Hi Guys,

Here is an update after the weekend has quickly been and gone.

So we started checking round the vac pipes for splits and we found that the vac pipe from the distributor to plenum chamber one of the connectors had broken, so the first job was to repair that.

Then, my dad said he had read online that slightly twisting the pins on the MAF connector could make a big difference. So we did that and ran the engine.

Good news is after 40 miles of driving the Disco did not over fuel, that issue appears to have been cured.

Now what happens is when you start the engine from cold on petrol it runs ok until it starts to get warm.

Once it is warm it struggles with its idling, stalls when you pull up at junctions or even if you take your foot off to slow down it struggles to keep going.

Also, I don't think it's misfiring it feels like fuel starvation, when you take your foot off the throttle it drops power for a second then comes back and it might do this once or twice or for a few minutes but then it would run ok for a few more minutes until you put your foot down a bit, then it starts again.

Thank fully we break up for Christmas on Wednesday afternoon, so the plan is, to test the MAF sensor, coolant temp sensor and run the engine up to temperature and then do a fuel pressure test with the engine running to see if it loosing fuel pressure under different loads.

I am also going to use it over the Christmas period to see if the over fuelling issue comes back or if it has been cured for good.

Has anyone got any other thoughts, is there anything else I could do?

Thanks

John
 
Hi Guys,

Here is an update after the weekend has quickly been and gone.

So we started checking round the vac pipes for splits and we found that the vac pipe from the distributor to plenum chamber one of the connectors had broken, so the first job was to repair that.

Then, my dad said he had read online that slightly twisting the pins on the MAF connector could make a big difference. So we did that and ran the engine.

Good news is after 40 miles of driving the Disco did not over fuel, that issue appears to have been cured.

Now what happens is when you start the engine from cold on petrol it runs ok until it starts to get warm.

Once it is warm it struggles with its idling, stalls when you pull up at junctions or even if you take your foot off to slow down it struggles to keep going.

Also, I don't think it's misfiring it feels like fuel starvation, when you take your foot off the throttle it drops power for a second then comes back and it might do this once or twice or for a few minutes but then it would run ok for a few more minutes until you put your foot down a bit, then it starts again.

Thank fully we break up for Christmas on Wednesday afternoon, so the plan is, to test the MAF sensor, coolant temp sensor and run the engine up to temperature and then do a fuel pressure test with the engine running to see if it loosing fuel pressure under different loads.

I am also going to use it over the Christmas period to see if the over fuelling issue comes back or if it has been cured for good.

Has anyone got any other thoughts, is there anything else I could do?

Thanks

John

My first thought is you have an air leak.

If it is an idle stabilisation/control problem you need to remove and clean the idle control valve (stepper) and check it is working (plenty on line about this), also check the throttle potentiometer, make sure the base voltage is correct and that it scales properly and operates smoothly with no notchiness. You should also check your ignition timing and if you're feeling sporty check and set your base idle.

Have you checked the vac advance unit is actually working and that the diaphragm isn't perished. Dead easy to check, pull off vac pipe from plenum and suck - if you can suck air through it then you need a new one which will go a long way to resolving the issues you describe.
 
Hi Kev,

I found a website last night that describes how to strip and clean the stepper, I will add those other items to my check list.

Have a nice Christmas mate

John
 

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