Hot running problems

untill you know the fault it will cost more in guessing

Yep that's true, although the things I've so far replaced needed replacing anyway.

I now think its got something to do with the lpg system, ran it only on petrol today and it was fine, started perfectly after it was hot. I've done some googling and found someone who had a similar problem with starting where the lpg was leaking into the manifold playing havoc with mixture settings.

Bit of an update with this, changed the MAF and it runs okay now.

Except for sometimes it won't start when cold, until I take No1 plug out and place it on top of the rocker cover to see if there's a spark and it will pretty much fire straight up.

I know the dizzy cap isn't genuine, am trying to find one on the internet as my nearest dealer is a good 30 miles away. Could this likely be the problem?

Pay for the diagnosis mate, get it running reliably on petrol before you look for problems on the gas side. You can spend a lot of money replacing parts to no effect.

If 1 cylinder was out it would run a bit rough but would still start and run.

gooselogan said:

Bit of an update with this, changed the MAF and it runs okay now.

Except for sometimes it won't start when cold, until I take No1 plug out and place it on top of the rocker cover to see if there's a spark and it will pretty much fire straight up.

I know the dizzy cap isn't genuine, am trying to find one on the internet as my nearest dealer is a good 30 miles away. Could this likely be the problem?

Click to expand...

buy gen/OEM ignition stuff only.....the rest is **** poor

It's been running fine on gas so don't think that has any problems.

Think its got something to do with the ignition side of things now, changed the leads to ones that were on it before and it ran better. First I'll get an OEM dizzy cap and see how things go from there.

Still more problems

Changed the leads to the ones that were originally on it and I think the sometimes not starting problem seems to have gone, haven't used it much this weekend so don't totally know yet.

But when in park it will happily rev up whilst on petrol but as soon as I try and drive it won't rev past 1800rpm, just drops back down and will then rev up again to 1800 and so on. It will drive fine if you don't go above 1800.

I do plan on getting a diagnostic once I've got a bit of money unless there are things I can rule out without needing one?

Bit of an update, still got the won't rev above 1800rpm in petrol problem, haven't had time to get a diagnostic done so still at a lose on what the problem is.

But I did find out today that when just started it will rev and drive happily for a couple of minutes and then the problem will come back, if its turned off and started again instantly after it will be fine for another couple of minutes and again problem will come back and so on.

Well I'm guessing lack of fuel then. Does it sort of struggle when approaching 1800 or it pulls hard towards it and then cruises happily at 1800?

If it starts struggling then it's losing fuel altogether, which could be ECU, whereas if airflow meter is sluggish it might not be reading the higher air volumes properly.

Get my jist?

Its fine when approaching 1800, then it will just drop as soon as it hits it and then be fine until it hits 1800 again.

It isn't the ECU, changed that for another known good one and it's still the same.

It's now sorted, was the TPS So far it all seems to be running as it should on both petrol and gas, don't want to set light to it now lol


So to recap if anyone has similar problems in the future;

- Not always starting was due to cheap and poor quality HT leads, fixed with new leads
- Not running on petrol when hot and general running rich was down to the air flow meter
- Not revving above 1800rpm after a few minutes on petrol was down to the throttle position sensor, this also caused poor/next to no mid throttle response on gas and poor mpg (if that's possible with these engines)
- Fuel pump was also replaced, can't be certain if this was a problem or not but new one runs quieter and the plug was wrecked on the old one.

- Throughout all this I also found several air leaks which have no improved the braking as the servo is getting the vacuum is requires
- The engine earth lead wasn't attached, can't of helped anything
- Plenum was also cleaned, was very dirty so always a good thing to do
- Lots of plugs were also cleaned to make sure good connections were made


Thanks to everyone that has helped, I owe you all a pint

Guinness mate, cheers

I''l get that in the post noisy, I'll make sure I clearly mark 'this way up' so they don't spill it

I lol'd

I have 3.9 V8 Disco which runs Great except on journeys over 50 miles when the engine starts overheating, it seems the viscous fan is not working and i only started having this problem after putting some k seal in it to stop a leaking core plug.....is this a coincidence ? can anyone help ?