Newbie needs help :-)

[Mick the Gas]

Hi all, I carry out profesional autogas conversions on petrol vehicles so are quite familiar to the workings of modern cars, but,,, My wife recenly got herself a Audi A4 softtop V6 3.0ltr 2003. Real nice car and she loves it. She has used it for a coupke of months and thought it was time I converted it to LPG. Fine thinks me I converted these engines before, no problem. I had the need to remove the battery from the car, and thts when things went wrong. The car no longer revs past 1500/2000 and the revs bounce from idle to 1500. I thought it maybe the fbw throttle setings so used my icarsoft vag2 to reset the tps/actuator. I can hear the throrrle open and close with ignition on and see it move on the scanner from 1.5 at idle to 100 at WOT but it still wont run! any ideas ?? sorry for the long post, but its one thing telling a customer I need more time to sort out a problem, its a whole different thing telling the wife her beloved A4 dont work! :-) Any help i would be very grateful for, and if I can help anyone with LPG problems id be very happy to do so.

[Steve Q]

Welcome to the forum Mick :) 

You'll find the members on here are a friendly and helpful bunch :) so I'm sure someone will be able to help. Have you run the engine on gas or liquid fuel when these issues have appeared?

Cheers

Steve 

[Mick the Gas]

Hi Steve and thanks for the welcome. The A4 hasn't run on LPG yet, I was in the finishing stages of the conversion when this happened. From what ive been able to find out it seems like the throttle is still the most likely cause, but not really sure. I wonder if my vag com 2 is lying when it says its reset the throttle. no sure how good the icarsoft tools are when used on Audi's. Seems a bit harsh to get this fault just from removing the battery, but maybe its not unusual? Hopefully someone will be able to shed some light.

Cheers, Mick

[Mick the Gas]

Just a follow up incase anyone else has the same or similar problem. I found and fixed the fault yesturday, although it did take me nearly all day After spending most of the day checking every bit of the engine I could think of and talking to any mechanic friends I could think of, one of them suggested trying to drive the car however slowy it may go, to see if it refound it's settings. Why not give it a go thinks me, Iv'e tried everything else. (I hadn't tried to drive it up until then as I didnt want to cause any further damage) It was then I realised it wasnt actually going into gear, the stick moved the dash display moved but I couldn't feel any take-up by the box. This got me thinking, the engine wasn't the problem, the engine was in major Limp mode. (Nice of it to tell me) I checked to autobox using the vcds and sure enough there was a fault stored. The fault related to a blown fuse, (id checked as many fuses as I could find) more hunting thru manuals showed the fuse lives next to the engine ecu and supplies the gearbox ecm. Tried a new fuse and it blowed straight off. So that got me thinking about changing the battery(thats when the trouble started) further inspection, and I found some damage to the main harness that runs along the fire wall, past the battery. I had, carefully lifted the loom out of the way when I removed the battery but a previous owner obviously hadn't. There was a messy repair in the loom, which had been neatly hidden and I had upset when moving it. Two wires soldered and heat shinked later, fuse replaced, fault cleared. Car back to normal

The main point to make here is that the engine was in Limp, major limp, restricting the revs to a little more than 1000 rpm popping, banging in the manifold if you tried to rev past that, BUT no fault codes in the engine ecu, no check light on dash, all live engine readings seemed normal. Lucky I had something to read the autobox faults or I think I would still be there now.

So car now runs lovely on petrol and autogas, took me all day, but could of been a lot worse.

[WPAWS]

glad you got it sorted  how much did the conversion end up costing ?

[Mick the Gas]

Hi, yep it was a relief, nothing worse than braking the wifes car! The conversion went well and i didnt charge myself labour so only cost me the parts But I would usually charge 1600 with  good quality  kit (either Emer, which I used on my wife's or BRC, which is quite popular) the A4 has a 70ltr tank in place of the spare wheel, which gives reasonable range and doesn't effect the boot space. Real nice to be filling up at 55p p/l rather than 1.20