W124 '87 LPG/PETROL Starting problem

[sandyxo]

Hi all, after spending loads (again...sigh) on the July/August MOT, and thinking nothing else could go wrong, the crank position sensor (thanks Ian once again) being replaced and all running fine 2 weeks ago she started running like a 'pig' then cleared and was fine. Last week had a problem starting, she didnt want to, eventually did and ran ok until Friday, wouldnt start although firing, got the AA Saturday morning, he couldnt find a fault, said there was a strong spark, used his Easy Start, after half an hour she started and ran fine again, I did nearly 100 miles yesterday with no problems at all, ran smooth and fast, went out this morning, a few coughs and hiccups, started then stopped, wouldnt keep going. Battery started getting low so its now on charge. Am I destined to just being able to use every other day or when the AA have looked, will she ever start again? I'm now considering getting rid of my 'baby' as I really do need a car that wont let me down, maybe she's just tired? AA man said for her age she's a good engine, what do I do? Please help as I will be gutted if I have to get rid. Thanks all

 

[Gazzaj]

Does it do it in both LPG and petrol?

 

[mkfs9]

Start on petrol then switch to lpg when you have warmed up the engine a little. You may be freezing the vapouriser, common when the outside temperature drops. Not a problem in the summer though.

 

[sandyxo]

Does it do it in both LPG and petrol?

According to the AA man, it seems worse on petrol, he thinks its a fuel problem. It seems to start on LPG better, although I know I shouldnt do this. After I charged the battery for a few hours I tried it again and it 'popped' this was on petrol, it did fire but didnt maintain even with me trying the accelerator. After trying it on the auto petrol/gas mode it again fired but didnt maintain. I then tried it on gas alone and after 3 goes it started, I could then drive it as normal. I must mention that I have always had to put the accelerator to the floor when starting, its been like that since I bought it 5 years ago without a problem, until now. Thanks for replying, I'll try anything!

 

[sandyxo]

Start on petrol then switch to lpg when you have warmed up the engine a little. You may be freezing the vapouriser, common when the outside temperature drops. Not a problem in the summer though.

Thanks for replying. It wont start on petrol, that seems to be the problem, it will run on petrol if I run out of gas without a problem, but for a few weeks now it just wont start on petrol and I've had to use the gas.

 

[simon_wall69]

Can you hear the fuel pump when the key is turned? Should be a faint hum.

 

[sandyxo]

Can you hear the fuel pump when the key is turned? Should be a faint hum.

Hmm cant say I've ever noticed it but it must happen cos its always worked lol, sorry I know I'm being a bit vague. I do get a sort of running water noise from behind the dash, previous owner said its nowt to worry about and I've got used to it. I think shes fed up of me tho, last week my panel lights and one main beam stopped working too, probably just a fuse and a bulb, the ABS light comes on when it gets bored, always has, auto electrician cant find a fault, maybe dodgy sensors? Do you think it could be the fuel pump then? If so, why didnt the AA man pick up on it? The last time a fuel went on me (Rover on LPG) I got a bad burning smell, not had that this time, although I have been getting a strong smell of gas when I get out of the car???

 

[Gazzaj]

Main Beam? ABS ? Fuel problems, Reeks of Over voltage relay to me

 

[sandyxo]

Main Beam? ABS ? Fuel problems, Reeks of Over voltage relay to me

I havent a clue what that is! What do I do about it? Garage, auto electrician or scrap yard? I do hope that thats the solution and I can sort it, thanks

 

[Gazzaj]

I might be wrong just wait for some other people to add to this thread but The over voltage relay is behind the battery tray, and you can get them from Euro Car Parts. they have a fuse in the top which you should check first, think its red (10a)
I know the symptoms of Over voltage relay I had where fuelling issues to the engine, faulty ABS and my N/S Beam wouldnt work.

 

[Smudge]

I have some OVP relays for these engines.
But check the fuse in the top first before you replace it. Also if you don't use petrol for starting often enough you may end up with stale fuel and a blocked fuel filter/pump.
Have you ever suffered with blowbacks in the LPG system, common if it's a single point ? The gas will also rot the rubber in the inlet manifold too, might be worth checking that and the idle bypass pipes by rotary air valve. All of these will give air leaks and make for bad starting.

 

[sandyxo]

I've just had a look, the only thing I can find near the battery is in front of it. Theres a small black thing with 2 10a fuses in which I checked and they're fine. In front of that is another small black thing with one fuse in which I checked its a 7.5a which had gone so I've changed it. The car started but lights and panel lights are still the same. For some reason it wont let me quote, not my day is it lol

 

[sandyxo]

I have some OVP relays for these engines.
But check the fuse in the top first before you replace it. Also if you don't use petrol for starting often enough you may end up with stale fuel and a blocked fuel filter/pump.
Have you ever suffered with blowbacks in the LPG system, common if it's a single point ? The gas will also rot the rubber in the inlet manifold too, might be worth checking that and the idle bypass pipes by rotary air valve. All of these will give air leaks and make for bad starting.

I've just checked, changed the 7.5a for a new 7.5a, started it on petrol, it did start but wouldnt maintain, did it on auto petrol/gas switch, it started but popped on second try it started and kept going. I dont know how to check the rubber or inlet valves, how do I do this?

 

[Smudge]

You will need to remove airfilter housing.
The idle bypass is to left and below fuel metering unit.
You will need to remove metering unit and airflow meter to check if large rubber manifold base is cracked. If this car has been on LPG for a while and it is a single point system. Then more likely than not all the rubber in the inlet will be in poor condition. Easy job to do but takes an hour or so
Might be worth checking fuel pump relay too.
That will be in same area as the ABS relay. About the same size as a fag packet.

 

[Gazzaj]

There is an easier way of checking the seals. By some brake cleaner, fire up the car ( If it will)and on tick over spray brake cleaner around the inlet manifole gaskets and listen to any change in the idle, if it cuts out of=r alters i any way you have a leak.

 

[sandyxo]

You will need to remove airfilter housing.
The idle bypass is to left and below fuel metering unit.
You will need to remove metering unit and airflow meter to check if large rubber manifold base is cracked. If this car has been on LPG for a while and it is a single point system. Then more likely than not all the rubber in the inlet will be in poor condition. Easy job to do but takes an hour or so
Might be worth checking fuel pump relay too.
That will be in same area as the ABS relay. About the same size as a fag packet.

Right, ermm...I'll give it a try when the rain stops. I'll post back as soon as I've confused meself further

 

[sandyxo]

There is an easier way of checking the seals. By some brake cleaner, fire up the car ( If it will)and on tick over spray brake cleaner around the inlet manifole gaskets and listen to any change in the idle, if it cuts out of=r alters i any way you have a leak.

Ok I'll try that too Anyone live near Holywell fancy a bit of car DIY? I make a good toasty and a brew and I've got chocolate digestives! Ahh well, worth a try lol. Thanks to you both for your help, I'll post back when I've got some news

 

[Gazzaj]

your about four hours from me, the brake cleaner is a crude test but when I was in the dealerships, its commonly used

 

[Smudge]

Only 1/2 hour from me but I am too busy at this time of year ,sorry.
If you need any bits for it though I have a couple I am breaking.

 

[Gazzaj]

Only 1/2 hour from me but I am too busy at this time of year ,sorry

Look what you could have won !!