Bit of a grump - how to test my new ITP

[SteveT]

Originally Posted by HarryM1BYT

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

Thanks, Harry. I don't know if there's an easy way to do that. The thing is, to change the UBP I had to remove the battery and the battery box in order to get to the UBP inlet pipe, which is on the bottom.

Maybe I did that wrongly.

What I will do in the next hour or so is remove the pipe from either the UBP outlet or possibly the filter. The ITP would then have to push the diesel through the UBP. If it works, I'm sure the ITP is fine. If it doesn't, I haven't actually proved it's broken because I don't know whether it should be able to.

Steve

[SteveT]

Yep - I'm a complete idiot. Here's why: when I changed the ITP yesterday I accidentally put the old one back in!

I can't believe it.

Here are some findings that someone may find useful.


1/ The old pump was still running, but its speed was wavering all over the place and sometimes it made what can only be described as a deep "purring" noise. The new one makes a constant high-pitched whine.

The old one still does that when I have it on my workbench: the speed varies up and down, and the current varies, too. Interestingly, when the pump slows down the current reduces, which means it isn't partially seizing - rather that is typical of almost-worn-out brushes.

Conclusion - be careful with the listening test: the ITP may make a noise even when faulty. A healthy pump makes a continuous high-pitched whine.


2/ The old pump was only in there between 18 months and two years. It is branded "ENERGY" and has the manufacturing date mark 04-10.

It is identical to the replacement I bought on eBay, but that is dated 11-11. I think a two year lifespan is dreadful.

Conclusion - I have serious doubts about the quality of the ENERGY branded pumps. Of course, I'm only speaking from a sample size of one, but it's maybe something to consider when buying a replacement ITP.


3/ The high-speed stuttering and hesitation has gone. Ever since I bought the car I've had problems with the engine losing power and hesitating above 4000rpm when thrashing it up through the gears.

The new ITP has cured it completely, and it now revs cleanly to 4400rpm before changing up.

Conclusion: loss of power above 4000rpm may be a useful early warning of ITP failure (I mean more useful that seeing if the car breaks down when there's less than a quarter tank of fuel!).


4/ Testing your ITP. With the new ITP running and the UBP disabled I disconnected the outlet pipe from the under-bonnet filter to see if the ITP had enough heft to push diesel through the UBP and filter. After several seconds a very weak and slow dribble appeared at the filter outlet. I would say it's not enough for a definitive test.

Conclusion - it is not very feasible to test the ITP by looking for fuel flow at the under-bonnet filter outlet with the UBP disabled. Looks like we're stuck with the listening test (unless you've got some posh test equipment for looking at the current waveform).


I hope some newbie in the future will find some of these observations useful.

Thanks again to everyone who helped - I really appreciate it, and you encouraged me to take another look at the ITP.

Steve

[FrenchMike]

Well Steve good news , but i would like to know what my test would give at 4000 rpm ?

Certainly less than 4 volts

Mike

[crofts]

I'm no expert in this dept. but did think I had seen several times to disconnect the pipe on the UB side to check flow from UBP. I assume this would be out of the filter into a bottle. Yes/No ? ?
I can clearly hear my ITP by listening between rear tyre and wheel arch...........drivers side, of course !
I usually have a reasonable amount of fuel in the tank. On ONLY one occasion did I go down to the low fuel light. I did not have a problem but believing I had created one by doing this I checked the ITP. No sound.....dead.
As pointed out, because I always had reasonable amount of fuel in the tank it had been running for 'how long' on just the UBP. Something most of us realise now.
Far as I know, if the UBP goes then car will not run whatever the level of fuel

[SteveT]

Originally Posted by crofts

I'm no expert in this dept. but did think I had seen several times to disconnect the pipe on the UB side to check flow from UBP. I assume this would be out of the filter into a bottle. Yes/No ? ?

Yes, exactly. You want one of those plastic measuring jugs from the kitchen - the 1 litre size is just right. Being plastic you can distort it a bit so it sort of wedges into place, with the spout underneath the pump outlet. Pack a good amount of kitchen roll around it, just to be sure.

If the UBP is working correctly you'll get a good solid flow.

I'm still thinking about ways to definitely test the ITP, because in my case the hearing test didn't work. It was still making a noise (although I admit it was wavering about and sometimes going very slowly). To be fair, now that I know I'm listening for a continuous whine I probably won't get caught out again.

Originally Posted by crofts

Far as I know, if the UBP goes then car will not run whatever the level of fuel

Yes, that's right. I've got two new pumps now. If I disable the UBP, the ITP is not capable of pushing more than the weakest dribble through the under-bonnet filter, and the car definitely won't start.

In a nutshell, if the ITP fails you'll break down if the tank gets below 1/4, and you may notice a loss of power and stuttering at more than 4000rpm. If the UBP fails, your engine won't run at all.

Steve