Jeep Cherokee 4.0 Limited Poliauto/Powertorque Help Needed

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stuart_g · #1 Post by **stuart_g** » Fri Apr 28, 2006 9:50 pm

Advice needed please. My son bought a 1992 Jeep Cherokee 4.0 SE Limited in 2002 & had Alternative Automotive Fuel Conversions Ltd of Bow Brickhill nr Milton Keynes convert it to LPG. Three months after conversion it started to misfire on LPG & become sluggish. We took it back & AAFC said the system was becoming blocked by poor quality fuel. They cleaned it out & after a few months the problem came back. Again they cleaned it out & advised us to find an alternative gas supplier. (He was using Shell so switched to BP) After a few months - same again! Again AAFC said it was poor gas & they would clean it this time but in future would have to charge. (The system was about a year old by now.) A friend who works with LPG fork lift trucks said it was "heavy ends" and it was a common problem. We took it to a couple of places in Northampton nearer to where we live and they had a go at sorting it but they weren't familiar with the system. It went back to AAF Ltd one more time for a service & again it was ok for a few months. We then took it to another more local LPG specialist who advised us to scrap the conversion & fit a Prins system at £1500. No way can my son afford that & since then he's given up on LPG & run on petrol for the last 2 years. Now he drives 35 miles each way to work and back & can't afford the petrol. I can't tell what kit was used. One label reads Type Powertorque SITI ECU ser. no. KJ6785332 & another reads Poliauto Automated LPG Vaporiser Regulator CPD5. Can anybody help with advice? Can anybody identify the type of system that was used? Can it be cleaned out without specialist knowledge? Is there an upgrade or new part that would cure the problem? Or is there a good LPG specialist who might sort it out in the Northampton Leicester Peterborough triangle?

alexf2828 · #2 Post by **alexf2828** » Fri Apr 28, 2006 10:03 pm

Just sounds like a vapouriser strip & clean and/or gas filter,shouldn't be too hard DIY,can the guys who serviced it last time tell u how its done?

stuart_g · #3 Post by **stuart_g** » Fri Apr 28, 2006 10:45 pm

Thanks Alex, That gives me some hope. I used to know about engines when they ran on SU carburretors - haven't touched a spanner in years tho. Maybe it's time I got back to it! I'll follow up your suggestion with AAFC. Stuart

alexf2828 · #4 Post by **alexf2828** » Fri Apr 28, 2006 11:32 pm

U get lots of oily crud building up in these places,thats the "heavy ends"

go_lpg · #5 Post by **go_lpg** » Sat Apr 29, 2006 8:57 am

Stuart, 'Heavy ends' (HE) is a long chain polymer that can be produced from LPG at the vaporisation stage. In effect it is a form of liquid Plastic. In itself it is not harmful but it can have some effects when present in larger quantities. You will find it present in ALL gas sold in UK to varying degrees. You don't say what type of system this is but from the symptoms and the vehicle itself I'll take a 'flier' on it an guess that it is open or closed loop with a single inductive mixer fed by an inductive vaporiser. If so, some vaporisers are much more susceptible to 'Heavy ends' build up than others. The model I'd recommend to replace your existing one is the OMVL R90E. Not only does it have very good characteristics and performance but high resistance to HE problems. IMHO it is simply the best inductive vap. on the market and has been for years. And more ....If the installer takes advantage of the R90E's versatility, the vapour supply line can be fitted to the lower outlet (R90E's have two, on upper and one lower) which almost negates any problems with HE build up. Any HE will then go into the engine to be burned along with the fuel gas and will not collect up against the diaphagm, introducing a 'bias' and throwing it out of its fine balance (the real problem with HE build up). As for your present vaporiser, and if economy demands it, you may find that there is a little drain plug on the bottom of the vap. chamber which could allow you to simply drain off HE yourself. Regards Steve <a href="http://www.go-lpg.co.uk" target=_top>www.go-lpg.co.uk</a>

lebesset · #6 Post by **lebesset** » Sat Apr 29, 2006 10:53 am

agree 100% with steve except on one thing , you get heavy ends EVERYWHERE ! I used to strip and clean my vaporisers at least twice a year ,but since changing to the OMVL using the bottom outlet the problem disappeared but if you don't mind regarding this as routine maintenance a strip down is no more complicated than changing the brake pads

stuart_g · #7 Post by **stuart_g** » Sun Apr 30, 2006 2:18 pm

Steve & Lebesset (and Alex), thanks. I don't know what system this is, The only names I can see are a couple of labels with Powertorque and Poliauto on. My son didn't keep the paperwork. I think the vaporiser must be a Poliauto (see my 1st post) How much would it cost approx to replace it with the OMVL R90E you mention? Is it a DIY job? And/or how can I get a manual or instructions on how to strip it down and clean it out. The original installer is some distance from us now and in any case I got the impression (maybe incorrectly) that he got fed up because we went back so often.

#8 Post by **admin** » Tue May 02, 2006 11:50 am

Power Torque are an equipment supplier in Coventry. You may wish to speak to them direct - tel 02476 635757 ask for David Wood

stuart_g · #9 Post by **stuart_g** » Tue May 02, 2006 8:08 pm

Thanks Damian. If I take some photos of the installation can I post them on this forum to see if anybody can identify the kit? I see there is a button to upload an attachment next to Preview/Post Message Cheers Stuart

stuart_g · #10 Post by **stuart_g** » Tue May 02, 2006 8:10 pm

Anybody out there can tell me the best place to get an OMVL R90E? And cost? still keen to learn how to strip down and clean out what we've already got to see if that solves the problem. Thanks

volvo940 · #11 Post by **volvo940** » Tue May 02, 2006 9:06 pm

Got mine from <a href="http://www.wtv-uk.co.uk/vaporizers.htm" target=_top>http://www.wtv-uk.co.uk/vaporizers.htm</a> I was happy with the price/delivery time and service

lebesset · #12 Post by **lebesset** » Wed May 03, 2006 9:47 am

stuart , exact layouts vary a bit , but there is nothing more complicated than cleaning a food mixer just take the vapouriser off and undo the screws...if ~Ican do it a 10 year old can

stuart_g · #13 Post by **stuart_g** » Thu May 04, 2006 9:59 am

Thanks Peter and Lebesset, have checked out wwtv-uk.co.uk, prices at £109/£114 - seems reasonable but if the vaporizer we've got just needs a good clean that would be preferable. Funnily enough just bought a food processor....now, where are my screwdrivers!?!?!

stuart_g · #14 Post by **stuart_g** » Tue Jun 06, 2006 12:19 am

Have now had my son's Jeep fixed by Steve at Go LPG... fantastic! Steve could not have been more helpful. I brought him a vehicle with an unknown system (not many Poliauto's about!) that had been playing up for a couple of years despite previous "fixes" by the original installer. He sussed it out and had it running properly within a couple of hours. He also took the time to check other aspects (like spark plugs and HT leads) AND advise on replacement items that would enable the Jeep to get full up to date certification. Both my son and I were really impressed - he's one of those guys who does it for the love of a job well done rather than the money. I cannot reccomend him highly enough!!! Well done Steve and many, many thanks.

quantum · #15 Post by **quantum** » Tue Jun 06, 2006 10:19 pm

Stuart, were you able to confirm whether he has single injection, or multiport injection? I agree that this does sound like a single-port system, as these can be susceptible to this. Something Lebesset said in passing is very important: "but since changing to the OMVL using the bottom outlet the problem disappeared" Heavy ends build up if they are not able to drain. So if your son does have a single-port injection system, make darned sure that the vapor-out port of the converter, is aimed down.

stuart_g · #16 Post by **stuart_g** » Tue Jun 06, 2006 11:04 pm

Hello Bill, You got me there..! I didn't ask but if Steve picks this up he may be able to confirm. There is an injector to every cylinder (6 cylinders) but only one hose (vapour out port?) feeding all the injectors. This one outlet is facing mostly upwards. The installation is very awkward - there's not a lot of room in there and Steve was very patient in taking it all apart. But we found a good way to clear the heavy ends - just let the gas blast them out!! Not intentional but the solenoid that was supposed to cut off the supply was stuck open!! A couple of hairy moments there but a gentle tap with a hammer freed the stuck solenoid - by then the brown stuff had been blown out. The plugs and HT leads weren't in good condition - Steve pointed out a spark arcing from the back plug to the block. I think this was as much contributing to the poor running as the build up of heavy ends. Steve said gas is much more sensitive to misfiring and poor timing than petrol. He fixed the ignition problems too and it's run like clockwork since. I can see future clearing of the vapouriser will be a problem as it's near impossible to invert it without taking it right off. Maybe a vapouriser with a (second?) downward facing outlet will make it easier but the Poliauto seems to be doing the job well enough for now. If Rob (my son) decides to change it'll go back to Steve. Otherwise I guess I'll be stuck with cleaning it out now I know how it's done!

quantum · #17 Post by **quantum** » Wed Jun 07, 2006 3:50 pm

Right, LPG systems must have a good ignition system, as it's harder to ignite. Props to Steve for finding that arc. Rob has a multiport system, which puts out a higher vapor pressure than single-injection. (single, injects gas into a venturi, like an LPG carb) Normally multiport is not susceptible to converter fouling because of this. Man, if this is fouling so frequently, y'all must have LPG from oil refining (opposed to natural gas drying), and which is not produced well. I suggest adding a filter into the liquid line; these are often built in to a lockoff at the tank. It'll be cheep. (~L30) It would be ideal though, to put vapor-out, down. I shouldn't think blowing it out with compressed air would be too good for the delicate diaphragm/regulator. But Steve knows better than me.

go_lpg · #18 Post by **go_lpg** » Tue Jun 13, 2006 4:37 pm

Stuart, to recap - Rob's is a multi point system - Makes the fitting of an R90 E vaporiser inappropriate. Your vap. may live again if removed and resited correct way up and correct way round which would also make draining easier. Tank venting needs review. Level indicator on tank reads counter-clockwise and can mistaken for reading full when actually reading empty. Tank was empty, gas system is live all of the time, even with ignition off, as both solenoids (tank and under bonnet) are stuck open. Results in gradual leak down of tank contents. Needs sorting out. Gas all over the shop! I ended up draining the heavies as a result of taking the vapour hose off and not being able to get it back on again! (It got frozen solid due to gas escape). Vaporiser fitted East/West instead of North/South which leaves it vulnerable to the effects of intertia and momentum. Vaporiser has no visible means of lower portion draining, what appeared to be a drain plug wasn't for heavies but actually for coolant (Water all over the shop!) With current setup it must be removed and inverted to drain heavies. HT lead No 6 shorting to cylinder head - Temporary tape fix for now but replace all HT leads and plugs whilst you are at it. Pleased I could help. Bill, yes, our UK gas is dirty as a rule. Rob has a liquid filter under the bonnet but doubt that it would take out the heavy ends, i am interested to hear about the tank end filter you wrote about.

quantum · #19 Post by **quantum** » Tue Jun 13, 2006 5:10 pm

It's a lockoff/filter combo, right at the tanks. Has a large fiber disk filter, of about 4", and is intended for liquid. (Don't know the brand, but can check if needed) I've never looked at the element, but I should think that if heavy ends are tarry it would capture them, although it may allow them to dissolve back into the stream.