V8 Driving me mad!

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khaos

khaos

New Member
Posts
2,907
Location
Sheffield, South Yorkshire.
So it's been a while since I've been on here with never having any time to spare after starting a new job!

I'm sure someone on here will be able to help me because my 1995 disco V8 is driving me mad. I have bought it to drive around during the summer while my orange defender gets the full chassis up rebuild she deserves. Unfortunately, after a month or so of ownership, the novelty of a V8 is wearing a bit thin. Apart from the fact I can't get it above 15mpg on petrol no matter how hard I try there is one major thing annoying me...

At some point a previous owner has fitted an lpg system in an attempt to stop themselves crying every time they have to fill up. The problem is that it works fine up until about 2000 rpm on lpg and then I lose all power. After this has happenes I can literally put my foot flat to the floor and it hasn't even got enough power to get up a speed bump. If I turn the engine off and back on its fine again... Until I hit about 2000 rpm.

This cycle continues the entire time I'm running on lpg and if I'm honest I am not an expert on petrol engines and the amount I know about lpg can be written on a stamp.

Hopefully someone will stop me pulling my hair out with this problem.

Thanks!
 
storm99 said:
Its ####ed??
Click to expand...

Well that was the conclusion I came to earlier when I got out and launched the keys across the drive before going out in the audi instead. But now I'm calmer I think it must be something so simple. It literally runs perfect on petrol and even better on lpg until it hits around 2000 rpm. You can floor it to the point where it pins you to the seat and it pulls and just loses all power at 2000 ish. It only does this on lpg!
 
Sounds like not enough gas pressure/supply (or air) at higher rpm. But that's as much as I dare say.

I never bothered with lpg cause it takes space, extra trouble and does not give the power you need.

Then I hardly use more than 3000 rpm while driving my V8i. Above that it starts to guzzle the petrol and I don't need more rpm. Even take corners in 3rd gear as this drives more comfortable.

I reach 1:8 in ltr/km. Think that's 23 mpg
 
FlyingDutchman said:
Sounds like not enough gas pressure/supply (or air) at higher rpm. But that's as much as I dare say.
Click to expand...

Fair enuff but, if that were all that was wrong then why doesn't the power come back on when the revs drop back down? First guess would be that some valve somewhere was sticking. But if the fix is to turn-it-off-and-on-again then that starts to feel electrical. LPG ECU? ???? Watching with interest...

(23mpg? In my dreams. Not even when I'm on petrol).
 
Difficult to say from a distance.

Goto start trouble shooting and go over all systems one-by-one to see if they work properly.

But I guess you know that.
 
It sounds like the LPG is tuned properly and cutting into "safe" mode. My dad had a similar fault on his LPG after he took it back they reset ECU and did a fresh map and it worked fine. I get 22 mpg but I just let it sit at 2k and pull me upto speed.
 
As far as I know the whole point of a V8 is high torque at low rpm. Pulling power, not speed.

That the engine is able to do 6000 rpm does not mean it needs to be done.
 
Hi chaps

Just to check as i dont think u mentioned where uv filled ur lpg tanks up to full capacity? What uv discribed is what always happens to me when my tanks run low as i guess inlike on fuel where uv got fuel then u dont! Lpg relys on pressure so as the pressure drops off u gradually loose ur supply. Only thing i can suggest is check the tanks are full or atleast 20 litres. My lpg system tends to play up and isent always relyable but i get enough use out of it to keep it on the road!
 
Sounds very much like filters to me. I have my system serviced every 8000 miles and the difference between old and new filters even at this mileage is remarkable. I full LPG service should sort everything out
 
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