help wont run!!!!

Hi people. Im having problems with my cabby!!  Its a mk1 gti cabby 1990. It been running without fault until last week it sarted to jolt and miss whilst driving, almost like fuel starvation.
I have bypassed to fuel pump relay to check to see if this was at fault, and it ran pretty much without fault. I have changed the pump relay for a brand new one which now primes the pump unlike the old one. The car started first time after and ran for about half a mile then boom, back to the jolting and kangerooing down the road until eventually cutting out. It would then not start for a while and when it did run for about 30 secs it peatterd out and wouldn't start again.
I managed to get it running the other day for about a minute or so but then it started to run rough and eventually cut out. the fuel pump runs fine even when the car cuts out and the spark is fine.
I have noticed that there is a rumbling noise from the metering head just as the car starts to play up almost like there is a blockage, i was just wondering if anyone had any ideas??
Also is there a separate filter in the metering head itself as someone once told me there is a small gause type one on the main feed pipe to the head?  any advice gratefully received.

matt

check the lift pump is working, disconnect a wire to the main pump and turn key 1 click. if lifter doesnt prime, theres your problem

Hi John many thanks for getting back to me. I have checked the lift pump as you suggested, I removed it from the tank and primed the system the pump worked ok. I have also removed the main feed pipe to the fuel distributor head to see if there where any signd of crap in the pipe and journal, it all appeared fine. Strangly though after charging the battery and putting it all back together i started it and it ran perfectly with no juddering or cutting out like before!! This was howver at idle and not driving it. I have been back to the car today and it started first time, after a roadtest the car seemed to perform ok until i hit between 3500 and 4000 rpm when it lost all power very quickly! If i ease of it comes back on, it will do this every time at the same engine load. It may be worth noting that the wire to the isv has broken and it does tick over fairy high due to this,but this has been an issue for some time, im not sure this would effect the engine under load like this though? It definately feels like fuel starvation or a sudden loss of something. I was wondering if as you say one of the pumps could be on its way out as it only does it under load. I have looked at the airbox and the flap is moving freely and the whole thing seems very clean. its worth noting that prior to this fault the car was left forn a couple of weeks with very little fuel in the tank, so im thinking when started it may have picked up some crap?
Any advice again gratefully received as i want to get it up and running for the shows!!!

Many thanks again John.

Matt.

a new fuel filter is something i would try, cheap and easy. there is sometimes a filter in the fuel line banjo bolt on the metering head inlet you can try swapping this for one without.

have a look inside the tank as per:
The Mk1 Golf Owners Club

then i would look at the main pump perhaps, check the fuel reservoir under the car too, if its running low then that would suggest the lift pump is struggling to keep up.

though you might want to look at the ignition system too before you spend too much money, the fuel pump relay needs a rev counter signal from the coil so if the missfire is coming from the ignition system it can effect the fuel pump relay and so in turn the fuel pump. look at your dizzy wires, the dizzy cap, arm and leads to ensure all is well there. if in doubt renew it all with bits from here:
AVS Car Parts - [The VW - Audi - Seat - Skoda Parts Specialist]

Hi John, many thanks for the advice before. I have checked all the obvious stuff as mentioned before and still no joy. I been testing various things on the car and noticed that the micro switch on the throttle body no longer click when opening to wide throttle. Am i right in thinking this also operates the fith injector at higher revs? Could this be the problem as the missing or lack of all power only seems to occur at between 3500-4000rpm? I am at a loss of what to do next if this doesn't cure the fault, both the pumps seem to be fine the rotor arm and cap are in good condition and i have cleaned out the metering head and replaced the fuel filter!!
Any more advice gratefully received.


Many thanks Matt

there should only be a throttle closed switch on a k-jet, this is for the cold throttle enrichment and should only spray fuel when you floor it cold. the metal valve on the back of the airbox is what picks up on when you floor it, the throttle switch should only be open when the throttle is open, and the temperature control is handled by the 5th injector thermoswitch.

it may be there is an electrical issue, i would look at the fusebox next. drop it off the hangers and inspect it closely for water damage, also pull each relay out and check the pins for corrosion.  look at all the fuses too in particular the fuel pump one

thanks  again john for getting back. I have re set the co level and repaired the wiring the asv which was dameaged. I have swapped the fuse box for one which i know is good and checked the condition of the connectors afor corrosion etc. All seems well there. The car sarts first time every time and drives faultlessly every time– up until I hit 3800 rpm!!!  The only thing i noticed. is that the no 18 relay seems to be slightly water damaged, this i belive is a X contact relay?
Its driving me mad now as i have very little time to dedicate to the car and i am reluctantaly thinking i may have to take it to a garage!!  Do you or anyone know of any decent vw specialists in the tamworth/ staffordshire area?  
or failing this anymore ideas????

Many thanks again
matt

Just had another thought regarding the poor running, i was wondering if it would be worth changing the ignition amplifier as i read in some other posts these can break down when warm?? In your opinion would this effect the running under load?
I do also remember some time ago that i had similar running problems but this time the car would just jerks and kangeroo at lower revs.  I found that the no5 fuse for the fuel pump had got vey hot and was causing a poor contact. The car ran fine after replacing the fuse, i do sometimes think that the issue may be fuel pump related as it only happens under load, it will rev freely and run very well until driven fairly hard.

Any more ideas or experiances gratefully received :wink:

Just a quick update. I spent a few hours testing things tonight wiring , coil, ignition ect and they all seem to be ok. I roadtested the car again after and noticed that when the loss of power occurs there was also an audible clicking from the fuse box. I checked the fuel pump relay and found it to be quite hot, i am assuming now that it is starting to break down internally when there is load on the fuel pump. To check this i by passed the relay with a bit of wire and presto the loss of power above 3500rpm has now gone.
Im therefore thinking about changing the main fuel pump and the lift pump to?
Has anyone had similar problems or could they advise me if  this is a good cause of action to be taken?

many thanks again all for the Advice

sorry ive been away! i would start by checking the lifter pump, make sure it runs when the fuel pump relay is on and check it actually pumps fuel. an easy way to do this is fit the 18 x-over relay into the pump relay socket and pull one off the wires off the lift pump so it comes on with the ignition. listen to the noise the main pump makes if its quite loud then it may need replacing.

if all is well with a bypassed relay perhaps its the relay itself that is bad, or the fuseboard

Hi John, thanks for getting back I appriciate you are a busy man helping people out! I have changed the lift pump today along with a new fuel filter, checked and cleaned any very small debris in the tank. I have checked the fuse box for signs of heat and broken contacts which all seems in good order. The relay fuel pump relay is only a couple of weeks old so i have used it despite it getting fairly warm the last time it was driven. Went out for roadtest and again the fault is still there. Im just hoping now that it is the main pump causing this as I have purchased one to fit this weekend. If this doesn't work im at a total loss of what could be causing it!!! It will prob be something very simple but very hard to find!!!

was the relay a genuine vw one or a pattern? the cheaper ones arnt so great. for a test try a #18 relay in the pump relay socket, its not safe in a crash as it will only bring pump on with ignition but if it works faultlessly then i would look into your relay

Just another update!!  I fixed a currant draw tester inot the number 5 fuel pump fuse to see what was happening when the fault occured. The pump was pulling between 10.3-10.6 amps under load up until the point where I lost all power to the pump! I have now changed both the lift pump, main fuel pump, fuel filter. I have also cleaned all the fuel lines and checked the wiring to the pump. The fuel pump relay although only a few months old has been changed also due to getting hot.
The problem now seems to be solved!!!
I have now done over 80 miles trouble free, so happy days.

Many thanks to all you guys for the help and advice.
I hope this helps other people with the same problem

Hello again all! Just after I thought the problem was fixed it has returned!!! I have run the car with the no 18 relay in place of the fuel pump relay. The car runs fine and the problem is sorted. However when replacing the stop gap no 18 relay with a proper fuel pump relay from euro parts the problem returned!!!! hit 3800 rpm and it just stops the pump wrking. The relay seems to be of a good quality and cost £25 so not particulary cheap. The fuse box has been changed to. I was wondering if this could be a wiring issue as there is another extra contact on the fuel pump relay compared to the no18 one. would this contact be the cause of the fault or is it worth trying a genuine vw relay?? I have coverd 300 miles plus with the stop gap 18 relay in place and im now thinking keep that in, but on the other hand i want ther car safe and working right!!! Any ideas fellow golfers???

Thanks matt.

is the relay the type with an internal rev limiter? this could be the reason. the extra pin vs the 18 relay is a rev counter signal from the coil. i take it rev counter works perfectly?

Hi John. many thanks for getting back. I think the relay is a standard type without the limiter, The fault occured with the old orginal one to. The rev counter works ok although sometimes i have to give the top of the dash a tap to make it kick inj when first starting it, although not all the time. Is it now worth checking/ replacing the  wire from the coil to the fuse box which picks up the rev counter feed? s it only occurs under load is it possible the wire may have poor continuity or a poor connection somewhere? Maybe an earth point fault somewhere to ?

Thanks again John

yes to all of the above, the rev counter issue might point to why as without a rev signal the relay wont work!