Disco Depressing

[Michelle]

Ok - I've posted a couple of things about my car and not had much response but I'm getting to desperation point now and gonig to try again.

#1 - doesnt want to start when warm (eg I've just gone for a drive, pulled up somewhere, but when I go to start again the sound is very sluggish and doesnt fire upwhen it should. Normally you jhust have to breathe on the ignition and she fires up immediately when warm).
I took it into the gasman for a dyno tune. He replaced the mixer and the sparks (leads are fine). I had already replaced the battery. But still not happy starting when warm on gas. Havent noticed the same issue on petrol but thats a whole other kettle of fish..

#2 since the gasman tuned up the car, it runs like a bucket of **** when its on petrol. He's done something to it - and its effed everything up (no I"m not going backj so he can charge me more, fit more stuff I dont need etc). Timing perhaps? On the petrol it idles really badly, from between 750rpm drop down to 200 rpm, then up again etc etc - rough as guts and shaking the w hole car. When driving with petrol the power is still good, engine r unds smooth under acceleration - but as soon as I pull up at at intersection the car cuts out. Thankfully it starts again with no fuss (starting well warm with petrol at least, so sluggish start seems to be LPG problem..so why couldnt LPG expert find the effing thing...christ its enough to make me cry).

I tried to trade it in on a ford ute today ...

As I said I'm getting desperate. I need reliable car to get to my miserable work to pay the effing loan for the effing car now that I've spent the first wto years of it paying off the interest..

[Donk]

Sounds very much like the choke is sticking on which would cause it to flood when warm...Just a thought but worth a check...:kiss:

[pheel steel]

Sounds like an air leak along the fuel line.

[Michelle]

Thankyou for those possibilities. I will have them checked out next week when my bank balance recovers from -300 lol...
Does a '95 discovery even have a choke? It idles rough as guts on the petrol too (smoother on gas but still a little flickering). I will have that option checked but I think it cuts out because revs drop to near 0, if it was idling properly (500 - 750 rpm) with out this wavering it would be stable (what controls the revs...bloody computer I suppose...how does one adjust it...bloody dealership I spose....)

[YUG]

i dont know about the gas problem..but if the vehicle is hard to start when the engine is hot,it is usually caused by a vacuum in the fuel lines....is she easy to start when the engine is cold ?

with a bit of thought that may also be your problem in the gas line as well,i have a suspicion either a line is not tight,or (and as i say i dont know much about gas)but i assume there must be a switch over valve somewhere,you could be sucking in air there......

i know you dont want to go back to the people who worked on the engine,but this may be one of those times that you have too....threaten them with a write up in your local paper......

[tomm]

I had similiar probs with my 3.9 auto (not lpg) .. turned out to be breathers gunked up.
Could take a look at those ..

[Michelle]

Tom, what are 'breathers'? and where are they?

YUG - she is easy to start when sh e's cold. What is the significance of that? (eg what does it mean). SHe's easy to start cold on gas. SHes easy to start cold on petrol She's easy to start warm on petrol (thankfully since we cut out at every traffic light) but unhappy to start warm on gas (never ever fails, you understand - its just the sound isnt right when shes doing so - like slow...as if battery is unhappy but battery is fine, new).

I think among other things the timing has been adjusted incorrectly to better suit the gas. Its a known issue with dual fuel cars that they can be tuned too much for one fuel at the expense of the other. But WHAT is actually at fault at these times I dont know.
And it doesnt explain the unhappy warm starts on gas...

I'll ring up the gas man tomorrow and tell him hes made my car run like a bucket of ****, and ask him what he did so I can pay someone else to undo half of it..

Do ya th ink that'll go down well? heeh

[Piston Broke]

Just re-read your thread, my answers was not applicable. :rolleyes:

[tomm]

Hi Michelle..
My V8 auto would pull up at and tick over for a few seconds ok .. then the engine would start 'hunting' with the revs dropping and rising before finally cutting out.
Vehicle would always start up again with no prob's.

I had the vehicle serviced and problem was identified as blocked breathers .. guess that they would be identified in a workshop type manual .. do you have a Haynes manual out there?

Hoses were flushed out rather than renewed .. sorry can't be of much more help than that!!

As for the gasman .. why not rip into him .. hey if nothing else it gives you the opportunity to blow some steam !!! :p

Have fun ..

[martin55]

have just joined up and your fault is so depressing to me, as I am a mechanic here in australia, I used to convert cars to lpg, am not familiar with you model, is it fuel injected or carby, I would re tune the engine for petrol only a proper tune will diagnose a problem some where, be it in the starting system, electrics, timing, cylinder compressions, ignition and timing, induction leaks etc. on gas there is very little changes one can make when tuning to make much difference from petrol to gas. if the car is fine on petrol then the fault is with the gas, one thing comes to mind and that is to make sure the switching from petrol to gas works otherwise you could be running on both fuels at the same time this applies to carby models only.

[Michelle]

thanks for your input.
The thing starts on petrol fine, but cuts out frequently. Starts less happily on gas, but runs nice and smoothly.
THanks for confirming that theres not much in making it run good for gas that would upset its petrol behaviour. All I can think is that the gas bypasses whatever it is thats upsetting the engine when its on petrol (if that makes sense). I'm not aware of the difference in pathways for the different fuels. Normally the gas is more sensitive to any problems
Going by the symptoms and the hints at the back of the Haynes manual - I've got a few things to check out including air filter, breather hoses, inlet manifold gaskets, something or other plenum chamber gasket, fuel filter and lines...
I would not be suprised if it was intake manifold gasket ...I'm hearing a little tinny scraping sound on occasion..
Anyway will book in for next wednesday to get it sorted. Have also whacked in some injector cleaner (it is a fuel injection model car) so next time I'm running on petrol we'll give them a blast and see what happens.

[90mile]

Air flow meter not gelling with the lpg setting..
return for petrol and recheck.
are your lines and mixer icing up??

[martin55]

if you are a bit mechanical you can do some checks yourself, you are thinking it could be inlet manifold gasket, two things yu can do, 1 get yourself a trigger spray bottle and fill it with water then with the engine idling spray water around each inlet manifold gasket and I mean over, under,sideways,anyway to get at then gasket joints all the way round, this is what will happen, the water will get sucked in at the leak and will momentarily improve engine idling, usually the speed goes up, dont worry about the small quantity of water being sucked into your motor it won,t hurt it, if you notice any diff in speed then there is a fault at that point. 2 borrow a vacuum guage if you can, a proper auto diagnostic one is best because they are graduated and indicate what faults can be at certain vacuum levels, buy one if you have to they don,t cost much, now you have to find a suitable connecting point, usually there are many small vacuum hoses on the inlet planem chamber, the planem chamber is the larger section of the inlet manifold that all the individual cylinders are joined into, just pull off a small hose and push on the vacuum guage hose and instantly you will have some kind of reading (providing the engine did not stall when you pulled off the hose}just start her up and see whwt reading you have, if you purchased a new guage then follow the fault finding chart in the box, low reading is retarded ign, or inlet manifold leak (not necessarily a gasket) fluctuating guage is cylinder valves poor seating,normal engine is a steady guage 18-22 hg. have a look round for any pipes off or squirt your bottle around anything you think could leak air into the manifold, make shure all hose clamps are tight especially where the gas mixer comes in. points of note before I close, when on gas the air flow meter nor the computer nor any other sensor has any bearing on the fuel control in effect you have turned it all off, all injected aussie cars have a timer relay, every time you hit the start key the engine will start up on petrol then the timer relay kicks in and automatically switches to gas after a couple of seconds that providing you are switched to gas. when switched to gas the earth return wire circuit on all injectors are cut, so while the sensors around the engine are sending signals to the computer and the computer is sending impulses to the injectors the injectors dont work and therby don,t inject fuel, but its all there waiting to go even the fuel pump is still running charging the fuel lines just waiting for you switching to petrol again. time to sign off good luck:)

[Michelle]

"when on gas the air flow meter nor the computer nor any other sensor has any bearing on the fuel control in effect you have turned it all off,"


hmmm..... I wonder...

Cos if it was inlet manifold or any other area ...the idle would be bad on gas as well wouldnt it? Surely a gas system wouldnt like air leaks and would complain even more than petrol?

Sorry, rambling, tired...

Thanks again

[martin55]

hmmmm--you wonder, well try this, your injectors are turned off when on gas otherwise they would squirt fuel into the manifold, therefore the air flow meter, comuter and all the sensors have no bearing on the performance of your engine, in other word they are all turned off. The fact is that gas is much more forgiving than petrol so any faults there are would not be as pronounced when on gas the notion you have about gas being more critical is incorrect.

[Michelle]

oh, ok - I was just spouting what my gas mechanic told me (but he was referring to sparks and leads and dizzy etc - if they're not up to scratch then the gas will show it more than the petrol because it is harder to ignite... so I wrongly assumed that all faults would upset gas more than petrol)

Thanks again.

[Roger Whittle]

I'm still new at Disco's and anyway mine's a TD5, but I have an 'off the wall' suggestion. A mate of mine has a 4.6 litre HSE Rangie on LPG which had a fairly horrible problem with many, although not all of the symptoms you mention. It certainly ran badly on both fuels, but not always at the same time. It eventually become very difficult to start and of course it 'defaults' to petrol when off. It appears, from reading all the entries in this thread, that you have tried or considered pretty much everything from the 'front end', the fuel systems, ignition, breathers etc., so why not think laterally and start from the other end, which was where my mate's problem lay. I don't know if you have to have all the emmissions stuff we have in Europe - you probably do - but the Rangie's problem was quote; collapsed or collapsing Catalytic Convertors. The engine was being suffocated by its own exhaust, but the problem was variable because the elements of the 'CAT' moved around with motion.

[Sandy M.]

Michelle, sounds to me like their could be two separate problems with the car. Firstly the ignition timing, when set for gas, could be too far advanced which causes the engine almost to backfire when starting up, that will give a slow "turnover" on the starter, and poor running.
Secondly the problem with the car "hunting" when running on petrol could be down to a faulty or dirty Air Flow meter, or there is another gadget which lives at the back of the plenum chamber [I'm fekked if I can remember what it is called :( ] but it often needs a flush out with carb cleaner to keep it sweet.

BTW if it was my car I would be back at the workshop the next day with my Mr Angry head screwed firmly into place.

Happy Hunting, Sandy.

[Michelle]

left my Mr Angry head in my pocket and it shrank in the wash!!!

Have bitten the bullet and booked it in to the LR mob to check out and will hand in a list of all suggestions as well...

I dont think its something the gas man changed or can fix - perhaps I just hadnt run it on petrol for several weeks and so didnt realise the extent of the problem until I did. Either way theres more wrong with it than JUST ignition timing so I'll kill two birds with one stone by going to LR to confirm.
i had a poke around the various vacuum leads, etc but I'm too afraid of moving the wrong t hing...oh for my 30yo straight 6 toyota crown where I could do some of the work myself LOL (too bad about the lack of speedo, handbrake and decent heating!)

roger: ..hmm...at 10yo the catalytic converters are on the list for an overhaul I think if I remember rightly what I read in the manual....
Something else to consider...
They're on the exhaust line arent they..which means that they should affect both LPG and petrol systems?...though there are less emissions from LPG so issue would be reduced and perhaps not very noticeable...? maybe...
d'oh...anyway mystery will be solved next wednesday.

Am now taking bets :D.
I'll donate all my points to whoever had the closest answer lol...

[Michelle]

oh heres my little list compiled from the troublespotting section of the Haynes manual

Bad hot start: air filter, EFI fault, timing, compression
Bad Idle: Air filter, EFI fault, Vacuum leak, inlet manifold leak/plenum chamber
Stalling: Fuel filter, EFI fault, Vacuum leak, fuel pump

* catalytic converters....

[Michelle]

ok 90mile and bigsandy in the lead, with martin a close third...
Could be a threeway split of the prize pool..will know in a few hours.
Thanks :D

[Michelle]

How embarrassment (http://www.momofreaksout.com/media/2/20050330-effie.jpg)

Fuel mixtures...wtf...

Oh well I should be pleased...

[graham]

Is all well with the Disco now Michelle ?

[Michelle]

:o wellllll...

Runs heaps better, on both fuels. Idles lovely, doesnt cut out,
BUT..
Hot start still not happy, on either fuel...

Its going in next week to get the power steering hose replaced, I'll hand in my little list and ask them to check (vacume hoses, breathers etc etc..everything thats been suggested)
But so relieved my engine hasnt blown up or something as I thought it might have from the way it was going..

[Big Red]

I have just caught this thread and was going to suggest mixture.

My first bet would be the coolant temp sensor, NOT the one for the temp gauge, but the one that tells the ecu what temp the engine is at in order for it to adjust the pulse width of the injectors to deliver the correct amount of fuel.

I would think it has went open circuit telling the ecu that the engine is cold, therefore you would have no problem starting from cold, but as soon as the engine warms up,the injectors are still delivering far to much fuel as in a cold engine.

When the system is working as normal, the coolant temp sensor tells ecu to leave the injectors open longer thus delivering more fuel when cold.
As engine heats up, the pulse width of the injectors is slowly drawn smaller in order for less fuel to be delivered.

This fault would also effect the idle as it would be like pulling on a manual choke when the engine is hot and would flood the engine.

Hope you managed to get things sorted ok:D

Gordon