Buzz test injectors before installing them?
Thread Starter
|
Mountain Pass
Joined: Jan 2005
Posts: 115
Likes: 10
Buzz test injectors before installing them?
Most of my injectors buzz very weakly so I picked up some used, cheap but supposedly good used injectors with 130K miles. i'm thinking of getting a new valve cover gasket and doing the buzz test on them before I install them. Is this possible or do they have to be grounded, etc? Just trying to save myself the work of replacing bad injectors with bad and I could theoretically return the used injectors for a refund if I find them bad....
Tuned
Joined: Jul 2007
Posts: 305
Likes: 14
To complete the circuit I'd say that they must be grounded at some point. I'm not a diesel expert but I am an electrician. They are going to vibrate I would imagine so ground them at a point that a small arc burn won't interfere will a machined fit.
Tuned
Joined: Mar 2016
Posts: 354
Likes: 0
They have a power wire and a ground wire so they dont need to be grounded themselves. Not sure how accurate of a test it would be, but I guess if there was a major difference in sound with one it may indicate an issue.
Fleet Mechanic
Joined: Jul 2003
Posts: 1,614
Likes: 22
From: Springfield, PA
At a minimum of 110, 120Vdc if newer. The buzz test only powers the solenoid and lifts the poppet valve. It has no effect on the rest of the injector when there's no high pressure oil applied to them. So you won't be testing the movement of the plunger or needle.
This is a good question. I now wonder why they buzz, it's not like the poppet valve is oscillating up and down during the test. Or does it?
This is a good question. I now wonder why they buzz, it's not like the poppet valve is oscillating up and down during the test. Or does it?
Cargo Master
Joined: Nov 2005
Posts: 2,766
Likes: 56
From: East Tawas, MI
I think it just shows sel action. I can't see a mechanical reference. Kinda like a system happy check where your getting correct voltage and ohms to the unit. Unsure tho? Good quest.
Denny
Denny
Thread Starter
|
Mountain Pass
Joined: Jan 2005
Posts: 115
Likes: 10
my impression is that the solenoid is turned on and off rapidly which flutters a valve. The seat of the valve wears over time so "poppet valve armature clearance" is reduced. the worn valves flutter less so they don't make as much noise as unworn ones as they buzz or slam back and forth? I don't have a great understanding of the process, though. hence my questions.
I did run across this kit which includes a bunch of spacers that will somehow adjust the clearances inside a worn injector. I think its all related to what is going on with a buzz test in general.
https://www.ebay.com/itm/7-3L-POWERS...9321ecffe73d8c
I did run across this kit which includes a bunch of spacers that will somehow adjust the clearances inside a worn injector. I think its all related to what is going on with a buzz test in general.
https://www.ebay.com/itm/7-3L-POWERS...9321ecffe73d8c
Trending Topics
Papa Smurf
Joined: Nov 2009
Posts: 1,080
Likes: 204
From: Woodstock, GA
I did the kit 150,000 miles ago.... now approaching 480,000.... original injectors... Getting 17-17.5 mpg, but its just a daily driver. Always thought when I get to 500,000, I'll get new injectors for the beast.
my impression is that the solenoid is turned on and off rapidly which flutters a valve. The seat of the valve wears over time so "poppet valve armature clearance" is reduced. the worn valves flutter less so they don't make as much noise as unworn ones as they buzz or slam back and forth? I don't have a great understanding of the process, though. hence my questions.
I did run across this kit which includes a bunch of spacers that will somehow adjust the clearances inside a worn injector. I think its all related to what is going on with a buzz test in general.
https://www.ebay.com/itm/7-3L-POWERS...9321ecffe73d8c
I did run across this kit which includes a bunch of spacers that will somehow adjust the clearances inside a worn injector. I think its all related to what is going on with a buzz test in general.
https://www.ebay.com/itm/7-3L-POWERS...9321ecffe73d8c
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread Starter
|
Mountain Pass
Joined: Jan 2005
Posts: 115
Likes: 10
Well I hooked up my used injectors to the wiring harness, just laying in the engine bay. At 32 degrees today, only one of the loose injectors buzzed. The other three loose and all four of the injectors on the other bank failed to buzz.
I measured the armature plate clearance on one of the original injectors and I couldn't get a .002 feeler under it. One of the "replacement" injectors had around .002. New clearance is supposed to be .004".
I measured the armature plate clearance on one of the original injectors and I couldn't get a .002 feeler under it. One of the "replacement" injectors had around .002. New clearance is supposed to be .004".
Laughing Gas
Joined: Mar 2017
Posts: 833
Likes: 4
You can get a "budget rebuild" from Rosewood for $500. This will likely be a wayyyy better option than installing used injectors, unless you really enjoy frequetly pulling out inectors 
1999.5 - 2003 AD Split Shot Injectors | Rosewood Diesel Shop of C******, OH
1999.5 - 2003 AD Split Shot Injectors | Rosewood Diesel Shop of C******, OH
Thread Starter
|
Mountain Pass
Joined: Jan 2005
Posts: 115
Likes: 10
I ended up shimming the old injectors to restore the armature clearance from zero to .003 inches. Mostly because
i'm lazy but partially as an experiment. After shimming, all the injectors sound pretty good on the buzz test.
I started the engine without preheating it at below freezing temperatures today. I used to have to plug in the block heater even when it was 70 degrees outside to get it to start up. $75 for the kit $75 for a valve cover gasket and a few hours to install the shims seems to at least have solved my cold start issue.
I'm going to save the wiring off the old gasket so I can again buzz test injectors without them being installed in the engine. I still have 7 extra used injectors for future use.
i'm lazy but partially as an experiment. After shimming, all the injectors sound pretty good on the buzz test.
I started the engine without preheating it at below freezing temperatures today. I used to have to plug in the block heater even when it was 70 degrees outside to get it to start up. $75 for the kit $75 for a valve cover gasket and a few hours to install the shims seems to at least have solved my cold start issue.
I'm going to save the wiring off the old gasket so I can again buzz test injectors without them being installed in the engine. I still have 7 extra used injectors for future use.
Thread Starter
|
Mountain Pass
Joined: Jan 2005
Posts: 115
Likes: 10
Here is the shim kit I used. Comes with tools and instructions. Only requires pulling the valve covers and solenoids from the injector tops.
https://www.ebay.com/itm/INTERNATION...72.m2749.l2649
I found that my injectors had already been worked on. One was a different brand, had the most armature clearance, and sounds best on the buzz test. The other 7 had "ADP" scribed onto them and 3 were already shimmed. (4,6 and 7). cylinder 8 is failing the cylinder contribution test for some reason.
https://www.ebay.com/itm/INTERNATION...72.m2749.l2649
I found that my injectors had already been worked on. One was a different brand, had the most armature clearance, and sounds best on the buzz test. The other 7 had "ADP" scribed onto them and 3 were already shimmed. (4,6 and 7). cylinder 8 is failing the cylinder contribution test for some reason.
Lead Driver
Joined: Apr 2011
Posts: 8,259
Likes: 346
From: Northern California
Aside from starting how does it run and sound in various driving conditions ?
ive been wanting to rebuild my own injectors mostly for the experience of it,
Bitterroot makes and sells the tool and all the parts.
https://bitterrootdiesel.com/collections/1999-2003-7-3-powerstroke
Here is a great video on the process
ive been wanting to rebuild my own injectors mostly for the experience of it,
Bitterroot makes and sells the tool and all the parts.
https://bitterrootdiesel.com/collections/1999-2003-7-3-powerstroke
Here is a great video on the process
It's a Van Gogh
Joined: Feb 2010
Posts: 7,802
Likes: 1,333
From: Elk Grove, CA
Here is the shim kit I used. Comes with tools and instructions. Only requires pulling the valve covers and solenoids from the injector tops.
https://www.ebay.com/itm/INTERNATION...72.m2749.l2649
I found that my injectors had already been worked on. One was a different brand, had the most armature clearance, and sounds best on the buzz test. The other 7 had "ADP" scribed onto them and 3 were already shimmed. (4,6 and 7). cylinder 8 is failing the cylinder contribution test for some reason.
https://www.ebay.com/itm/INTERNATION...72.m2749.l2649
I found that my injectors had already been worked on. One was a different brand, had the most armature clearance, and sounds best on the buzz test. The other 7 had "ADP" scribed onto them and 3 were already shimmed. (4,6 and 7). cylinder 8 is failing the cylinder contribution test for some reason.
And thanks for posting up your results on the shim kit, good to hear it worked for you.
Thread
Thread Starter
Forum
Replies
Last Post
eatont9999
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
2
May 8, 2012 09:20 AM
parrisw
1994.5 - 1997 7.3L Power Stroke Diesel
22
Nov 25, 2008 08:10 AM