Fuel injector Rebuilding/testing and TM and compression testing

[Wildchild467]

How much compression would the multifuel test at? I haven't seen anywhere that had the specs on what the compression test pressure should be or the leak down pressure in this thread or other ones I have searched.

 

[m-35tom]

just an educated guess would be 600 min

 

[Ford Mechanic]

I never came up with a way to adapt a guage to check it

 

[Wildchild467]

I recently took an old injector (shim style injector) and made it into a compression tester. I took the guts out of it, cut about 3/8 off the end of the nozzle (so it had a bigger hole), welded the high pressure line port shut and then will use the 1/8" NPT port to hook to the compression tester. I haven't used it yet, but when I do, I will post the results.

 

[Ford Mechanic]

Good idea, I just didn't have a extra injector sitting around

 

[rustystud]

View attachment Scan0047.pdf

How much compression would the multifuel test at? I haven't seen anywhere that had the specs on what the compression test pressure should be or the leak down pressure in this thread or other ones I have searched.

Here you go.

 

[FarmerRob]

For anybody in the east Texas area, there's a place in Longview that tests injectors for free and will rebuild them for $20-25. I'll be taking all six of my injectors in from the two trucks I currently have plus the spares I got with a truck I bought a while back.
When I drove from MI to TX two years ago, my truck developed a high-RPM miss and top speed dropped to 54 MPH after my first fill-up on the trip.

 

[Jeepsinker]

Where is this place (what city), and do you have their phone number? I have some injectors I'd like to get serviced.

 

[gimpyrobb]

For anybody in the east Texas area, there's a place in Longview that tests injectors for free and will rebuild them for $20-25. I'll be taking all six of my injectors in from the two trucks I currently have plus the spares I got with a truck I bought a while back.
When I drove from MI to TX two years ago, my truck developed a high-RPM miss and top speed dropped to 54 MPH after my first fill-up on the trip.

Where is this place (what city), and do you have their phone number? I have some injectors I'd like to get serviced.

Hope this helps...

 

[FarmerRob]

Where is this place (what city), and do you have their phone number? I have some injectors I'd like to get serviced.

The name of the place is Promax. Don't have the number off hand but Google knows it.

 

[brianp454]

Diesel Injection Service in Portland, OR will do it. I posted a youtube video of it. They did a checkout of my injectors and a spare set for a buddy at a very reasonable price.

 

[FarmerRob]

Yep, your post and video is why I started looking for a place near me.

 

[TMNT]

I know this thread has been dormant for a few months, but it looked like a good place for me to add my fuel injector testing and calibration questions.

Disclaimer: I've been working on this for about a month. I've searched, read, cross-referenced, and read the related and similar threads that I could find. And yes, I read through the relevant sections of the TM's but I have not been able to find the specific answer that I'm searching for.

I have a 1970 Deuce with an LDT-465. It has the AMBAC 2-hole fuel injectors #12354296, dated 05-92. The truck has been running pretty good, but it has always been a little ragged on a cold start and there is a rhythmic sound in the exhaust note that sounds almost like a miss, but not that bad. I assumed it was because I could have an injector that was not performing the same as the other five. I also get quite a lot of white smoke, indicating some raw fuel going into the exhaust. I'm wondering if I have an injector that is popping early or maybe (and hopefully not) a compression problem on a cylinder. I thought I would start with the "easy" stuff first: valve clearance and injectors.

I finally decided to tackle that issue. I set the valve clearance, and I removed the injectors for service. The injectors were clean looking with only very small amounts of carbon "dust" on the nozzles.

Here's the problem: I have not been able to find a shop local to the north side of Atlanta, GA, that has the correct line fitting to connect to the injector for pop-testing. I spent some time today at Royal Brass and Hose, and it seems that the high-pressure connection is a metric connection of some type but nothing seems to match it properly. Does anyone know the correct nomenclature for the injector line fittings?

The injection shop called AMBAC to discuss the issue, and AMBAC acknowledges the issue and AMBAC said they could service the injectors. AMBAC says they have an adapter but they won't disclose the connection type. AMBAC is suggesting that the shop send the injectors to them and it sounded like they were saying $30 each, plus shipping. I'm not sure I want to do that yet, as I would like to have or to develop a local shop for this injector work.

I've seen the YouTube videos reference above and I see that the Portland, Oregon shop is using an adapter between the injector and his high-pressure line. I'm attempting to reach him to find out what he's using there, but he may not want to disclose the "secret" if it affects his business.

Does anyone know of an Atlanta area shop that can pop-test these AMBAC injectors?

On the up-side, this shop will clean, test and set the injectors for $19 each, if they can figure out how to hook them up. They service injectors, turbos, and electrical systems for commercial trucks and equipment.

I want to test the compression, while I have the injectors out, but that seems to be whole 'nother set of problems to adapt a compression tester to the injector port. I had intended to scope the cylinders with the injectors out, but the hole is too small for my scope.

So, while my injectors are sitting at the shop, I'm cleaning and painting the valve covers, injector plates, injector lines, and pretty much anything else that I can get to now.

Any help, advice, or info is greatly appreciated.

 

[Katahdin]

I'm subscribing to this thread too, I just dropped off my M109A3 injectors to a fuel injection shop in Windham, ME for testing. Cost is $10 injector for the test, then they up charge from there.

I'm going with what TM 9-2815-210-34-2-2 (1981 date) says about pressures:

• New nozzles should open between 3050 to 3150 psi.
• Used nozzles should open at a minimum of 2800 psi.
• There should not be more than a 300 psi difference between any two nozzles in a complete set.

I'm going to assume the higher pressures listed in the injector specs are intended for other diesel-only engine makes and models.

I thought about buying or making my own pop tester, but I think I'm starting to accumulate too much deuce related clutter. I figure I'd only want to have my injectors tested and cleaned once every 5 years or so.

 

[TMNT]

I'm subscribing to this thread too, I just dropped off my M109A3 injectors to a fuel injection shop in Windham, ME for testing. Cost is $10 injector for the test, then they up charge from there.

I'm going with what TM 9-2815-210-34-2-2 (1981 date) says about pressures:

• New nozzles should open between 3050 to 3150 psi.
• Used nozzles should open at a minimum of 2800 psi.
• There should not be more than a 300 psi difference between any two nozzles in a complete set.

I'm going to assume the higher pressures listed in the injector specs are intended for other diesel-only engine makes and models.

I thought about buying or making my own pop tester, but I think I'm starting to accumulate too much deuce related clutter. I figure I'd only want to have my injectors tested and cleaned once every 5 years or so.

I found that it says that 3050# is for new springs (new or rebuilt injectors). The new springs will "take a set" to 2800#, so the correct number for "used" injectors is 2800#. I've seen a lot of debate about this and people setting the pop pressure as high as 3700#. I plan to go with the values stated in the TM (2800#) for my "used" injectors. That is, if I ever get them on the tester!

 

[Scar59]

Subscribed also, I have a spare set that needs a check out. Diesel Injection Service has a nice shop here in town. I'll see what they say.

 

[Ford Mechanic]

I found line nuts with the right thread and pitch and then did my own flare with a flaring tool to hook it to the injectors.

 

[Wildchild467]

I recently took an old injector (shim style injector) and made it into a compression tester. I took the guts out of it, cut about 3/8 off the end of the nozzle (so it had a bigger hole), welded the high pressure line port shut and then will use the 1/8" NPT port to hook to the compression tester. I haven't used it yet, but when I do, I will post the results.

Update: I used this adapter I made and it works great.

 

[TMNT]

I found line nuts with the right thread and pitch and then did my own flare with a flaring tool to hook it to the injectors.

Finding the correct line nuts is the problem. The guy at Royal Brass pulled out pretty much every type and size, metric and standard, and nothing seemed to be a perfect match. He had a huge kit for checking connector sizes and nothing seemed to work. I even rifled through the selection at Lowe's and a plumbing shop.

Any idea what the specs are for the line nuts? Metric, SAE, something else?

 

[TMNT]

Update: I used this adapter I made and it works great.

That makes perfect sense. I just need an old injector now.