Willum
Active Member
It may be that I was the only one in the world who didn't know about this - but I doubt it. All the same, forgive me if this an egg-sucking exercise...........
For those of us who have a Sevel-built X250 base unit (Citroen/Peugeot/Fiat) from the last 10 years or so:
There is a problem with the earth strap from the engine to the chassis that can cause a whole raft of weird faults and having a computer, or several, at the heart of the system, all kinds of faults appear and disappear in random fashion.
Lots of faults can appear on the dash readouts, or just one. My (Fiat) showed its hand by, for absolutely no explicable reason, increasing the idle RPM from the normal 850-ish, up to 1400. That was in a motorway service station - quite a long way from our destination. It otherwise ran and drove fine and, happily, got there without incident.
It didn't do it again but I promised myself I would inspect the wiring harness in the engine bay for abrasion damage - another common fault that should be looked for, even if no problems are seen (prevention is MUCH better than cure in this instance)
Next time I tried to start it, it was just a tiny bit sluggish. I was curious but it started fine and that was that.
The next time it was more sluggish on the starter and the glowplug light flashed for a long while after it started. The idle then did the same trick and increased to about 1400 RPM.
The next time (five minutes later) I started it - it didn't. Just a click and a dash full of lights.
The battery 'at rest' voltage checked out OK but not brilliant, 12.9, rather than the usual 13.2.
I won't bore you with the rest of the tale of trying to find out what was wrong. Most of it was me sweating on it not being a computer/wiring meltdown. The remaining effort was expended on research.
Here's a link to a lengthy discussion I found about the problem. The guy who started - and solved - it is pretty clued up and generous with his time and advice.
http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/X250-Engine-earth-fault/21815/
The shortened version of the solution to the problem was:
1. Remove the left hand headlamp and the top of the air filter and check the wiring harness where it crosses the steel tube bracket for the computer mounting. Mine had the protective, corrugated, hard plastic, split conduit already fitted. If yours is OK and doesn't have any conduit, I strongly suggest you fit some. Fried computers are expensive to replace.
2. Next, fit a new, corrosion-protected earth strap. There are several suggestions as to where to fit them. I went from the well cleaned existing chassis mounting point to one of the bolts that holds the starter motor to the engine. It's the starter motor that takes the biggest current draw - by far - so the best point to connect it in my humble opinion. Cut out all the middle men.
The strap I fitted was a £5-odd Halfords battery negative lead, 24" long, and did the job nicely. Braided straps are fine, but tend to let the water and salt into the crimps more readily - most likely the root of the problem with the original strap.
Don't be tempted to use thin, cheap, nasty cable, with skinny terminals. Something with at least an 8mm conductor, ie, 8mm excluding any insulation sleeving, is what is required. Something as thick as the cable that connects your battery to the chassis is even better. It carries several hundred amps when you turn the key.
The INSTANT the strap was fitted, all the problems went away, the battery voltage went back up and after a switch-off and restart, all the 'alleged' engine/system faults reset themselves.
Knowing what I know now, I would suggest that one is fitted regardless of any problems manifesting themselves. It's a bit late when it makes like a Christmas tree and you break out in a sweat in the middle of nowhere.
Just for interest's sake, the RPM increase is because the earth is so bad, the alternator voltage drops, the computer thinks it's too low because of load, so it increases the RPM to compensate.
Will
For those of us who have a Sevel-built X250 base unit (Citroen/Peugeot/Fiat) from the last 10 years or so:
There is a problem with the earth strap from the engine to the chassis that can cause a whole raft of weird faults and having a computer, or several, at the heart of the system, all kinds of faults appear and disappear in random fashion.
Lots of faults can appear on the dash readouts, or just one. My (Fiat) showed its hand by, for absolutely no explicable reason, increasing the idle RPM from the normal 850-ish, up to 1400. That was in a motorway service station - quite a long way from our destination. It otherwise ran and drove fine and, happily, got there without incident.
It didn't do it again but I promised myself I would inspect the wiring harness in the engine bay for abrasion damage - another common fault that should be looked for, even if no problems are seen (prevention is MUCH better than cure in this instance)
Next time I tried to start it, it was just a tiny bit sluggish. I was curious but it started fine and that was that.
The next time it was more sluggish on the starter and the glowplug light flashed for a long while after it started. The idle then did the same trick and increased to about 1400 RPM.
The next time (five minutes later) I started it - it didn't. Just a click and a dash full of lights.
The battery 'at rest' voltage checked out OK but not brilliant, 12.9, rather than the usual 13.2.
I won't bore you with the rest of the tale of trying to find out what was wrong. Most of it was me sweating on it not being a computer/wiring meltdown. The remaining effort was expended on research.
Here's a link to a lengthy discussion I found about the problem. The guy who started - and solved - it is pretty clued up and generous with his time and advice.
http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/X250-Engine-earth-fault/21815/
The shortened version of the solution to the problem was:
1. Remove the left hand headlamp and the top of the air filter and check the wiring harness where it crosses the steel tube bracket for the computer mounting. Mine had the protective, corrugated, hard plastic, split conduit already fitted. If yours is OK and doesn't have any conduit, I strongly suggest you fit some. Fried computers are expensive to replace.
2. Next, fit a new, corrosion-protected earth strap. There are several suggestions as to where to fit them. I went from the well cleaned existing chassis mounting point to one of the bolts that holds the starter motor to the engine. It's the starter motor that takes the biggest current draw - by far - so the best point to connect it in my humble opinion. Cut out all the middle men.
The strap I fitted was a £5-odd Halfords battery negative lead, 24" long, and did the job nicely. Braided straps are fine, but tend to let the water and salt into the crimps more readily - most likely the root of the problem with the original strap.
Don't be tempted to use thin, cheap, nasty cable, with skinny terminals. Something with at least an 8mm conductor, ie, 8mm excluding any insulation sleeving, is what is required. Something as thick as the cable that connects your battery to the chassis is even better. It carries several hundred amps when you turn the key.
The INSTANT the strap was fitted, all the problems went away, the battery voltage went back up and after a switch-off and restart, all the 'alleged' engine/system faults reset themselves.
Knowing what I know now, I would suggest that one is fitted regardless of any problems manifesting themselves. It's a bit late when it makes like a Christmas tree and you break out in a sweat in the middle of nowhere.
Just for interest's sake, the RPM increase is because the earth is so bad, the alternator voltage drops, the computer thinks it's too low because of load, so it increases the RPM to compensate.
Will
