CDT Lumpy tickover - Page 2

Paranoid Carlos · 31st December 2006, 18:33

Cleaned Maf wire with alcohol, recleaned egr valve which only had the lightest covering of soot, checked hoses etc, still the same, in fact now on starting from cold there is a 100 rpm drop for a couple of seconds, very peculiar.......Am starting to wonder if it's the Asda diesel I put in.
I might have imagined it but it seem smoother when the maf was dissconnected.

Simon · 1st January 2007, 15:43

If your engine seems smoother with the MAF disconected then it may be the MAF that's playing up (ie. Faulty).

I'm not very 'up' on the in's and out's of the CDT engines but does Roverron's MAFAM replace the standard MAF sensor? If so and your MAF is faulty then it may be an oportunity to upgrade the MAF to one of Roverron's MAFAM upgrades.

Of course, I may be talking

so excuse me if I am

Roverron · 1st January 2007, 17:45

Quote:

Originally Posted by Simon D

If your engine seems smoother with the MAF disconected then it may be the MAF that's playing up (ie. Faulty).

I'm not very 'up' on the in's and out's of the CDT engines but does Roverron's MAFAM replace the standard MAF sensor? If so and your MAF is faulty then it may be an oportunity to upgrade the MAF to one of Roverron's MAFAM upgrades.

Of course, I may be talking

so excuse me if I am

Unplugging the maf will certainly make the engine smoother if the maf is a out of spec.
Conversely, if the maf is fine, you should not feel much difference BUT because the engine is bit overfulled without the maf connected, this can give a smoother if lumpy feel.

Many owners have fitted a mafam and told me how much smoother their engine is. (Apart from the boost in low down performance and earlier upchanging of the auto box.)

The mafam does not replace the maf, it plugs in between it and its connector to boost the signal.

Ron

Simon · 1st January 2007, 17:48

Quote:

Originally Posted by Roverron

The mafam does not replace the maf, it plugs in between it and its connector to boost the signal.Ron

Ah ha! I knew I might have been wrong. Thanks for the correction!

:lol:

Paranoid Carlos · 1st January 2007, 17:58

I have a mafam and Tu3 fitted already, It really is strange and I doubt if most owners would notice.......On first start up in the morning it's like it takes a few seconds to clear itself, to get onto 4 cylinders, then it's fine, tootle along and a soon as you get to lights or something involving neutral, ticks over ok for a few seconds (10-20) then seems to go up and down a bit, almost like it's getting a reading it can't understand and is trying to compensate and then going the other way........ Think I am going to have try a new MAF

Paranoid Carlos · 8th January 2007, 10:29

New years day had a knock on the door from a workmate, very appologetic etc could I help him, he knows I fix up my cars myself etc, His CDT Zafira was running like a bag of nails, sounded very poorly the knock when acelerating sounding like it was about to throw the crank, had a little mooch around (don't know much about vauxhall diesels) cleaned connectors etc etc refered him to someone who may be able to help diagnose etc, got talking about my tickover problem,

Guess what we both filled up at the same supermarket one daY apart. Got to be worth a try we both say, go to the local Shell put half a tank in and a bottle of comma diesel magic, within about 20 miles my cdt is back to purring like a kitten and the Zafira is I would say 99% better (no knock) just got a murmer on tickover but he only put about a quarter of a tank in.................

I think we have both learned a lesson........(plus I got 4 cans of lager out of it)

M47Rman · 9th January 2007, 18:12

Quote:

Originally Posted by paranoid

New years day had a knock on the door from a workmate, very appologetic etc could I help him, he knows I fix up my cars myself etc, His CDT Zafira was running like a bag of nails, sounded very poorly the knock when acelerating sounding like it was about to throw the crank, had a little mooch around (don't know much about vauxhall diesels) cleaned connectors etc etc refered him to someone who may be able to help diagnose etc, got talking about my tickover problem,

Guess what we both filled up at the same supermarket one daY apart. Got to be worth a try we both say, go to the local Shell put half a tank in and a bottle of comma diesel magic, within about 20 miles my cdt is back to purring like a kitten and the Zafira is I would say 99% better (no knock) just got a murmer on tickover but he only put about a quarter of a tank in.................

I think we have both learned a lesson........(plus I got 4 cans of lager out of it)

Great news
What is that old saying about only getting out what you put in? Seems extremely apt in this situation. Trouble is you never really know until after the fuel has gone in! One place to avoid in the future.:lol:
Andy

Simon · 9th January 2007, 22:47

Glad to hear there was a simple solution to all of the detective work you have put in! Makes you think though - what was in that Asda desiel you originally put in?!

Paranoid Carlos · 10th January 2007, 09:55

Been over a week now still running lovely, before I didn't want to drive it convinced it was going to stop every time I stopped at a junction.

apywell · 10th January 2007, 19:12

Interesting thread this is.. my 75 has been suffering from lumpy running (at about 1500 revs) and at tickover. But this only happens from time to time (but daily). I used to fill up with Diesel at Sainsburys. Then last week I filled up at a BP station and put some REDEX Diesel performance stuff in it that also cleans injectors atc... I have noticed very little difference only that my MPG seems to have improved. A shame really because I had hoped it would have cured the lumpy running forever......

Then the other day I noticed that the lumpy running never appeared at all, but that it was a warmer day (about 11 degrees).

Could it be the MAF? If someone could tell me (or show a pic) where the sensor is, I'll unplug it to see if she runs smooth again.

Is the MAF sensitive to the outside temperature?

cheers
Alan

10th January 2007, 19:12	#20
apywell Gets stuck in Rover 75 Saloon. 2.0 Diesel Auto. Connoisseur SE. Join Date: Nov 2006 Location: Derby Posts: 723 Thanks: 0 Thanked 0 Times in 0 Posts	Interesting thread this is.. my 75 has been suffering from lumpy running (at about 1500 revs) and at tickover. But this only happens from time to time (but daily). I used to fill up with Diesel at Sainsburys. Then last week I filled up at a BP station and put some REDEX Diesel performance stuff in it that also cleans injectors atc... I have noticed very little difference only that my MPG seems to have improved. A shame really because I had hoped it would have cured the lumpy running forever...... Then the other day I noticed that the lumpy running never appeared at all, but that it was a warmer day (about 11 degrees). Could it be the MAF? If someone could tell me (or show a pic) where the sensor is, I'll unplug it to see if she runs smooth again. Is the MAF sensitive to the outside temperature? cheers Alan __________________ If there's one thing I've learned, it's that life is one crushing defeat after another until you just wish Flanders was dead. Now has an S-Type 2.7 diesel V6 twin turbo with Jag voice, bluetooth, sat nav, front and rear park assist, electric fold mirrors etc, etc, etc.....

31st December 2006, 18:33	#11
Paranoid Carlos Posted a thing or two Starlight CDT Conn SE Join Date: Nov 2006 Location: Erdington, Birmingham Posts: 1,057 Thanks: 0 Thanked 0 Times in 0 Posts	Cleaned Maf wire with alcohol, recleaned egr valve which only had the lightest covering of soot, checked hoses etc, still the same, in fact now on starting from cold there is a 100 rpm drop for a couple of seconds, very peculiar.......Am starting to wonder if it's the Asda diesel I put in. I might have imagined it but it seem smoother when the maf was dissconnected.

1st January 2007, 15:43	#12
Simon Banned - Join Date: Nov 2006 Location: - Posts: 10,318 Thanks: 0 Thanked 4 Times in 3 Posts	If your engine seems smoother with the MAF disconected then it may be the MAF that's playing up (ie. Faulty). I'm not very 'up' on the in's and out's of the CDT engines but does Roverron's MAFAM replace the standard MAF sensor? If so and your MAF is faulty then it may be an oportunity to upgrade the MAF to one of Roverron's MAFAM upgrades. Of course, I may be talking so excuse me if I am

1st January 2007, 17:58	#15
Paranoid Carlos Posted a thing or two Starlight CDT Conn SE Join Date: Nov 2006 Location: Erdington, Birmingham Posts: 1,057 Thanks: 0 Thanked 0 Times in 0 Posts	I have a mafam and Tu3 fitted already, It really is strange and I doubt if most owners would notice.......On first start up in the morning it's like it takes a few seconds to clear itself, to get onto 4 cylinders, then it's fine, tootle along and a soon as you get to lights or something involving neutral, ticks over ok for a few seconds (10-20) then seems to go up and down a bit, almost like it's getting a reading it can't understand and is trying to compensate and then going the other way........ Think I am going to have try a new MAF

8th January 2007, 10:29	#16
Paranoid Carlos Posted a thing or two Starlight CDT Conn SE Join Date: Nov 2006 Location: Erdington, Birmingham Posts: 1,057 Thanks: 0 Thanked 0 Times in 0 Posts	New years day had a knock on the door from a workmate, very appologetic etc could I help him, he knows I fix up my cars myself etc, His CDT Zafira was running like a bag of nails, sounded very poorly the knock when acelerating sounding like it was about to throw the crank, had a little mooch around (don't know much about vauxhall diesels) cleaned connectors etc etc refered him to someone who may be able to help diagnose etc, got talking about my tickover problem, Guess what we both filled up at the same supermarket one daY apart. Got to be worth a try we both say, go to the local Shell put half a tank in and a bottle of comma diesel magic, within about 20 miles my cdt is back to purring like a kitten and the Zafira is I would say 99% better (no knock) just got a murmer on tickover but he only put about a quarter of a tank in................. I think we have both learned a lesson........(plus I got 4 cans of lager out of it)

9th January 2007, 22:47	#18
Simon Banned - Join Date: Nov 2006 Location: - Posts: 10,318 Thanks: 0 Thanked 4 Times in 3 Posts	Glad to hear there was a simple solution to all of the detective work you have put in! Makes you think though - what was in that Asda desiel you originally put in?!

10th January 2007, 09:55	#19
Paranoid Carlos Posted a thing or two Starlight CDT Conn SE Join Date: Nov 2006 Location: Erdington, Birmingham Posts: 1,057 Thanks: 0 Thanked 0 Times in 0 Posts	Been over a week now still running lovely, before I didn't want to drive it convinced it was going to stop every time I stopped at a junction.