Nemo 1.3 Hdi only revs fully when brake pedal pressed when static

[nemo14]

Hi, New on here and hoping you may be able to help. I have a 2014 Nemo 1.3 Hdi and a strange issue has begun since replacing the EGR valve. Initially van ran fine after fitting new EGR, but then went back into limp mode briefly, then was ok again. Diagnostics showed an PO402 air circuit fault, flow too low, I reset and all seemed well except… when stationary it will only rev to 2.5/3k revs, but when driving it revs normally and freely. So I dug deeper, checked all fittings, pipes and terminals and all seem ok. I have also tested and cleaned MAF and checked for air/vacuum leaks and couldn’t find anything. Finally I thought I would try pressing the brake pedal and accelerator, and hey presto problem gone, revved fully and continued to do so. Unfortunately as soon as engine is turned off and restarted it has same problem. Am I missing anything obvious? Thanks in advance.

[BarneyRubble]

I wonder have you run the teach-in process (EGR Adaption) for the new EGR valve using Diagbox (or similar)? If it's a new part, that normally needs doing, so the ECU can operate it properly. Once done, that would possibly fix the issue. If you haven't got access to a tool like that you could ask your local garage to teach it in, or failing that, _sometimes_ you can just disconnect the battery for 30m or more and then reconnect it and everything will adjust itself automatically. That said, I don't know if that would work in this case, and don't forget your radio CODE, otherwise you may end up with the engine problem and a locked out radio.

[nemo14]

Thank you.
No, was not aware of that. Battery has been disconnected 3 times for long periods since EGR fitted. It’s so strange that all operates normally when driving, then reverts after ignition off.

[PaulC5]

Did it do this before the egr valve was replaced ? Did you fit an aftermarket new egr ?
A similar topic which might have resolved itself after replacing the egr and it self learning. viewtopic.php?t=59107

[nemo14]

Did it do this before the egr valve was replaced ? Did you fit an aftermarket new egr ?
A similar topic which might have resolved itself after replacing the egr and it self learning. viewtopic.php?t=59107

Thanks.
No was not doing it before new egr fitted, it was an aftermarket part. After reading the similar topic you referenced, I wonder now if vacuum solenoid could be the issue. As soon as I depress brake it clears issue and revs freely, so seems vacuum related…but not sure

[nemo14]

Update
I thought I would try basics again, so disconnected battery for 30 mins, reconnected and before starting also did a throttle position reset, started up and revved perfectly. Switched off and restarted 3 more times, reset date and time, all ok, great. So I switched off tidied tools and shut bonnet. Then tested again… and unfortunately back to only revving to 2750!
So I guess it must therefore be electrical. So I am going to leave battery disconnected for an hour or so and see what happens…

[PaulC5]

I think egr valves are not used until the engine warms up a bit so if testing with a cold engine it might appear as if nothing is wrong. However, I might not have this right.

If not too difficult, fit the old egr valve back and if the fault then goes it might suggest the aftermarket one is faulty. Or maybe just plug it in without fitting.

[moizeau]

My van, 1.6hdi 16v has never been able to rev more than 2.5k while stationary in neutral, drives and revs fine. Thought it was normal, stops MOT testers ringing it's neck and bouncing valves.

[nemo14]

Thanks for all replies.

In the end I left the battery disconnected over night. Next day all good apart from still not revving above 2750 when static, but drives great, so much better.

It was booked in for MOT today, I did mention it doesn’t rev above 2750 when I dropped off. But it passed without any advisories, and apparently the revs restriction is quite normal, so all good