LPG hesitates under load

[Gordonsvan]

Hiya, I hope the forum expertise can help with this problem. I have just bought the van and have no previous experience with LPG.

Transit 2005, 2.3L petrol/lpg 50k miles
It was made as an LPG vehicle, it is not a conversion.
It is great running on petrol but when on LPG it hesitates whilst accelerating as if it isn't getting sufficient fuel. When it is up to speed it seems ok, the problem only occurs under load.

I borrowed a scanner today which retrieved these OBD codes:

p0201 injector circuit open cyl 1
P0202 injector circuit open cyl 2
P0203 injector circuit open cyl 3
P0204 injector circuit open cyl 4
P0401 EGR flow insufficient
P0402 EGR flow excessive
P1131 DTC definitions not found! Refer to service manual

Is there a recommended order of things to check? Thank you for your suggestions.

[mealic]

Hello and welcome to the Forum and the wonderful world of the LPG Transit.I too have the 2.3 Bi-fuel.When it`s running well it`s great ,but sometimes..............just sometimes.
Anyway over to your problems.First of all,take no notice of the first four faults thrown up,they all say that when plugged in and I don`t know why.The second two are caused by the problem you have, I think.This is now what I have found to be the simplest and certainly the most economical repair.(free )
There is a small vacuum pipe that runs from the back of the LPG regulator(the cylinder on the lower part of the system) up to the MAP Sensor on the top left inside the bulkhead.The pipe then runs down to a tee and continues to the inlet manifold behind the throttle body.Where the pipe fits to the manifold is an elbow and this rubber gets soft and sloppy.Trim back about 15mm or so and re-fit the pipe(you can only see this bit using a mirror).
The vacuum varies the pressure at the regulator.If there is no vacuum the engine will overfuel and most likely cause the two other faults and obviously not run correctly.
Try this first and see if it sorts your problem.Please let us know either way.
Good luck.

[ake]

The injector codes will always be present due the the way the LPG system disables the petrol system, basically disconnecting the wiring to the injectors.

[mealic]

The injector codes will always be present due the the way the LPG system disables the petrol system, basically disconnecting the wiring to the injectors.

Yes,that figures Ake.Thanks for that

[Gordonsvan]

Thank you, it is interesting that Ford seem to allow the OBD system to log "faults" which are not actual faults. I'll trim the pipe as suggested and report back the results.

[Gordonsvan]

I am finding it difficult to identify the correct pipe to trim. Please can you be more specific as i dont want to remove or cut the wrong one. Thank you.

[MinorMatt]

Any pipe that looks degraded/perished

[mealic]

Sent you a PM last night and you didn`t ring me!!

[longlivekevin]

Hi chaps, I have the same 2.3 Mk6 Bi-fuel. Ive just changed the front section of the exhaust, and unfortunately had to run the engine for a little while with no complete exhaust fitted (long story, but I had no choice). Having fully fitted the exhaust, the engine just isnt running right. very rough, but not to bad up the rev range (3k and over). I have plugged in my little OBD jobby, and its picking up the following "P0401-powertrain" error.

the vacuum pipes (at least the ones i can get to all seem fine and tight)

Any ideas?

[Jonah]

Hi Guys,

It's been a while since i last visited the forums, but recently my van (2.3 factory fitted LPG Koltec Reg 2003) has developed this fault,it runs sweet as a nut on petrol and weirdly it also runs sweet on LPG when idling, rev the engine stays on gas, but when the van is under load it will not accelerate, (if maintaining a constant speed ie: not moving the accelerator pedal, the van runs quite happily on gas) but once the accelerator pedal is moved (to slow down, change gear or speed up) the van will not accelerate, the only option is to switch back to petrol and the van instantly picks up speed and drives normally, Now i'm not one to come calling at the 1st sign of trouble, i've taken the van to two separate lpg service garages...1 suggested the vapouriser had gone which they replaced, made no difference wasn't impressed as it was a few bob down the drain, the other thought the vaccum pipes needed replacing, all hoses have been replaced between the MAS sensor, the vapouriser and the manifold, which i did myself, wasn't that, thought i'd try replacing the RPM filter as that seemed to be a possibility, wasn't that, hoping someone might have experienced this issue and offer some advice on what i could try next? Thanks

[mealic]

Get another oxygen sensor. Fits in exhaust downpipe. a Bosch 4 wire universal for a Transit should do. Be about 25 quid on ebay. Comes with all instructions.............you just need a soldering iron.

[mealic]

If changing the sensor has no effect you will have to clean out the distributor on the LPG system. This is between the vapouriser and the injection pipes. I`m suprised that a "specialist" didn`t suggest this.You can do it yourself but you do need to know what you are doing.I presume that the main filter to the supply line at the vapouriser end was changed .

[DodgeRover]

Theres a thread over on the LPGdiscussionforum about factory gas transits, I think its in the having problems section, there is loads of info and a list from someone who maintained a fleet of them of basically what failing causes what fault.

[RustWidow]

Hmmm that sounds complicated, I'm glad we didn't go for the one on eBay now lol good luck with rectifying the fault

[Jonah]

Get another oxygen sensor. Fits in exhaust downpipe. a Bosch 4 wire universal for a Transit should do. Be about 25 quid on ebay. Comes with all instructions.............you just need a soldering iron.

Many thanks guys, i have ordered a sensor will fit and report back, in the meantime i'll read up on the LPG issues in the having problems section.