Warm starting problem (16v)

[mattnorgrove 0]

OK chaps here goes, had this problem since I owned the C (4 months now). When the engine is given a good run and is up to proper temp, then left for a couple of hours, and the ambient temp outside is warm, the engine is plain refusing to start. It takes about 20 secs worth of cranking, then will fire up on 1 cylinder then 2, 3 then 4 given plenty of revs. Have posted this prob before and thought i had solved it by changing the injectors as previously advised, but the problem persists. Also previous to the injector swap, i changed the plugs, dizzy cap, rotor arm and ht leads.

 

Please help as this is driving me mad and continuing to embarass me in front of the missus ( "shed" is her opinion, desperate to prove her wrong)

 

Cheers guys....

[nocrap 0]

So did the problem go away completely when you changed the injectors, later to return?

[mattnorgrove 0]

No just the weather was cooler for a while so didnt notice it as much, although its never been right completely. Was thinking if the problem is related to air temp as it seems to be, could the previous owner have fitted one of those dodgy +15bhp resistor mods, that fools the ECU into thinking the air is always cold? If he had fitted one of these, where would i look to remove the bugger?

 

Thanks for the swift reply btw...

[davidwort 0]

No just the weather was cooler for a while so didnt notice it as much, although its never been right completely. Was thinking if the problem is related to air temp as it seems to be, could the previous owner have fitted one of those dodgy +15bhp resistor mods, that fools the ECU into thinking the air is always cold? If he had fitted one of these, where would i look to remove the bugger?

 

Thanks for the swift reply btw...

 

If it's temperature sensitive like that then one thing you could check are the temp senders on the head, you know one is good because you get a sensible reading on the gauge on the dash, try swapping the wires over, there are three identical senders on the 1.8 16v all around the water outlet on the side of the head, just swap them round and see if the gauge reading is the same and the engine runs the same.

After that you could try disconnecting the cold start injector cable and see if that makes a difference when hot you might be flooding the engine if that is operating when hot.

Failing that I'd search and ask on the Club GTI forum, there's been quite a few valvers with starting issues on there recently.

 

It is also possible for fuel to vapourise in the fuel lines, which is why there is a small fan switch attached to the front left of the head nr the fuel lines. It switches the rad fan on to keep under bonnet temps cool to help prevent this.

 

David.

[mattnorgrove 0]

Cheers, with the risk of sounding thick (when it comes to the C i probably am though) i reckon i can find the temp sensors on the head, but which dash reading will these affect? Also where is the cold start injector located? If it helps, the after-run on the fan works ok....

 

Thanks again for the swift reply...

[nocrap 0]

Cold start injector is located on the right hand side of the block, you'll see the normal injectors into 1,2,3 and 4 and then a further fuel rail with the injector attached

[davidwort 0]

Cheers, with the risk of sounding thick (when it comes to the C i probably am though) i reckon i can find the temp sensors on the head, but which dash reading will these affect? Also where is the cold start injector located? If it helps, the after-run on the fan works ok....

 

Thanks again for the swift reply...

 

water temp gauge,

 

...and fan run on is determined by rad fan switch OR head switch (front left), if the water temp at the rad switch drops below fan operating speed and head switch/wiring is duff you'll get no under bonnet cooling when the fuel lines need it.

[nocrap 0]

anyone near you with VAG-com?

[Supercharged 2]

anyone near you with VAG-com?

 

It's a 1.8 (mechanical system)

[mattnorgrove 0]

Cheers, Midland VW are 10 mins away, so if after a bit af a look i still can't figure it, i'll get them to run the diagnostics on it. Wanted to sort it mysef tho as need to learn how the beast works. So the head switch is also responsible for after-run?

[mattnorgrove 0]

anyone near you with VAG-com?

 

It's a 1.8 (mechanical system)

 

So thats VAG-COM out of the equation then?

[davidwort 0]

Cheers, Midland VW are 10 mins away, so if after a bit af a look i still can't figure it, i'll get them to run the diagnostics on it. Wanted to sort it mysef tho as need to learn how the beast works. So the head switch is also responsible for after-run?

 

Both the rad fan switch and the small switch on the front left of the head will run the fan if either is up to temp.

 

Nothing to interrogate on a 1.8 16v with VAG COM

 

There's a lot you can check before resorting to taking it to a garage,

On this age of valver I'd go over all the vacuum lines (to check for perished hoses) and exposed wiring connectors (looking for corrosion).

If the car runs OK from cold and idles fine and pulls smoothly through the revs to the red line there's a lot you can cross of the list already.

Try to get hold of a Haynes passat manual 88-92, this covers the 1.8 16v ignition and fuel system. You'll find some k-jet articles on the web too, for starters:

http://www.volvoclub.org.uk/tech/fuel_i ... onic.shtml

http://www.auto-solve.com/mech_inj.htm

 

You're not a million miles from Stealth so if you're really stumped I'd doubt there's many people with as much knowledge of k-jet, they can check fuel pressures etc and could set your car up on the rolling road at the same time, 16v owners are always pleased with the result after taking a trip there (I'm one)

[nocrap 0]

It's a 1.8 (mechanical system)

 

Thats a shame :cry:

[mattnorgrove 0]

Thanks for the tips and links, was after a manual, i've got the Bentley one but cant really find what i need, i'll invest in the passat one then i reckon.

 

Thanks for the links too....

[davidwort 0]

Thanks for the tips and links, was after a manual, i've got the Bentley one but cant really find what i need, i'll invest in the passat one then i reckon.

 

Thanks for the links too....

 

A bit more searching on the car maintenance google group and I discovered that like the switch to keep the fuel in the lines from vapourising (running rad fan) the pressure accumulator, under the car at the back nr the pump and filter also maintains pressure in the system to help prevent fuel vapourisation, loose the pressure and hot starting will be a problem, so it could be you fuel pressure accumulator and filter that needs cleaning/replacing. There's a minimum pressure the system should maintain 20 mins after switch off, 2 bar or something, you'd need the right gauges and connectors to check, but I guess cracking open the fuel supply line to the metering head immediately after switch off and then again after running leave it for half an hour and crack the supply joint, if the pressure sparaying out seems about equal it's probably not that.

Be careful with the lines though, hot engines and spraying fuel dont mix! - you need some rags to open the joint into, not much sprays out.

I know my system seems to hold pressure for ever.

[mattnorgrove 0]

Once again thanks for the advice, I had a good read of the auto solve websites explanation and had started to suspect the accumulator. The guy i bought the car from had just changed the WUR so i'm gonna rule that out. I'll whip it apart the wknd and give it a clean out, or maybe just replace it. Any idea on cost/source (do gsf do these or would an OEM one be better?)

 

Thanks again...

[davidwort 0]

Once again thanks for the advice, I had a good read of the auto solve websites explanation and had started to suspect the accumulator. The guy i bought the car from had just changed the WUR so i'm gonna rule that out. I'll whip it apart the wknd and give it a clean out, or maybe just replace it. Any idea on cost/source (do gsf do these or would an OEM one be better?)

 

Thanks again...

 

there's a how-to on the forum giving some prices of the fuel filter and associated brackets, not sure about the accumulator itself, GSF site says 86 quid for an accumulator :( I'd probably try a second hand one with a new filter first