V70 CNG Bifuel pulsing idle isn't the ETM

[CNGBiFuel]

Well I'm pleased to say I've joined the fray. I now have my first Volvo. A P1 Bifuel CNG, and thanks to you all, I went in with my eyes open.

When you're after a CNG Bifuel, you've not much option, with only 50 odd in the country, it's Hobson's choice. It gets worse, if you want a V70. Most CNGs are S40s.

I've a bigger and better Homefill compressor coming soon, I have a old Phill system now. (Don't bother, utter rubbish) Anyway, i need your help.

This 90K example, a 1999, V70 P1, had a fluctuating idle, only on gas, and it didn't phase me, ETM thought I. After-all, I'd heard in this very parish that the ETM can often be at the route of Bifuel woes, even when the same car works on petrol fine. I know about the stepper and Necam distributor, but often I understand, ETM is the first place to look. My logic? Even if the iffy gas running, is not the ETM, with 90K on the clock, it soon will be. So i thought best get it out of the way. My V70 exhibits the engine management light intermittently on, flick the switch to and from gas and for 10 mins it goes out.


I changed the ETM to a contactless version. spokoluzik is fairly local to me and he did it in whilst i waited. No messing, I recommend him. This swap did not cure the issue, in fact spokoluzik said it probably wouldn't, and as it always did, it runs fine on petrol, (still with intermittent Engine management light). No different. There are no fuel filters on my CNG model which seems odd:

I got this from Swedish forum, and it confirms this:

http://www.forumgas.se/forum/viewtop...=1345&start=50


1995: Manometer + solenoid in conjunction with high-pressure regulator. in-line filter. in-line filter.
"SERV. NO. 01228547" ECMs labeled "SERV. NO. 01228547"

1996 : Unclear on the color of the high-pressure regulator. Manometer + solenoid in conjunction with high-pressure regulator. market filter, ECM etc. Unclear on the filter, ECM, etc.

1997: Black high-pressure regulator. Manometer + solenoid in conjunction with high-pressure regulator. in-line filter. in-line filter.

1998: Black high-pressure regulator. No pressure gauge + solenoid in conjunction with high-pressure regulator. in-line filter. in-line filter. Sensors in the low-pressure. ECM labeled "SERV. NO. 16206304" "ECM: Volvo S70/V70 CNG GB5252S VOLVO_F3.S19 Typesp.nr: 183970016" 'VOLVO 9445332 "(Necam labeled ECM).

1999: Black high-pressure regulator. Unclear whether the gauge / filter / sensor. Water heating also of low pressure.
"SERV. NO. 16206304" "ECM: Volvo S70/V70 CNG GB5252S VOLVO_F3.S19 Typesp.nr: 183970016" 'VOLVO 9445332 "(Necam labeled ECM).

2000: Black high-pressure regulator. No pressure gauge + solenoid in conjunction with high-pressure regulator. Inget in-line filter. No in-line filter. Oil separators in connection with high-pressure regulator. New steppermotor to the manifold. Water heating also of low pressure.

Another reason, I looked to the ETM first was that despite this car being a 90K example, it has not been run too much on CNG, where would most get it anyway, I had ben told the last owners ran it exclusively on petrol, finding out only later, they had not bought an LPG car. An all too common issue with CNG cars. I want a short-term fix, in fact I've been talking to classicswede, and feel a new front-end coming on very soon. For now, to get me out of a jam, where should I look next?

[mikealder]

Chuck a new set of the correct grade Volvo Spark Plugs in to the car before you try anything else and while you are changing the plugs take a good look at the coil packs for any evidence of tracking or even damged ends that could cause the spark tp jump to the head rather than where it is needed.

Make sure you get the plugs from the dealer for the car and they are the correct grade to run CNG, something the previous owner might not have been bothered about if they ran it on petrol all the time - Mike

[Unreal master tech]

Sounds like gas distributer could be faulty it is common issue that the bi fuel cars have our government had a fleet of 12 and every car had one at least every other year although these cars were hardly run on petrol and for some reason the gas distributers caused problems it could be also that the gas pressures are not set correctly? It might also be worth checking the gas filter as it is easy to replace & if it's not been done in a while will not be helping matters! It is under the bonnet next to the air filter a silver junction in the rubber hose after the govenor! Good luck!!

[CNGBiFuel]

Thanks mikealder

Forgot to say, spokoluzik, bless him, ran diagnostics on it and found nothing of note. Plugs I can do, cheap and easy.


Unreal: I'm not seeing a filter. I've followed the gas line back from the distributor, on mine hte distributor is on the top of the firewall, about a foot right of the center line of the vehicle. Gas line goes into the transmission tunnel and I lose sight of it then. According to that Swedish forum there is none. But that can't be right???

Gas distributor clean next I suppose.

our government had a fleet of 12

Is that who bought them, ah, I did know they were sold mostly to our political class. I know a Wiltshire mayor got one. In 1999 only 4 came into the country, and I believe there are only two surviving S80s. Unless you ahve them, Rare.

[Unreal master tech]

The distributer is down underneath the inlet manifold if you look here you see all the small pipes going to the inlet manifold if you follow the large pipe from the distributer back you should see a filter it is not what you expect it to look like from my memory though it actually says gas filter on it?it is normally held with hose clips? As for people who bought them,it seemed the Scottish government got them as they were great cars for chauffeur driving and the fact the they were cheap to run on gas made them a good choice as I said this was a fault we got to know from memory the distributer was over £500 to buy but very easy to replace but am sure(I think) you could find the company who made hem and thy were a lot cheaper! If you need any assistance get some pics up and I can try to help!! There was 2 different types of gas cars from memory the labels on the units are either green or red? The system I am talking about is red but am sure I still have course notes somewhere if you are still struggling I will look them out?

[CNGBiFuel]

My distributor is not positioned as showmn here,

http://www.aa1car.com/library/cng_volvo.gif

It is where the green fuel line intersects the black 'Powertrain module line'

I will post pics tomorrow. It has a Red label dist. Wht you speak of i think is a Parker type filter. Correct? See attached

[CNGBiFuel]

As promised, pics. I havve traced the s/s gas lien back and there is no filter. The joint on the bulkhead looks very factoery. No empty holes where a filter now missing should be.

I take it for a quick fix before i hand it over to classicswede for a magical new front-end, I undo the s/s joint and fire carb cleaner/STP injector cleaner into the s/s pipe.

My car is a Volvo V70 Bifuel from year 2000. It has one big gas tank in behind the rear seat backrest. Not 3 x tanks as later CNG

[CNGBiFuel]

More pics.

I can't afford a new one of these every 12 month, unlike your politicians, I'm paying! 'sides I understand it is NLA anyway. I think you can get a seal- kit to revamp.

The makers will not sell direct, Volvo part only.

KOLTEC-NECAM BV KOLTEC-Necam BV
Rudonk 4 Rudonk 4
4824 AJ Breda 4824 AJ Breda
Tel. +31 (0)76 548 23 00 Tel +31 (0) 76 548 23 00
Fax +31 (0)76 554 198 74 Fax +31 (0) 76 554 198 74

[CNGBiFuel]

Found these two diags. on a Swedish forum

[Unreal master tech]

Hi mate good photos unfortunate news is this is not the system I have worked with it has the (green label) but looking at it from the pictures and what the fault is I would still advise the distributer is the cause of the fault it might be worth asking people who supply and fit cng/LPG conversions as they might be able to source you a new distributer or help advise on how to clean them properly? I know for sure if you ordered through Volvo you will look at a lot of money for one so might be worth investigating all avenues!! Good luck sorry I can't be of any use!