pugtech

My 1980 US Manual was running fine. Parked it overnight and now it starts for a few seconds then sputters and dies. Please check my logic:

With ignition on, I get 12V on both conductors at the injector
With ignition off, I get near 0V on both conductors at the injector
No light from a noid when cranking
(I jumped the AFC relay just in case)

This tells me that the AFC relay is good and the control unit is getting power. I think the control unit is bad or it's not getting a rotational signal from the distributor. Is there a testing procedure for the sensor? Is this the infamous green wire I've read about? In the WSM, is the L-Jet the same as LH?

Thanks much...

w3lfd

I'm having a similar issue, you can check out the progress in this thread. https://rennlist.com/forums/928-forum/382430-afc-troubles.html

I am at least able to get mine to start by manually depressing my AFC flap. maybe something discussed there will help you.

Jack Riffle

I am having a slight problem with this. Can't reconcile the two. If not for the second statement, I would say it's a fuel pump relay or the fuel pump itself, since, as you say in the first statement it runs for a few seconds and that makes me believe it's running on the small amount of fuel that the cold start injector provides............Must have another Captain Morgan and ponder this.....

pugtech

I believe you are correct, it's running on the cold start injector. The regular injectors are not firing so I suspect the control unit but there may be another test I can do before placing the order.

Thanks...

j.kenzie@sbcglobal.net

You may be running on your cold start injector with no function of main injectors.

Jack Riffle

Okay, pondered this with the Captains help. There is a ground wire on the passenger side cam cover coming from the injection harness. If this ground is corroded or disconnected THERE WILL BE NO POWER TO THE INJECTORS and the car will not run. I learned this the hard way. Check this out.

pugtech

Does anyone know how to confirm the signal to pin 1 (Engine speed from TZS 16) on the L-Jet controller? Would any other sensor inputs to the controller cause Zero firing of the injectors (not a single noid blink)?

Thanks!

w3lfd

I was going to test mine with an analog (kind with a needle) voltmeter. I should think you would see a fluctuation in the needle if you are getting signal. You are going down the same road I am on my 1982. My noid light was basically useless. When I got someone to crank the starter, there was no signal on the noid light. I was able to get the car to run by depressing the AFM trap door while someone else was starting the car. I'm still working on getting mine going, but I've had temp 2 sensor / idle switch / aux air valve recommended to check, so that's my next step on mine. Hope you get it running.

pugtech

I replaced the L-Jetronic controller and the car started right up.

hacker-pschorr

The brain box in the footwell or the AFM under the air cleaner?

I've been collecting parts. I now have two L-Jet computers, three AFM, three ignition amps, two spare green wires, and a glovebox full of jumper leads.

pugtech

The controller in the footwell...

dr bob

Stupid stuff...

A local here spent DAYS diagnosing similar symptoms. Bought CIS gauges. Refurbed ignition. New WU regulator, and lots of others tuff since control pressures were so far off. Final verdict...
















It was out of gas.

Gauge showed there was a little, but there wasn't enough.

Good news is that the fuel system was cleaned out, new o-rings and seals in the fuel distributor, new WUR, etc. And I lnow where I can borrow the CIS gauges.



Start with the easy stuff!

BlackShark

I guess I'll jump in on this one as well. My 81 didn't just suddenly not start one day, seemed a little more progressive. Wouldn't start on the first try but would start. When it got to the point of not starting at all it seemed like jumping the fuel pump relay fixed it, but the next time it wouldn't start so it wasn't the fp relay. Now the symptoms are as above. It will start briefly, then die the first two or three times you try, then it doesn't seem to fire at all.

This weekend was going to try jump the FI relay to see if that makes a difference. Couldn't buy noid lights locally so I ordered a kit should be here next week. Also ordered a green wire from Roger. Even if that's not the issue this time seems like a good thing to replace every 25 years or so.

pugtech

Can you test the voltage at the injectors, with and without the ignition on?
- With ignition on, you should get 12V on both conductors at the injector
- With ignition off, you should get near 0V on both conductors at the injector
Do you have an L-Jet pinout?
- Confirm inputs into the L-Jet (power, grounds, sensors and pulsed signal from ignition box)
Once you have a noid on an injector, it will help a lot.

BlackShark

Friday night I jumped the FI relay, (2 87's to 30) and it started. Received a new relay from 928'srus on Saturday afternoon and it still started so it looks like it was the FI relay. Turned out to be an easy fix, I hope. It will have to start a few more times without issue to make me feel comfortable.