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K-Jetronic

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  • 10-06-2014 8:21am
    #1
    hazza
    Registered Users Posts: 72 ✭✭


    Have a problem starting my old car after its been standing a while, about 3 years. Its a 78 E21 323 with the k-jet fuel injection.
    My problem is it will crank but not start. But it will run briefly with a squirt of starter fluid - so a fuel problem?
    So far drained and replaced fuel, renewed vacuum/air hoses and plugs. Checked cold start valve, thermo-time switch, fuel distributer metering pin cleaned. WUR dismantled and checked. Next to check/replace is the fuel pump (runs when I jumper the pump relay) and fuel filter. There is also a accumulator on the fuel line keeps pressure in the line when engine off, dont know how to check this.
    Anybody out there with some knowledge/experience on these systems, would greatly appreciate some help. Need to move the car as I'm attempting to do some bodywork as well and garage is too small - cant even open the bleedin' doors.


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    #2
    jimgoose
    Registered Users Posts: 20,172 ✭✭✭✭jimgoose


    Retro Ford magazine are running a fairly in-depth guide to K-Jetronic systems last month, this month and next month. Common starting issues seem to be the cold-enrichment injector in the manifold - there's another Thermotime switch in there that can fail and keep it on all the time - and the tricky gubbins in the metering unit that traps pressure in the main injector lines when the engine is off. If the control and running pressures are arseways in there, starting can be a nightmare.

    I have last month's and this month's issues - if you like, I'll do colour photocopies of the articles and mail them to you.


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    #3
    hazza
    Registered Users Posts: 72 ✭✭hazza


    Thanks jimgoose - that sounds like a handy reference article, must get a hold of a copy.
    Yeah I think the pressures (control and system) are important and how they are balanced. Lots of info on the net but its a lot to grasp when your not confident to tackle it. Its apparently pretty solid once running but can be hard to troubleshoot once it goes out of whack.
    Oh and yes please I'd love a copy of the article if you could send it on, cheers.


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    #4
    kdevitt
    Registered Users Posts: 2,275 ✭✭✭kdevitt


    Can't help with specific k-jetronic queries, but I've just had an M20B23 removed from my 83 323i - its a k-jetronic engine too. Car only had 52k on it, but it was using a bit of oil. The whole lot is available more or less if you need it - new ht leads, plugs, refurbed alternator and a few other bits too.


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    #5
    jimgoose
    Registered Users Posts: 20,172 ✭✭✭✭jimgoose


    hazza wrote: »
    ...Oh and yes please I'd love a copy of the article if you could send it on, cheers.

    No problem. PM me an address and I'll pop it in the post this morning.


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    #6
    MercMad
    Registered Users Posts: 4,269 ✭✭✭MercMad


    Do you hear the fuel pump at all when you first turn on the ignition ?

    Does your car have the switch on the fuel distributor that senses the air plate moving , typically a blue plug similar to an injector plug ?


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    #7
    Bigus
    Registered Users Posts: 4,942 ✭✭✭Bigus


    Most common temporary fix was to short out the relay terminals, fuel pump should run constantly,in this case, just remove boxy small relay and short circuit the switching side on the block connector. Relay will indicate by diagram which of the four connectors is the switching side. If you can't here the pump run this is first thing to do, you could always run a live to the pump too.


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    #8
    conor2469
    Registered Users Posts: 523 ✭✭✭conor2469


    Hazza you said that the car has been standing a while, 3 years. I assume it ran perfectly 3 years ago when you put it away? Did you replace the petrol in the tank?


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    #9
    hazza
    Registered Users Posts: 72 ✭✭hazza


    Hi folks thanks for the helpful replies.
    MercMad wrote: »
    Do you hear the fuel pump at all when you first turn on the ignition ?


    Does your car have the switch on the fuel distributor that senses the air plate moving , typically a blue plug similar to an injector plug ?

    No sound of fuel pump with ignition full on (before starting ie. no resistance to key). Once cranking and I let go of ignition the pump runs on for a while (maybe 5 secs).
    No switch on the distributor - basic mechanical Kjet - fuel metering pin lifts in proportion to air in.
    Bigus wrote: »
    Most common temporary fix was to short out the relay terminals, fuel pump should run constantly,in this case, just remove boxy small relay and short circuit the switching side on the block connector. Relay will indicate by diagram which of the four connectors is the switching side. If you can't here the pump run this is first thing to do, you could always run a live to the pump too.

    Yeah I have shorted the relay and the pump runs constantly (noisy though- due to it being a roller bearing type?)
    conor2469 wrote: »
    Hazza you said that the car has been standing a while, 3 years. I assume it ran perfectly 3 years ago when you put it away? Did you replace the petrol in the tank?

    Was running before it was left idle. And yeah was one of the first things I did was to drain the tank and also removed sender unit and inspected filter.


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    #10
    conor2469
    Registered Users Posts: 523 ✭✭✭conor2469


    Pull out an injector, stick it in a jar and crank the engine, see if its spraying in a nice even cone, or at all for that matter.


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    #11
    hazza
    Registered Users Posts: 72 ✭✭hazza


    conor2469 wrote: »
    Pull out an injector, stick it in a jar and crank the engine, see if its spraying in a nice even cone, or at all for that matter.

    I had checked the fuel line to the cold start after I had cranked the engine and there was fuel to it. But could be flow issues
    But thats a thought to check injector flows - will look at that over weekend cheers.
    My only concern with injectors is if I take them out will i get them back in again? - thinking about those rubber grommet type seals...they look to be well hardened over time. Are replacements easily got?


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    #12
    conor2469
    Registered Users Posts: 523 ✭✭✭conor2469


    Actually pop out one of the main injectors for one of the cylinders and check it, there could be fuel getting to the injector but you want to make sure that it is actually spraying from the end.

    If the injectors are the same as the kjet cars I had then they are a simple push fit. Can be firm and reluctant to pull out but you can push them in by hand and you should feel a nice positive click when they are in fully. as for the seals I'm sure they will be easily bought, should only be a few euros. be sure to change them as the car will run very badly if they are perished.


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    #13
    hazza
    Registered Users Posts: 72 ✭✭hazza


    conor2469 wrote: »
    Actually pop out one of the main injectors for one of the cylinders and check it, there could be fuel getting to the injector but you want to make sure that it is actually spraying from the end.

    If the injectors are the same as the kjet cars I had then they are a simple push fit. Can be firm and reluctant to pull out but you can push them in by hand and you should feel a nice positive click when they are in fully. as for the seals I'm sure they will be easily bought, should only be a few euros. be sure to change them as the car will run very badly if they are perished.

    Thanks conor feel a bit more confident in tackling the injectors knowing that little extra info.
    Must get the system back together again over the weekend and will look at them in operation.


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    #14
    MercMad
    Registered Users Posts: 4,269 ✭✭✭MercMad


    The fact that is runs the pump when cranking could indicate two possibilities. Its a different circuit for cranking, so once the unit receives a signal that the engine is running then the second circuit takes over. This is to prevent the pump running continuously if a crash occurs.

    I'm not sure on that car where the signal would come from but it would be either a pulse from the coil/ignition distributor or a crank sensor since your car doesn't have the switch at the fuel distributor throttle plate.

    I might have a link to some better info......I'll search.


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    #15
    welder
    Registered Users Posts: 191 ✭✭welder


    Had a similar problem with a mk2 golf gti last year. Fuel pump outside the tank was stuck ( car had not run in 10 yrs or so) solution was to take pump off and keep swopping voltage from a battery to rock pump back and forth, kept moving a bit more each way each time and eventually freed up ! Refitted and fired up straightaway ! With K-jet start from tank and work forwards logically checking everything is working as it should before moving on to next item.


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    #16
    hazza
    Registered Users Posts: 72 ✭✭hazza


    MercMad wrote: »
    The fact that is runs the pump when cranking could indicate two possibilities. Its a different circuit for cranking, so once the unit receives a signal that the engine is running then the second circuit takes over. This is to prevent the pump running continuously if a crash occurs.

    I'm not sure on that car where the signal would come from but it would be either a pulse from the coil/ignition distributor or a crank sensor since your car doesn't have the switch at the fuel distributor throttle plate.

    I might have a link to some better info......I'll search.

    As far as I know your right with the 2 circuits for pump operation and yes it is a safety feature in the event of a crash. The car does have a crank sensor - so this might be the trigger for the second circuit.
    welder wrote: »
    Had a similar problem with a mk2 golf gti last year. Fuel pump outside the tank was stuck ( car had not run in 10 yrs or so) solution was to take pump off and keep swopping voltage from a battery to rock pump back and forth, kept moving a bit more each way each time and eventually freed up ! Refitted and fired up straightaway ! With K-jet start from tank and work forwards logically checking everything is working as it should before moving on to next item.

    Pump doesnt seem to be the problem as I can easily start it by jumping the relay contacts. But I think you are spot on when fault finding on the fuel issues - start at the tank and work forward. I've pulled so many bits off to check now that I may be causing more problems:(....but thats how to learn I guess

    Oh by the thanks guys for the inputs - appreciate it, cheers:)


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