How to tell if an injection pump is good - PeachParts Mercedes-Benz Forum

t walgamuth · #1 09-14-2008, 09:49 PM

A few months ago I sold a fellow shopfourm member an injection pump for a 240d. I don't remember any details and since I was selling a number of things back then when a deal was concluded I would purge the pm relating to them.

Yesterday or the day before he pmed me and said he had installed the pump but his motor still would not run and wants now to return the pump for a full refund.

He also said he has decided to install a 617 instead of the 240d motor.

I said if he could give me some evidence that the pump I sold him was no good I would be happy to refund his money.

Now he is getting testy with me.

Is there a way to tell if the pump is good or not?

It seems to me that he has no idea if the pump is good or not.

Tom W

pawoSD · #2 09-14-2008, 10:18 PM

He could bring it to a shop and have it checked....but that'd probably cost $$....

Jeremy5848 · #3 09-14-2008, 10:25 PM

If you loosen one or more of the delivery lines and fuel squirts out when the engine cranks, then the pump is at least pumping – whether at the right time and in the right amount is another matter. If fuel does not squirt, it could be because fuel is not being delivered to the pump or because the pump is indeed not working. (Was the pump working when you sent it to him?)

There should be a method for bench-powering the pump with an electric drill or some other motor so that you could see if it at least delivered fuel. Has anyone ever done that?

If it comes to it, have the buyer send the pump to you. Then bench-test it as above. If it can squirt fuel then it probably works and the problem is with the installer. If you can't get it to squirt fuel, maybe it is indeed broken and you should refund his money.

Jeremy

compress ignite · #4 09-15-2008, 12:10 AM

Comrade IP Purchaser seems to have decided whatever is wrong with the 240
is the IP (Without any evidence that he even knows how to "Set it Up" or time
it correctly) [ALSO,and most importantly,without any supporting evidence that
the IP is "Bad"]
So, since he's decided to move his base of dis-operations to another engine type (617) ...
He's got no earthly use for a four pipe IP and will you be dumb
enough to take it back?
Print out from local Bosch Service Station (with pump number on it) verifying
pump is bad...and I might TALK with him about it. (You'll not be bothered by
him or the pump again)

mrdjsk · #5 09-15-2008, 06:26 AM

Call Hans at H&R Fuel Injection and ask him if there's a way for the layman to test it to some degree. H&R is at 631-589-1600. He's an old world factory-trained injection specialist and is always helpful.

Stevo · #6 09-15-2008, 10:29 AM

In my experience the IP is seldom the problem, period

Which is probably the case here, now he has two good IPs

79Mercy · #7 09-15-2008, 10:29 AM

he probably doesn't have the timing set correctly.

#8 09-15-2008, 10:32 AM

Quote:

Originally Posted by Stevo

In my experience the IP is seldom the problem, period

Ditto. They rarely fail except from REALLY bad fuel, gazillions of miles, physical impact or user abuse (adjusting things not supposed to be touched).

mobetta · #9 09-15-2008, 11:11 AM

I am sure the person in question could resell the IP for the same $$ he paid. There are always peeps running veg that would want a spare, although there are surprisingly few failures posted on this board, from veg or otherwise.

caveat emptor and such, anyhows..........

I am sure that it at least did not have holes in the bottom such as that other 60X IP recently subject to discussion around here.

Palangi · #10 09-15-2008, 11:27 AM

I don't know how you can be expected to warranty 25 year old used auto parts. Sort of defies logic.

Stevo · #11 09-15-2008, 12:27 PM

If one wanted to "HOME bench" test an IP, wouldn't rigging the set up for the "bubble timing method" for each delivery valve show that they each were working, Dono just a thought? I realize if it was that easy it wouldn't cost bezillions at an injector shop.

For you "drip" fans, wouldn't that work but be a little messy?

#12 09-15-2008, 12:39 PM

A bench tester costs more than $100,000 for a reason.

Stevo · #13 09-15-2008, 01:30 PM

Quote:

Originally Posted by ForcedInduction

A bench tester costs more than $100,000 for a reason.

OK, but, lets say I wanted to do something (besides sending it OUT) that would/might indicate it worked before I went to all the bother of installing it. Lets say it didn't have anything to do with this case? not trying to hijack the thread but it might be nice to know if there wasn't some way to check an IP out without getting to carried away, maybe give an indication the delivery valves were working meaning the little pistons were doing their thing. Obliviously this would be a "shade tree' test but wouldn't it tell you that you had a pretty good chance it was OK??

BTW, I'm not the guy that bought it, trying to figure out how to test them both for free

Diesel911 · #14 09-15-2008, 02:36 PM

Quote:

Originally Posted by Stevo

OK, but, lets say I wanted to do something (besides sending it OUT) that would/might indicate it worked before I went to all the bother of installing it. Lets say it didn't have anything to do with this case? not trying to hijack the thread but it might be nice to know if there wasn't some way to check an IP out without getting to carried away, maybe give an indication the delivery valves were working meaning the little pistons were doing their thing. Obliviously this would be a "shade tree' test but wouldn't it tell you that you had a pretty good chance it was OK??

BTW, I'm not the guy that bought it, trying to figure out how to test them both for free

The easiest/best way to test at home is to put it on vehicle. Also if an IP is full of fuel and you turn it by hand they will squirt out some fuel for you.

Suppose you made your own test stand and it had all of the things you need on it. Where would you get the specifications to check the IP?
The IP is supposed to put out certain amounts of fuel at certain rpms.
Without the specs for the pump you could only say that it puts out fuel.
You could create your own specs by running a good pump or better a rebuilt pump and recording what it puts out but that still dose not tell you all of what is going on in the IP.
An IP test stand like the one I used back in the 70s sold in North Carolina last year for $750 but it was pick-up only. The Ebay seller had bought it from a State School Surplus sale. So it is possible not to pay $100,000 for one.
Also I have seen them selling in the $15,000-$20,000 range used by used equipment sellers.
Another note: If your IP is not properly aligned on your test stand you can ruin bearings really fast.

nhdoc · #15 09-15-2008, 04:00 PM

I have thought about this in the past. The only way I can think of to truly test an IP is to connect hard lines and an injector to each DV, but don't install the injectors in the head and crank the engine. If the injectors pop and fuel mist sprays out of each one then the IP is probably fine. Testing any other way doesn't insure that the IP is putting out enough pressure to pop open the injector (2000± PSI). You'll need to be super careful that you don't touch the injectors while they are spraying or you might just land up with a diesel injection right through your skin though.