GolfGTIforum.co.uk
General => The garage => Topic started by: DreXeL on 30 October 2010, 13:11
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Ok, I've just finished my build, basic spec is:
2E 2.0 bottom end
Crossflow head (with necessary mods)
Newman 272 camshaft
Home made inlet manifold
R1 Carbs with 165 jets to start with (have 170s and 175s if required) fed by an R1 fuel pump.
Basically the engine will start and run, but after it's warmed up a bit it'll just cut out. I can then start it again and it'll run for like 10-20secs then die again. It doesn't splutter or cough, it just dies completely.
Any ideas?
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Forgot to mention, the problem seem unrelated to the choke as it does it weather the choke is engaged or not.
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Anybody have any ideas?
To feed the carbs I have the stock fuel feed and return in the engine bay connected to a t-piece, which in turn is connected to the R1 pump. The car is a k-jet, I'm not entirely sure how the standard setup works but it's acting as if the stock fuel pump is shutting off, perhaps this is because the k-jet system has been removed and it's not getting any 'feedback'? How can I 'trick' the stock fuel pump to never shut off if that the case? Or am I barking up the wrong tree?
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I don't think the stock fuel pump will work, I would say you need to swich to a standard electric pump from someone like facet.
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There's no reason it shouldn't work though, carbs don't need anywhere near the pressure of fuel injection, hence the t-piece setup. I just want to know if the stock fuel pump switches on and off as needed with the standard k-jet setup, and if it does how can I make it stay on all the time?
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loose the injection pump you only need the lift pump, t off that line to feed the carbs but place a restriction in the return line to the ank so you get a couple of psi at the carbs.
if you think it's a fuel pump run issue just take the relay out and bridge the contact terminals with a short pice of wire with a spade connector at ether end pushed in to the fuse box.
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Bike carbs can only handle up to 3 psi of fuel pressure, so are better off run with only the standard bike fuel pump, which itself pushes fuel better than it pulls, so should ideally be mounted close to the fuel tank. ( Fraid im no expert, this info is shamelessly stolen out of an article in Classic Ford!!)
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Ok, I've just finished my build, basic spec is:
2E 2.0 bottom end
Crossflow head (with necessary mods)
Newman 272 camshaft
Home made inlet manifold
R1 Carbs with 165 jets to start with (have 170s and 175s if required) fed by an R1 fuel pump.
Basically the engine will start and run, but after it's warmed up a bit it'll just cut out. I can then start it again and it'll run for like 10-20secs then die again. It doesn't splutter or cough, it just dies completely.
Any ideas?
How long do you have to leave it before you can start it back up after it has cut out? Sounds electrical to me.
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Bike carbs can only handle up to 3 psi of fuel pressure, so are better off run with only the standard bike fuel pump, which itself pushes fuel better than it pulls, so should ideally be mounted close to the fuel tank. ( Fraid im no expert, this info is shamelessly stolen out of an article in Classic Ford!!)
thats why you use the std fuel lift pump out of the car. with a return line thats slightly restricted, or remove the gti lift pump and fit one from a carbed car then the fuel pump from the bike can be used but somtimes they refuse to lift fuel when the tank is low as they themselves are soposed to be fed fuel under gravity
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Bike carbs can only handle up to 3 psi of fuel pressure, so are better off run with only the standard bike fuel pump, which itself pushes fuel better than it pulls, so should ideally be mounted close to the fuel tank. ( Fraid im no expert, this info is shamelessly stolen out of an article in Classic Ford!!)
I'm using the standard R1 pump for exactly that reason, the standard GTI pumps are feeding the R1 pump through the t-piece.
How long do you have to leave it before you can start it back up after it has cut out? Sounds electrical to me.
It'll start straight back up then run for a bit then die again. It runs for a shorter amount of time before cutting out each time I re-start it until it won't start at all. I then have to leave it for a while before it'll start again.
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OK, looks like it's not related to engine temp at all. Went out and started it this morning from cold and it fired up first turn of the key, (in fact it starts from cold better than the old engine on k-jet). It only ran for about 20-secs before dying again, so it didn't even get a chance to get warm. I'm starting to think it's electrical now, I've ordered a new dizzy cap, rotor arm and HT leads, lets see if they help.
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Is the fuel pump still running when it cuts out.
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No, the stock pumps switch off as they should (I can hear them switch off just after the engine cuts out) and the R1 pump automatically shuts off when the float bowls are full. The R1 pump is still running up until it cuts out, then switches off just after.
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I am sure and maybe someone else will confirm but the pump should run all the time, if so that is why it is cutting out.
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Which pump are you referring to? The R1 pump isn't designed to run all the time, it runs until the float bowls are full then stops, then starts again to keep the bowls 'topped up'. I did try bypassing the R1 pump and connected the carbs directly to the t-piece. Still the same result.
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Which pump are you referring to? The R1 pump isn't designed to run all the time, it runs until the float bowls are full then stops, then starts again to keep the bowls 'topped up'. I did try bypassing the R1 pump and connected the carbs directly to the t-piece. Still the same result.
Main fuel pump from memory should prime on ign then run all the time the engine is running.
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Main fuel pump appears to be running all the time the engine is running, the fuel filter between the t-piece and the R1 pump is still full of fuel when the engine cuts out.
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Here's a pic of the fuel circuit:
(http://i255.photobucket.com/albums/hh142/DreXeLUK/FuelCircuit.jpg)
It's set-up like this: Stock fuel pump is in place, the stock feed and return under the bonnet are connected to a t-piece, this t-piece feeds the R1 fuel pump which in turn feeds the carbs. The R1 pump is designed so it only delivers what the carbs need, it shuts off when the float bowls are full.
Could it be that the stock pump is still forcing fuel through the R1 pump, even when off, thus flooding the float bowls?
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pull the plug off the lift pump and see if that helps?
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bypass the K jet injection pump thats under the rear seats, it moves WAY to much fuel, there will be excessive pressure at the T if useing that pump, just use the lift pump to feed the bike pump.
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Potentially stupid question: Do you mean physically bypass with some fuel hose, or just pull the plug on it?
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i didnt spot you still have the main pump there, if so no wonder its playing up! that baby pumps out 5bar of pressure and 128litres an hour!
if it was me i would remove the main pump and fit your bike pump where it used to be. to do this i would find a mk3 golf fuel filter bracket, strap the bike pump to that on 1 side, and use a mk1 fuel reservoir on the other side to help prevent fuel starvation.
edit: like this, but with a bike pump rather than a k-jet inline pump:
http://www.edition38.com/forums/index.php?showtopic=227331&st=340
I'd also change the plastic fuel lines for mk3 golf ones so you can use all push fit pipework rather than messing with threaded fittings
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OK, I tried pulling the plug on the main pump and still exactly the same thing. I then pulled the plug on the lift pump too, and still no joy.....
Anyway, just as I was about to start raging my Dizzy cap and HT leads arrived. Threw them on, reconnected the pump plugs and she fired straight up. 5 minutes later it's still running, so I decide to venture up the road, still running and driving sweet as a nut :D :D
Looks like it was the dizzy cap or HT leads all along. I'll still eliminate the main pump but for now it's running, and running nicely.
Thanks for all the help people :cool:
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just goes to show, try the cheap and easy things before you get too in depth :grin:
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OK, I tried pulling the plug on the main pump and still exactly the same thing. I then pulled the plug on the lift pump too, and still no joy.....
Anyway, just as I was about to start raging my Dizzy cap and HT leads arrived. Threw them on, reconnected the pump plugs and she fired straight up. 5 minutes later it's still running, so I decide to venture up the road, still running and driving sweet as a nut :D :D
Looks like it was the dizzy cap or HT leads all along. I'll still eliminate the main pump but for now it's running, and running nicely.
Thanks for all the help people :cool:
must admit my money was on the coil.....didn't think it was fuel related tho :wink: