bwoodry

My Engine dies.

This is a 90 C4.

It has been raining, and so far over the last two days dies after driving in the rain. If I apply WOT I can keep it running but then it dies. I can shut off the car competly then restart ,, then in a moment or two it dies again. Again WOT will keep it running and if I maintain high revs it will run.

The Drivers side rear floor board is soaking wet.
The DME is not wet.
The DME harness runs through the wet area.

I changed the DME Relay yesterday.

Recent work.
New coil, plugs , wires, rotor, caps, AC compressor.

The shop looked at the Flywheel speed sensor and indicated the heater hose was missing in this area. They replaced the heater hose and indicated the missing hose may have been causing the flywheel sensor to overheat causing it to fail.

I just called them to let them know this did not solve it.

Seems I have a wet electrical system or a ground fault or other.

Any ideas as I am now looking at all connections and the wire loom to the DME.

I will be checking the rear fuse box in case they moved something in this area but seems that it is water related.

Tks
BW

H964

O2 sensor

Heirsh

what mike said

bwoodry

Can I bypass this until Tuesday,,

Also how do you check for a bad sensor with a meter.??

Tks

BW

bwoodry

Also I removed the cat and sheilds and installed a cat bypass from fabspeed three weeks ago. I was very careful with the sensor and connections,, I checked the connections on the sensor coupling inside the engine bay perhaps the condensation from the airconditioning lines is dripping on the connections..?
Bw

JasonAndreas

If you look under your driver's seat there is a white 3-pin connector. Pull the connector and you should be able to pop the outer pin and swap it to the other outer pin, you want to jumper the center pin to ground. So the blue/red wire would be connected to the brown wire.



I would make sure all the ignition wires are seated properly and then I would run the car with the everything dry for 3-4 minutes. If you have no problems spray the O2 sensor with water. If the engines dies than you probably damaged the O2 sensor and/or wiring when you installed the bypass.

The heat radiating from the catalytic converter (and/or bypass) is a LOT hotter than the output from the heat exchangers!

bwoodry

The car will run , it ran today for 1 hour or so then died,, then shut of engine reset and runs then dies,


I checked all connections in ignition etc , o2 sensor etc,
Ran the car , she runs good ,,
sprayed water on the sensor while it was running and the car started to miss and run poorly, but did not die, then took the water off and it runs ok. So I will change the o2 sensor but any other ideas?
Bw

bwoodry

When an o2 sensor fails what does it do to the DME , why can you bypass the sensor and keep the car running but if it fails it does not run? What happens?

dfinnegan

I don't know for sure, but I would think that bypassing the O2 sensor would put the DME in open loop mode. With a bad sensor the DME is chasing the bad values coming from the sensor and trying to correct where it shouldn't.

H964

just disconnect it and you will be fine. you can do it from the engine compartment on the left side.
i believe you have an after market sensor, and they usually cause this problem when they get wet.

axl911

Have you checked the ICV and its connections?

Also check the idle contact switch.

Car throw and CEL code?

bwoodry

What do you check on the ICV other than theconnections?
Where is the Idle contact switch?

CEL Code? can you give me more detail?

Tks

Bob

bwoodry

What do you check on the ICV other than theconnections?
Where is the Idle contact switch?

CEL Code? can you give me more detail?

Tks

Bob

dfinnegan

You can clean the ISV (ICV above). If it's fouled with oil it will effect the idle.

The ISV is the silver component toward the upper right in the photo below

The idle speed switch is below

dfinnegan

The Check Engine Light (CEL) can be used to read some of the fault codes from the DME. Check out this write-up here on rennlist