[CNGBiFuel]

I have contacted the forum Admins and had no reply.
I assume they do not see my as a trader per se. I sell these for less on here than on eBay simply because eBay charge me £40 odd per sale.
I'm pleased the admins took my suggestion to change the title of this section to include CNG LNG etc. After all Volvo can claim all credit, Volvo WERE the volume manufacturer PIONEERS in this technology.

Glider only - Thank you glider. I understand you had rough running at 3000ish rpm too, this would not be a stepper issue, please ring me if this side of the car has not been sorted. I strongly suspect 1-2 dicky coil-packs (a known issue) or tired, silly snake-oil LPG or multipoint plugs, or a combination of these. I owe you a core deposit. You will see this in the next day or so.

For the rest of you...


Necam (Necam now known as Koltec) Volvo Type B Stepper Motor


If your Bifuel randomly cuts out...
It is highly likely it is the stepper motor. A known issue. Whereas, initial starting issues (from COLD) or rough running, would indicate problems with your regulator and/or distributor, starting issues HOT, after cutting out, would more often be your stepper.

HIGHLY UNLIKELY YOU NEED A WHOLE DISTRIBUTOR.
This is a myth put out by Volvo because they sell boxes, and had no clue about the real issues and selling the complete assembly (@£8-900+) got rid of customers for another 25,000 miles. At main dlealer level Volvo know little. See your local LPG specialist. Back in the day, Volvo often subb'ed these jobs out to them. Event the specialists would swap the dizzy in blind hope.

The first time I had the stepper replaced, I was told by an independent lpg garage that they only last a few years, and he was right

Without my mod this is correct.

Replacement of stepper, and cleaning is a DIY task, I detail at the foot of this page, how to change your stepper. Unless you have well on 200K+ miles you will not need a new distributor. Even then, kept soaked in GT85, and clean they cope.

I recondition these and correct the ongoing fault with Necam Stepper motors.
I correct the Triac issue, Necam are well aware of this problem, however for clear reasons they don't fix it.
I've had owners come to me on their second and third distributor / stepper. Young 'glider' here, is I'm afraid, typical. This mod fixes the problems with Volvo BiFuels permanently.

Also as part of this service I offer you my wealth of experience to fault-find your Volvo and prevent recurring issues. Very simple and reliable, the Necam system is maligned simply because few understand them.

My steppers after modding fit CNG & LPG Necam distributors fitted to Volvo S70 V70 S60 S80 with the flat top stepper motor . There are two types of stepper motor by Necam. Not to be confused. This is the Volvo specific model. Often called a Type B.

See Red Cross indicated pic. Shown by red cross, is the non-Volvo Type A, you will not receive a Type A. Type B has a flat top.


My steppers and my support.
Either way, you have my experience in solenoid set-up, regulator management , what to clean, what to replace and general fault-finding of your Necam system. 15 mins of my time if you collect, and up to three phone calls of my time if you need to call me. I will walk you thru' fixing your Volvo Bifuel. My knowledge is such that you will be able to fix your LPG/CNG Volvo.

Outside of Necam, I have a greater understanding of these systems than any in Europe. Other sellers are box-shifters, and/or whole-unit-swappers.


Changing your stepper motor.
On post 2000 models, the Necam stepper got moved from a simple to get at place on the bulkhead on pre 2000 to between the radiator and the block.

One for grazed knuckles this...

On 2001-2005 era S80 S60 V70s, with the car running on gas disconnect the solenoid cable under the air box to purge the system of gas. Reconnect before you forget.

Disconnect battery. The distributor is close to some chunky cables that can supply lots of amps if you put a spanner in the wrong place!

Clamp the lower power-steering hose near the pump and disconnect the top hose and move out of the way. (Don't get oil in the alternator) Unbolt the dip stick pipe (10mm socket]. You don't have to remove it but it's easier if you do. Remove the pipes and cables and undo the 2 nuts on the distributor / engine bracket / rubber mount. Careful here, the rubber might be perished. If you do shear the rubber mount, Demon Tweeks Part No. FSEFPA905 - Facet Fuel Pump Mount x 2 will fit). Leaving the bracket on the distributor might be easiest. Remove; some jiggling required. Knuckles will be in fine order about now. Do not smoke!

Make sure the outside of the stepper motor is clean, if you get dirt into the distributor on removal of the stepper, the bill is some £400.

Remove 2 x 3mm Allen bolts and remove stepper motor. Careful here. Two reasons, 1) Shaft of stepper easily bent. I won't want it back if you bend it. 2) A large spring washer about the size of a 2p bit, a large compression-spring, and if you’re unlucky a ball-bearing will fly about. Watch yourself.

Unclip piston from spring on motor’s piston/plunger-tip (note which way up piston goes - deeper side away from stepper to accomodate large compression-spring). Remove clip-spring on old motor plunger-tip and assemble on new motor. Watch for the O-ring sitting on the neck of the stepper (usually Brown in colour).

The stepper was likely fried because of dirt loading the motor, the distributor probably needs the slots cleaning, these are not easily seen but are down the distributor barrel. Pour some Wynns/Comma injector-cleaner (Wynns because it’s the same stuff and cheaper than STP) into the distributor. Fill to 5-10mm from top. Put a large coin, (2p piece is good) over the opening and let it soak 3-4 hours or overnight. 2p is there to stop dirt and injector-cleaner evaporating.

On P1 pre 2000 cars getting the motor off is quicker, this makes it easy enough to start the car running petrol and when it flips to LPG/CNG and floods, let it stall on the injection cleaner. Reattempt starting and the injector cleaner will clear. Drive 20-30 miles to let cleaner clear and pull the stepper off again and lubricate piston with GT85 PTFE. Do not use WD40 or any other lubricant containing silicon. You risk contamination of your Lambda o2 sensors.

Because firing the car up on P2 models is not so simple at this point I suggest a Turkey baster to syphon out the excess Injector cleaner. Then GT85 PTFE spray the piston, making sure the injector cleaner does no dilute the PTFE. If you're that keen, do this in 20-30 miles as you would a P1.

Make sure pistons etc is spotlessly clean before reassembly. Don't bend the motor sliding the piston in. Expensive if you do.

Put it back together and check for leaks.


TWO WARNINGS
1) LPG is dirty, dirty stuff which produces heavy-ends to clog your distributor and thus fry your stepper motor. Applies to CNG to a lesser extent.

Getting to the stepper motor and soaking with a 2p cap is best, but pouring injector cleaner down the low-pressure pipe from the regulator is fair substitute. it will certainly make for better running and keep the stepper from overloading, hence frying.

Fire injector cleaner in there and let it soak every 6-10,000 miles. I do mine at 5,000 (earlier vehicle so easy to do]. Fail to do this, and if the erratic supply (or last year nil supply) and high prices are anything to go by, next time you won't be able to source its replacement, let alone, easily or cheaply. Volvo stopped selling cars with this stepper motor eleven years ago, and didn't sell vast numbers then. How long can it be before this part is declared obsolete at any price?

2) Some are not fitted with a filter between the regulator and the distributor. These are £4.00 (£90.00 from Volvo). Fit one. Check this, if I recall -16mm.

There is a design flaw within the stepper that means that they will often go wayward. This I fix for you, better than new. Follow my advice and I can assure you, Volvo Bifuels are very decent vehicles, which with clean fluids, will do mad mileages. Thye'll not crumble away before your very eyes, unlike a Merc (and some Beemers) of the same vintage.

There's a few more known issues that appear on these vehicles at around 90-140,000.
Those that spring to mind are PCV, cambelt, an auto gearbox flush, heater core and ETM (on 1999-2000 MY) - all DIY jobs. Flush your autobox tomorrow if you own a 2001-2003. Attend to them and you'lll see another 100,000 miles before they need doing again. Hence you own one of the cheaper cars to run on the road today.

Read diagnosis carefully. To repeat:
If from COLD the car runs sweet and even, your regulator and distributor are likely OK. When HOT or COLD if running rough you have either:

1) A coil pack going. A known issue at 90,000 miles and over. Easy to swap.
2) Plugs getting tired or set over 0.7mm. Leave snake oil multi-point and LPG plugs alone. Good quality single point Denso or NGK are best, and far cheaper. Low-spec plugs changed often is better.
3) Dirt in distributor. This will cause lumpy running, poor starting or poor changeover. Clogged, your distributor gives your stepper motor more work to do. So likely frying it, Hence as the car gets warmer you see more cutting out. Cutting out is almost always the stepper. Which is why you are reading this.

The problem comes when you have a combination of clogged distributor, worn plugs/coil packs, these will all show lumpy running or poor starting. The stepper motor will be causing the cutting out. No amount of cleaning / plugs etc etc will help you if the distributor has got dirty enough to damage the stepper and cause cutting out.

Many of you have seen stepper motor issues before. You’ll recognise the symptoms. More Tech support when you buy. I can help with distributor/regulator set-up and ECU issues. My unit fits your car if your stepper has a plain flat top. The two types are not compatible. Flat top is Volvo only.

In short, poor starting HOT or COLD is unlikely to be your stepper motor, injector cleaner used at intervals will sort most issues, if not, (assuming you've decent plugs and coil-packs] regulator and solenoid issues is where I'd be looking next. However... random cutting-out? No amount of cleaning will have you escape this, this si a battle you will lose, you need this stepper to win- remember to clean as above before you install. Do this and a few other DIY tasks and your car is good for 300,000+ miles. I do 45-60,000 a year (55,000 last year) in mine.
All stepper sold after rewoking get a stint in my own car for a minimum of 800 miles to be sure your stepper works under all conditions.

Follow the guide I provide with your stepper to the letter (especially about periodic cleaning) and these steppers will not trouble you again. Ignore it and sob into your beer

Good luck