Poor running

[TROOPER88]

Hi
I recently acquired a 93 4.0 Chim and have only driven it a couple of times.

It seems to have a running issue; when the car gets up to temp it does not run very smoothly, may be a slight mis-fire.
When I come to a halt it wants to cut out, the orange light comes on the dash but it does not die completely.

I removed and cleaned the stepper but it looked pretty clean. I then removed one of the plugs and it is black (sooty), I mean really black..

I understand this means over fuelling / too rich a mixture.

Is there anything that is common on these that could cause these symptoms?

I do not want to simply put a new set of plugs in if the same thing is going to happen again.

Any advice is much appreciated

Cheers

[PH430]

Black sparkplugs will be rich running.

Looks like the temp sensor gives incorrect info to the ECU. Maybe you have air in the coolingsystem and the temp sensor is not giving the right info. Or check connections on the temp sensor.

I hope it work out.

[TROOPER88]

PH430, I will check the temp sensor.

I drove the car yesterday for a couple of miles. The poor running/misfire seems to be under 3000rpm.

I removed a spark plug from the other side of the engine and this is also very black.

Is there any checks I can do to try and identify the problem?

Cheers

[PH430]

How is the fuel consumption.

Are the sparkplugs black or do you have carbon on them.

Check also connections on the trothlle pot sensor. Also check the standard voltage on the sensor. With butterfly clossed it must be 0,32 till 0,35v.

Cheers

[jojackson4]

+1 with the ecu temp sender but don't get the one with the plastic nut there st

[TROOPER88]

Where will I find the temp ECU sensor in the engine bay?

I will check it tomorrow and report back.

Many thanks for taking the time to reply guys

[PH430]

2 inches at the front of injector 1. Has got the same connector on it but a different color.

Pieter

[jojackson4]

Looks like this

[TROOPER88]

Ok just had a look and easily located what I believe is the ecu temp sender; top of the engine next to the first injector.

Got the multimeter out and whilst holding the black lead against the block and the red inside the plug, I got the following readings at each terminal:

4.97v
0.05v

Is this correct?

[TROOPER88]

TROOPER88 said:

Ok just had a look and easily located what I believe is the ecu temp sender; top of the engine next to the first injector.

Got the multimeter out and whilst holding the black lead against the block and the red inside the plug, I got the following readings at each terminal:

4.97v
0.05v

Is this correct?

Also did the same test on the switch located under the throttle pot next to an injector and got identical readings.

[jojackson4]

The temp sencer is restive between the two coneckshions and alters when the engen temp alters

[PH430]

The résistance

15gr. = 2910 ohm
20gr. = 2270 ohm
30gr. = 1620 ohm
40gr. = 1160 ohm
50gr. = 820 ohm
60gr. = 590 ohm
70gr. = 450 ohm
80gr. = 330 ohm

Good luck!

[swallet]

Will just throw an alternative suggestion in as I had a similar issue with my '98 450.

Turned out to be the coil. It was on its way out and once the engine was hot it was enough to push it over the edge.

Easy to check the coil by putting a multimeter across it.

I found out the hard way when my coil caught fire !!
Thankfully extinguisher was at hand and when the new coil was fitted my hot stalling was cured.