Hello everyone,

Nice to meet you all!

We have an issue with our engine unfortunately and was wondering if any one of you would be able to help us out as it's such a random issue and we are struggling to get to the bottom of it. I'll explain.

We have a Class A RV (Forest River Georgetown) Ford triton V10 6.8ltr. F53 Chassis 2006.

Last April we installed an LPG system and it works really well.

Anyway, since we had the system installed, we have started having the following issue (it’s probably a byproduct of it as another person with the same engine specs has the same issue after installing LPG).

Intermittently, the RV stalls while we are driving.

Now, there is a lot of confusion about this issue as after many times, it's hard to determine what's causing it as it happens so randomly. I have heard about LPG system might make your vehicle stall while you are slowing down approaching a roundabout.

Though, the issue happens on both system! LPG and Petrol!
It mainly happens at slow speeds(10-20mph) but also once at faster speeds (35-45mph). It seems to be happening as soon as I leave the accelerator, the rpm go down suddenly very low and then it stalls. I put in N and turn the keys on and starts straight the way with no doubts. Last 2 times it happened, it turned OFF and turned ON itself without me doing anything?! It happens when the engine is cold and also when it's hot. It usually happens 3/4 times every 200 miles or so (mainly when we are going slow and always when we leave the accelerator). If we are just idling and going a long (like on slight downhill) it doesn’t happen. Only when I am going fairly slow and pressing on the accelerator, as soon as I leave it it stalls. I tried using manual gears (3,2,1) and because the rpm when I leave the accelerator stay up and don’t go down, the issue doesn’t seem to happen.

The guy that installed the LPG doesn’t know why it’s happening. We will be going to another mechanic next week.

Do you have any idea of why this is happening? Has anyone of you have ever had this issue and managed to fix it?

Thank you so much for reading and I really hope some of you skilled people might come up with some ideas so that we can present them to the mechanic and he can have a check to all these potential causes.

We really hope to get this sorted soon as it's a bit scary to drive sometimes. Luckily when it happens, the breaks still work, but the steering wheel gets really hard so we are taking curves really slowly!

THANK YOU ALL!

 

I'm not familiar with LPG systems, But I'll assume it runs as an alternative but you can still use your gasoline system and run the engine normally? Is it stalling out on the gasoline also when you take your foot off the accelerator?
I would start by
#1 cleaning the TB, remove all carbon deposits

#2 Checking for air (Vacuum) leaks in the system.

#3 Remove the neg cable and cover the post so the terminal doesn't accidently hit it. Grab a wire with alligator clips on each end. Clip one to the positive side battery cable and the other to the neg battery cable and let it sit and drain any residual electricity out of the capacitors 10 to 15 minutes. Reconnect the neg battery cable. Now make sure ALL of your accessories are turn OFF. Put key in ignition and turn to on position, let your cluster and lights all prove out, then start the vehicle and let idle for 10 minutes. This method should relearn your ECU for correct idle.

As an after thought to what I just wrote, I would assume the LPG burns differently than gasoline.....and I hope others with actual knowledge chime in on this but IF the LPG is burning differently than gasoline, I'm wondering if your plugs might be going bad, or heaven forbid the LPG has prematurely worn your piston rings out and you're starting to have low compression symptoms. Sure hope you can figure it out and keep us updated on the outcome.

 

LPG on a motorhome? I wonder how large of a tank you had to install to get any range.