Bad Idle and cut out. Help please

[skid 1]

Since i returned home from offshore my 95 vr6 has had problems with its Idle and slow speed running when its hot.

I initially found the ISV muffler box was cracked badly and had a vacuum leak. This got repaired with Araldite and is totally sealed now.

i have checked the whole intake system for leaks and nothing has been found.

I cleaned and lubed the ISV.

I cleaned the MAF and checked it was working by testing the voltage across its wires and it comes out as good.

The car seams to start and idle well while cold but occasionally when hot the idle becomes so erratic, hunting up and down, sometimes delayed throttle action.

The car keeps chucking these codes up every time i clear and re check.

 

00537 - Lambda (Oxygen Sensor) Regulation

11-10 - Control Limit Not Reached - Intermittent

00553 - Mass Air Flow Sensor (G70)

29-10 - Short to Ground - Intermittent

Why is the MAF coming up when the voltage checks show it as good and its clean?

Are the Lambda probes prone to going or could it be something else?

 

Any advice would be great?

[Dox 23]

Mine will rev up and down after a flat battery, it sorts,itself out after a few journeys / heat cycles.

 

Clear the codes and take it for a drive before rescanning that way you'll get the actual codes rather than ghost codes from your investigations.

[skid 1]

Battery gets disconnected while I am away so it was never flat. Had a few runs in it, cleared codes various times but still coming back 😖

[Dox 23]

Battery gets disconnected while I am away so it was never flat.

 

Same thing, ecu loses power and needs to relearn the sensor values.

[Jon_vr6 1]

Checked the wires going to the MAF? These sometimes rub against something and break.

Also I'd be getting the lambda sensor checked too

 

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[robrado974 1]

I had exactly the same thing when I left the car with no battery connected. I'm expecting the same again as the car has not been run in 6 months, due to me working on it . Mine took a fair while to get back to normal running standards.

[skid 1]

Maf wires are good as i checked them. They have been repaired in the past and they are good.

Just had the car MOTed, unfortunately it failed for having honeycomb plates on......past every other MOT with them on!

 

But it struggled to get through emissions to start with and came up with these figures on its first Fast idle test

CO Max 0.30% 2.62% Reading FAIL

HC MAX 200 PPM 60 PPM PASS

LAMBDA 0.97-1.03 0.93 Reading Fail

 

Second Fast idle test:

CO Max 0.30% 0.29% Reading PASS

 

Natural idle test @ 600-800rpm

Max 0.50 0.45% PASS

 

Could this be a sign of the Lambda sensor being out?

Edited February 16, 2017 by skid
Missing info

[Dox 23]

 

 

 

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[Dox 23]

EMISSIONS HELP

 

CO high, co2 low hc high, o2 high - rich mixture with ignition misfire

 

CO high, co2 low hc high, o2 low -faulty thermostat or coolant sensor

 

CO low, co2 low hc low, o2 high - exhaust leak after cat

 

CO low, co2 high, hc low, o2 high - injector misfire, cat ok

 

CO high, co2 low, hc medium to low, o2 high - rich mixture

 

CO high, co2 high, hc high, o2 high - injector misfire, cat not working, combination of rich mixture and vacuum leak

 

CO low, co2 high, hc low, 02 low, good afr and cat operation- system normal .

lambda typical range 0.97 to 1.03 [ ideal lambda 1 ]

The emissions limits to be met are specified for both the fast and normal idle tests. At fast idle, CO must be at or less than 0.2%, HC at or less than 200 parts per million (ppm), and the lambda value(1) must be between 0.97 and 1.03. At normal idle, CO must be at or less than 0.3%

[skid 1]

Translation plz Dox?

[skid 1]

Well i replaced the Lambda probe today and the car is still doing it.

Wires to it was checked and they seamed all fine.

 

Tried it tonight from cold start, and idled well till it hit 75 deg and then it started searching up and down!

[jekel 10]

Well i replaced the Lambda probe today and the car is still doing it.

Wires to it was checked and they seamed all fine.

 

Tried it tonight from cold start, and idled well till it hit 75 deg and then it started searching up and down!

 

Idle is most commonly MAF or ISV, the test readings you got across MAF terminals isn't guarantee is all well. Fact doing when hot would tend to lean towards MAF. MAF and ISV's is always something keep spares for, got any mates local that can come round and swap? Disconnect MAF when doing it, any better, if so - MAF, no worse - probs MAF.

I'd clean MAF as matter of course and change blue temp sensor for new VW one, pretty cheap and easy swap, at least check ohms readings.

ISV damper box was leaking, is foam inside breaking down, getting stuck in pipes, in ISV? Can reroute pipes run without damper, bit noisier, if foam breaking down, I'd pull the lot out, or get new damper, hard to get and a right rip off for what they are.

 

Was at Europarts while back and were selling MAF's for 30 quid or so in sale, seemed rude not to buy one keep as spare, put on car bout year ago, not a Bosch, had on car for bout 6 months worked perfect, got new Bosch and spare Bosch, swapped back to Bosch - exactly same so still working perfect after 6 months, and sat in garage as perfect spare, probs won't last 20 years but for price, worth the buy.

[skid 1]

AS i said the MAF and ISV have been cleaned numerous times.

I was a bit unsure about buying a cheap MAF compared to a Bosch.

 

I changed out my Yellow sensor for a new replacement from VW and this is now Black.

Can you clarify what sensor needs to be done(How many wires, and is it right,centre or left looking at them?)

I was going to leave the Muffler box as its repaired now but i will change it for a new one now.

[jekel 10]

AS i said the MAF and ISV have been cleaned numerous times.

I was a bit unsure about buying a cheap MAF compared to a Bosch.

 

I changed out my Yellow sensor for a new replacement from VW and this is now Black.

Can you clarify what sensor needs to be done(How many wires, and is it right,centre or left looking at them?)

I was going to leave the Muffler box as its repaired now but i will change it for a new one now.

 

The yellow one works the gauges, no effect on running, it's the blue one, 2 pin, middle of three that is the ECU reads, worth a change, easy enough, can do without draining coolant if your nifty.

If you look on here can check readings on 2 pins with ohm guage and check readings for certain temps. but then got to know temp it's reading, and for price they are I'd just renew.

See if anyone local will lend you a MAF and ISV to test.

 

Cheap MAF was on half price at Europarts, and then extra 30% off that or something with code, think bout 90 ish normally, but lot cheaper than Bosch bout 300 think, for 6 months worked perfect, may do fior many years, I've got a Bosch too but they were practically given em away that day, worth it just for a spare.

[skid 1]

I tried the blue one today, once I disconnect the plug the engine coughed and spluttered so it must be working.

I also did a resistance test and it worked out according to the MFA reading temp.

But I ordered a new one for peace of mind.

Haven't managed to find any cheap MAF's online yet unless I get something on EBAY from Spain.

The only mate that has a MAF I could try, his Raddo hasn't ran for 10 years, so a bit sceptical to try it.

[jekel 10]

I tried the blue one today, once I disconnect the plug the engine coughed and spluttered so it must be working.

I also did a resistance test and it worked out according to the MFA reading temp.

But I ordered a new one for peace of mind.

Haven't managed to find any cheap MAF's online yet unless I get something on EBAY from Spain.

The only mate that has a MAF I could try, his Raddo hasn't ran for 10 years, so a bit sceptical to try it.

 

I wouldn't buy any cheap MAF can only say the ones from Eurocarparts working fine, so far. Have a look see if got sale on, google "eurocarparts offer code" always some discount available.

MFA reading is oil temp innit, not same as water temp but give you idea on ohms. When disconnected will default to 70 degrees, so fact changed little doesn't mean working OK, just means recording a temp., see what new ones like.

MAF or ISV probs still favourites.

[skid 1]

Can get a discounted MAF from Eurocar parts for £116 just now, but waiting to try my friends one first.

I got my New blue sensor and ISV muffler box from VW today, but won't manage to fit it all till 2moro morning. I will reclean my ISV again at the same time.

Car ran perfect this morning for 20 mins and has jumped about and cut out since.

Exhaust tip is black as anything!

[Jim Bowen 1]

About 75 degrees is when the idle switches over from the isv iirc and then uses info from the ECU to set idle.. Am sure i remember being told that.

 

Mine would idle dodgy until it hit that temp, bought a brand new ISV and that fixed it, had cleaned and tested original isv and also bought a 2nd hand one, but they didn't change anything.

 

Not sure it will be your ISV, but you can get cheap ones for under £40.

[skid 1]

Well new blue temp sensor and ISV Muffler box fitted, MAF and ISV re cleaned, new spark plugs too and it still occasionally hunts up and down when it's warm and running about town.

Mate never got back to me with a shot of his MAF so looks like I might have to take the plunge and buy one.

God knows what else to try?

[jekel 10]

Well new blue temp sensor and ISV Muffler box fitted, MAF and ISV re cleaned, new spark plugs too and it still occasionally hunts up and down when it's warm and running about town.

Mate never got back to me with a shot of his MAF so looks like I might have to take the plunge and buy one.

God knows what else to try?

 

Only things I now of that cause that are MAF, ISV, and less commonly the

[jekel 10]

Well new blue temp sensor and ISV Muffler box fitted, MAF and ISV re cleaned, new spark plugs too and it still occasionally hunts up and down when it's warm and running about town.

Mate never got back to me with a shot of his MAF so looks like I might have to take the plunge and buy one.

God knows what else to try?

 

 

ISV and MAF are still favourites, only other thing I know of that will cause that hunting is the TPS, but normally pretty reliable. What you really need is mate with spare parts to try or VAGCOM.

If it's a good car and your keeping it could just renew everything like I did, but had just put new engine and box in, brakes suspension etc. etc. so seemed stupid not to renew every sensor and ancillary.

Most things will run disconnected, will take default readings from other stuff so try disconnecting MAF, ISV, TPS when running, if no change it's deffo kaput, but could be it's working but not 100%.

[skid 1]

I have vagcom myself and have checked it heaps since I did the blue sensor and latest clean out but still no code coming up!

[skid 1]

Well I splashed out on a genuine Bosch MAF, which I got from Germany for £138 delivered.

Let's hope that once I get home from offshore and fit this, that will be the problem sorted!

[gazvr6 10]

Where did you get your maf from skid?

[robrado974 1]

Sorry if I've miss read the post, but I'm sure you said the car has not been run for a long time ?. Maybe the ECU is learning the engine . Mine was the same after disconnecting the battery for a long time . It took a good few miles of full throttle and then idle , for the car to settle down .