Ford Scorpio Forum - Print Page


    
      
        Ford Scorpio Forum
        (https://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl)
      

        General >> Problems >> Rough idle AND no fuel filler "hiss"
        
(Message started by: Mike_Floutier on Apr 24^th, 2008, 3:14pm)

Title: Rough idle AND no fuel filler "hiss"
Post by Mike_Floutier on Apr 24^th, 2008, 3:14pm

Hi,

I'm still trying to figure out why I'm getting this rough idling - (it dissappears under load btw eg. even putting the air-con on nearly removes it)

I read on the site that a lack of vacuum in the tank/evap system could be symptomatic of unmetered air getting into the manifold which could cause the poor idle.

Because I run on lpg, my petrol tank is usually pretty much empty. I noticed yesterday (when I put a couple of gallons of petrol in) that there was NO HISS when I removed the filler cap.

I'll have a look at the pipework near the EVAP canister at the weekend because I know I removed it when I did the cv joints so I might have disturbed something.

QUESTION - Am I right in thinking that there is supposed to be one pipe near the EVAP canister that is just hanging loose and open?

OTHER QUESTION - Can someone point out exactly where the EVAP system pipe appears in the engine compartment (on the site it says "on the off-side" but I can't see it and I want to check that it's ok.

FINAL QUESTION - I noticed (when looking for said pipe) that the little plastic pipe from my EGR goes into some sort of valve which has an electrical connection. What I noticed was that I've got a coolant leak which drips straight onto the connector for this EGR thingy.

Any idea how this might be affecting things?

Thanks and sorry to be so long-winded

Mike

Ps I just read on http://www.fordscorpio.co.uk/egrmonitor.htm that the "EGR valve thingy" I mentioned with the coolant dripping on it is actually the "Electronic Vacuum regulator (EVR)" which doesn't sound like it's something one should be spraying with coolant. COULD that be my problem??

Title: Re: Rough idle AND no fuel filler "hiss"
Post by TiberiuS on Apr 24^th, 2008, 5:30pm

Hi Mike.

Sure, some pressure inside the tank is normal but the car will run fine with no pressure or with the petrol cap removed completely, I don't really understand how it can be taken that lack of pressure inside the tank means inlet leaks, not unless the hose at that end is missing/broken wide open and the unmetered air is getting in there instead of providing any vacuum at all to the evap lines. Not sure whether unmetered air could even lose enough vacuum elsewhere in the inlet manifold to stop the evap system working without killing the engine but if it did it'd have to be one helluva lot of air getting in meaning little or no vacuum getting to the engine, pulling a small hose should be enough to make the engine race, then stumble and die completely if enough air gets past the throttle body and MAF.

Not sure how LPG would affect things but on a standard petrol setup a miss only at low RPM could well be unmetered air getting in, unlit blowtorch pointed around the inlet manifold/hoses is the way I've found them a few times although I didn't just tell you to do that, you understand..

Any chance of removing and plugging the evap line at the manifold?

Hope this helps :)

Regards, Bruce.

EDIT: Stepping out of my depth here, don't remember much about the inlet/EGR setup on my Scorp. But, just had a look here (http://www.fordscorpio.co.uk/egrmonitor.htm), I remember the EGR valve was above the exhaust manfold at the rear.

The couple of times I've hunted inlet leaks I just unplug everything I can in turn from the manifold and seal the holes, see if it improves the symptom. Including EGR and brake booster. Prehaps try removing the vac hose from the top of the EGR to start with? All depends if the valve is ok and the diaphragm sealing properly though..

Title: Re: Rough idle AND no fuel filler "hiss"
Post by Mike_Floutier on Apr 25^th, 2008, 12:44pm

TiberiuS,

What can I say? You said "Perhaps try removing the vac hose from the top of the EGR to start with?".

Well, guess what, I thought I knew best. So I tried everything else in the list.

Finally I looked at the EGR and a little voice in my head said; "Just take the pipe off!". "No You're kidding" I replied. "Oooh, ok then, it can't do any harm".

You cannot believe how nice it is to hear my Scorp idling perfectly smoothly for the first time in 6 months.

As a private hire driver I am driving it most of the day so I cannot tell you how grateful I am!

Thank you TiberiuS!!

Mike

Title: Re: Rough idle AND no fuel filler "hiss"
Post by TiberiuS on Apr 25^th, 2008, 7:37pm

Hi Mike, glad it worked :)

So you're looking for a fault in the EGR system itself, eh?

So you now know the EVR valve is working because it's keeping the EGR open all the time. Looking at the EGR sensors page it seems the DPFE sensor sends a voltage back to the ECU to tell it to run the EVR depending on difference in inlet/exhaust vacuum so maybe a loose hose to the DPFE could trip it into opening the EGR all the time?

Regards, Bruce.

Title: Re: Rough idle AND no fuel filler "hiss"
Post by Mike_Floutier on May 3^rd, 2008, 2:31pm

Hi Bruce,

You asked about how I was getting on with the EGR problem.

In the original post I'd said:
Quote:

I noticed (when looking for said pipe) that the little plastic pipe from my EGR goes into some sort of valve which has an electrical connection. What I noticed was that I've got a coolant leak which drips straight onto the connector for this EGR thingy.

. To be honest I think that this is the cause of the problem.

As I understand it the EVR receives the vacuum input from the inlet manifold and then, under command from the PCM, releases a measured dose of that vacuum to the EGR diaphragm which lets a certain amount of exhaust gas back into the inlet manifold.

What I think is happening with mine is that it has had so much coolant dripping on it in the last 250,000 miles that it has got very fed up and left the vacuum door pretty much wide open.

Since I run on gas I felt it wasn't unethical to disconnect the vacuum pipe from the EGR (and presumably not detrimental to the engine). I also plugged the resultant open-air inlet to the manifold.

I certainly runs sweetly now. Especially since I got that new coil pack. I just have to sort out the rumble/vibration from (presumably) the propshaft flexible coupling and I'll have a car that drives almost like new.

Thanks again for yor help!

Mike

Title: Re: Rough idle AND no fuel filler "hiss"
Post by TiberiuS on May 4^th, 2008, 11:19pm

Hi Mike, sounds like you've got this covered now.

But might be worth checking the little vac hoses to the DPFE sensor (isn't there supposed to be two hoses feeding it to measure the pressure difference?), if I'm thinking right, a crack in one of these could make it tell the EVR to be pulling vacuum all the time.

Got your point though, I didn't realise the EVR took vacuum from the inlet manifold.

Ahh well, at least it helped a bit :)

Regards, Bruce.

Title: Re: Rough idle AND no fuel filler "hiss"
Post by Mike_Floutier on May 5^th, 2008, 8:43am

Bruce,

It wasn't "a bit", you said:

Quote:

Prehaps try removing the vac hose from the top of the EGR to start with?

That's what I did and it solved it completely and immediately.

Thank you!!

Mike

Title: Re: Rough idle AND no fuel filler "hiss"
Post by david49uk on May 25^th, 2008, 12:49am

were is the egr ill try that.

Title: Re: Rough idle AND no fuel filler "hiss"
Post by Simmo on May 25^th, 2008, 6:25am

Have a look at THIS article (http://www.fordscorpio.co.uk/egrrepair.htm) and there is a picture of it. ;)