TensorWorl

Hi, I am having a bit of a problem trouble shooting one of my GS's. The car will start and idle fine for 3-5 seconds and then die. I initially thought it was a bad MAF sensor when I searched on here and so I swapped out 3 different ones from other GS300's I own and that didn't fix the problem. I also read similar problems on here related to the TPS/Accelerator position sensor and noticed that it would die more quickly if I pressed the throttle so I thought it was either a fuel issue or a TPS/accelerator pedal position sensor and I had one of those lying around of the same year so I put that on. That didn't work either. I then sprayed engine starter in the intake after starting it and it will stay idling as long as I keep spraying engine starter in and it idles very nicely.

There are no CEL's but it might be that the car isn't running long enough to pull a code. I don't know.

I read that sometimes when a coil goes bad or there's a short it will sometimes have the same issue. So I guess my question is, am I going about this correctly? Should I replace the coil packs or the fuel pump next or do something else completely? Thank you very much y'all

Nad1370

Air -- Fuel -- Spark

These 3 make any car run.
You already figured out that spraying starter fluid keeps it running.
So i would chase the fuel side of it.
Could be a fuel pressure issue.

Hook up a volt meter at the fuel pump and see if voltage gets cut off before the engine dies out.
If that happens, apply straight voltage to the pump and see if the engine stays running.

isfvss

Sounds like fuel pump.

TensorWorl

So I swapped fuel pumps out of a working GS300 and it does the same thing. I also tested the fuel pump separately and it for sure is good. I suspect something is causing the ECU to cut the fuel pump. I remember reading about how some people changed the spark plugs and damaged the wires going to the coil packs and had similar problems. I am going to check the coil packs.

Aeok18109

Check your codes. I know when the ecu senses an ignition fault be it coil pack connections or igniter it kills power to the fuel pump. You spraying starter fluid bypasses that.

Check your connections at coil packs and trace the wiring back. Brittle and patchy harnesses seem to be common on these vehicles

TensorWorl

Thanks Aeok. I'm not getting any codes which is weird. I was thinking maybe it's not running long enough to trip a code. I looked at the coil packs and it looks like the previous owner tried to replace some connectors with cheap plugs and just connected wires with twist ties. So I think that's the problem. I am going to swap out for connectors I have that are OEM and do it the right way. Hopefully that works.

TrueGS300

I had several broken connectors when I bought my gs. For me I had one occasion where the igniter connector came loose. I played around with the coils and injectors until I checked the throttle and maf etc. When I got to the igniter, the connector shoved back in a bit and the car started up fine. I zip tied it tight because its missing the clip that actually snaps it in place. Same with my throttle. Someone really messed them all up in the past. But check all these connections.

TensorWorl

I took a look at the coil packs this evening and replaced two of the connectors because they essentially broke after I took them off because they were so brittle. After this the car sounded like it was running on 4 cylinders and still died after a few seconds. I went through again and the other connector had broken from being wiggled so I replaced it too. After that it was back to idling great but only for a few seconds. I also had a CEL code but it was for the TPS sensor I had forgotten to plug back in. Plugged it in and it went away. I tried swapping out the injector and that didn't do anything either.

I am honestly at a loss at this point. I think the ECU is getting some kind of signal that is causing it to cut fuel. I just don't know what that thing is. This could be completely wrong though. Anyone have any thoughts?

Aeok18109

When mine was going haywire and shutting off after a few seconds it was for sure the coil pack connections and the wires. Make sure the coil packs are in cylinders 2 4 6. I had a ton of frayed wiring. I replaced 6 wires. 14“ sections of 16g wiring. Soldered and heatshrunk the connections.

Wires going from 2 to 5, 3 to 4, and 6 to 1

Make sure your igniter is plugged in. Maf. 2 electrical connections on TB and one on the rear of the Y pipe after the TB near the brake booster
Also a connection on the passenger rear of the valve cover little Grey plug

Vacuum line from passenger valve cover to intake piping
vacuum line from cam gear backing plate to intake piping(feeds power steering)

Two coolant hoses.

Clear codes and try again

Also get your codes. I paid 180 for a much better OBD2 scanner than the 50 cheapo I had for years.

The cheap one only ever gave me manufacturer control. Nothing specific like the new Bosch 11xx I forget the module number. Got it at O'Reilly


Also ECU WILL CUT FUEL IF IT'S MISFIRING BAD/IGNITER CODES

sbagdon

For my GS4, it was one of the OCV plugs... the "clip" was broken off, and it wouldn't stay on. Found one at the local salvage yard, figured out how to remove the wire/lead from the plug, and swapped over a plug fitting that wasn't broken. And am very careful when removing plugs in the engine bay, especially on a car that's 20yrs+ old, now.

gs3murphy

Aeok18109

****ed timing belt job will get ya every time. Bet you a nickel that was the issue from the start. I doubt a few. O rings on a fuel pump gonna be the issue with it being off time

TensorWorl

When I swapped the fuel pump out I swapped the whole assembly so it's almost certainly not that. I will keep y'all updated.

gs3murphy

TensorWorl

So I got around to soldering and replacing all three coil pack connectors. Put it back together and it's the same damn problem. :/