DJ lots of black smoke Help needed!

[spanishfly]

Hi can anyone please help, I'm desperate. My van is undriveable and I just don't know what to try next??? I'm in Cornwall, Launceston. It starts first kick, no throttle but with rough idle and kicks out big clouds of smelly black smoke. The van is a 2.1 Joker Auto DJ 1988\9 Had it 10 years. It is driving me crazy as I daren't drive it without the gas working and the summer is slipping away.
Things I have done,
1/.Cleaned Earths fitted new crimped and soldered eyelet if any sign of corrosion, fitted new homemade lead made from battery cable alongside the original frayed one from body to block.
2/.Replaced plugs, regapped to 1/25000 for LPG gas which doesn't work, fires up but immediately cuts off fuel.
3/.Resistance on plug leads as per Bentley
4/.New Fuel regulator.
5/.I assume timing isn't far out as starts first kick.
6/.New temp senders on thermostat housing. Blue and Black.
7/.I have a spare ECU which makes no difference same symptoms.
8/.TPS switch clicks at beginning and end
9/.AFM supplied by Steve at Gasure so presume it's ok. The resistances check out with Bentley at the ECU plug end also I have a spare almost brand new AFM that I blew up with the gas a couple of years ago, potentiometer vane doesn't move but electronics should be good, same symptoms when plugged in.
10/.New wiring harness from black box which includes the black temp sensor, dizzy plug, expansion tank plug and IS plugs( incidentally my van has a manifold preheater fitted in the rubber oil breather tube but plug is square not rectangular boot so I've bridged this lead, does anyone have the square type???
11/.Hall ignition control box with 7 lead multi pin on sidewall a year old.
12/.Cream IS box a year old.
13/.Cleaned cigar tube with brake cleaner, hums and buzzes.
14/.Cleaned all the plugs I can find by releasing spades and sanding.
15/.Newish rotor, arm, Cap
16/.Injectors rebuilt…
17/.Short manifold rubber hoses replaced with silicon, petrol hoses replaced.
Help with the gas would also be good because if the gas flowed I could drive it to someone for help…
Gas was working until I changed the brake switches in the dash. Now I have power to the petrol and gas switch at the dash but the gas supply shuts itself off when selected.
I also changed a rotten wire in the engine bay that ran to the vaporiser. Can send photos/video….?
Thanks
Simon

[syncroandy]

I've very little experience troubleshooting 2.1's, mine ran OK as long as I had it. Assuming the black smoke is excess fuel, something is causing excess fuel to hit the cylinders. Might be worth checking the injectors, or possibly the ECU is seeing a bad input causing it to keep the injectors open too long. Have you checked the AFM ? You have taken the LPG out of the equation ? There are workshop manual procedures for checking the engine which might be worth following.

[spanishfly]

Thanks SyncroAndy, I've added more detail to my post. Injectors were rebuilt a few weeks ago so don't think it will be that.
Will try AFM as per Bentley again.

Removed AFM and as per Bentley page 24.28 measured between
2 & 3 = 578-1200+ as vane moved changing values
3 & 4 = 567 within the range of 500-1000

But following test for temp 1 sender in AFM
between 1 & 4 meter reads 1. which isn't in the range.

Does this mean the temp sender in the AFM isn't working?
When I compare with the blown up AFM I get the same results, 2&3 changing 3&4 in range and 1. between 1&4

Incidentally if I measure between 2&4 I get 70 ohms on Steves' and 870 ohms on the blown up one? Not sure why that would be or what these tests are saying?

[spanishfly]

I haven't intentionally taken the LPG out of the equation. Upon checking the new wire I soldered in which came from a small silver cylinder half the size of a coil under the car, (solenoid?) I've attached it to the black terminal of the alternator. Could this have been the wrong one, would it make more sense if it were connected to the red terminal? Would that mean the gas would flow whilst the alternator was running? And stop when not?

[silverbullet]

Excess fuel wont make a perol engine cough black clouds, that's diesels.
I would hazard a guess that its holed a piston (possibly due to lpg and running lean on cruise, hard to say) and that is the cause of the rough running and oil burning.
What are the spark plugs like? Is one obviously oily and wet compared to the others?
Take all of them out and probe with a stiff wire at TDC for each cylinder, get a small bright led torch and look down each plug hole. If its burned a piston it should be obvious.

[spanishfly]

Thanks silver bullet, the clouds of black smoke are all sooty, all plugs caked in sooty deposits after a few minutes. The smell is very definitely petrol, really really flooded none of the acrid burnt oil smell…?
Also doesn't use any oil or water.

[marlinowner]

Is it possible that the wiring to the lpg switch is wrong so that when switched to petrol the lpg is on as well, when you switch to lpg then both lpg and petrol are off? Shut the lpg valve on the tank and see if that helps petrol running.

[silverbullet]

Hmm. You have changed/swapped or exchanged just about everything bar the core engine!
Have you checked that the engine air intake hose in the D post hasn't collapsed or is blocked with something?
A severely restricted air supply might make it run very rich, given the petrol smell.

[spanishfly]

Cunning plan marlin owner will try that in the morning or would do if I knew how to turn off LPG. I have a tank in the spare wheel holder and its full! Not sure there is a cut off, at least I haven't seen it.

[spanishfly]

Thanks Silverbullet, good thought but as I have LPG fitted there is a length of fat tube and a K&N filter so intake snorkel not connected.

[silverbullet]

Good idea Marlin! If you pull the multiplug off the lpg controller it should just run on petrol. At least mine does.

[ghost123uk]

Just popped in to say, agreed, definitely take the LPG out of the equation, but when I (occasionally) mix up my LPG/Petrol switch and it runs on both, it does run very lumpy (as you would expect) but it doesn't produce lots of black smoke. I am not very familiar with the injected vans, but very severe over fuelling (of petrol) is indicated. Sorry, you pretty sure knew that didn't you

[spanishfly]

Well yes I did, but it feels good to have other voices helping out not just me muttering to myself! Thanks
All these problems started with a backfire so any comments from those who've suffered an LPG hiccup would be particularly enlightening!

[ghost123uk]

All these problems started with a backfire so any comments from those who've suffered an LPG hiccup would be particularly enlightening!

Ah, a backfire, don't injected DJ's have a fairly delicate air flow meter thingy that forms part of the petrol fuelling system? Someone will be along soon.........

E D I T - Found this - http://archive.club8090.co.uk/viewtopic.php?f=3&t=14462" onclick="window.open(this.href);return false;

[spanishfly]

Yes, they do seem to. I'd read that, but it seems inconclusive, at least no sign of anyone saying don't worry just chuck in a ….. whatever it is.

I guess there aren't that many 2.1 autos with LPG but I can't believe mine is unique! The Vanagon people do mention the same problem though they usually refer posters to a magic box from van cafe' which is a bit far away from here!

What confuses me, one of them anyway is the Bentley test for the intake air sensor which does indeed look very fragile. It says to measure the resistance between terminals 1 & 4 on the AFM. It then suggests the resistance value should be 2.3-2.7k with resistance rising as air temperature drops.

I get a reading of 1. (which if I understand correctly means infinite resistance) on mine and on the blown up spare. It's of course possible that the one I bought was already broken, and that the explosion that bent the vanes on the spare was easily capable of breaking the delicate looking sensor.

What would really help is if anyone has time to test a spare of theirs if they have one and confirm a reading similar to Bentley.

I guess it would make sense that if that sensor is telling the ECU there is an ice age the ECU would over fuel to compensate.