revs dropping. like misfire.

[kris_taylor1988]

Hi. 
Hoping someone can help.  Got a 306 hdi and every now and then when you start car if you let it idle the revs will drop and almost cutout.  It's like it's misfiring. A couple of times I have had to keep revs up for a bit as it was cutting out. 

Thanks 

Kris

[Poodle]

Could be fuel pressure regulator.

[kris_taylor1988]

Alright will have a look at that. Could it be anything to do with power (as in enough getting to injectors) as it does it when first started and is worse if not start for couple of days. Thanks

[Poodle]

Can't see why tbh, what are the chances of getting it on diagnostics?

[kris_taylor1988]

I'm going to get a pp2000 this week sometime so will be able to soon hopefully.

[andywhy]

Could be air in the fuel lines or (unlikely as HDi's shouldn't need them) bad glow plugs?

[shervo]

Mine also does this occasionally not to the point it cuts out though. Mine just fluctuates by 100rpm. A good rev always stops mine and I recently cleaned the tps and it stopped for a week (could be coincidence)

[mr_fish]

Exact issues I have, has never cut out but revs fluctuate.

Haven't found the issue yet.

[Poodle]

It won't be air in the fuel as it's a pressurised system. Won't be glow plugs either, not sure how they'd cause cutting out..?

Will have to keep us updated, looks like there are a lot of people who could use a solution.

I'd be looking at the electricals as there's very little we can do to test the mechanical components on the fuel system ourselves. TPS is a good shout, definitely worth giving it a clean up.

[andywhy]

Bad glow plugs might cause bad idle and near cutouts when it's cold if it can't fire properly, but as I said it's unlikely as its a HDi anyway.

[mr_fish]

Bad glow plugs might cause bad idle and near cutouts when it's cold if it can't fire properly, but as I said it's unlikely as its a HDi anyway.

Mine still does it even after a 100 mile drive back along.

Once you get back on the road it'll drive fine.

One thing I did have a while ago was a TPS fault, random EML came on while driving.

Read and cleared the code and it hasn't flashed up since, though I probably should of used the PP2000 measurement feature for the throttle pedal.

Just my experience.

[Poodle]

Fair enough, didn't twig it would cause issues, but now i think about it i see what you mean.

[kris_taylor1988]

Sorry taken so long to reply.

Thanks for all answers I will have to have a look at what has been said so far. I will keep the thread updated though. Hopefully I can sort it out. I don't cut out often only when left for few days not being used. Using normally everyday I will get revs dropping ect every now and then.

[kris_taylor1988]

I have managed to stop the idle dropping and cutting out as was getting annoying. I put new earth from battery to body and engine to body. Started car and idle is steady so hopefully that has sorted it. Will have to test throughout the week. Fingers crossed

[JTaylor2005]

I have to admit I have always thought that the earths on these cars look a little weak considering that they have 150A alternators. The cables look capable of carrying about 80A haha. My corsa and 1l fiesta 2014 both have much better earthing connections than this pug haha

[JTaylor2005]

Having just cleaned my earths up its made no difference to my car revving up and down on idle haha -_-

[shervo]

I cleaned my earths up about a month ago and also added a battery to chassis and engine to chassis earth and made no difference

[kris_taylor1988]

Seems to have sorted mine, which I'm happy about. don't know what could be causing yours then. Hopefully you can find solution.

[JTaylor2005]

Probably the throttle position sensor as that seems to go on most of them by the sounds of it. Its good that urs was such a cheap fix though haha. No doubt others may have same problem with same fix as you