Thread: Series 2 Disco V8 idle issues

Hi and welcome to the forum.

Being a '96 yours will be a Discovery series 1 not a seies 2. That will make a difference in what engine masnagement issues you may have. My first thought would be to check the MAF.

Many thanks for your response. By MAF sensor are you referring to the air flow meter? In my experience these are specialist only service items due to their sensitivity. Can much be done to diagnose it?

Get yourself some "carby cleaner" and "electrical contact cleaner".

Use the carby cleaner to clean out the throttle body area. Then take the IAC valve out (unscrews by hand) and clean that and the hole it seats into. Put it all back together.

Then take the air flow meter off and use the electrical contact clean on it. Spray the cleaner into the small port which houses the hotwire.

Reassemble and test the idle.

I find with my RRC (fitted with Disco engine and injection) that this service process has to be done regularly to stop the poor idle symptoms you are describing.

There are a few easy adjustments and a few upgrades that can be done to your V8 Disco. Use the search function and look for Gen III fuel injectors and adjusting the AFM.

Cheers and thanks for your response. I'll give what you suggest a crack today and report back. Nice to have joined such a helpful forum

Sounds to me like she is sucking air from somewhere. Automatic advance hose something like that

Originally Posted by Peppercorn

Sounds to me like she is sucking air from somewhere. Automatic advance hose something like that

Cool I plan to check all the vacuum hoses ax well.

Does anyone know if there is a pic anywhere on this site that shows the location of the key engine components like IAC. Im sure i'll find it all but as I'm not really familiar with this engine it would speed things up

Problem solved. Thanks everyone for their help.

Turns out it was the AFM, has been pretty roughly adjusted at some point. The hex head voltage adjusting screw was completely stripped, resembled a Phillips head screw that was badly mangled. Checked output voltage with the multimeter, it was .03 vdc. Adjusted to 1.3 vdc after doing some research here and finding the AFM adjustment PDF. Runs fine now. But noticed after a decently long drive that the problem returned, checked voltage again and it had dropped to .5 vdc. Seems with the engine vibration the adjusting pot rotates - I can only put this down to previous adjustment abuse. So I reset it to 1.3 vdc and injected some silicone into the adjustment housing to lock it in place. Will be a pain next service when it needs readjusting but saves it from randomly moving about.

Long term looking for a new afm. Can anyone point me in the right direction?