ljet gurus needed, help Options

[type11969]

My '76 Westy running a 2.0 ljet camper special engine decided not to start the other day . . . right before I was planning on driving it up to the poconos for NYE weekend. Better in my garage than up there. I haven't had a whole lot of time to troubleshoot but this is what I have so far:

Fuel pressure is at 38-40psi when cranking
Injectors get 12v with the ignition on
An led inline with an injector connector flashes when cranking
I smell fuel when I stick my nose in the tailpipe
Timing light indicates that I have spark
Grounding a plug also indicates that I have spark

All of the above seem to indicate that it should still start considering it was running fine over thanksgiving weekend. Only thing I did between then and now was pull the windshield to take care of some rust/install a new seal.

Some other things to mention

It will fire, barely, when initially cranking . . . thought this might be the engine running off of only the cold start valve but the LED test seems to indicate that the injectors should be firing.

If I pull a plug, stick my hand over the hole and crank my hand sure doesn't reek of gas . . . which seems to indicate that the injectors are not firing. Then again, I've never tried this before so I'm not sure how much my hand would smell of gas anyway.

So maybe the injectors are not getting enough voltage to fire? But enough to trigger the LED? I am going to pull one rail to check the spray.

Any other ideas? This is cross posted on thesamba so apologies for any repeat readers.

Thanks,

Chris

[ClayPerrine]

Get some carb spray, and spray it into the intake. I usually disconnect the hose from the aux air regulator to the big air flow meter hose. Fill up the intake and try cranking it. If it fires, it is fuel delivery. If it doesn't, check the ignition.


Fuel delivery. Start with 4 clean jars the same size. Pull the injectors and put them in the jars. Crank it and see if the jars fill up the same amount.

If not, then use a noid light to check each injector plug to verify the pulsing.

You can also use a automotive stethoscope to verify that the injectors are actually clicking......


Oh..and take a fuel sample. Could be water in the gas.

[type11969]

The injectors were just rebuilt, but yeah, I gotta run all those tests. NOID test was covered by the LED. Good idea about the stethoscope.

Thanks,

Chris

[Sleepin]

Fuel delivery. Start with 4 clean jars the same size. Pull the injectors and put them in the jars. Crank it and see if the jars fill up the same amount.

Cool idea Clay!

[RRietman]

My '76 Westy running a 2.0 ljet camper special engine decided not to start the other day . . . right before I was planning on driving it up to the poconos for NYE weekend. Better in my garage than up there. I haven't had a whole lot of time to troubleshoot but this is what I have so far:

Fuel pressure is at 38-40psi when cranking
Injectors get 12v with the ignition on
An led inline with an injector connector flashes when cranking
I smell fuel when I stick my nose in the tailpipe
Timing light indicates that I have spark
Grounding a plug also indicates that I have spark

All of the above seem to indicate that it should still start considering it was running fine over thanksgiving weekend. Only thing I did between then and now was pull the windshield to take care of some rust/install a new seal.

Some other things to mention

It will fire, barely, when initially cranking . . . thought this might be the engine running off of only the cold start valve but the LED test seems to indicate that the injectors should be firing.

If I pull a plug, stick my hand over the hole and crank my hand sure doesn't reek of gas . . . which seems to indicate that the injectors are not firing. Then again, I've never tried this before so I'm not sure how much my hand would smell of gas anyway.

So maybe the injectors are not getting enough voltage to fire? But enough to trigger the LED? I am going to pull one rail to check the spray.

Any other ideas? This is cross posted on thesamba so apologies for any repeat readers.

Thanks,

Chris

Chris; one very simple thing to check at this point is the temp sensor in the cyl head. the connector can be pretty funky. I just went thru an L-jet diagnoses and when I finally got fuel after changing the ECU, it would start/sputter/start/sputter as if it couldn't get out of cold start mode. looked at that temp sensor connector, hard wired it, sucker started right up.
good luck
Randy

[davesprinkle]

Check your dual relay. Remember that the fuel pump is enabled two ways:
1. If the starter motor is cranking.
2. If the AFM flap is deflected.

If the car want to start when cranking but dies otherwise, then the AFM section of the dual relay may have left the building.

Also, check the wires on your injector resistor pack.

[bcaschera]

[/quote]looked at that temp sensor connector, hard wired it, sucker started right up.
good luck
Randy [quote]

I think this is the issue with my l-jet, how did you "hard wire" it ? and to what? (IMG:style_emoticons/default/popcorn[1].gif) I thought i hade a fuel pump issue but i workd well when isolated. (IMG:style_emoticons/default/confused24.gif)

[RRietman]

looked at that temp sensor connector, hard wired it, sucker started right up.
good luck
Randy

I think this is the issue with my l-jet, how did you "hard wire" it ? and to what? (IMG:style_emoticons/default/popcorn[1].gif) I thought i hade a fuel pump issue but i workd well when isolated. (IMG:style_emoticons/default/confused24.gif)

By hard wired I mean I just eliminated the plastic connector and the spade connectors that connect the sensor to the wire harness. the whole thing was broken/brittle and wasn't making a good contact. solder and heat shrink= no voltage drop. makes it a little tough to change that sensor in the future, but it works.
Randy

[type11969]

Works! Why, not sure. Every test I tried it passed. Fuel pressure was good. Injectors worked, volume dispensed was equivalent and the spray pattern was good (verified by the glass jar test). Static timing was fine, spark was good all around. Put it all back together and she sprung to life. Well, took some cranking and some starter fluid but then, once running, ran fine.

The one thing I think it might be is the thermo-time switch. I found that when I was cranking to check the spray pattern the plenum would fill up with fuel and leak out the throttle body. This occurred with the AFM disconnected so I am not sure if that is part of the "shut-off" circuit. I did check and the cold start valve is not leaking when pressurized. The plugs never looked fouled though so I'm not sure this is the case. Easy enough to check, just gotta find the time.

Thanks,

Chris