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        General >> Problems >> Stalling
        
(Message started by: EinA on Dec 20^th, 2004, 6:35pm)

Title: Stalling
Post by EinA on Dec 20^th, 2004, 6:35pm

The Story,

2.9 24V Cossie (LPG)

It started to stall when first pulling off and some times when hot. Then today the wife took it out, It stalled and on restarting there was a loud bang (backfire?) and smell of burning.
The car starts fine but when accelerating +/- 1500rpm
it dies.
Checked the codes;
P0102
P0175

Drove it slow round the block stalling 3 or 4 times with the result of two more codes
P1132
P1152

It was running on LPG at the time, I've just read some of the LPG installs on the Site and it looks like some damage might have happened with the backfire.

I do have a short OBD file if thats a help

David

Title: Re: Stalling
Post by EinA on Dec 20^th, 2004, 11:50pm

Update from OBD file

LongFT1 and LongFT2 stay at 0 during short test run

Title: Re: Stalling
Post by Dave Boulton on Dec 21^st, 2004, 5:29am

David,

Others will confirm but I'd suggest staying off the lpg for now until you get things sorted. The codes you've found point to a failed MAF (or dodgy wiring):

P0102 Mass Air Flow circuit Low Input
P0175 System Too Rich - Bank No. 2
P1132 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 1
P1152 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2

So you've got a MAF with voltage out of range and your upstream oxygen sensors are kaput - or there's a loom/wiring problem. It could well be in LOS hence the lack of performance.

I would start with an inspection of the wiring to the MAF and the oxygen sensors & yes, please zip up the 3 files from your scan & post them to http://www.anyboard.net/autos/cars/scorpio/index.html

Dave

ps. Out of interest - do you have a multi-point or single-point LPG system?

Title: Re: Stalling
Post by EinA on Dec 21^st, 2004, 8:05am

Hi Dave,
Thanks for the info. Have posted the obd zip.
I think I've got a single point system from what A.Higgins had said previously. (no time to even look yet)

Q - Can a backfire take out the MAF?

On the site somewhere last night I read about doing damage with a backfire. The story said about 40 quids worth of damage. This is to cheap for the MAF so what else could be damaged :(

David

Title: Re: Stalling
Post by Dave Boulton on Dec 21^st, 2004, 1:29pm

David,

Had a quick look at your scans (pushed for time a bit today). I'd suggest you raise this in the OBD Advice section where you should get more detailed help. Sounds to me like you'll need to get the car running properly on petrol first. I'm sure some of the LPG owners can advise on what damage might have occurred - I've got no experience of it I'm afraid.

Was the car running on petrol when you took the scan you posted? Next time you scan whilst running on petrol it would be worth logging the FUELSYS12 parameter to see whether the stalling is related to closed-loop/open-loop fuellling. The MAF and HO2S are obviously not reading right - I'd still favour giving the wiring a good inspection before doing anything else.

I'm probably not going to get to look at the forum much for the next few days so best of luck with this.

HTH,
Dave

Title: Re: Stalling
Post by Steve_S on Dec 21^st, 2004, 1:44pm

absolutely yes, I was lucky when mine backfired, it only took out the intake trunking. but I did have backfire flaps fitted in the airfilter box which may have saved the Maff.

You need to find the cause of the back fire before running on lpg again, probably week mixture or ignition. The cossie does not like lpg and platinum plugs, I changed mine to ngk triple ground plugs and not had a problem in 2 years. Any problems with the ignition circuit is likely to lead to a backfire.

You need to check very carefully all your trunking and piping to ensure there is no damage, even the slightest leak will cause problems. Have a look at the maff sensor inside the truncking by the air filter You should see the thin of silver wire of the sensor , if this is broken or missing then you will need a new maff. If it looks ok then try cleaning it with a spray of carb cleaner.

Title: Re: Stalling
Post by EinA on Dec 22^nd, 2004, 3:13am

Update

The car was on petrol when I did the OBD scan.

Had a quick look in between working/shopping/sleeping

Found the top of the Resonator assy box blown off and split down the middle.
And the Suction pipe connection to the throttle housing also split along its seems.

Had to order from local FMD,
Rule number 1 - ask for discount first or they whine that the orders already processed.

Title: Re: Stalling
Post by EinA on Dec 22^nd, 2004, 3:21am

Question to Steve_S

backfire flaps - more information please

And if they're fitted in the airfilter box how does that save the MAF. Which is between the airfiter box and the rest ?

Title: Re: Stalling - final report for the interested
Post by EinA on Jan 7^th, 2005, 7:37pm

Damage done due to possible backfire.
Top of the Resonator assy box blown off and split down the middle.
And the Suction pipe connection to the throttle housing also split along its seems.

http://tinypic.com/172ykg

After replacing the two damged parts and cleaning the Maf all running fine again with no error codes on Petrol.

Conclusion - that there was a small air leak when I bought the car and it just got worse, also possible contrubutions from the spark plugs when using LPG and the MAF.

Then changed the spark plugs to Iridium as hopefully more suitable for running on LPG.
Before testing with LPG. Ran before and after OBD's to see the difference with the spark plugs.
The after scan shows the fuel trims switching much faster.
The old plugs were showing signs of heat damage. So this could also be a factor in the differences.

Then tried on LPG all seems OK. Did 500 miles over christmas with no problems.

David