Strange Coughing Problems, Advice Needed Urgently

[ReubenGB]

Hi All!
Myself and my girlfriend bought our '89 T25 July last year in Corwall. We had an LPG conversion done in Devon, and after working hard all summer we took a few months off to travel from the start of this year. At Chirstmas we took the van to yorkshire and then back to east sussex, before leaving for France at the send of December. Since then we've driven down to the south of spain, through France and Portugal. In the south of France we had some engine troubles; we ran low on LPG as we were avoiding toll motorways and outside of those the gas stations were few and far between.

When we ran low on gas we switched to petrol, and after 20km or so the van started slowing down, coughed, and died. It then started again, drove a few kilometers and stopped, same again, and then wouldn't start. After a tow truck and lots of drama I won't go into, it seemed the van wouldn't run (or start) on petrol when the engine got hot. Fortunately however, we were able to get gas and continue on our journey; we tried to get a mechanic to look at the van but we couldn't find one with the time or inclination, and our french is not good! One suggested it may be what I now know is the ignition module ( I didn't know what it was when he pointed to it, and I didn't understand the name in french!), but he didn't have time to look in detail, simply said a friend had had the same problem with a VW t25, and that was the problem. My girlfiend does on the other hand speak spanish, so we decided to carry on and sort it out when we arrived in Spain. The van ran perfectly on LPG, and through some carefully planning of lpg stations, we made sure to never run low on gas, and all was well.

After arriving at our destination (Seville, where my girlfirend's sister is living at the moment), we had the same problem, on gas. The van coughed and then stopped, going down a hill, and wouldn't start again. Once the engine was cold again it started, but soon stopped. Thus began a very lengthy saga of trying to fix the problem. First the ignition module was changed; the mechanic in SPain agreed with the French guy, and when he took off the ignition module and took it apart he said the wires were fried and when the engine got hot, it stopped functioning. I had also changed the ignition coil myself as I had read of VW's with the identical problem coming from the ignition coil, and bought a replacement. Once that was changed we drove 3km, the van stopped again. It wouldn't start, even with the engine cold. Starter problem was the starter motor which, to the mechanic's surprise, was still the original, and once that was changed it was still stopping, but started ok afterwards. The distributor (also original) was knackered, and we managed to get hold of a second hand one (couldn't find a new one anywhere) from another '89 van but that had only 30,000 miles on it. Mechanic said the distributor was old but in good nick. The problem seemed to disappear. Then began starter problems again, and it wouldn't drive on petrol. It seems the fuel pump was now malfunctioning, so a new fuel pump was put in, and the van ran perfectly. The mechanic assured us all was well. We then drove from Seville to Malaga (2 weeks ago). 60km into the journey, going down hill, driving on LPG, the van started to slow, then cough. Changing down a gear seemed to help briefly, then it started to cough even more, and we switched to petrol. Another cough as we switched, and then the engine stopped losing revs, as we started to climb the other side of the hill. The remaining 80km we drove with petrol, without issue.

We were hoping to drive back to cornwall now to work the summer , but I don't know if the van will stop after 10, 100 or 1000 miles! So, it is with that in mind I'm exploring any possibility I can, and would be very grateful if anyone has any ideas what the problem could be. I've heard of similar problems due to partially blocked fuel lines, although we've experienced the same problem with both petrol and LPG so it seems unlikely to be a fuel problem...

We're in email contact with a mechanic near Seville at a place called Karvans, who works solely on VW T25 vans, but he says he's never seen a van with an LPG conversion, and doesn't really know anything about an LPG system so he's not sure he could find the problem...

Anyway, as I said, any advice would be extremely appreciated as we are rather demoralised by the whole situation!

[itchyfeet]

What makes you think any of these problems are related, they could jusf be a series of breakdowns.

Many of these vans have been neglected over the years and do a thousand or two a year, take these on long journeys in heat and the neglect shows. It is typical to have to mend and replace several things a year.

Many LPG installs are not to the same quality of wiring that a new vehicle will have, your latest lpg proboem could just be a bad connection as petrol is currently ok.


what engine is it dg carb or dj injection?

oh and welcome to 8090

[kevtherev]

To clarify, any advice will not be used by you, but relayed to a garage or mechanic?

[Smcknighty]

I know nothing of petrol vans but..


LPG likes a good spark - plugs aren't mentioned anywhere here. If the plugs are older (or maybe not gapped properly) LPG may run rough whilst petrol is ok
LPG does have a filter - I've run my LPG (not a van a Volvo!) for 2 years plus cycle before changing and not seen issues, doesn't mean it's not a problem - maybe continental LPG has more crap to be filtered out
LPG tank levels lie - sometimes they run out before you realise also if they sit without driving then the fuel lines may purge - e.g if I don't drive on LPG for a bit the car struggles on cutover
LPG relies on coolant - the vaporiser for LPG uses coolant to keep from freezing solid - if there's an air lock (vaporiser higher than bleed point depending ) the vaporiser can freeze up and gas stops
If LPG is sold at petrol stations clearly there are LPG garages around. Stand by the pump and wait till someone comes and get your girlfriend to ask them who they use!

[ReubenGB]

What makes you think any of these problems are related, they could jusf be a series of breakdowns.

The only thing that makes me think it may be the same persisting problem is that it's kind of the same symptom every time it stops...it runs fine for a while, then out of nowhere just starts slowing and then coughing, and then dies, except the most recent time when switching to petrol stopped it dying...

That said, the starter motor I'm sure it wasn't related just as you said not much past maintenance, it seems like the previoud owners didn't take much care, just after we got it we discovered a slow oil leak from the filter...which was completely rusted through to the point of crumbling away , so I dunno when they'd last changed the oil or done any other maintenance on the engine!!!

Oh, and it's a carb motor, 1900cc, water cooled of course.

[ReubenGB]

To clarify, any advice will not be used by you, but relayed to a garage or mechanic?

Advice will be relayed to a mechanic, we currently have a very nice mechanic but he's not a VW man, just general, hoping to get it to a VW mechanic but they say they're very busy right now...

[ReubenGB]

I know nothing of petrol vans but..


LPG likes a good spark - plugs aren't mentioned anywhere here. If the plugs are older (or maybe not gapped properly

Thanks for the tip! Plugs haven't been checked.
LPG filter has been checked and is all clear. Our mechanic knows a guy who does conversions and he had a look, couldn't see anything wrong with any of the parts of the LPG system.

Worst part is I don't know how long I have to drive before I can be sure it's OK...if ever!! As I said, did 60km in gas fine and then it started dying, 80 in petrol no trouble but does that mean petrol is fine, or just good luck??

Anyhow, will certainly get plugs checked, thanks!

[itchyfeet]

What makes you think any of these problems are related, they could jusf be a series of breakdowns.

The only thing that makes me think it may be the same persisting problem is that it's kind of the same symptom every time it stops...it runs fine for a while, then out of nowhere just starts slowing and then coughing, and then dies, except the most recent time when switching to petrol stopped it dying...

That said, the starter motor I'm sure it wasn't related just as you said not much past maintenance, it seems like the previoud owners didn't take much care, just after we got it we discovered a slow oil leak from the filter...which was completely rusted through to the point of crumbling away , so I dunno when they'd last changed the oil or done any other maintenance on the engine!!!

Oh, and it's a carb motor, 1900cc, water cooled of course.

ok but you have from your long description had the coughing on both fuels yes?
and after having it on one fuel the other fuel runs ok this time.
so more likely an intemittant ignition problem, could just bad bad earths to heft hand engine head and below coil or a broken wire.

a faulty ignition switch could also be to blame

[ajsimmo]

Has the loom between ignition amp and dizzy been checked/changed? It sits on top of the engine getting hot and can fail with age. I've seen a couple with this type of fault, and engine faltered or stopped when the loom was lifted up from its normal resting place indicating a broken wire inside. Can be very intermittent like yours.

[ReubenGB]

OK thanks for all the advice!!

Now it's the weekend no one's working in Spain but I'll relay all suggestions to the mechanic on Monday.

@itchyfeet Yes we've had problems on both fuels, so far it seems to run fine on petrol but have the problem on gas.
Could I try cleaning up the earths myself rather than wait for Monday? I'm not extremely knowledgeable with mechanics but not completely incapable either...
Would ignition switch problems manifest whilst driving or only starting up? It's starting fine at the moment, problem seems to rear it's head after driving for a while, like something's overheating...

That brings us on to ajsimmy's idea...is the loom obvious/can you describe it to me? If I can point to it rather than try to translate to Spanish that would probably be useful!! When it fails do you think it stops like I described? It feels like it's run out of fuel when it stops; starts slowing down and coughing all of a sudden, but obviously on a full tank...

[ermie571]

ok - a bit of an off the wall idea here...

if the van is running on both fuels it won't run well. It can't as the LPG and Petrol ignite at different times. Is your system switching over properly?

example one from own experience. Running on LPG. would start and run. drove a couple of miles...and it would start to cough, and slow. Eventually held no revs and died. Leave for half an hour, and it would restart. Drove me nuts. Took to an LPG fitter. They put the probe up the exhuast....the solenoid was letting petrol through....a very small amount, but enough to upset it.

Second time,,,,I was driving on lpg....started to loose power. eventually stopped. Emptied boot...strong smell of petrol...that was wrong. I had knocked the switch to the middle position in the cab - it was in the switch over position to petrol...ie it was letting petrol in to charge the carb....switched it back to gas, emptied the carb, and away it went.

So, I wonder if your switching is an issue? If the switch is wearing out?

Just a stab in the dark...but if you have an LPG mechanic local might be worth an ask.

Good luck!

[ReubenGB]

So, I wonder if your switching is an issue? If the switch is wearing out?

Actually, that's the one part i forgot that we changed...

Whilst the van was with the mechanic it stopped switching from the electrical control in the front, so the mechanic wanted to test it on petrol bypassing the switch; putting the fuel line directly from the pump to the engine. When he pulled off the fuel line from the switch it sprayed petrol all over the place, briefly... He said there shouldn't be fuel there, that it should go back to the tank when it switches...
So he bought a new switch for €20 and had a mechanic who does conversions put it in...

The only thing is I don't know if I trust the new part/mechanic...

[itchyfeet]

Easy to test
Your lpg should have four switch states, on mine these are indicated by lights (in brackets)
lpg ( green or yellow)
petrol (red)
lpg and petrol ( greenor yellow and red)
nothing ( no lights)


from petrol switch it to nothing and it should cut out idling adter a few minuites

[ajsimmo]

Ok, another thought has occurred to me along the lpg installation lines...I wonder if the installer has used a common earth in the engine bay for the lpg solenoids and the petrol shut-off solenoid. When hot this earth contact could break down giving trouble on whichever fuel you're running on at the time. Breaking down at the roadside for a while (cooling the connection), then switching fuels and all's ok could possibly be a red herring.

[ReubenGB]

Easy to test
Your lpg should have four switch states, on mine these are indicated by lights (in brackets)
lpg ( green or yellow)
petrol (red)
lpg and petrol ( greenor yellow and red)
nothing ( no lights)

As far as I know the LPG indicator had only two states on our conversion, in LPG it shoes green&yellow lights, in petrol a single red light. I have never seen it with no lights or both at the same time...