Bit of a grump - how to test my new ITP

[SteveT]

I'm in a bit of a grump because I've just changed both pumps on my diesel 75 and I'm not convinced the new ITP is working. I'm also not convinced the old one wasn't working.

This arose because I reported to you guys that my car started to stutter above 4000rpm and then suddenly cut out, refusing to restart. The fuel level was low and we suspected a failed ITP. I put some diesel in the tank and the car started, so that seems to confirm the theory.

So, I took my old ITP out and replaced it. I connected a 12V battery across the terminals of the old one and it ran. That's worrying. (The new one ran, too.) Made me think the old ITP might have been OK. I also replaced the UBP, which was working but now both are brand new and I'm happy about having two new pumps.

Here is why I'm grumpy: it still won't rev over 4000rpm when the throttle is floored - it hesitates and misfires. Also, I can't hear the ITP running.

Here's my question: is there any way to test that the ITP is actually running and pumping diesel? For instance, I thought about removing the electrical connector from the UBP, disconnecting the output pipe from the filter, and switching on the ignition.

Does the ITP have enough heft to push the diesel through the UBP and filter?

Or is there any other way I can test the ITP?

Thanks,

Steve

[FrenchMike]

You have an electric /pressure test :

BP test.jpg

More accurate than listening at the filler cap...

Mike

[SteveT]

Will that test the ITP, though? Or will the UBP manage that pressure on its own?

Steve

[FrenchMike]

Originally Posted by SteveT

Will that test the ITP, though? Or will the UBP manage that pressure on its own?

Steve

That tests the final low pressure including UBP,UBP etc..

In the same idea ,you can test the final High Pressure on the common rail:

HP test.jpg

Good luck

Mike

[SteveT]

OK, thanks, Mike.

I'm sorry: I've probably misunderstood your point. I think the UBP will generate that pressure all on its own, regardless of whether the ITP is running or not. So my thinking goes that the pressure test won't tell me whether the ITP is working.

Am I missing something obvious?

Thanks,

Steve

[FrenchMike]

Originally Posted by SteveT

OK, thanks, Mike.

I'm sorry: I've probably misunderstood your point. I think the UBP will generate that pressure all on its own, regardless of whether the ITP is running or not. So my thinking goes that the pressure test won't tell me whether the ITP is working.

Am I missing something obvious?

Thanks,

Steve

Well,the simplest way is listening at the filler cap .
Key position 2 (before starting) during 1 minute or so ...

But if the 4 volts value is good ,then everything is OK !
(this information is directly sent to the ECM)

[Mike Noc]

Originally Posted by SteveT

OK, thanks, Mike.

I'm sorry: I've probably misunderstood your point. I think the UBP will generate that pressure all on its own, regardless of whether the ITP is running or not. So my thinking goes that the pressure test won't tell me whether the ITP is working.

Am I missing something obvious?

Thanks,

Steve

Steve you're spot on - the car will run happily on just the UBP as long as there is plenty of fuel in the tank.

So as Mike says listen for the ITP, or let the tank go down to the fuel low level light before filling up and if it doesn't conk out before then the ITP is working as it should.

Mike

[SteveT]

OK, thanks. I'm going to lift the back seat as there's no obvious noise from the filler.

If it's working, then that loss of power/hesitation/misfire at 4000rpm must be another fault.

I'll have a play tomorrow and will report back if there's anything interesting to say.

Thanks again,

Steve

[chrissyboy]

when i used to be at a garage we used to test the pumps vai the fuse .we used to attach a fuse loop into where the fuse for the pump went in the fuse box and using a volage clamp clamp the loop and connect to a pico ,looking at the readings and the wave forms you can tell if a pump is working 100%,just like the range rover we did this week ,it used to cut out when driving and the revs over 300. by doing the above it showed us the pump was weak and couldnt supply the extra fuel needed.. more speed = more fuel .changed pump and all was well.

[HarryM1BYT]

Can the pipe between ITP and UBP simply not be disconnected at the UBP to see if there is flow from the ITP?