1982 242 DL plugs are full of fuel, spark is fine, engine suddenly dies and will not start. Fuel pump fine.....where to go next????
Thanks

Bill

 

82, thats K-jet (CIS) rather than LH ?

is the cam turning? (remove oil cap, have someone crank starter while looking in at the camshaft, is it turning?)

'spark is fine', how have you tested this? usually wet plugs means no spark.

 

Fuel Injection system.....does that answer you first question??
Cam is turning over......removed spart plug, grounded it and good spark...
removed injectors none leaking under static test....
finding a lot of bare wires in engine area.....working on that now

 

K-Jetronics and LH are two different fuel injection systems. early 240's used k-jet which is also called CIS (Constant Injection System). Later ones were LH which is electronic injection. 82 was the switchover year, and could either.

in K-Jet, the injectors are all plumbed to a fuel distributor assembly which has an air flow plate that modulates the fuel pressure hydraulically. in LH, each injector has a electrically controlled valve which is modulated by the computer to control how much fuel, and the airflow is measured by a 'MAF" mass air flow sensor also known as a AMM (air mass meter).

one thing to check... on both KJet and LH, the fuel pressure regulator has a vacuum hose connected to the back of it. disconnect that vacuum hose and see if its full of gas. if it is, the fuel pressure regulator has failed, and its probably flooding the engine.

bare wires is bad, for sure. pain to deal with as many wiring harnesses for older model cars are now unobtanium, and even if they are available, they can be rather expensive. rewiring the whole engine by hand is labor intensive and error prone, and frustrating because you have to reuse the existing connectors (you CAN get the various pin inserts for the shells, but most of the connector shells are also no longer available).

best resource for wiring harnesses is Dave's Volvo Engine Wire Harness Page

 

Thanks pierce:
yep, I have the k-jet system. will look into fuel pressure regulator hose to see if it's has gas in it.......what if the hose has a leak in it..what type of problem will be seen in the engine??????
thanks again

Bill
snowing in Boston on Sunday
might be able to work on the car

 

if the vacuum hose has fuel in it, that means the fuel pressure regulator diaphragm has failed. you need a new FPR. if the vacuum hose splits, you just lose vacuum, and your fuel pressure is a little high, but no fuel gets into it.

wait, I'm not even sure K-Jet uses the same sort of fuel pressure regulator as the LH cars. I know it uses higher fuel pressure than LH. I know little about k-jet systems other than theory, so I'll have to defer to others with experience.

 

It has a "warm up regulator" behind the distributor cap...and it is quite expensive...junk yard part...
this part shoots the fuel back to the tank as I have read as soon as it starts? So if it continues to let fuel go by it might be flooding your plugs??????? check you k-jet.org...

$265 for a rebuilt one from a shop in Texas...and you have to send yours in....
Try a late model SAAB or an 80 BMW to 83 I think...they have the same warm up regulator but double check the numbers. I found one on an 82 3 series BMW...junk yard.

 

fuel injection systems all use a closed loop system, where the pump sends gas through the injection system, and the excess gas goes back to the tank.

I couldn't find a 'fuel pressure regulator' per say on my parts catalog drawings of the 82 B21F k-jet version. it showed a "control pressure valve" which I think is used by the lambda (o2 sensor) system, a 'frequency valve', the fuel distributor, the 'volumeter' that has the air plate and modulates the fuel distributor, the constant idle system (which is an air valve and controller). there's some sort of 'pressure accumulator' down by the fuel pump.

K-Jet.org | Mechanical Fuel Injection Power! is a good site for k-jet stuff.

 

Bare wire are repaired. The fuel injectors are flooding the engine. Have all injectors in a glass jar, when cranking the engine all injectors constantly pouring fuel in the jar. Just about fills it up in a matter of no time. There is no on off of the injector, more like a flow of fuel....like there is no control of the injectors....

K-Jet electronic injectors, not mechnical

Thanks Bill

 

In Rolls Royce manuals I think they call that fuel pressure regulator something stupid like 'fuel accumulator.' That may give you another search string. This may sound stupid, but look at the air metering flap and make sure that it moves and closes when no air is passing through it. It will be on the K-jet body next to the round thing where all the injector lines come together, but in the airway of the intake. if it's staying open that will make a lot of fuel flow.

I really have no idea what that means, but if it's K-jet, the injector are purely mechanical. They always inject fuel (hence constant injection) but flow is mechanically regulated by the body in relation to the movement of that the flap-thingy in the airway. Good luck!

 

The fuel pressure accumulator is for warm starts. It is a spring with a diaphragm that holds pressure on the system when you shut the car off. Something to do with vapor lock I believe. Not 100% necessary. I had an 84 VW Jetta that did not have one when I bought it. It would always start but started much better when I put a new accumulator on it.

 

My mistake. The volvo has the LH Jetronic fuel injection. I think the ECU control the injectors by electrical pluse. But am not sure. So, maybe the ECU is bad cuz the wires were bare, burning out the unit...my best guess

Thanks
Bill

 

on the volvo k'jets, the flap is UNDER the throttle body and intake manifold, real pain. its much simpler on the benz 300E engines where it sits on top of the intake path, you just remove the air cleaner to access it.


anyways, this article has a very good explanation of Volvo K-Jet. the 'fuel pressure regulator' function is done IN the fuel distributor (my k-jet benz has an external one)
http://www.k-jet.org/articles/inform...jet-in-detail/

 

oh, whole different system. phew, if some wires were bare, ALL insulation in the engine compartment is suspect, and much of it is buried under the black sheath tubing where you can't see it..

I wouldn't write off the ECU without further tests.

the injectors are wired together, one side of all 4 goes to the fuel injection power relay (so its powered when the engine is on), and the other side of all 4 goes to pin ? of the ECU, which 'grounds' this pin to turn on the injectors. the sort of circuit is more prone to failing 'open' than permanently grounding itself.

 

Interesting. I still can't figure out why it's called and accumulator.

I can imagine. Makes it hard to just look at.

I think it's a crossed wire that's grounding out the injectors giving it an infinite pulse-width.

For anyone who is interested:
The fuel pressure regulator keeps the pressure in the fuel rail at a constant pressure above the intake manifold's pressure (like 42psi). That way the flow of gas through the injector orifices is constant. The amount of fuel that's injected is controlled by pulse-width modulation (PWM). The time that the injector is open controls the amount of fuel. It can be calculated easily by a computer. Every two revolutions of the engine the correct the correct amount of fuel needs to be injected for ignition. The injectors "batch fire" (meaning all four at once, like Pierce mentioned). So the amount of pulse width for the right amount of fuel is split into four parts occurring every half revolution of the engine. In two revolutions the charge (gas air mixture) is all there and it gets sucked into the combustion chamber.

So after all that. I agree with Pierce that you should check the wiring and make sure it's not grounding the injectors. You handy with a multimeter?