Running a bit Rich!

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scott02464

scott02464

Active Member
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Up North!
As you can see from the spark plug me 4.0 V8 is running a bit rich! The spark plug in the pic had only been in there for about 10 miles!

Question is, how do i stop it running rich (Other than switching engine off ;))

Also the pipe after the Air box is drawing in air, at the connection where the red arrow is pointing to. Is this a problem? Or should it not be sucking any air in at all?

Scott
 

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what was it doing for that 10 mins? if just idling from cold, I'd say it doesn't look too bad.
 
That loose air pipe is not too much of a problem because it is before the air-mass meter, although it is technically unfiltered air.

Re the rich running, do you have an LPG conversion?

I would say, check for fault codes, if none found, clean the MAF meter, check operation of this and the lambda sensors and reset the long-term fuel adaptions.

Mine has been a problem in this respect, a pair of new NTK Lambdas have now fixed it (I hope) and it's achieving 21mpg on a run.
 
I would stop the air leak and run some carb cleaner by the TPS through the inlet.
You could have a duff temp sensor which would make it run rich.
Is the air cleaner/filter newish, that may be choking it
 
Sorry for late reply guys!

Yes it's a brand new air filter. Also i gave the maf clean with electrical switch cleaner, it's seemed real clean with no dirt or anything coming off (clear switch cleaner)

It's LPG too. Il look into the temp sensor!

What is the TPS (to run carb cleaner through)
 
I think your car is GEMS (going by the pic of the MAF?) You may find the LPG has caused the car's ECM to alter it's fuel trims to that of rich running..

I believe this happens due to the LPG system needing servicing, supplying less gas due to semi-blocked LPG filters/ heavy ends and the ECM increases the injector duration (or so it thinks..) into supplying more fuel. This has the knock-on affect of messing up the carrect 14.7:1 A/FR. This is fine as the old V8 seems tollerant of a rich mixture, especially as an LPG MoT gives greater leway to pass the emissons test.
The big problem is, running rich long term can poison both your CATS and Lambda probes.

Have you had it on a gas analyser?
 
David_Cooper said:
I think your car is GEMS (going by the pic of the MAF?) You may find the LPG has caused the car's ECM to alter it's fuel trims to that of rich running..

I believe this happens due to the LPG system needing servicing, supplying less gas due to semi-blocked LPG filters/ heavy ends and the ECM increases the injector duration (or so it thinks..) into supplying more fuel. This has the knock-on affect of messing up the carrect 14.7:1 A/FR. This is fine as the old V8 seems tollerant of a rich mixture, especially as an LPG MoT gives greater leway to pass the emissons test.
The big problem is, running rich long term can poison both your CATS and Lambda probes.

Have you had it on a gas analyser?
Click to expand...

That sounds about spot on mate with the lpg servicing! Been dying to get it done (although not had it long)

So is it best to get the LPG serviced then get the ECM reset to original or the other way round? (if that make sence?)

Iv not had it on a gas anayliser bud.
 
I think the rule of thumb with these cars is to get it spot-on on petrol first, then service the LPG system (vapouriser rebuild, filter change etc), finally tuning the LPG system and fuelling with a laptop-based programme.
I've been through this with mine and have not allowed it to run on gas until I'm 100% with the petrol fueling. Mine killed both the Lambda sensors and while the (Titania) sensors are now cheaper than they were, I still had to pay £112 for a pair of half-decent ones. As above, I'm now getting mpg figures I'm very happy with and expect the LPG system to be more economic than before.
Incidentally, the theory about the GEMS system is just my opinion, others such as 'eightinavee' etc are much more knowledgable about these cars' quirky injection systems.
 
scott02464 said:
Sorry for late reply guys!

Yes it's a brand new air filter. Also i gave the maf clean with electrical switch cleaner, it's seemed real clean with no dirt or anything coming off (clear switch cleaner)

It's LPG too. Il look into the temp sensor!

What is the TPS (to run carb cleaner through)
Click to expand...

TPS = Throttle Position Sensor in the intake
 
Just an update on what iv found!

Iv had it on the computer and it came back with 2 'Oxygen Sensor faults, Upstream, Bank B) Both faults were for the same sensor.

So going to replace the offending sensor.

Iv already got on order some Spark plugs and some decent HT Leads (Got cheap leads on from previous owner!) So will fit them anyway.

So good news that iv found somet that i can go on :D

When all done ill post the results, It may help someone later on with a similar problem!

Scott
 
Lovely, sounds like you're on the right track now.

If you're feeling flush, replace both Lambda sensors. Believe it or not, they are actually consumable items- Bosch recommend they should be changed every 100k. Although they would say that, I'm inclined to agree. The switch slower when they get old and if one has failed, t'other is probably not long for this world!
 
David_Cooper said:
Lovely, sounds like you're on the right track now.

If you're feeling flush, replace both Lambda sensors. Believe it or not, they are actually consumable items- Bosch recommend they should be changed every 100k. Although they would say that, I'm inclined to agree. The switch slower when they get old and if one has failed, t'other is probably not long for this world!
Click to expand...

Thanks for that mate! It makes sense like you say to do both!

Il be glad when its done lol! Will keep you informed mate ;)
 
Dont even think of changing the oxy sensors until you have done the plugs and leads,chances are there is nothing wrong with the sensors.The ecu will log codes for the sensors if they fail to switch - often this is because they cant switch because of a rich mixture induced by a misfire.
Oxy sensors rarely fail,and people talk about them switching slowly - but its only what they have heard.They often are still working well close to 200k if the engine has been looked after properly.
Remember they are made using precious metals that are expensive and rare - its not very clever to just bin them.
 
eightinavee said:
Dont even think of changing the oxy sensors until you have done the plugs and leads,chances are there is nothing wrong with the sensors.The ecu will log codes for the sensors if they fail to switch - often this is because they cant switch because of a rich mixture induced by a misfire.
Oxy sensors rarely fail,and people talk about them switching slowly - but its only what they have heard.They often are still working well close to 200k if the engine has been looked after properly.
Remember they are made using precious metals that are expensive and rare - its not very clever to just bin them.
Click to expand...

Ok mate will do, ill get the new plugs and leads on first, get the fault code reset (If its come back on) and go from there then ;)

Thanks for the info :)
 
Right as promised heres the out come of the problems i was having!

Just to re cap,

The symptoms were, Slight misfire, Running lumpy when just pulled up to a junction/traffic lights, wanting to cut out when idling, very blackened/sooted up spark plugs.

Had the codes read and it had 2 faults showing on the 'upstream O2 sensor bank B' both faults were for the same sensor. Had that cleared last week. Since then i had been running on the old 'blackened' spark plugs until today.

Today i changed the plugs (I adjusted the gaps to 0.7mm) and changed the HT leads. By the way the old blackened plugs were a nice browny colour when i took them out!

I had the fualt codes read again today and no O2 sensor faults showing at all!

Everything all seems to be running sweet now! (For now!)

Hope this info helps someone out in the future and thanks very much to all the guys that gave me help and info regarding this, its all much appreciated! :)

Regards, Scott
 
Right this is starting to do my bastard head in now!! :mad:

Its been a couple of days now since i thought my problems have gone away, but no!

The engine still doesnt fire staright up, i have to keep the starter going with a bit of gas (Before it was a turn of the key and it fired straight up!)

When cold it runs really ****e, when at idle speed the revs have dropped right down (Just before stalling) Then when i go to accellerate theres no power for about 4-5 seconds then it splutters into moving!?

When moving its fine, then when i come to a juction same again, until it warms up then fine!

Today i changed the 'Crank Position Sensor' but still its the same old ****e!! Iv cleaned round the throttle housing, iv cleaned the MAF, all clean to start with.

Guys this is proper doing my head in now, What else can it be? :(
 
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