OMVL Dream XXI Wiring diagram.

[quat-fro]

Hi folks,

A friend of mine has the above mentioned system fitted to a Corrado 16v engine which has been transplanted into a Transporter van. It's the very early one without any following numbers or letters.

The LPG system worked in the car, and now runs really badly in the van, seemingly unable to sense throttle demand...

Mechanically, all is sounds, pipe work isn't kinked or dented and we've drawn to the conclusion that either a wire is missing or broken and or, the diaphragm of the reducer is on its way out - Sucking on the vacuum pipe to it, I can't get my tongue to stick to it, suggesting a leak somewhere.

Could anyone point me to the wiring diagram? or provide a modern link to one? I've found a few threads on here about the same thing but the links are clearly out of date and lead to nothing!

Cheers,

Tom.

[LPGC]

Tom,

At first I didn't take in the fact you've simply transferred the same engine from one vehicle to another.

If the above is true then it should run absolutely fine.

Check vacuum hoses are connected as they were before.

Does the engine run OK on petrol?

The Dream XXI doesn't read 'throttle position', it reads injector pulse times and if you've transferred the engine and it's full loom including petrol ECU it should still read those the same - or your engine would at least misfire all the time on petrol.

Any more info? Am I correct in assuming you've transferred the job lot, engine, petrol ECU, etc, into the van?

Simon
LPGC - Google

[rossko]

The Dream XXI doesn't read 'throttle position', it reads injector pulse times

The original Dream XXI is independently mapped, does not read host injector times, and needs a throttle position sensor connection (blue/yellow wire for a linear type)

Manual+diagram at
http://www.fesautogas.co.uk/dream21cinst.zip

[LPGC]

Blaze is talking about the short lived Dream C. Some of these had the vacuum port on the ECU itself instead of using a remote map sensor.

The slave type sequential Dream N system doesn't say N on the front either. On the back, if you check serial numbers, some of the more recent Dream ECUs have the suffix C at the end of the serial number. The more recent ones have the suffix D and usually have OBD fuel trim reading ability.

Incidentally, for any installers who would like Dream C functionality (standalone type injection), I have just developed a system which allows the later slave type sequential systems such as the Dream N to work the same as Dream C - but much more reliably!

I've got both types C and N here.

Simon
www.Lpgc.co.uk
07816237240

[quat-fro]

Thanks for the replies, I forgot to subscribe to this one to get notified!

I also forgot to mention, it's the Corrado / Golf Mk2 2.0 16v on K-Jetronic. and was basically a straight swap.

The throttle body only has closed and full throttle switches so LPG modulation must only be metered with vacuum, right?

Engine runs absolutely sweetly on petrol, you couldn't find a fault with it, except when you switch it over to LPG and it'll run and can propel you along, but seems unable to provide enough torque to maintain more than 30 mph bizarrely.

Interesting that it may not necessarily be the oldest 'non-suffix' XXI ECU, I'll have to have a nose again and double check, this one DOES have the vacuum hose to the side of the ECU...I've found on LPG-kits that you can get a cable, dongle, CD with software and wiring diagrams and everything, but according to them if it is the very early one then apparently I need a 'Key' or it'll all be completely useless - Or is it just printed on the back somewhere?!!!

Any suggestions on the best course of action would be very much appreciated.

I have considered maybe just getting another slightly later ECU and separate MAP sensor if I can't obtain the key but if this could be cured relatively easily, then that would also be cool. Other than that, which front end kit would anyone suggest I upgrade to which would happily work on a K-Jetronic system?

Cheers,

Tom.

[Tubbs]

Originally with the first gen ecu's they needed a dongle, i dont remember them needing a key or if it was it was printed on the dongle. They weren't very good, but if it worked it worked. Now you may find someone like tinley tech will have an early bigas ecu gathering dust that they will sell you for much cheapness. I would be concerned about the k-jet bit of your post. If it was k-e-jet then no problem. But with the early type they didnt need an injection pulse just rev multipliers ! oh how much fun where they ! if anyone else is old enough to remember ! Gas injections come a long way since then.

[rossko]

The throttle body only has closed and full throttle switches so LPG modulation must only be metered with vacuum, right?

There is an alternative wire for throttle switch on the diagram I pointed you to, but yes it'll never have sparkling performance without proper TPS.

you can get a cable, dongle, CD with software and wiring diagrams and everything, but according to them if it is the very early one then apparently I need a 'Key'

Did you have a nose around the FES Autogas site I pointed to? Dream XXIC software available, this is the last (dongle-free) release.
http://www.fesautogas.co.uk/dreamc.zip
You'd still need the lead of course.
Alter nothing until you have got a secure backup of settings.

As it used to work and now doesn't, that might not help you at all. Follow up your hunch about diaphragm - if you pull off the vacuum pipe when running, does gas come out of it?

How about the tank or supply pipe? A kinked pipe will limit flow, an upside down (or empty?) tank will supply only vapour, either will give a severe ceiling on horsepower. How long was this stuff sat around, could the solenoid or regulator be gummed up?

Other than that, which front end kit would anyone suggest I upgrade to which would happily work on a K-Jetronic system?

There is no real alternative.

[quat-fro]

A ha! So basically, we're stuffed for anything moderner / newer / supported...

I did read the site in that link of yours but I don't quite understand whether it's the correct software for the ECU or not, plus, as you say, still need a cable etc.

I'll chase up those leads and report back...

[mat_fenwick]

If you phone up FES and ask for Nick, he's pretty helpful and should be able to advise what you need. But check out all you can before spending money, although a lead would be useful anyway.

[rossko]

A ha! So basically, we're stuffed for anything moderner / newer / supported...

I reckon so. The vast majority of current systems require to be slaved off a pre-existing electronic petrol injection system. I suspect even the exotic ones with 'independent' maps like OMVL Piro require injection triggers?? But of course there is LPGC's newly developed system which he says will match things up.

The vac pipe on the ECU is a key identifier, you want Dream XXIC software.

Most likely to go wrong with these older systems is the mechanicals, which haven't changed really, so they are maintainable.

[LPGC]

I think I may have mentioned on this or another thread...

I have developed a system which enables recent slave type (or N or P type if we're talking AEB electronics) to work on older none EFI engines - So this would enable you to run a modern sequential system on a Bosch K Jet or even a carb engine.

A TPS is easy to make if your vehicle doesn't have one - I made a TPS for my 1990 carburettored Talbot camper van using nothing more than some rubber piping, a potentiometer, a couple of resistors and some bracketing. Same vehicle has a lambda probe in the exhaust and runs a closed loop AEB175.

'Manufacturers' of some of the 'brands' (note the inverted commas because they're all actually AEB) of the AEB pre N systems released cracked versions of the software for the pre N systems - to get owners of vehicles and installers repairing these vehicles off their backs a bit as they don't want to support those systems anymore. Not sure about OMVL, I think I asked Nick at FES about this once as he couldn't get hold of the dongles etc anymore. I think Romano does the cracked software - and since they're basically the same unit it should be possible to connect to the on chip debug port (actually inside the ECU) and change the firmware to Romano then use cracked Romano software...

Most likely to go wrong is the injectors, followed by map sensor or reducer, followed by rest of ECU.

Simon
www.Lpgc.co.uk
07816237240