Gas conversion = air shocks electrical fault

[Suberman]

Hi, looking for some insight into a problem after yesterday's duel fuel conversion. The 'Check Engine' warning light was permanently on when I drove her home. This morning, the front air springs were completely flat. I started her up, drove a bit, still completely flat.

I had her towed back to the garage. During the tow the front air shocks partially inflated ( a good sign!). The guy who did the conversion said the warning light was on because the gas injector switch was giving a false signal to the warning system. He kept saying he didn't touch the air shock compressor/tubes etc.

I said because they partially inflated it didn't look like a leak in either one, but an electrical problem, like the 'check engine' light staying on was something more. He tried to get me to bring it back next wednesday when he has to do the tune ( after the conversion). I said I'd paid $200 to have it towed to his garage, and wasn't going through that again. He said he'd ring Subaru and see if he could find out the problem. I'm not very comfortable about the way he's skirting around taking some responsibility, but I don't want to push a stalemate. I've already paid him $3000 for one thing ( albeit he forgot to install the valve kit ).

I'd appreciate if any of you guys could get your head around what the air shocks problem might be. The car was only roadworthied six weeks ago.
Everything tells me it's connected with something the gas mechanic has done. I've had no problems otherwise.

cheers,

[Point]

he hasn't mounted something and put a screw through a wiring loom somewhere has he?

[chriSTIan]

I know that when i worked om my air supension car,i had the front on stands for a while(took engine out),when i dropped it back on its wheels it was all the way down,lower than the std height.
Drove around like that and pushed the suspension button a few times and it came good again. No check light but.

[steptoe]

what conversion kit went in ?

if it came with an electrical diagram - ask him for it for your future records

trace the wiring that was installed from the converter and stepper motor gas vapour adjuster and of to the gas computer

check the mounting ponts / bracket of the converter to see if it comes suspiciously close to the air shock electrics

where'd he get his power supply from ? not the air shock fuse side of things ?j

[Fabes]

The check engine warning seams to be a common problem after a Gas conversion. the foerester forum has a thread regarding this, maybe something to do with the cat converter?

http://www.subaruforester.org/vbulletin ... lpg-11357/

[Suberman]

Guys, thanks for replying.

point, that was one of the things he was discounting, showing me a couple of bracket mounts ontop a wheel well and the compliance plate were the only holes he'd drilled.

chriSTian, that sounds like my problem, all the way down, except that didn't show till next morning. I pressed the esm button a coupla times ( which I noticed had been switched off). Drove round for a few minutes, flat fronted and bouncing everywhere. Shockers went up (halfway) right after the towtruck guy drove it up onto his tray. Stayed that way at the garage.

<b>steptoe</b>
good question. I'll ask him about the kit and for the wiring plan when he (hopefully) rings today. As I said, we checked out the brackets and they aren't really near the shock electrics.
<b>where'd he get his power supply from ?</b>
That's the burning question I reckon. Even if he has fixed it, I'll find that out.

Fabes,
this on the warning light from the uk forrester site you posted -
It seems the engine management light is very sensitive on a misfire esp with cold lpg. My fitters lengthened the time it took for the lpg to kick in in order to warm the kit up.
&
Had a gut feeling, took it to lpg place who confirmed it was a misfire on C4 (code). Turns out the lpg injector bank serving that side is bumping like a goodun, new one is on its way.

There's some things for the mechanic to check as well.
In any event, say something happens to the petrol injector system, and the 'check engine' light is permanently on, what then? Doesn't sound good to me.

[steptoe]

'only' holes drilled ? Given that AS1425:2003 and earlier requires the gas service line from tank to converter has to be secured to the body or chassis at no less than 600mm apart between securing clips ,there would be more than those holes described made - maybe not drilled but tech screwed. You most likely have an inboard gas tank - it also usually has to have holes drilled to retain it with correct grade bolts. And more holes and cutting to fit fill line and filler, hole for service line and ducting from tank to outside and usually a few more tech screws to secure the duct flange to body. The gas computer can sometimes be secured with a screw too.


I have been a non participating indvidual (in the event) when a drill bit going up as a pilot hole for tank install went right through the core of an ABS wire above on the inside under the boot carpet on the hump of a Commodore , requiring some 'attention'

Not that I want to support a concidence that your suspension died just after this job. Coincidences do happen . Time will tell

[Suberman]

Well, he didn't have a wiring plan with the kit ( Empco 1 or something like that he called it). He can't use his computer equipment to fault test the engine, something about incompatability, and subaru won't give him their proprietary software. Doesn't have the 'check engine' fault codes because of this.

'only' holes drilled ? Given that AS1425:2003 and earlier requires the gas service line from tank to converter has to be secured to the body or chassis at no less than 600mm apart between securing clips ,there would be more than those holes described made - maybe not drilled but tech screwed. You most likely have an inboard gas tank - it also usually has to have holes drilled to retain it with correct grade bolts. And more holes and cutting to fit fill line and filler, hole for service line and ducting from tank to outside and usually a few more tech screws to secure the duct flange to body. The gas computer can sometimes be secured with a screw too.

You know steptoe, he's not a bad bloke, but typical of someone uncomfortable in a corner, he understates and hedges on just about everything he tells me.

I have been a non participating indvidual (in the event) when a drill bit going up as a pilot hole for tank install went right through the core of an ABS wire above on the inside under the boot carpet on the hump of a Commodore , requiring some 'attention'

Not that I want to support a concidence that your suspension died just after this job. Coincidences do happen . Time will tell

Yeah, there's not much co-incidence about it for mine. But I know where I stand ( I paid and signed the 'job completed' form for my refund when I picked up the car Weds night). We'll be in a stalemate if I escalate being right. Helping him with the problem seems like my best option to keep him on it. When he tries to sell me a pup I'll keep saying it wasn't like that when I brought it in.

[steptoe]

maybe Impco, and if it is I think it may be the self learnng computer (learns from O2 sensor) and I don't think they have a diagnostic facility like other systems. Looked at one of their kits just yesterday and may install it tonight or tomorrow if the money being offered is fair and reasonable otherwise I will watch me mate get in deeper in his own sh1t. I will however grab a look at their computer set up to see if it does have diagnostic.

Ask the guy just where the computer/processor is located for future reference. AK him if he is stuck, maybe he could discuss this problem encountered with his supplier who may have heard of this before due to others maybe making a mistake. Ask if he is willing to divulge his supplier, it is probably in your owners guide instruction book anyway ( you did get one did you not?) You may be able to give then acall youself -on your best telephone manner too )

[steptoe]

The check engine light topic - some conversions require the check engine light function to switch off when on LPG just because so another relay is hooked up to the fuel select switch just to shut the power off to the light - nothing else.

It appears not to have been done with your conversion - it may need to be considered by the installer. Does the light come on in petrol mode as in start on petrol and stay on petrol drive on petrol ?

[Suberman]

Ask the guy just where the computer/processor is located for future reference. AK him if he is stuck, maybe he could discuss this problem encountered with his supplier who may have heard of this before due to others maybe making a mistake. Ask if he is willing to divulge his supplier, it is probably in your owners guide instruction book anyway ( you did get one did you not?) You may be able to give then acall youself -on your best telephone manner too )

Good idea, I'll note these things down. Not to be mean, but he needs all the help he can get.No, I didn't get an owner's manual for the gas. But I'll see if I can get the name of his supplier.
Thanks for your input steptoe, much appreciated.

[Suberman]

The check engine light topic - some conversions require the check engine light function to switch off when on LPG just because so another relay is hooked up to the fuel select switch just to shut the power off to the light - nothing else.

It appears not to have been done with your conversion - it may need to be considered by the installer. Does the light come on in petrol mode as in start on petrol and stay on petrol drive on petrol ?

Light come on in petrol mode? I don't know, I haven't run it in petrol since the gas was put on. I'll check it out tomorrow. RE the relay, yeah, I suspect he's just left out a step there and prefers to gloss over it.
Unfortunately the problem/leak with the front air shock(s) at rest is still there.
At least they're coming up for driving.

[steptoe]

No stickers either ? tellng you to keep min 1/4 tank of petrol ? Your system is more than likely to start on petrol and then switch to LPG after certain programmed parameters eg 1200rpm and 30 deg water temp have been met.

It may be his first vapour injected subie

get a compliance plate attached somewhere and maybe even the emisions compliance plate (only needed on 2004 and later but looks good)


And your shocks pump up OK when running engine and air dumps with ignition off ?

[Suberman]

No stickers either ? tellng you to keep min 1/4 tank of petrol ? Your system is more than likely to start on petrol and then switch to LPG after certain programmed parameters eg 1200rpm and 30 deg water temp have been met.

It may be his first vapour injected subie

I suspect it's his first. A tiny yellow sticker on the rear reg plate. Didn't say anything about petrol tank. System starts on petrol then switches, not keen on the 1500rpm idle though. Sounds strained.

get a compliance plate attached somewhere and maybe even the emisions compliance plate (only needed on 2004 and later but looks good)

Got a compliance plate.

And your shocks pump up OK when running engine and air dumps with ignition off ?

Exactly. Taking it back to him for the valve kit and tune tomorrow. Any other suggestions?

[Gremlins]

Sounds like the airshocks problem is due to an air leak somewhere in the system rather than a problem with the electronics. The airshocks are known to misbehave in funny ways like you're describing once they get a bit older so it may just be co-incidental that they've decided to fail at the same time the gas kit was installed, but then again it might not be. I'd be locating the small air lines that run from the airshock compressor (under front left guard from memory) to the air shocks and make sure the gas converter guy hasn't been screwing/drilling anywhere near these. The compressor is high pressure but low volume so it won't really be able to keep up pressure in the system if there is any sort of leak. Probably only need to check the lines going to the front as it sounds like the back is OK. Also check any screws anywhere near the wheel arches/strut towers haven't gone all the way through and into the airbags.

Edit: Just saw your post about the valve kit. One of the probs with the airshocks is sticking valves in the compressor, so if these are replaceable (I always through the whole comp needed replacing) it would be a good place to start with the problem.

[Suberman]

Sounds like the airshocks problem is due to an air leak somewhere in the system rather than a problem with the electronics. The airshocks are known to misbehave in funny ways like you're describing once they get a bit older so it may just be co-incidental that they've decided to fail at the same time the gas kit was installed, but then again it might not be. I'd be locating the small air lines that run from the airshock compressor (under front left guard from memory) to the air shocks and make sure the gas converter guy hasn't been screwing/drilling anywhere near these. The compressor is high pressure but low volume so it won't really be able to keep up pressure in the system if there is any sort of leak. Probably only need to check the lines going to the front as it sounds like the back is OK. Also check any screws anywhere near the wheel arches/strut towers haven't gone all the way through and into the airbags.

Edit: Just saw your post about the valve kit. One of the probs with the airshocks is sticking valves in the compressor, so if these are replaceable (I always through the whole comp needed replacing) it would be a good place to start with the problem.

Thanks for that Gremlin. Any way to check this valve business in the compressor?

[Gremlins]

Thanks for that Gremlin. Any way to check this valve business in the compressor?

Not that I know of, other than to get another known good compressor and swap them over and see if it resolves the problem. (might not be cheap though, unless you can find someone with one sitting around surplus that you can borrow to prove the point). I'd definitely rule out any screws through airlines or airbags first before going for the compressor.

[steptoe]

you say 1500 rpm idle ? what goes on here ?

I mentioned 1200 rpm as an eg of what some systems can be programmed by the installer to switch over to LPG once started and running on petrol and at the also programmed eg 30 deg C. so , for eg, START and just drive off the LPG will cut in seemlessly at those revs if water temp in converter is also satisfactory. It does not switch back to petrol every time the revs drop below that mark