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33631

General Discussion Area / Re: LPG installation WIP

« on: 06 December 2007, 22:38:28 »

Was it you who posted a picture of a very nice job done on positioning the LPG injectors just next to the petrol injectors a while back?

If so, can you dig it up again, please?

Kevin

33632

General Discussion Area / Re: LPG installation WIP

« on: 04 December 2007, 18:49:42 »

what are the issues with this?

Just be a bit careful of filling it up and then immediately leaving it in the sun (some hope!). The tank can overpressure as the fuel expands whereby it vents some fuel to the atmosphere. Not a potential bomb or anything, just a waste of fuel.

If you fill it up and then immediately burn off the extra it won't do any harm. Might as well make use of the extra capacity.

Kevin

33633

General Discussion Area / Re: LPG installation WIP

« on: 03 December 2007, 19:17:03 »

oh yes......240 miles on LPG and the guage on the tank is just above the red (70l tank)

  Glad to hear it.

Yes fair point for petrol.....but a smaller spark may not be enough to ignite the lpg

Agreed. Depends what the issue is, really. I guess a bit of experimentation is required.

Kevin

33634

General Discussion Area / Re: LPG installation WIP

« on: 03 December 2007, 18:58:40 »

So, did the LPG conversion behave for you today, Jay w?

Kevin

33635

General Discussion Area / Re: LPG installation WIP

« on: 03 December 2007, 09:38:04 »

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

33636

General Discussion Area / Re: LPG installation WIP

« on: 02 December 2007, 23:52:25 »

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

33637

General Discussion Area / Re: LPG installation WIP

« on: 02 December 2007, 15:11:29 »

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

33638

General Discussion Area / Re: LPG installation WIP

« on: 02 December 2007, 13:39:23 »

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

33639

General Discussion Area / Re: LPG installation WIP

« on: 02 December 2007, 11:13:47 »

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

33640

General Discussion Area / Re: LPG installation WIP

« on: 02 December 2007, 10:47:19 »

NGK do make an iridium single electrode plug specifically for LPG converted cars - BKR6EIXLPG for the V6 allegedly.

Kevin

33641

General Discussion Area / Re: LPG installation WIP

« on: 01 December 2007, 23:30:09 »

Only think I can think of, is the nozzles may need angling better? I might talk to sassanch, 'cos we couldn't realistically get the nozzles next to the petrol injectors..

This is a good point. Injector angle isn't ideal going through the walls of the manifold. I guess at certain RPM there could be a bit of reversion in the intake that's blowing the gas back up the intake tract :-/

It sounds like you've got 2 different types of misfire though. James' car idled smoothly and misfired only under load.

Would be worth finding out what sassanach did. I have a feeling he posted some pictures on here.

Perhaps the Romano through plenum nozzles do work then?

They certainly allow you to get a better angle. However, I've been looking at a lot of conversions on the web and many of them have pretty haphazard nozzle placement.  :-/

What plugs do you use, Martin? Just standard VX 2 electrodes?

Kevin

33642

General Discussion Area / Re: LPG installation WIP

« on: 01 December 2007, 21:32:24 »

mine is currently no where near as good as you, it is very gutless and feels like something is being retarded, i have to pull away on petrol and flick it over to gas once we have it up about idle........

Have you done any manual tuning? I had to add a lot of fuel to James' one further up the range. Can't remember if we tried to drive it immediately on LPG after the auto calibration but that procedure only really sorts out the fuelling close to idle. Shame that damn file didn't load.

One thought: I was using the latest version of their software downloaded from www.ac.com.pl IIRC. Maybe worth installing that software in case the file format has changed and we have incompatible versions of software?

I do hope it's not a compatibility problem!

It's hard to see what could be incompatible :-/ It only requires the injector drive signals and the RPM signal to run and these are working as evidenced by the injector durations and RPM in the live readouts.

It feels like an ignition misfire too. Maybe the output of the coil packs is a bit marginal for LPG. Have you tried closing the gaps on the plugs slightly?

Kevin

33643

General Discussion Area / Re: LPG installation WIP

« on: 01 December 2007, 00:40:04 »

This must be a wiring issue. I'm damned if I can think how it's come about but, when running on petrol, the LPG system is just looping the injector signals through to the petrol injectors to which they were originally connected. Tapping into the RPM and 2 Lambda signals shouldn't be an issue.

I think if the checks we've already discussed don't bear fruit I'd be inclined to try disconnecting these 3 signals from the LPG system and removing the plenum and reconnecting the injector signals to the correct injectors. Let's try and get it back to running properly on petrol. If that's OK, something has gone wrong with fitting the LPG electrics.

What are the specific cam and knock sensor fault codes? Open / short circuit or incorrrect signals?

Don't discount the possibility, however remote, that the LPG system's loom is incorrectly made up :-/

It worked with no problem with James' car but they are presumably hand made and the possibility of error exists. Then again, as I say, I can't see how it would generate these errors unless something's gone wrong with the connections to the petrol ECU. Is it worth buzzing these through with a multimeter to be absolutely certain they go to the correct pins?

Don't give up on it at this stage. I think you're very close and I'm sure James will confirm that the system seems to work very well when it's behaving.

I'm sure we can work out a way to help if you don't manage to resolve it.

Kevin

33644

General Discussion Area / Re: LPG installation WIP

« on: 30 November 2007, 22:47:04 »

when i set up the loom i connected it number for number so 1 is on 1 and 2 on 2, so on

I don't think there'll be a problem with that, as each cylinder is handled individually by the LPG ecu, as long as each cylinder is wired up to the same number in all 3 cases. Might be something to try if all else fails though :-/

Kevin

33645

General Discussion Area / Re: LPG installation WIP

« on: 30 November 2007, 20:10:37 »

Sounds like you need to get the issues on petrol sorted first  

One other thought. I don't suppose you've got some of the injectors crossed over on the piggyback loom?
Also, did you wire them according to cylinder numbers or as grouped on the LPG loom?

We grouped them as on the lpg loom, one branch of the loom to each bank:

LPG loom number             Cylinder number
1                                         1
2                                         3
3                                         5
4                                         2
5                                         4
6                                         6

As long as the same numbers are feeding the same cylinders and that number is fed from the petrol injector plug for that cylinder it should be OK but you never know. It would be easy to get them crossed due to the shape of the intake manifold.

Your observations on LPG sound about right. I had to add a lot of extra fuel to James' car in the mid range to get it to run ok.

EMail sent with his final settings

Kevin