vanster

I'm now working on my 81 full time but first of all I can't get it to stay running
Here is what I have done to date:
Dropped the fuel tank and power washed it
New filter
7 gallons of gas
Witch Dr cleaned the injectors
New plugs
New vacuum lines
Temp II sensor
I can get it to fire using starter fluid and gas is coming thru the fuel lines. Using starting fluid it will run for 5 seconds and but no more.
Could this be fuel pressure?
Dirty fuel filter?
Vacuum issue

dzaprev

Check if injectors are working with a noid light .

vanster

Can I jump the ECU relay similar to jumping the fuel pump relay?

The Forgotten On

Yeah, it's just a 4 pin relay IIRC.

vanster

Thanks Blake
I'll report back soon

vanster

I jumped the #8 relay and it really didn't make a difference. It still will run for about 30 seconds on it's own then die. If I use starter fluid it will start a bit easier but it still dies. The plugs are dry however if I let it sit for 20 or 30 minutes it will start on it's own without ( no starter fluid ) then die after 10 seconds. It's running on all 8 and sounds OK, just won't keep running

skpyle

Van, random stupid thought: could it be running only on the cold start injector? And when that drops out, no run?
Like I said, just a thought.

vanster

Seth,
It feels like it, not a bad thought. How do you bypass the cold start? It's really warm out today which helps. I keep trying to get it to run with starter fluid hoping to get it warm.

skpyle

Van, unfortunately I have ZERO experience troubleshooting L-Jet. We won't even mention that my LH-Jet 928 has not run in 2 1/2 years.
Let me research and get back to you.

vanster

I find the challenge with this actually very rewarding, frustrating but rewarding once we solve it.

Mrmerlin

how old is the pump

drscottsmith

dr bob

Van --

Unplug the cold-start injector and see if you still get that first few seconds of run with it disabled. It won't solve the problem, but will narrow it down to the other injectors.

A 'noid light would seem a good tool to try, to see if the injectors are indeed getting energized.

dr bob

Hmmmm... Belay that last. Looking at wiring diagrams, I don't see any cold-start injector. Does one actually exist on your car?

Injection-everything relies on the AFC relay in position XVI, no fuses, powers directly from the 30 bus at the CE panel. That relay is almost a simple 53B relay, but has a diode built in to "protect" the relay coil from energizing backwards from 31 (ground) back to 15 (hot on ignition switch in run or start position) although I can't see how that would be a concern. The relay closes when key is in run or start position. Anyway, that relay powers the injectors themselves and the controller. You can test for battery voltage at W2, W3, W4, W5 while cranking to see if the relay is carrying enough current. The hot side of the injectors receive battery power via the relay, while the controller grounds the other side of the injectors to get them to open. If the controller isn't trying to open them, a weak relay may in fact supply enough current to show battery voltage even while cranking.

The injection controller gets control signals that tell it the starter is cranking, and it also gets ignition/tach pulses from the spark box. These need to work to get even that initial run for a few seconds, at least on the spark side. Not clear how we'd get a look at why it sort of runs then craps out. Have you confirmed that you still have ignition on crank after the brief run ceases? Inductive timing light is a handy tool for a casual look. Might be as easy as a fubbled green wire?

Lizard928

The car does have a cold start injector.

Follow the suggestion about checking for injector pulses with a noid light.
Test all 8 injectors plugs for signal.

What condition is the green wire in?