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Bosch K-Jetronic fuel injection?....


Wobby
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It a mechanical fuel injection,

Air is sucked from under the airbox past a rising plate, as the plate rises more fuel is delivered to the engine.

That the basics, there a lot of other parts like thermo time switches and warm up valves but they get very complicated. 169144-ok.gif

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I knew this forum would have the knowledge!! beerchug.gif

Its fitted to a Westfield kit car. The engine is a ford pinto 2.0 thats been turbo'd. Have a starting problem from cold. It refuses to start unless we lift the flap a fraction to force it to inject fuel, this is a problem as although it will the run when held on the throttle, for the engine to run it needs the ducting in place to create airflow to lift the plate.

So we get it to start, holding it on the throttle with the plate held open. Then let it stop put the bits back together and away it goes. No big deal but does need sorting. It does have 2 extra injectors for cold start (not checked these are working but we think we can hear them activate). They're not on a timer, just on a switch on the dash blush.gif

Main problem is when you lift off the accelerator we get unburnt fuel through into the exhaust, this ignites and makes bit of a noise with the occasional flame out the end of the exhaust. We have just changed the head, the old head was a leaded head (we think) and had suffered valve damage (not stripped to confirm yet).

Also as we go up the revs its seems to run out of steam and misfires. The cam and valves are standard btw. No working rev guage so not sure of revs. It seems to fly once on boost then misfire so you have to change up! It has a boost switch but it just fisfires on full boost. Low boost is 160bhp and full boost is 190bhp, my guess is we are around 130bhp. Car weighs 570kg so it feels fast to us but do need it running better as we are going to track days in a month or so.

On the metering head there is 2 allen ket adjustments. One is for idle and the other is for fueling levels higher on higher air flows. Not sure if we should mess with these setting without correct equipment.

It does have a warm up valve that seems to have bimetalic/ heater strip that allows extra fuel through until it heats up over a few minutes. The electrical connection looks to have never been connected.

My thoughts are that at least on injector is not sealing and is dribbling fuel into the manifold. We can check this and the quantities of fuel to see if they are injecting similar amounts of fuel.

My other thoughts is that the CR is too high for the turbo and we get detonation. The turbo was fitted by Turbo technics a long time ago. I think the engine has had a lot of parts replaced since then.

Going to take the car to a rolling road tuner who specialises in ford turbo'd engines. But would like to get as much corrected first.

Sorry to babble, but thats the ideas and any thoughts would be appreciated. I have probably made the car sound bad, but its not. Start it up and you develop a big silly grin that just gets bigger and bigger!!

Thats once you've started the fecking thing smile.gif

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[ QUOTE ]

I knew this forum would have the knowledge!! beerchug.gif

Its fitted to a Westfield kit car. The engine is a ford pinto 2.0 thats been turbo'd. Have a starting problem from cold. It refuses to start unless we lift the flap a fraction to force it to inject fuel, this is a problem as although it will the run when held on the throttle, for the engine to run it needs the ducting in place to create airflow to lift the plate.

So we get it to start, holding it on the throttle with the plate held open. Then let it stop put the bits back together and away it goes. No big deal but does need sorting. It does have 2 extra injectors for cold start (not checked these are working but we think we can hear them activate). They're not on a timer, just on a switch on the dash blush.gif

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Sounds like the plate stop is too low, Remove the metering head, Look under the plate and you see a little spring that holds the plate up when it fully down, bend this to make the plate sit a touch higher in the chamber.

[ QUOTE ]

Main problem is when you lift off the accelerator we get unburnt fuel through into the exhaust, this ignites and makes bit of a noise with the occasional flame out the end of the exhaust. We have just changed the head, the old head was a leaded head (we think) and had suffered valve damage (not stripped to confirm yet).

[/ QUOTE ]

Because it mecanical there no over-run cut off so you will allways get fuel injected on over-run

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Also as we go up the revs its seems to run out of steam and misfires. The cam and valves are standard btw. No working rev guage so not sure of revs. It seems to fly once on boost then misfire so you have to change up! It has a boost switch but it just fisfires on full boost. Low boost is 160bhp and full boost is 190bhp, my guess is we are around 130bhp. Car weighs 570kg so it feels fast to us but do need it running better as we are going to track days in a month or so.

[/ QUOTE ]

Sounds like the fuel leaning out at the top end of the rev range, try firing the cold start injectors when it happens.

[ QUOTE ]

On the metering head there is 2 allen ket adjustments. One is for idle and the other is for fueling levels higher on higher air flows. Not sure if we should mess with these setting without correct equipment.

It does have a warm up valve that seems to have bimetalic/ heater strip that allows extra fuel through until it heats up over a few minutes. The electrical connection looks to have never been connected.

My thoughts are that at least on injector is not sealing and is dribbling fuel into the manifold. We can check this and the quantities of fuel to see if they are injecting similar amounts of fuel.

[/ QUOTE ]

Very common fault is leaky injectors on this style of injection, Least new injector are quite cheap

[ QUOTE ]

My other thoughts is that the CR is too high for the turbo and we get detonation. The turbo was fitted by Turbo technics a long time ago. I think the engine has had a lot of parts replaced since then.

Going to take the car to a rolling road tuner who specialises in ford turbo'd engines. But would like to get as much corrected first.

Sorry to babble, but thats the ideas and any thoughts would be appreciated. I have probably made the car sound bad, but its not. Start it up and you develop a big silly grin that just gets bigger and bigger!!

Thats once you've started the fecking thing smile.gif

[/ QUOTE ]

What boost are you running?

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Thanks Tobes 169144-ok.gif

Boost gauge is now fixed and shows towards 14-15psi when the misfire is bad. This is on the low boost settings for the ECU. There is a variable rev limiter fitted but i dont think we are anywhere near it when it misfires. When we have hit the limiter before you can sort of tell its the limiter (i think smile.gif ). Its off like a shot as the boost comes in then seems to misfire lose acceleration at maybe 10psi. I think 10psi is enough to cause detonation on a standard head with standard CR.

Will try firing up the cold start injectors as we get to the misfire. Could knackered injectors cause this problem? From what i have read the system should cope with upto 210bhp max.

There is an idle mixture adjustment, through a hole sitting inbetween the metering head and air plate. Would this be worth an adjustment? It just lifts the plate slightly to make it inject more.

Thanks again beerchug.gif

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[ QUOTE ]

It was also fitted to my Mk2 Scirroco GTI, and I know very little about it. If you're very lucky, I might have a set of 8V 1.8ltr injectors sitting around on a shelf.... 169144-ok.gif

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Would these fit/ work on my system? Trying to source the injectors. Stamped on an injector is 463223. Sent this to a supposed expert with these systems and he says thats not a part in any catalogues frown.gif

He says it will be in the format.... 0 437 502 xxx

Is there that many different ones? We will get this car sorted if it kills us. And if we get it sorted then it WILL probably kill us laugh.gif

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Injectors are Bosch 0 437 502 012, wheres the best place to buy a set of new ones? What sort of cost involved? Seems £125 (ish) is normal for them.

2 injectors seem to produce a one sided spray (poor description!), athough none are over bad we decided to fit 4 new ones if we can.

Found the cold start extra injectors dont work! No wonder we have to lift the flap to get it to start. Seems to be an electrical problem, we have started to trace the wiring!

Thanks for the advice 169144-ok.gif

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[ QUOTE ]

Thanks Tobes 169144-ok.gif

Boost gauge is now fixed and shows towards 14-15psi when the misfire is bad. This is on the low boost settings for the ECU. There is a variable rev limiter fitted but i dont think we are anywhere near it when it misfires. When we have hit the limiter before you can sort of tell its the limiter (i think smile.gif ). Its off like a shot as the boost comes in then seems to misfire lose acceleration at maybe 10psi. I think 10psi is enough to cause detonation on a standard head with standard CR.

Will try firing up the cold start injectors as we get to the misfire. Could knackered injectors cause this problem? From what i have read the system should cope with upto 210bhp max.

There is an idle mixture adjustment, through a hole sitting inbetween the metering head and air plate. Would this be worth an adjustment? It just lifts the plate slightly to make it inject more.

Thanks again beerchug.gif

[/ QUOTE ]

The idle adjustment hole only effects idle, So it wont cure you misfire.

The firing the cold start injector is a test to see if the mixture is leaning out on boost.

Looks like they have used a Saab metering head/injectors for the conversion, with that injector part number. 169144-ok.gif

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Will replace injectors if we can find some! Is it worth having them tested? Can they be recalibrated?

Going to run the cold start injectors once we get them working to see if it reduces the misfire.

Thanks for the Saab info, at least we now know where to look smile.gif Are the injectors interchangable off other systems?

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[ QUOTE ]

Thanks. Best i have found so far is £46.50 inc VAT each but he hasn't got them in. Will take him a few days to get them.

Is injector cleaner worth a try tobes?

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Injector cleaner can work, but it's very slow. You could take them out and get them cleaned on a injector cleaner, This cost but could work out a better way than injector cleaner.

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[ QUOTE ]

i think my old XR3I used the bosch K injection system, try some ford breakers for spares...

Maybe ?? :-)

[/ QUOTE ]

Lots of cars used K-Jet injection but every system is different. The fuel supply on a XR3I wont be up to fuelling the turbo pinto engine

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re wired the cold start injectors and got them working, starts great now smile.gif

Was let down with someone for the new injectors, are going to order them from GSF (cheaper and sounds like he will get them!). Away in Scotland at moment so will be a few weeks before we get injectors sorted.

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Have you seen how much fuel squirts out of them! gonna give them a try during hard acceleration and switch them on from about 4.5k. Wont they flood the engine? have located an expert on these engines, sadly hes in Plymouth! Has anyone used steel plates with the head gasket to reduce CR? I think this will be our main problem

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Thanks for the info Tobes. Appreciate the lower comp pistons are the best option. We are after a simple fix to allow us to track the car over the summer. During this time we are also looking to build a replacement engine, probably with a cosworth head and either with or without the turbo. I think the de-comp plate may be an option to us.

Done a few alterations today. Did try to switch the cold start injectors on while flooring the accelerator. TBH its terrifying, clinging onto the steering wheel for dear life and then trying to watch the rev guage as well. I tried twice and i do think it seemed to help us get past the area of the revs where it pinks but TBH i couldn't look properly, just not got the time or bollocks! blush.gif

I think the distributor is a standard pinto one. It will advance the engine way to far, this is what i think is part of the problem. Disconnected the vacuum advance and blanked the tube, this should have reduced the total advance when we lift off the throttle. With the vacuum on and with the fueling system we had a banging in the exhaust on a trialing throttle. This has reduced although is still present.

I have also reduced the engine timing, its now showing as firing ATDC, this has reduced significantly the pinking and now allows the engine to rev fully. It has lost some power lower down but the engine feels better at all revs.

A warm day today and the engine hasn't overheated although temperatures are very high if driven hard.

Going to change the radiator next and measure the cc of a standard head and check piston height at TDC.

Any extra advice appreciated. I think a correctly set up distributor for the turbo would be a big improvement for us. The advance curve for the standard one has too much advance.

Thanks again 169144-ok.gif

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Can we just clear up some things?

Have you cured the cold start problem? with raising the plate?

The problem up the top end of the rev range on boost. At first you said it had a misfire and now your saying it pinking?

Back to the Distributor,

Removing the Vacuum side of the distributor advance wont make any differnce to the advance on WOT (wide open throttle). Vacuum advance in only for part throttle.

You got to take the distribtor out and inside there will be some weights with springs, You need to change the springs for a stronger unit, These stop the weights coming out so fast and hold the advance out longer. There will also be some limit stop you can try bending these it a touch to reduce the overall advance.

Next question. What fuel you running the engine on? and any form of intercooling?

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