Justin Geer

i acquired an 83 us model. I can get the car to start but the moment i let go of the key so it goes to ON its like the fuel system just stops and it slowly fades to a stop after a couple of seconds. I have a 2nd jettronic controller and it does the same for both. I checked and cleaned all ground spots per diagrams i have found. anyone else had this issue? Im thinking maybe the key switch has a bad ON contact or a thermal switch maybe?

AO

Yep... sounds like the ignition switch might be on it's way out.

James Bailey

Run a jumper wire from the jump start post over to the small +terminal on the coil. That can be used as a test, the engine should run after you crank it until you pull the wire.

Strat_928

I am thinking ignition switch as well as possible engine harness, though there are a lot of write-ups on no start or quick-dying conditions though, you can do a search on this forum, especially anything you find by Wally or Stan....they know Electricals!

I have an 83 US as well. My electrical problems were 1st with grounds points, easily fixed, won't start when hot, fixed overheating, found a loose oil sending unit, and completely rebuilt the engine harness and replaced the 14 pin connector on passenger side of engine bay.....these last two are likely to be an issue at some point unless the car was garage kept with low miles....
Then replaced the starter with smaller hi-torque model and the ignition switch, new alternator (higher power like 115) and a yellow top Optima battery and and zero gauge battery cable from the battery to the starter....this was all over a year mind you, some to fix issues some just to upgrade in general.

Good luck

IcemanG17

couple ???

1: what is the temp of the engine when you do this test? Also what is the ambient temp?

my thinking....there are two SEPERATE fuel systems on L jet cars....the main system runs of the AFM-Ljet brains and its sensors (temp II etc)....the cold start system will provide enough fuel to fire briefly then die...it is independant from the L jet....it will work if the engine is cold enough (I forget the cut off for hot start) even if the L jet brain is disconnected...

This tells me you have fuel....and if you had a spark issue it wouldn't fire at all.....so your spark must be okay?

Try this.....check the resistance of temp II....my guess is its WAY off.... On my 84 L jet it would not run at all with a bad Temp II...not start, nothing....I literally jumped the temp II with a piece of wire (which simulates hot conditions) and it ran just fine.....pull out the jumper...it would choke on fuel and instantly die (infinite resistance is extremely cold, so lots of fuel)