So the past few weeks I’ve had a problem that I’m chasing, starts fine, runs fine till I’m in 4th gear, say at 40-50 mph, it then acts like it’s a dropped a few cylinders, knock it into neutral, give it a few throttles and it goes back on eight, yesterday it did it but stalled, only the once, normally it will just go really low and I can catch it.
Changed plugs, TPS, MAF, gonna swap CPS today, fuel pump is 18 months old, so I don’t think it’s that,
My initial thought was the maf, maybe this is why my lpg is acting up, any ideas appreciated, plugging in diagnostics today to see if any stored faults.
Until I got to the last line, I was going to ask if you'd plugged in a code reader. If the one you use does live data, drive with it connected and see what it shows when it does it. Check the fuel pressure too.
Just remembered that I had a fuel pressure regulator fault, which disappeared when I changed the fuse box, gonna dig it out and install as a precaution.. ( pressure reg )
It feels fuel related, So hopefully that will fix it.
But yours is a Thor, isn't the pressure regulator in the fuel pump housing inside the tank?
It’s on the line coming in, l/h side of bananas
Errrrr is it?
Wasn't anything on the line on our red one - I know this as we replaced the line with decent quality fuel hose after some monkey snapped the plastic line and bodged it back together.
AFAIK Thor is returnless, and thus cant have a rail mounted regulator.
Maybe I’m wrong with the part, just know I’ve got to change a part, thought it wa fuel related, has a pipe off each end, one end goes to throttle body, never got round to tracing the other end and won’t for a few days ( back has gone, ffs )
Will try to get part number
no10chris wrote:
Maybe I’m wrong with the part, just know I’ve got to change a part, thought it wa fuel related, has a pipe off each end, one end goes to throttle body, never got round to tracing the other end and won’t for a few days ( back has gone, ffs )
Will try to get part number
Rigid plastic pipe would be the throttle heater feed?. Known to be brittle and troublesome, Guess its one of the pipes connected to this plate on the bottom of the throttle housing that you need to replace.
Doubt thats anything to do with it, though I seem to remember someone else (on here, not sure who offhand) had issues with running after removing that plate, due to the threaded holes providing a hole in the bottom of the throttle area that bypassed the MAF and butterfly and stopped it running properly. But unless you've taken the plate off and not filled the holes in that shouldn't be your problem.
It’s not the throttle heater, standing in front of car, r/h side of plenum, pipe comes up from under the car, clips into bracket, has 2 wire plug going to it, outlet goes to throttle body ( rear side )
I’m lucky enough to have quite flexible throttle heater pipes, as I’ve had engine out twice and bent them about quite a lot, lol
So I did a bit of digging, knew it was something to do with fuel, it’s the purge valve !
Well I thought I’d found my lpg problem this morning, was out tinkering, found 2 of the lpg hoses had slight splits where the clips go round, so trimmed and refitted,
Gonna order new as I think P.O. changed as 2 types of pipe and one doesn’t fit as snug as I’d like.
still only 15 secs on lpg, grrrrrr,, on the positive side, I changed the purge valve and it now ticks over nicely, possibly the last thing I would of thought could cause tickover problems, but after a google search it can, any fresh ideas on my lpg welcomed..
To clarify - When it feels like it's running on less than 8 cylinders happens on petrol? You say this happens when it's just gone into 4th gear ? Unless the problem is gearbox related it won't just happen in 4th gear so try to find the conditions for the engine when this happens... Is it for example after gentle / moderate / hard acceleration to (say) 40mph and have backed off the throttle to continue at said 40mph, so when the engine is under less load and at lower rpm after acceleration? Does the same happen regardless of hot/cold engine? What happens if you don't back off the throttle but continue accelerating in 2nd/3rd/4th gear? If fault is really only in 4th gear then problem might actually be gbox related, I've driven plenty automatic cars where the engine lacked torque in certain conditions because the gbox ECU sensed gbox clutch slippage and instructed the engine ECU to retard ignition timing to reduce torque... Talk engine conditions not gbox conditions unless it really only does happen in 4th gear.
Probably jumping the gun a bit but assuming the above happens on petrol, does the LPG system always shut off after 15 seconds or does 15 seconds just coincide with getting into 4th gear? In which case the LPG system might be shutting off if it senses loss of rpm pulse or petrol injector pulse. Does it really feel like it's on 7 or 6 cylinders (with engine vibration and missing exhaust sound) or just down on power? There could be correlation between misfires (for electrical reasons) and the LPG system shutting off.
Would've just blanked the evap purge valve off.