Hello guys! I’m having problems with my Tjet tipo.
It started randomly misfiring and giving out the “P008BGAS RAIL PRESSURE” error when on LPG, so the LPG pressure regulator and LPG sensor were changed and that solved the misfiring but the P008B keeps popping up.
Now it misfires sometimes on cylinder 4, and rarely also on 3, when on LPG.
It also stutters when on WOT around 3000RPM and sometimes below that, pulls strong above 3000RPM.
Below 3000RPM sometimes the engines pulls and pulls slightly like an elastic, for example when on 1/2 throttle.

Changed parts: Pierburg solenoid, oil vapour canister, blow off valve, spark plugs, tried switching coils when it misfired for the pressure regulator, haven’t tried again.
What could be causing the P008B error and the misfiring?
All filters have been changed multiple times.
What could cause the weak spot around 3000RPM and the non linear power output?
I have Multiecuscan on iOS but it doesn’t appear to have all the parameters you get on a PC.
I don’t know how to start diagnosing, especially the LPG pressure error

Thankyou !!

UPDATE: throttle valve relearning results in “not correct.
I suspect throttle valve dirtiness or malfunction, investigating.

We dont get factory LPG here..

So knowledge is limited

varesecrazy said:

We dont get factory LPG here..

So knowledge is limited

Click to expand...

No problem! But updating could be helpful for someone around I hope!
Anyway, the throttle valve relearning not being “correct” should be a hint.
The OEM LPG is just a landi renzo “well fitted”.
?

There was a time when LPG conversions were big news over here but it seems to have died a bit of a death now a days - or am I just out of touch?

Pugglt Auld Jock said:

There was a time when LPG conversions were big news over here but it seems to have died a bit of a death now a days - or am I just out of touch?

Click to expand...

LPG on a carb was simple and gave an equivalent running cost of @33%

Since ECUs became the norm you need a dedicated ECU.. and running costs are @50%
Due to increasing fuel duty..

SOME cars were available with Factory LPG

Eg. Vaux. Fleet market..

But really only made sense on 'Gas Guzzlers'.. unless you did mega miles

The 'dual fuel' VED discount didnt apply to retrofit.. just new registrations

I suspect insurance could be an added cost too..

Does anybody know what could be causing the throttle valve relearning failing to succeed?
The throttle valve moves but the result in MES is not correct. This could be causing the slightly jumpy idle.