disco 1 running problems

[pechanec]

My 1996 disco 1 |(4.0L) starts well and idles smoothly, but starts sputtering when driving,except usually good at full throttle if I can get it there.Soot and sometimes black smoke from exhaust. Have replaced fuel filter, throttle position sensor, idle air control valve, fuel pressure regulator, airflow and air temp sensors. Air filter clean, 34psi at fuel rail. plugs and wires changed recently.Anyone have  an idea what may be wrong? Thanks!

[Matt H]

Plugged Cat?

[binch]

There's an idea....collapsed cat core ???

[pechanec]

Gonna check out the cat today keep u updated. Didn't even cross my mind. Thanks.

[Red90]

Are you getting any codes?

[pechanec]

The cat is good.  Can't get any codes on the reader.  Any other suggestions? Thanks.

[Red90]

Go through and check each sensor as per the manual, even the new ones.  Last straw would be to try someone else's ECU.

You have checked timing?  Checked that it is advancing properly as the engine revs up.

[peterlucas]

Be interesting to know what your fuel psi is while driving, when it's acting up

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[Matt H]

O2 sensors?

They are not used when the engine is cold (start up) or WOT so it jives with your symptoms. They are a wear item and get lazy once they have a few miles/years on them.  Easy to test as well.

[pechanec]

I'll check all that on the weekend.  Reality has come a knocking.  Ill keep u informed as to the results.Thanks.

[tony]

I had a Disco I that did that due to a faulty speed sensor that had not fully failed, so the speedo was reading correctly but the engine was not getting a signal. finally one day the fault showed up on the speedo and i replaced the sensor and the fault went away.

[pechanec]

Changed the speed sensor did nothing.  On to checking more things.

[Red90]

You need to not replace sensors but test them at the ECU to determine if the signals are making it to the computer. You need to test them all in order to work your way to the problem.

[Matt H]

Yes. Red90 gives good advice. There is a case to be made for "swapnostics" if you have a known good replacement part on hand but it is best to individually test components and the harness. If you get the chance to look at a factory trouble shooting and service manual you will find that all the tests are designed around proving or disproving various components and connections in a set order.

This speeds up diagnosis, limits expense and reduces down time.

Did you test the O2 sensors?

[pechanec]

This is what is happening. We live in the sticks. Edmonton is about 1.5 hours away. Went through the the records we where provided and found a notation from TRS in Calgary that they will not touch this rover due to all the after market upgrades it has been through.


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