Hi all, I've recently bought an August 1984 Mk2 Gti, unfortunately it doesn't start. I've checked for a spark and it has one. I've checked the engine timing and that is also fine, at TDC the rotor points at the groove in the distributor body. This point me to an apparent problem with the fueling system. I've taken apart the airbox and the airflow meter flap isn't stiff at all, it seems to be set at the correct position. I removed the metering head to check operation of the plunger, pressed it right in and tried starting the car and still it would turn and turn with no cough or splutter. I noticed that when I removed the plug to check for spark that was no smell of fuel. I'm thinking that the pressure isn't building up to what it should but I don't have a pressure gauge to test this, is there a way of testing without the gauge? The car has been standing for a long time as the last tax disc ran out a year ago. I'm guessing a problem with the metering head but need some learned heads to help me nail it. Thanks Jon
You could try disconnecting the fuel feed pipe from the fuel distributor, if you have fuel there try disconnecting an injector hose. If you have fuel pressure it should p**s out as soon as you loosen a connection. Start at the fuel pump & work forwards if the there is no fuel at the metering head HTH
Fuel pumps often die when they're sat for a long time. Bridge the thick connectors where the fuel pump relay plugs into the fuse box, switch the ignition on, and you should hear a pump running. If not, check you've got 12v with the ignition on, to the fuse board where the relay plugs in. To test the lift pump, you need to do the same, except take the electrical connector off the main pump, so you can hear if the lift pump is running. If the pumps run, it's probably the relay. If the pumps don't run, it's new pump time. I'm assuming A reg Mk2's have the same fuel system as the later ones, rather than just one pump. The other way is to run power direct to each pump in turn, using leads and croc clips, and check if they operate. Either take the battery off the car, or use a spare one.
Lift pump is in the tank, accessed through the boot floor. Sorry if you alreday knew that but I had my car for year before I found out it had a lift pump
If you have fuel in the metering head move forward from there as mentioned... maybe the injectors are blocked? Pull them out one at a time and drop it in a clear container and crank the engine. Mine worked ok before doing a rebuild, but two were blocked after. Maybe moving all the fuel lines worked some sediment loose?
I forgot to mention, I have tested both pumps off the car and they both run, it won't keep pressure once built up, and neither will they prime once the ignition has been switched on. After some research, it seems that the fuel pump relays differ and not all of them will prime, just the same as some have built in rev limiters and some don't. I did disconnect one of the pipes from No1 injector and nothing sprayed out on starting... How do you remove the injectors? They have some give in the inlet manifold, should they?
Forgot to add, I removed the fuel tank (to deal with some rust) and set it up off the car with the original wiring and they still powered fine (I can rule them out, fuel sprayed out of the supply line to the metering head and even from the two injector lines when I moved them to gain access to the removal bolts for the metering head)
When you say "removal bolts for the metering head" you didn't undo the allen headed ones did you? AFIK they adjust the flow balance to each injector & are best left alone.
To remove the injectors you just give them a good tug, they might be bit stiff but they should pop out. If you're loosing fuel pressure once the engine is switched off it sounds like the accumulator might be faulty. What part of the UK are in? If anyone local has an 8v k-jet it might be worth swapping known good parts until you track down the problem.
No I only removed the 3 flat headed screws to seperate from the air flow meter. I'm in Swansea, don't know of any mark 2 K-jets around here, how many parts are interchangable with the 16v? What mark 1 parts are the same?
As mentioned it would be unlikely for all 4 injectors to be faulty, but there is no harm in checking to see if fuel is getting through one at a time. They have a little rubber washer that acts as a seal in the head that pop in and tug out. They will need replacing if there old and loose there elasticity with the heat over time. You mentioned the timing is all fine... I once used the incorrect mark on the camshaft pulley with two blocked injectors and it would not fire up.
Don't pull injectors by the pipes! Use a big flat screwdriver to tease them out. Lever against the rocker cover once you've got them started. Definitely worth testing if you're getting spray from the injectors.
replace the fuel filter, i had the same issue. fuel would get as far as metering head but not enough pressure to open the injectors. had same problem a 2nd time and that was due to a faulty non-return valve in the fuel pump. that time i didnt even get fuel to metering head, and when outlet pipe was removed from pump and engine cranked nothing came out of there either!
Right, we've had developments! I got it started today, didn't let it run for too long due to it having no downpipe and unknown oil in it. I opened the air flow flap very slightly whilst cranking and it spluttered into life! Once I let go however it would cut out. I adjusted the wire to let the flap rest higher and it would idle at around 1050rpm. Not good. After a rev it would cut out. Do you think the warm up valve has failed? What do the K-jets idle at when cold? I also have another question, are these supposed to be sequential injection? If so which way does the metering head distribute - as in clockwise or anti as you look down on it?
non-sequential injection, Continuous Injection System (CIS) or Kontinuerlich (K) Jetronic just sprays out a mist of fuel from all the injectors all the time the engine's running, the rate of delivery depending on the position of the air flap among other things. have you had a look at the Auxiliary Air Valve? this should have the effect of opening a bit of throttle to keep it going when cold. worth a read: http://www.scribd.com/doc/3299223/Bosch-KJetronic-Fuel-Injection-Manual-
What does "Adjusted the wire" mean? Did you adjust the throttle cable? That's not the way to set tickover - there's an idle adjustment screw on the throttle body.
think he means the spring clip which sets the rest position of the metering head flap. the correct way to set this is to have the metering flap flush with the narrowest point of the cone towards the front, closest to the fuel metering unit. if manually lifting it help this would suggest wur may be faulty as the control pressure is incorrect for cold running. copuld be low fuel pressure condition, especially as it cuts out when revved. replace the filter
Yep that's the one John. I've put a brand new filter on it so if there is a pressure problem it must be elsewhere. Would it be worth trying another accumulator? I want to test the WUR but I can't find my multimeter to test the resistance. Next job on the to do list. If I left it running until it warmed up, theoretically it should run fine when warm?
I made a slight balls up, guess who left the Auxilliary air valve pipe disconnected underneath the induction hose Starts spot on, doesnt cut out when revved, but idles at 1150, I tried to put the air flow meter flap back to its original position, this didnt help. Also what should be the colour of the oil pressure switch on this?
