Ongoing KJet heck…any ideas?

[AllHailKingVolvo]

Hi all,
I’ve had all manner of consternation whilst trying to sort the B200E in my ‘88 740.

The car was running fine, but broke down due to fuel pump failure. Replaced the fuel pump and the car wouldn’t run. Found a dry joint on the pump relay, reflowed the solder and still it won’t run despite the pump actuating when cranking as per what a KJet car should do.

The old fuel pump was the wrong size-I’m surprised it ran at all. The new one is the correct larger bore 6 bar pump for the system.

The car has spark but no fuel is coming out of the injectors when cranked (I pulled one and put it in a jam jar whilst my stepson cranked it over) and lifting and closing the metering flap under the intake bellows makes no difference.

There is pressure at the distributor (cracking off the banjo bolt creates a mushroom cloud of fuel!) but no fuel seems to be progressing beyond there.

Does anyone have any ideas? I’m thinking either fuel distributor or metering unit, as beyond that all there is is injectors, and I don’t see how all four of those can fail at once.

Any and all advice very gratefully received!!

[Laird Scooby]

Originally Posted by AllHailKingVolvo

Hi all,
I’ve had all manner of consternation whilst trying to sort the B200E in my ‘88 740.

The car was running fine, but broke down due to fuel pump failure. Replaced the fuel pump and the car wouldn’t run. Found a dry joint on the pump relay, reflowed the solder and still it won’t run despite the pump actuating when cranking as per what a KJet car should do.

The old fuel pump was the wrong size-I’m surprised it ran at all. The new one is the correct larger bore 6 bar pump for the system.

The car has spark but no fuel is coming out of the injectors when cranked (I pulled one and put it in a jam jar whilst my stepson cranked it over) and lifting and closing the metering flap under the intake bellows makes no difference.

There is pressure at the distributor (cracking off the banjo bolt creates a mushroom cloud of fuel!) but no fuel seems to be progressing beyond there.

Does anyone have any ideas? I’m thinking either fuel distributor or metering unit, as beyond that all there is is injectors, and I don’t see how all four of those can fail at once.

Any and all advice very gratefully received!!

It sounds as if there's an airlock in the fuel distributor Phil - as you know air can be compressed but the fuel can't so you might sort it by bleeding the distributor - crack the banjo bolts to the injectors on the fuel dizzy one at a time while cranking until fuel comes through each then nip up again.

Also as a precaution, before you do that, squirt some Easystart into the air intake and make sure it fires on that, just to confirm it is only a fuel problem.

Try tapping the top of the fuel dizzy with the end of a hammer handle while cranking too, it's possible the pressure valve is stuck. If so, add ~300ml of synthetic ATF (eg Carlube ATF-U or NAPA mva) to a full tank and pro rata less for anything in between.

Overall it sounds as if t's a silly fault that you can easily clear - as soon as you find it!

[AllHailKingVolvo]

Originally Posted by Laird Scooby

It sounds as if there's an airlock in the fuel distributor Phil - as you know air can be compressed but the fuel can't so you might sort it by bleeding the distributor - crack the banjo bolts to the injectors on the fuel dizzy one at a time while cranking until fuel comes through each then nip up again.

Also as a precaution, before you do that, squirt some Easystart into the air intake and make sure it fires on that, just to confirm it is only a fuel problem.

Try tapping the top of the fuel dizzy with the end of a hammer handle while cranking too, it's possible the pressure valve is stuck. If so, add ~300ml of synthetic ATF (eg Carlube ATF-U or NAPA mva) to a full tank and pro rata less for anything in between.

Overall it sounds as if t's a silly fault that you can easily clear - as soon as you find it!

Thanks Dave! Alas it’s proving somewhat more troublesome than I had anticipated. I’ve cracked off the banjo bolts to the injectors (one by one, then all together to see if that cleared anything) whilst the car was being cranked and I still can’t get any fuel through. The only injector getting fuel seems to be the cold start injector (I managed to get fuel through the banjo to this one when cracked off), which is of course electronically controlled rather than pressure activated so doesn’t need the pressure.

Am I right in thinking this indicates a fuel distributor fault? I’d imagine even if the pump was weak (which it shouldn’t be as it’s new! There would still be fuel coming through the injector feed pipes, as the injectors themselves are what hold pressure and release it when required, as I understand it.

I’m foxed by this…I know it’s a relatively simple system which makes it all the more frustrating that the car has been off the road for three months now with an issue I can’t fix!

[Laird Scooby]

Originally Posted by AllHailKingVolvo

Thanks Dave! Alas it’s proving somewhat more troublesome than I had anticipated. I’ve cracked off the banjo bolts to the injectors (one by one, then all together to see if that cleared anything) whilst the car was being cranked and I still can’t get any fuel through. The only injector getting fuel seems to be the cold start injector (I managed to get fuel through the banjo to this one when cracked off), which is of course electronically controlled rather than pressure activated so doesn’t need the pressure.

Am I right in thinking this indicates a fuel distributor fault? I’d imagine even if the pump was weak (which it shouldn’t be as it’s new! There would still be fuel coming through the injector feed pipes, as the injectors themselves are what hold pressure and release it when required, as I understand it.

I’m foxed by this…I know it’s a relatively simple system which makes it all the more frustrating that the car has been off the road for three months now with an issue I can’t fix!

I think you need to lift the lid on the fuel distributor Phil. It's a long time since i've done one so can't remember much now but i think there's 8-10 bolts/screws round the edge then lift it vertically, being careful not to drop anything. A sheet of something white under the car will help find anything that does drop.
I suspect the airflap mech and/or the valve operated by it is the problem, you have fuel pressure in the distributor or you wouldn't have it at the CSI so it points to the metering mech/valve operated by the air flap.

[panda529e699]

When I was adding a turbo to my B230E I came across some info which may be useful.
One involved removing all 4 injectors and putting in a container or something, linking the fuel pump relay, and whilst the pump is running lift the metering flap up by hand, I used some good fine pliers, and monitor the out put from each injector.

Another one was that excessive control pressure can cause no fuel at the injectors, it may be possible to lift the metering flap manually but once its back together the pressure causes the problem. Releasing pressure at both pipes on the Warm up regulator was mentioned.

Andrew