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Bosch VP30 simple fault diagnosis

142K views 26 replies 18 participants last post by  Dave 45 
#1 · (Edited by Moderator)
As fitted to Rover 25 and 45, MG ZR and ZS

As a rule, the Bosch VP30 pumps fail in one of 3 ways. It's quite easy to diagnose what the problem is.
First of all the three problems.
1 Timing solenoid failure​
2 Metering solenoid failure​
3 Pump psg5 ECU failure​
Let's look at each one in turn.

The image shows the position of the parts on the pump.


1. Timing solenoid failure
If this happens the engine will still run but will sound like an old tractor on its last legs. You'll also get a loss of power. It's not advisable to run for a prolonged time as the timing is now heavily advanced and puts a lot of strain on the engine. This can start intermittently or suddenly happen.
The timing solenoid is under the pump. It can be replaced in situ. Here's a link to a how-to by Mad http://forums.mg-rover.org/showthread.php?t=412181. It's held by two Torx bolts which are quite hard to get at. Also, it's sealed against diesel so will be tight to get out. The wiring to it is not on a plug and will have to be cut and spliced. This also applies to the metering solenoid.

Here's a picture of the two solenoids removed from the pump.


2. Metering solenoid failure
If this happens the engine will stop. This usually happens suddenly without warning. It can be confusing as to what the problem is because if the injector pipe union is cracked open, diesel will still come out. It's just not under enough pressure to cause the injector to open.

Replace the metering solenoid in situ is fairly easy if you have the tools to do it. This youtube vid shows a metering solenoid-removing tool being made. It can be made from 32mm pipe, you don't need to use a socket


You'll need to remove all the injector pipes and the extensions that they are bolted to. Once the sleeve has been loosened the metering solenoid can be extracted from the pump, but it will be very tight. To refit, you'll need to use a "C" spanner.

As you tighten the sleeve it draws the metering solenoid into the pump. It will get tight when it's fully home. You'll need to use the extracting tool to just finish off the job as it has to be done up very tight. Careful positioning of the metering unit is essential as it can spin around and the removal tool won't quite do 1/4 of a turn.

Here are some tools I made and used:


3 Pump psg5 ECU failure
This unfortunately will 99% of the time give exactly the same symptoms as a metering solenoid failure. Sometimes, but not always it will put the engine light on.

To successfully differentiate between metering solenoid failure and pump ECU failure there is a simple test you can perform. Cut the two wires from the pump ECU to the metering solenoid. put a multimeter on the two wires from the pump and get somebody to turn on the ignition. You should see 12volts or thereabouts, and then dropping to about 6 volts when the engine is turned over.

If no power is registered the ECU has failed. If you do get power then the metering solenoid has failed.

If the pump ECU has failed is usually down to a crack in the circuit board which cannot be repaired. The easiest thing to do is replace the pump in this circumstance as removing the circuit board from the pump is very difficult due to overly tight Torx screws that are not very strong.



As you can see I managed to get them out but don't even try unless you have a quality T10 Torx bit. A cheap one will just break off in the top of the screw.

After replacing solenoids
The pump will be totally drained of diesel and despite pumping the priming bulb and bleeding at the injector pipes the engine can be very hard to start afterward.
 
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#5 ·
This is an accurate summary from my experience.

When my psg5 ECU failed I got a "loss of communications with fuel pump" (to paraphrase my SP ACR 4 reader) message and a "fuel quantity solenoid" error also came up after a period of cranking. I,m not sure how the latter code was derived with the pump ecu dead unless the main ECU knows the lift sensor is not being lifted, in which case slackened pipes should give the same fault. I got no EML, the car just stopped.

I took the pump to CF Parkinsons in Lincoln and they could not extract any fault codes from the psg5 and confirmed my worst fears. They replaced it and with it comes both solenoids for reasons mentioned above; they are not pluggable and there are no splices in my repaired pump.

There are people who claim they can repair the ECU for about 250- 300 quid, its not the route I would take, its not far off that for a new one if you go to a decent non ripoff Bosch agent, and you get both solenoids thrown in.
 
#19 ·
No, as stated in your other thread.

If the glow plug light isn't comming on (and I'm guessing the engine management light isnt either), then chances are the ECU isn't getting power.

If the pump is dead the ECU will still try to switch the plugs on and off at the appropriate time.
 
#27 ·
Hi
Reading your points on the VP30 pump I have an engine light come on (amber with an exclamation mark in it) Had two diagnostic tests done both showed fuel pump problem both times they cleared the fault codes first time first time the car ran great for about 20 miles no problems then light came back on had same reading cleared that then about a mile later came back on, but car still drives not to bad you have to put more revs on to pull away and slip the clutch a bit more feels like the turbo is not kicking in, but will get up to motorway + speeds but will not exceed 4K revs even from stationary feels like there is rev limiter , no change in sound of engine. Any help appreciated.
Dave.
 
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