Rev counter and Hold light

[Channelswimmer]

Hi there, Very new to these forums.

Just had my fuel pump overhauled at huge cost and now the rev counter is eratic - sometimes it works correctly, sometimes it doesn't work at all and sometimes it darts everywhere quite erratically. The Hold light comes on when the rev counter is being erratic. I have booked it back in with the same mechanic on Friday but said I would ask a couple of questions to assist him. .
The hold function was working but doesn't seem to work as well now and I'm not sure it works at all when it's flashing.

Any help greatly appreciated

Steve

[g8dhe]

The rev counter is driven by the ECU, and the ECU flashes the HOLD light when it has a problem! The most likely cause is probably the input signal from the sensor to the ECU for rev's, possibly it wasn't reconnected properly or maybe damaged in some way during the earlier work ?
The Rev sensor is B2-19;

The location of B2-19 (connector) is on the next page from above.

[Channelswimmer]

That's brilliantm thank you very much

[Simon Jones]

Here's the sensor highlighted which you can see is just in front of the injector pump. New ones are expensive (somewhere close to £100 if I recall correctly).

[Channelswimmer]

Thanks. Would I need a new one or is there something I should do with the current one first? I have the van booked in with a mechanic on Friday but could do without the massive bill if. There are basic checks I could try between now and then. Which side is the pic taken from?cheers. Steve

[Simon Jones]

As I recall, its a hall effect sensor so works like an ABS sensor so it could be tested by attaching a volt meter and looking for a small signal proportional to the engine speed. The photo is taken with the engine out the van from the drivers side looking backwards, but you can see the cambelt which is normally hidden by plastic cover. You can also see where the banjo filter normally fits which is the shiny area below the sensor.

[Northern Bongolow]

could it be early signs of alternator failure. they sometimes give random(ish) signs like this. is it starting ok?

[rita]

As I recall, its a hall effect sensor so works like an ABS sensor so it could be tested by attaching a volt meter and looking for a small signal proportional to the engine speed. The photo is taken with the engine out the van from the drivers side looking backwards, but you can see the cambelt which is normally hidden by plastic cover. You can also see where the banjo filter normally fits which is the shiny area below the sensor.

Hi,I dont think that is the "Banjo" filter position,it is situated at the top of the injector pump.(just in case someone is looking for it)

[Simon Jones]

Oops, yes you're right. I think that's either the power steering pump, or the vacuum pump.

[Channelswimmer]

Thanks for all of your tips and advice. I put it in with the mechanic and all of your advice printed and images. He found a lot of moisture in the sensor so took it out, cleaned it up and replaced. It seems to be a bit better but not perfect. It's not dying out completely, the hold light isn't coming out and the hold function is working as normal which it wasn't when the hold light was flashing but it is still a bit eratic and jumps all over the place at times and I'm not sure the revs are accurately matching the real revs. Should I purchase a new sensor or just learn to live with it. Will it affect the van?
Driving to work today and someone drove in to the back so my local bodyshop place will now be on the lookout for a new back door and bumper!