ROLEXUS400

iTrader: (2)

Guys ive rarely found a problem that i could not handle,but this one has got me wrecked. The car is a 93 ls400.
The problem-the car wont start.
symtoms-no spark on passenger side,no injector pulse on passenger side. Drivers side is good.
codes- 15,22,41

code 41 tested and found bad tps confirmed
code 22 found broken/damaged coolant sensor confirmed
code 15 ignition 2- heres my problem

What u need to know-gauges/needles flicker on dash until u move shifter from park or nuetral then they stay on(weird)
i have swapped coils,ignitors,both operate when connected on drivers side-(components good)

if i remove the efi relay and wiggle it as it sits loosely on terminals i can watch the passenger side injectors and coil fire.(that tells me the circuit to them is good)

sometimes when removing/installing underhood fuse panel relays the gauge cluster will go limp_might turn off or might start flickering_(weirder)

i seem to have lost my ability to troubleshoot this and im so frustrated. Guys i need some help!

Originally car would breakdown every thirty minutes or so and then start after sitting a while-now it wont start but for a second and then shut off.when it does start for that breif second their is no fire on the passenger side coil ever.

deanshark

In the manual it says the "trouble area" for code 15 is; (ignition signal circuit)
Open or short in IGF2 and IGT2 circuit from No.2 igniter to ECM
No.2 igniter
ECM

Sounds to me like you have a problem in the wire harness somewhere. In or close to the relay connector. You say it works when you wiggle the relay so start looking for a loose connection in that spot.

LEXTEK1

Problem may be between igniter 2 to the ECU. Probably on IGF2. This is the confirmation signal that the igniter has fired. No confirmation= no continuation. It seems to fire once when relay is wiggled. Good diag so far. Not usually where we see an ECU problem but worth checking the caps anyway.

LEXTEK1

IGF and IGT diagram

ROLEXUS400

iTrader: (2)

Update- After deciding to keep at my instincts, I removed the entire harness from the the engine compartment. With the whole shifter throwing off the cluster,i felt like this was if not a lead in the right direction at least worth looking into. Well helllllllllllllllllo burnt wires. How many of thease cars have we seen with leaky exhaust?? The right side cat to manifold flange was pumping hot exhaust right onto the harness and burnt the wires together. Not yet a confirmed fix but definitly a problem. Im going to remove the engine-strip the entire harness,check,loom,and retape on the floor. Hook it up with some new exhaust seals and resurfaced flanges and studs if nessasary. Egr bypass is a must while im their and get it back in the car tommorow hopefully. My buddy has no idea what im doing to his car,but i told him id fix it (i love a challenge) I will keep you guys posted on the results. Im still confused how the shift selector wiring would backfeed the ipc, or could shut down an ignitor, but we shall see soon.

LEXTEK1

If the wires are melted going to the tranny, it could be backfeeding voltage/shorting to the cluster via the PRNDL lighting wiring of the nuetral safety switch. Car is designed to run with EGR! You should consider the possibility of the car needing to pass a dyno test.....

When you get it out and repaired. Wrap the area that was burned in some heavy duty foil to give it some protection.
Good luck!

deanshark

Good find on the burnt wires. It sucks that they're burnt but that very well might be the problem. Was it burnt between the igniter and the ECU? I was also going to suggest not bypassing the EGR, it doesn't do anything for ya. This is your buddy's car? What a good friend you are. Good luck on the fix, hope it clears everything up for ya.