to be the same price as my local BOSCH specialist but had them in stock.

I HAVE DONE THE INJECTOR TEST AS PER PROWLERS ATTACHMENT, AND THE INJECTORS ARE NOT SQUIRTING AT ALL. THEY ARE MERELY GETTING WET AROUND THE NOZZLE AS IF NO PRESSURE AT ALL.   
WHATS THE THING FASTENED TO THE FRONT OF THE ENGINE BLOCK, WITH TWO FUEL LINES CONNECTED TO IT, I'VE CHECKED MY HAYNES, AND IT'S DESCRIBED AS FUEL PRESSURE REGULATOR, AND THEN LATER ON IT'S A WARM UP REGULATOR?????? COULD THIS CAUSE THE LACK OF PRESSURE.

WORK DONE SO FAR:

NEW FUEL PUMP(BOSCH)
NEW FUEL FILTER
INJECTOR (BOTTLE) TEST
 
SUMMER'S HERE NEED TO GET CAR ON ROAD, PLEASE HELP……….

Was it the in-tank pump or outside one you replaced? my probs were due to a blocked filter in the outside pump not the uplifter.

I REPLACED THE LARGE PUMP  UNDER THE CAR(THE EXPENSIVE ONE!!).

DOES THE UPLIFT PUMP HAVE MUCH OF AN INFLUENCE?

I think the lift pump only really makes a difference when the tank is nearly empty but I'm not sure. There is a filter at the end of the lift pump that can get blocked with rust if the car's had a rotten filler neck in the past.

You might need to look at the fuel metering unit next (the bit that the injectors connect up to). Sometimes the plunger can get stuck that controls how much fuel is distributed. Take the air filter out and see if everything is moving about like you think it should do!

You could disconnect your return fuel line from the engine to the tank to see if fuel is being delivered to the engine. I'd expect a large quantity to be spirting out so be careful.

So whats the history about the problem? Did you buy the car with the problem, did the problem develop, or just suddenly happen?

Good luck,

Ross

THE CAR WAS RUNNING OK WHEN I BOUGHT IT LAST SEPTEMBER.
THE OIL WAS IN NEED OF CHANGING AND THE TOP END WAS WELL SLUDGED UP SO I FLUSHED THE ENGINE AND CLEANED OUT THE SLUDGE, AND THEN CHANGED THE OIL AND FILTER.  THE CAR THEN STARTED BURNING OIL REALLY BADLY, LEAVING A SMOKE SCREEN EVERYWHERE WE WENT. WITH 96K ON THE CLOCK I DECIDED TO CHANGE THE CYLINDER HEAD, AND OPTED FOR A TSR PORTED/POLISHED WITH MILD MODIFIED CAM. I DECIDED TO TAKE OUT THE ENGINE ALTOGETHER, AND CHANGE THE MAIN BEARINGS/BIG ENDS ETC.  ONE THING LEAD TO ANOTHER AND I ENDED UP RENOVATING THE FRONT SUSPENSION, POLYBUSHES,AND NEW BRAIDED FUEL LINES.
PUT IT ALL BACK TOGETHER AND NOW SHE WON'T START DUE TO FUEL PROBLEM.

I'M RATHER DISSAPOINTED, AND MUCH THE WORSE FINANCIALLY.