240: 1992 240 lh3.1 no start

[sloopy]

1992 240 with lh3.1
the engine was running fine maybe 3 months ago before doing suspension and brake work. i removed the intake plumbing to get access to the brake lines and have put it back. the only other thing i can think of that has changed is that i removed the abs and harness from the car. here is what happens:

1. i turn the ignition on and let the fuel pumps run
2. i start it, and it cranks strongly
3. i get a few fires, but the engine never runs

no fault codes on the ignition or fuel modules so far. i tried unplugging the maf and the o2 sensor. neither one worked in isolation or together. wiring in general looks fine as far as i can tell. it is also very hot and humid at the moment.

[woodenpudden]

Everything but injector pulse? Will it run on starting fluid? Sounds like the same **** mikep is working with on his LH3.1 wagon

[sloopy]

the injectors seem to be pulsing. i can feel them click during the self diagnostic test. i havent tried running it on starting fluid (i dont really want to try at this point) but im sure it would. the engine is mechanically sound. it seems like a fuel mixture problem. im going to order a coolant temp sensor.

[esmth]

I'd confirm both fuel pumps are running. The cranking with few/odd cylinder fires happened to me when the [wiring to the] external pump died. It could almost run on just the in-tank one, it would let some fuel dribble in but it couldn't stay running.

The humidity could also make the spark not happy. I had this problem on a wet morning of the spark arcing from the coil high tension wire under the boot to the coil case. (w/ bosch 2x2 wasted spark coil.) This one stumped me for hours as the plugs would fire perfectly fine when laid across the valve cover, but when installed in the engine, the it was easier for the spark to jump to the coil case. Only found this out once the sun went down. WD40 sprayed all over it and in the boots fixed it for awhile

[sloopy]

I tried starting it again this morning while the weather was not too hot yet. same thing. i will double check that the in-tank pump is working, but the main fuel pump is absolutely working and i can hear that it is pumping liquid. i ordered the coolant temperature sensor and im going to add some fresh fuel to the tank. there is about a gallon or two of almost 4 month old gas in the tank. i will double check the electrical connections on the ignition system. when the engine fires at all, it will fire immediately upon cranking and the nothing else. it fires better after priming the pump and running the diagnostic self test (the one which fires the injectors a bunch) which makes me think it may not be getting enough fuel.

[Jack leg]

My dad had a Lh3.1 240 that had a similar issue. He ended up selling it to another member here on the board and that member figured out the TPS sensor was bad. Once the TPS sensor was replaced the 240 ran fine. 2 cents

[sloopy]

thanks for the suggestion. i will test that as well.

[apachechef]

inline spark tester
ether

these simple tests are easier than making a post.

[sloopy]

no

[apachechef]

Originally Posted by sloopy

no

touche, lazier and more entitled then.

[sloopy]

turns out the main fuel pump was not running and what i was hearing was just the tank pump. also, when you remove the abs harness from the car, you are left with a matching pair of 6-pin connectors with matching wire colors. the main fuel pump wiring is routed through this. the car runs :o)

[dl242gt]

Good find. Glad you are rolling.