Runs for a few seconds and dies Options

[aexe]

Hey all. Hoping for some advice on a intermittent issue I'm having lately. 1974 1.8L L-Jet with Pertronix Ignitor electronic ignition. Full disclosure, I AM overdue for a valve adjustment.

Six weeks ago I was a few blocks from home and the car completely died, like I had shut the key off. Coasted to the curb, spent 2 hours trying to get her to start without luck. Left overnight. Walked home. Walked back in the morning and she started right up and drove with no issues for weeks.

This morning after my coffee stop near work, she did the same thing. Started up and then died completely. Would not start again. Left there and walked to work. Went back in the afternoon and she started right up no problem. Drove to 20 minutes to my shop space with the intent to swap to a new ignition switch, as I thought this might be the issue, as well as changing out the AFM as I had ordered a new one due to some FI issues I've been chasing. Replaced both this afternoon. Tested and fired right up, solid idle. An hour later I drove home, about 10-12 minutes. As I was pulling into the garage, the idle dropped but I was able to catch it and pulled into a spot. I spent the next half hour starting and restarting the car, finally taking this video for a reference. The car starts and runs for a few seconds, the idle sways, almost recovers and then shuts off, regardless of throttle position it seems. I was also checking voltage from the alternator to the battery which above idle seems to be in the mid 13's. Also, it was raining on the way home if that matters.

I would love ANY thoughts on the car's behavior in this video. Stumped. Thanks in advance.

https://youtu.be/kkCBQGRhI5s

[Spoke]

Not familiar with LJET. Does the fuel pump run when the key is turned on? Does it have contacts on the distributor like DJET? FWIW, I don't think the valve adjustment would cause the car not to run.

Because it comes and goes it sounds electrical. Do you have a gauge to monitor fuel pressure? Have you tried starting fluid? Starting fluid can let you know if it's gas (tries to run) or electric (won't run with starting fluid).

[914Sixer]

Vacuum leaks are a problem with L-Jet. Make sure your hoses are good and the seals on the oil filler neck. Also check your ecu wire harness, you may have a high joint. Wire in sheath is together when cold and goes open when engine gets hot.

[rbzymek]

My Pertronix Ignitor III would drop sparks at idle when it was hot. It was enough to cause a stall like you are experiencing. I would install points so that you can confirm or rule out. I returned my Ignitor III for a refund and waiting to receive the Ignitor II which is a different design but still has dwell control and reverse battery.

[SteveL]

I just resolved a similar issue, 74 1.9 LJet - car would run fine for 10-20 minutes, then die. Wait a few minutes, then restarted fine. Turned out to be a failing coil.

[aexe]

Thanks for the replies! I resolved the startup stall problem but simply adjusting the idle up after realizing that the timing of the shut off was darn close to how long the aux air valve would be open. Idle is now a little high once warm but we are on the road.

@SteveL I also replaced the cap, rotor and coil and immediately got better running and no stalling. The old coil even tested ok but a new one made the difference.

[jim_hoyland]

Good to hear your OK; L-Jet will also run for 5 -10 se SS if the connector at the AFM isn’t connected. ......Never had one come loose while driving, but have forgotten to reattach after servicing.

[porschetub]

Sorry but you can't test a coil,if the windings are bad it will only show up after you have run for a while which was obviously your issue ,plug leads break down in a similar way also.

If your timing is set correctly then do your valve setting then move on to how the FI is working,you need a good baseline to start with otherwise you are chasing your tail with other issues.


I would expect you will be looking for air leaks after that ,no afm based injection will tolerate leaks and will always revert to a high idle.


L-jet reponds on movement of the air gate on cranking to start the fuel pump via the ecu signal from the throttle position switch,no air and the fuel pump afm contact is in the game (closed ) and it won't run the pump.

Think thats right if not correct me...happy new year.