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[Kevin Wood]

Excellent! A lead to follow.

If the Lambda dips to 0 the cylinder is going lean. Suggests the gas injector is not firing. If you switch all other cylinders to petrol bar this one can you hear the gas injector ticking?

Also try swapping the connector into the gas injector and the pipe to the nozzle with another cylinder. Does the problem stay with cylinder 5 or swap to the other cylinder?

Kevin

[Jay w]

I have swapped the injector and the problem stays with no 5.

I have just double checked the nozzle and am able to blow and suck the feed pipe to the engine, i have a feeling that the issue may lie with the injection block, i am now going to swap then over and see where we go

[Kevin Wood]

If you've tried number 5 cylinder on a different injector (in that block) and number 5 still misfires it proves the injector is OK (as it worked on another cylinder). At this point I would suspect the feed from the ECU to that injector :-/

Kevin

[Jay w]

If you've tried number 5 cylinder on a different injector (in that block) and number 5 still misfires it proves the injector is OK (as it worked on another cylinder). At this point I would suspect the feed from the ECU to that injector :-/

Kevin

well this is what we have done so far

Swapped the yellow electro magnet
Swapped the plunger inside
Swapped the nozzle
Checked the feed pipes for kinks and blockages
checked the connections at the petrol injector end


Still the problem lies with no. 5

you can feel the injector clicking away when you have your hand on it.

what sort of voltage would you expect to see from one of these is you were testing it?

[Martin_1962]

Fantastic progress, you have a great start point now

Pull off the injector off for that bank, and try blowing into/sucking through the main gas inlet for it. If you can blow OR suck then you have an injector stuck!

THat is for stuck open - like that OMVL kit

Not sure what voltage triggers them

[Jay w]

well just to be double double sure we ripped apart the 1.3.5 injectors, we checked all the pipework, have nee over the loom and anything else that we thought might be the issue.

Put it back together..........



IT WORKS!!

fires up and runs lovely on all 6, still has a bit of hesitancy if you floor it from idle, but that is a mapping issue, and mapping is my weakest point.

Pulls like a train, in fact i had to keep checking it hadn't switched back to petrol, cruising at 80 and switched over to petrol and you couldn't feel the changeover or any difference in performance

Am well happy now, thanks guys for all your suggestions and encouragement
 [smiley=tekst-toppie.gif]

[Taxi_Driver]

Double check the number in case it's wrong. That was just from an internet search, but it sounds interesting. Not cheap though.  

Might be worth trying to gap the existing ones a bit closer first?

Kevin

You need a good spark for lpg.....and ive been recomended to open the gap up a bit by a few thou.....for single electrode plugs.......just about imposible to do on twin or quad plugs tho, so as i fit twin electrode plugs I leave them preset at 1mm.

I guess the above advice I was given......means a bigger spark in theory  :-/

[Taxi_Driver]

well just to be double double sure we ripped apart the 1.3.5 injectors, we checked all the pipework, have nee over the loom and anything else that we thought might be the issue.

Put it back together..........



IT WORKS!!

fires up and runs lovely on all 6, still has a bit of hesitancy if you floor it from idle, but that is a mapping issue, and mapping is my weakest point.

Pulls like a train, in fact i had to keep checking it hadn't switched back to petrol, cruising at 80 and switched over to petrol and you couldn't feel the changeover or any difference in performance

Am well happy now, thanks guys for all your suggestions and encouragement
 [smiley=tekst-toppie.gif]

Great news Jay  

Tho were back to this hesitancy when flooring it from idle......mine does it, James's does it and a few other Omega TD's on LPG do it to........so its either normal and nothing to worry about or theres summat not quite right......Ive even spoken to the guys that installed my system about it......they dont think its a problem.

Tho id be very interested if you find out what causes it.

Does yours do this Martin? Hesitate if you floor it either in N idling or in D from standstill?

[JamesV6CDX]

Yes, I have that bit of hesitation from idle too. As Kev says, might need the mapping checked again.

Really pleased you fixed it though. Let's have some pics of the install

[Jay w]

mine only hesitates when i slam my foot down from idle, if i introduce the power slowly and pull away smoothly then it is fine.

i know it still needs the map fettling with, i have 500 miles to do this week, so next weekend we will be back at it again

[Martin_1962]

Does yours do this Martin? Hesitate if you floor it either in N idling or in D from standstill?

Occasionally - but could be the DBW throttle body

[Kevin Wood]

IT WORKS!!

Excellent news

Keep an eye on it. I wonder if that injector was just stuck or maybe the wiring is a little loose in one of the connectors. Anyway, congratulations. You must be very happy after the rocky ride it's given you over the past couple of weeks!

You need a good spark for lpg.....and ive been recomended to open the gap up a bit by a few thou.....for single electrode plugs.......just about imposible to do on twin or quad plugs tho, so as i fit twin electrode plugs I leave them preset at 1mm.

Opening the plug gap does give you a more powerful spark up to a point, if you have enough HT voltage. The problem is that LPG needs more voltage for a given gap size so opening it will compound the problem if the coil is not able to produce enough voltage for a standard plug gap, hence closing it up will help if it's failing to produce a spark at all due to low HT volts.

mine only hesitates when i slam my foot down from idle, if i introduce the power slowly and pull away smoothly then it is fine.

I think this is either mapping or the acceleration enrichment for petrol is just not quite right for gas. Former can be fixed, the latter is not so easy. Also, with the 2.5mm jets the fuel was flat out at full throttle so add acceleration enrichment to it and they may simply not be able to provide enough fuel for a rapid transition from no throttle to full throttle.

Kevin

[Ken T]

Well done on getting it sorted.

I have nearly got all my parts together, I just need a dongle for a Dream 21C, a filler, a few pipe clips, and some jubilees, and am ready to start drilling holes in things.

Cheers Ken

[Jay w]

I think this is either mapping or the acceleration enrichment for petrol is just not quite right for gas. Former can be fixed, the latter is not so easy. Also, with the 2.5mm jets the fuel was flat out at full throttle so add acceleration enrichment to it and they may simply not be able to provide enough fuel for a rapid transition from no throttle to full throttle.

Kevin

Would there be any benefit in boring the jets out further, the theory being that the injectors wouldn't have to work so hard on WOT
I get the error message when i am near the redline or wide open throttle at the top end of the rev range

[Kevin Wood]

Would there be any benefit in boring the jets out further

Well, James' ECU was already complaining that they were too big. It's a toss up between getting enough fuel at the top end and not losing control of it at idle. The manual does say it's Ok to have the injectors full on at peak RPM as long as the lambdas stay indicating rich :-/ I'd be happier if they were 80% on at peak power. That's the normal target when sizing petrol injectors.

At some point I'll be drilling some bigger jets for my 3.2 so we can try them in a 2.5 perhaps?

The other possibility is to try tweaking the gas pressure up a little. I didn't notice if that vapouriser has an obvious adjustment on it?

Thinking about it further, I  don't believe jet size is the problem with the stumble. It becomes an issue at high load and high revs because there is insufficient time between each firing of the cylinder to inject enough gas. When blipping the throttle from 500 RPM there's ample time to inject as much gas as you like due to the low RPM so my musings about jet size are probably cr@p!

Kevin