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        General >> Give/Need advice to/from others >> Home Tune 24v
        
(Message started by: nice_1 on Jul 2^nd, 2007, 4:06pm)

Title: Home Tune 24v
Post by nice_1 on Jul 2^nd, 2007, 4:06pm

I have got a mobile tune a car guy coming around on wednesday. my 24v has some issues... when driving along at 2000 rpm (sometmes not all the time) the engine will die then rev again even though the throttle has not moved. I have cleaned the MAF. seems to have improved the fuel economy, but not this problem. I know this may point to the throttle potentiometer. Also the gear change 1st to 2nd seems to sort of slurr or slip.
I don't want to start just changing parts on what I think is wrong... Hence the Home Tune. I am hoping someone on the site could give any info i.e. voltage/ohm perameters of certain components they think may be suspect. As I know you guys on this site are going to have more knowledge on th 24v than the guy I've got coming around. I could then get him to checkout what you guys think and what kind of readings we should be getting........Hope that all made sense. As ever any advice, suggestions appreciated.

Title: Re: Home Tune 24v
Post by sector-9 on Jul 2^nd, 2007, 5:40pm

The 24V Cosworth is OBD-II compliant so if you or anyone you know has one of those handheld scan tools (about £45 off the internet) then that will read any fault codes stored in the ECU. Of course, that alone may not be enough to help pinpoint the cause, but it's a worthwhile investment especially as it should work on all 2001+ petrol cars.

Darren

Title: Re: Home Tune 24v
Post by nice_1 on Jul 2^nd, 2007, 6:15pm

Thanks for the advice about OBD. I was under the impression that it wasn't that simple. You needed adapters etc. for it to work?

Title: Re: Home Tune 24v
Post by sector-9 on Jul 2^nd, 2007, 9:36pm

No, OBD-II is an official standard and uses a standard plug across all makes and models of cars. The Scorpio's OBD-II plug is behind a flap in the roof of the coin storage compartment. However, there are a few "protocols" in use for OBD-II - VW in particular use their own so the code reader has to be able to support the protocols used by the manufacturer. FWIW, I bought a £45 one from Taiwan and it successfully diagnosed a fault on my brother's 2.3 Ford Galaxy EGR system so that alone has pretty much paid for itself.

Darren

Title: Re: Home Tune 24v
Post by TiberiuS on Jul 2^nd, 2007, 10:55pm

ElmScan is quite good (about £80), I've got one. Fine with the default (free) software if you just want to read/reset codes and it'll read the sensors, if you want something more comprehensive to start plotting real-time graphs of revs, fuel trims etc, extra software starts getting more expensive but great if you're in to tinkering with the car. I splashed out about £160 for the ElmScan plus some extra software, it would have cost me best part of £100 just to have it scanned by a garage though. At least I've got the scanner to use again and again.

Some of the guys on here favour www.obd-2.com.

Title: Re: Home Tune 24v
Post by TiberiuS on Jul 2^nd, 2007, 10:59pm

Thinking about your fault, it could really be anything. TPS would likely get worn at low throttle position so yes, it could be an issue. Other than that, what about the EGR system? Know nothing about this, could it cause the issue I wonder?

Dodgy fuel pump relay? Some fuel delivery issue starving the engine for a sec?

Bad coil (making it stumble, seeming like it dies)?

Just a few thoughts to get you going :)

Title: Re: Home Tune 24v
Post by nice_1 on Jul 3^rd, 2007, 4:20pm

Tiberius, sector 9, Thanks for your thoughts the faults with the car are really annoying!!!!! I sat in it today and held the revs at 2000rpm and the revs dropped off so I am hoping to repeat this with the diagnostics on the car.
When I mentioned the gearbox slipping issuse Mr Home tune he didn't seem to think anything he could do would effect this...Well i know from discussions on this site the MAF (which i've cleaned) can have a bearing on gear changes.....what about any other electirikery components??
I don't think its a coil pack issue.
As when I'm driving if I keep the throttle in the same position the revs will fall and rise...fall and rise. back to 2000 rpm with the throttle held in a constant position.

Fuel pump relay?? if i can duplicate what the car is doing for the home tune guy. Hope his equipment can pin point it.

would anything else effect the G/box?

Title: Re: Home Tune 24v
Post by sector-9 on Jul 3^rd, 2007, 11:25pm

Air leak in induction system? Revs rising and falling might be the ECU trying to compensate for a mixture different to what the MAF is reporting (try disconnecting the O2 sensors and see if that makes any difference).

Darren

Title: Re: Home Tune 24v
Post by TiberiuS on Jul 3^rd, 2007, 11:54pm

Unfortunately I know more about the fault code system on the Jag than I do about the Scorpio's.

AFAIK, if they're similar, the TPS going open circuit or something should set a code, you might get some clues there. You're looking for a smooth sweep with throttle movement, I found it easier to read mine with an anologue voltmeter, had it in the cab while I went for a drive and checked the reading when my issues occured. MAF could be a culprit still, it seems they're pretty much standard accross the Ford range so if you have a friend or relative with an Escort, Mondeo etc, you might be able to swap. MAF will give air intake values in Kg/second or something, pretty much useless unless you have an idea what the 'right' value should be. I'm not sure what readings a bad MAF would give but if someone has some ballpark figures it might help you. I have heard of this giving autobox issues, both here and on one of the Jag forums.

As Darren said, some kind of air leak - hence why I suggested EGR. But I know nil about the EGR system :(

Hope the above ramble helps.

Regards, Bruce.

Title: Re: Home Tune 24v
Post by Pegasus on Jul 4^th, 2007, 12:53pm

Hi,
as has already been said - an unmetered air leak (go to Troubleshooting pages) is favourite but possibly loose connection or a dodgy MAF (ie busted). A scan sounds like the best answer.

If you can get a scan that allows downloading of data into a spreadsheet (such as with obd-2.com) then if its the MAF a plot of MAF against rpm will make it obvious. Otherwise, look in Ford specific Enhanced data that check for correct voltages, etc.

BTW, the basic cost of connector from obd-2.com is $122 + pp (not bad given current $/£ rate) - the software is free and scans can be shared with others on this site for advice.

Paul

Title: Re: Home Tune 24v
Post by nice_1 on Jul 4^th, 2007, 3:58pm

Paul, Bruce, Daren. Thanks for you input. The "tune up" has been postponed until 4:30pm thursday. I will relay everything you guys have suggested and will keep you posted on developments.
Thanks again,
Richard.

Title: Re: Home Tune 24v- The Verdict.
Post by nice_1 on Jul 6^th, 2007, 7:02am

Well...It looks like money well spent.
The problems found were.
Pressure transducer(little box on the back of the bulkhead drivers side) broken vacum pipe.

vacum tank below the ABS unit some of the pipes had become disconnected.

Sticking Idle control valve. Which has been cleaned. however, its thought if the car now begins to have similar issues again in the near fututre this is likley to be the culprit.

Bad news, as we were looking at the engine running the crankshaft damper seems to be breaking up!!! their are what looks to be like bits of plastic sticking out from the centre. :(
Anybody got a crankshaft damper pulley for a 24v???

Other than that problem. The car now drives great no G/box slipping, no revs up and down. Just the damper to fix.....

Title: Re: Home Tune 24v
Post by Grumpyg1t on Jul 6^th, 2007, 11:24am

nice_1 was that a national company or a local outfit?

Title: Re: Home Tune 24v
Post by nice_1 on Jul 6^th, 2007, 10:38pm

A local guy. i have used him in the past. On other vehicles. He is very Knowledgable. I can't speak highly enough of him. His company is called TUNE-A-CAR. I don't know how large an area he covers. He Is based in sunbury on thames....His Number is 07831286361. :)