Homebuilt injector tester ?

rkpatt · Sep 16, 2006

Somewhere I read or heard about making a low cost fuel injector tester using a bottle jack or a grease gun for the pump . Is anyone familar making an injector testor ?

The reason for having my own tester is that the local injection shop lately seems to find a disproportional amount of "bad" injectors in sets that I take them to test just so they can sell me more new or rebuilts. At this point I don't want to go back to them for this service .

Thanks

Exekiel69 · Sep 16, 2006

The cheaper way would be to be there when they test the injectors so You can see the spray pattern on each one and You'll be the judge.

79 300sd · Sep 16, 2006

I found the info over at mercedesshop a while back and built one of the bottle jack style. Drilling and tapping (3/4" npt) the cap could be a problem for some, but I had a friend who owns an industrial machine shop do it for me.

If I build another one it will be the grease gun style. It looks like it should be a lot easier. I would also spend a little extra for a better gauge with a needle that shows what your maximum pressure was during a test.

c&p:

"Credit goes out to OLD300D who sent me this a while ago.

Pop tester parts list

--------------------------------------------------------------------------------

I bought all the parts from www.McMaster.com

1 8803T51 Bottle Jack ($12.74)
1 4000K763 3000psi gauge, 3/4" NPT ($10.04)
1 5269K311 Metric fitting, 1/8" NPT to 6mm tube ($3.12)
1 50925K197 Steel T fitting, 1/4" NPT, MxFxF ($4.27)
1 4513K341 Hex bushing, 1/4" NPT to 1/8" NPT ($0.85)
1 4513K347 Hex bushing, 3/4" NPT to 1/2" NPT ($1.18)
1 4513K344 Hex bushing, 1/2" NPT to 1/4" NPT ($0.95)

The jack must be disassembled, and the pressure relief in the cylinder plugged. I tapped it, JB welded a set screw into it, then ground it flat. Remove the seal from the top nut and tap it 3/4" NPT. I JB welded the bushing into this thread as well. The gauge and 1/8" NPT bushing thread into the T, the injector line is cut and is fitted into the metric tube adapter. I also tapped and fit the bottle jack for a funnel into the reservoir to keep fluid in the cylinder, as quite a bit is pumped out as you test injectors. I used ATF and Marvel mystery oil to fill the tester."

The 5269K311 Metric fitting, 1/8" NPT to 6mm tube fitting is for mercedes injectors. It is probably a different size for a ford.

David

edit: I think that the thread size on a grease gun is 1/8" npt.

h2odrx · Sep 16, 2006

Hey welcome to the site, I think that is the best first post EVER!!!!!

icanfixall · Sep 16, 2006

Guys.... These are great ideas of how to test an injector but... Please install a standard fuel filter BEFORE the fuel gets pumped thru a possible good injector. If ANY crap,,, And I mean any debris gets pumped into an injector its pretty much shot to .... Well its junk. Its really hard to clean out any trash that hangs up the pintle or plugs the hole up. Even using a spent fuel fliter will be better than nothing.

rkpatt · Sep 17, 2006

79 300sd - Thanks for responding . I guess thats where I saw it but I could find if when I searched the www.mercedesshop.com site ( I have a 1983 300SD work in progress ). I think I have an extra grease gun around. Do you mean you the grease gun type is better because it is easier to put together (no drilling tapping) or does it work better ?

Exekiel69 · Sep 17, 2006

79 300sd said:
I found the info over at mercedesshop a while back and built one of the bottle jack style. Drilling and tapping (3/4" npt) the cap could be a problem for some, but I had a friend who owns an industrial machine shop do it for me.

If I build another one it will be the grease gun style. It looks like it should be a lot easier. I would also spend a little extra for a better gauge with a needle that shows what your maximum pressure was during a test.

c&p:

"Credit goes out to OLD300D who sent me this a while ago.

Pop tester parts list

--------------------------------------------------------------------------------

I bought all the parts from www.McMaster.com

1 8803T51 Bottle Jack ($12.74)
1 4000K763 3000psi gauge, 3/4" NPT ($10.04)
1 5269K311 Metric fitting, 1/8" NPT to 6mm tube ($3.12)
1 50925K197 Steel T fitting, 1/4" NPT, MxFxF ($4.27)
1 4513K341 Hex bushing, 1/4" NPT to 1/8" NPT ($0.85)
1 4513K347 Hex bushing, 3/4" NPT to 1/2" NPT ($1.18)
1 4513K344 Hex bushing, 1/2" NPT to 1/4" NPT ($0.95)

The jack must be disassembled, and the pressure relief in the cylinder plugged. I tapped it, JB welded a set screw into it, then ground it flat. Remove the seal from the top nut and tap it 3/4" NPT. I JB welded the bushing into this thread as well. The gauge and 1/8" NPT bushing thread into the T, the injector line is cut and is fitted into the metric tube adapter. I also tapped and fit the bottle jack for a funnel into the reservoir to keep fluid in the cylinder, as quite a bit is pumped out as you test injectors. I used ATF and Marvel mystery oil to fill the tester."

The 5269K311 Metric fitting, 1/8" NPT to 6mm tube fitting is for mercedes injectors. It is probably a different size for a ford.

David

edit: I think that the thread size on a grease gun is 1/8" npt.

Excellent

.

oldmisterbill · Sep 17, 2006

I was thinking of making one using a hand operated hydraulic pump simular to the ones used on a porta power.I picked a pump up at a yard sale some time ago-brand new -light weight made of aluminum-2500 psi.
By the way did you give ur wife back her ceral ***** yet ? :backoff

79 300sd · Sep 17, 2006

rkpatt said:
79 300sd - Thanks for responding . I guess thats where I saw it but I could find if when I searched the www.mercedesshop.com site ( I have a 1983 300SD work in progress ). I think I have an extra grease gun around. Do you mean you the grease gun type is better because it is easier to put together (no drilling tapping) or does it work better ?

Exactly! The grease gun type is easier because of the drilling and tapping.

There are at least three threads over at mercedesshop about building these. The ones that I found were at least a year old.

I'm going out of town for a few days, but will try to find/post links to the threads when I get back.

Maybe you could use a copy of the mercedes instructions for injector testing.

David

79 300sd · Sep 17, 2006

icanfixall said:
Guys.... These are great ideas of how to test an injector but... Please install a standard fuel filter BEFORE the fuel gets pumped thru a possible good injector. If ANY crap,,, And I mean any debris gets pumped into an injector its pretty much shot to .... Well its junk. Its really hard to clean out any trash that hangs up the pintle or plugs the hole up. Even using a spent fuel fliter will be better than nothing.

Agreed! Also be sure to thoroughly flush out the tester before use. It doesn't take much to clog an injector.

I had to reopen and clean three of the first set of five that I did.

79 300sd · Sep 17, 2006

oldmisterbill said:
I was thinking of making one using a hand operated hydraulic pump simular to the ones used on a porta power.I picked a pump up at a yard sale some time ago-brand new -light weight made of aluminum-2500 psi.
By the way did you give ur wife back her ceral ***** yet ?

That's great, I didn't even notice the bowl in the picture before. LOL

The picture is one that I got from from a thread at mercedesshop. I can't take a picture of mine because I broke the wifes digital camera and haven't given it back to her yet. Maybe she won't need it soon and I can get her a new one for christmas!

79 300sd · Sep 17, 2006

rkpatt said:
79 300sd - Thanks for responding . I guess thats where I saw it but I could find if when I searched the www.mercedesshop.com site ( I have a 1983 300SD work in progress ). I think I have an extra grease gun around. Do you mean you the grease gun type is better because it is easier to put together (no drilling tapping) or does it work better ?

This link should get you started. It has links to a couple of other good threads.

www.mercedesshop.com/shopforum/showthread.php?t=123573

krawlr · Sep 17, 2006

That jack setup is sweet! ;Sweet

I see a trip to the surplus store is in the near future.

h2odrx · Sep 17, 2006

i stopped by the local diesel shop and asked what they charged to test injectors? $32 to test and they would sell me new ones for $32 plus tax? cookoo

typ4 · Sep 17, 2006

The pump shop I use tests for free and you can stand there and watch if they are able to do it riight then. They will do it for anyone and the prices they sell at are very fair. Another Diesel Performance shop here in town will do it for free also but he is a one man shop so I either flip him a few or offer and he usually declines, iI do send him some work tho. If a shop wont let you watch the pattern go somewhere else, some like to sell parts and I have never seen a full set bad enough unless contaminated or very high miles. my 2 c
russ

Homebuilt injector tester ?

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