Any ideas as to what could be causing limp home type issues?

[RobD63]

Hi folks, I have a 2010 Transit that has an intermittent fault, yes, the worse type.

Most of the time it runs like a dream and pulls like a train, but...

Occasionally, after stopping in traffic and then setting off, the engine will lose power and the van will struggle along at no more than 10/12 mph, no matter what gear I select. It does it very suddenly as though you've hit the brakes. It also does it sometimes when changing gear, so it's as if when the engine speed drops it goes into a sulk. It will then come out of it and run fine but, if not, pulling over and turning the engine off and then on again after a few seconds usually cures it. It's been an ongoing problem for the previous owner for about a year and he's now given up and bought another van but I may buy it off him if I can get this sorted. He says it can go weeks without it happening and then happen regularly.

It's been into three or four garages without any success and the only issued flagged up by a diagnostic check were EGR valve and MAF sensor problems so I've had both replaced without any change in the engine's behaviour. There are no warning lights that appear on the dashboard either before, during and after these occurrences.

Any of you heroes out there have any ideas on what might be causing this? I appreciate it may well be a number of things but I'm hoping these symptoms might give one of you a clue as to the most likely cause and how to proceed in sorting it.

Many thanks for taking the time to read this, I have my fingers crossed someone might be able to help.

[knobby1]

I'll go out on a limb here and say your SCV is sticking.....happened to mine some time back. A sticking SCV won't usually throw a fault code.

Live data will give an idea of actual vs desired fuel rail pressure....in theory they should be similar at all times. If not the SCV may be sticking...."hysteresis" is the common word for it.

I'd suggest doing an injector "leak-off" test, this will give a fair idea of your injector health ...and if that proves ok, then pump, pilot and injector learn first before condemning your SCV and/or PRV.

Lord Knobrot

[RobD63]

Cheers Knobby, very kind of you to take time with your thoughts. At twenty odd quid for a cheap replacement and a few beer tokens to my mechanic, I'm gonna give it a go and post back in a week or two what the results are.
Meanwhile, if anyone else has other thoughts and suggestions then please add to Knobby's contribution.
Thanks again folks.

[Airthies]

Cheers Knobby, very kind of you to take time with your thoughts. At twenty odd quid for a cheap replacement and a few beer tokens to my mechanic, I'm gonna give it a go and post back in a week or two what the results are.
Meanwhile, if anyone else has other thoughts and suggestions then please add to Knobby's contribution.
Thanks again folks.

If you pa £20 for an SCV you could be introducing more issues than you've got when you try to do learns etc.
Get genuine denso valves from a Reputable diesel specialist supplier, DO NOT CHANGE PRESSURE SENSOR!
A pair of valves (SCV & PRV) should set you back under £100 delivered, was around that last time I got a set.

Sent from my A55ho11 using Crapatalk

[andz327]

Hi folks, I have a 2010 Transit that has an intermittent fault, yes, the worse type.

Most of the time it runs like a dream and pulls like a train, but...

Occasionally, after stopping in traffic and then setting off, the engine will lose power and the van will struggle along at no more than 10/12 mph, no matter what gear I select. It does it very suddenly as though you've hit the brakes. It also does it sometimes when changing gear, so it's as if when the engine speed drops it goes into a sulk. It will then come out of it and run fine but, if not, pulling over and turning the engine off and then on again after a few seconds usually cures it. It's been an ongoing problem for the previous owner for about a year and he's now given up and bought another van but I may buy it off him if I can get this sorted. He says it can go weeks without it happening and then happen regularly.

It's been into three or four garages without any success and the only issued flagged up by a diagnostic check were EGR valve and MAF sensor problems so I've had both replaced without any change in the engine's behaviour. There are no warning lights that appear on the dashboard either before, during and after these occurrences.

Any of you heroes out there have any ideas on what might be causing this? I appreciate it may well be a number of things but I'm hoping these symptoms might give one of you a clue as to the most likely cause and how to proceed in sorting it.

Many thanks for taking the time to read this, I have my fingers crossed someone might be able to help.

When you replaced the maf and egr did that sort the fault codes ??

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[RobD63]

If you pa £20 for an SCV you could be introducing more issues than you've got when you try to do learns etc.
Get genuine denso valves from a Reputable diesel specialist supplier, DO NOT CHANGE PRESSURE SENSOR!
A pair of valves (SCV & PRV) should set you back under £100 delivered, was around that last time I got a set.

Thanks for that. My plan is to run the engine with a cheap replacement and if it seems to cure the problem then get a genuine replacement once I'm satisfied that the problem has been sorted. As I've already stated, it's intermittent so I'm just going through an elimination process without trying to spend too much as it may come to a point where I decide not to buy it.

[RobD63]

When you replaced the maf and egr did that sort the fault codes ??
[/quote]
To be honest I'm not sure as I haven't had a diagnostic check run since. The mechanic that fitted the MAF and EGR did say that the EGR that he took out wasn't original to the vehicle so he thinks that the fault codes that came up on the diagnostic that was done elsewhere may have been historic fault codes.

[Airthies]

If you don't want to spend cash then simplest job is to walk away.

Don't start guessing and fitting things without plugging it in.
Cheapest option (if you don't have a mate that'll do it for free) is a £15-20 Modified USB ELM327 and free version of forscan on a laptop.

If you don't want to spend too much then buying a cheap valves that dont work properly and then genuine valves is going to cost you more



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[andz327]

Mate do what mucker Airthies said get forscan on to a laptop..... its free and buy an elm327 switchable unit from tunnelrat electronics (cheaper than a sh!t prv)and get your van plugged in and see what's going on

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[Airthies]

And before you go fitting anything, Once you've got it plugged in, in this order!
1. read and clear codes, re read and see if any stay. Ask here if your not sure of any that are persistent.

2. do a set of learns
If learns go through ok, test drive van.

3.If learns fail....
Do an injector leak off test to see which ìnjectors Duff. If there's any poorly ones they won't let the learns complete. And after too many failed attempts it'll be stuck in limp mode.

4. If learns complete, see how it drives.

5. Fit genuine SCV PRV and repeat process.

If engine has any ticking or chuffing and a bit of a breeze when you have the oil filter cap off, it'll need injector seals done, not a big job and common on these engines.

There's loads of info on here about all of this already on the forum if you take your time to read up on other threads.


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[nick_theboatman]

Don't start guessing and fitting things without plugging it in.
Cheapest option (if you don't have a mate that'll do it for free) is a £15-20 Modified USB ELM327 and free version of forscan on a laptop.

I use:
1 a Bluetooth ELM327 and the ForScan APK off Playstore (you have to pay a fiver or thereabouts). Works fine and is convenient to go on the road with; couple of bugs in ForScan (the DPF regen doesn't work for example; made a report to the developer in Russia but he wants more info I haven't given him yet).

2. a USB ELM327 and Windows ForScan off their website. Works very well. Free. Does all sorts of nefarious stuff including re-programming the injectors and the learned values for whatever. The laptop battery is crap so the laptop doesn't stay up for long so not practical to go on the road with unless you have a passenger and a 12v fag lighter PSU.

[Brettbear63]

I had a merc Vito , which did the same sort of thing , it was a short in a wire which rubbed on a bracket ,on odd occasions . it conned the engine into thinking it was overfuelling and so went into limp mode , insulation tape fixed it .

[RobD63]

I'll go out on a limb here and say your SCV is sticking
Lord Knobrot

Sorry about the delay in posting an update but after fitting my cheap SCV I seem to have no more issues so it looks like that was the problem, thanks very much for pointing me in the right direction Nobby.
I shall now invest in a decent quality SCV and report back on how that goes.
Thanks for everyone else's input also.

[knobby1]

I'll go out on a limb here and say your SCV is sticking
Lord Knobrot

Sorry about the delay in posting an update but after fitting my cheap SCV I seem to have no more issues so it looks like that was the problem, thanks very much for pointing me in the right direction Nobby.
I shall now invest in a decent quality SCV and report back on how that goes.
Thanks for everyone else's input also.

Don't forget to fit a PRV to go with it...and then a full set of learns.

A bad SCV can often take the PRV with it.

Lord Knobrot