Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-17-2011, 08:31 AM   #1
Guru
 
skipperdude's Avatar
 
City: Whittier AK
Vessel Name: Apache II
Vessel Model: 1974 Donald Jones
Join Date: Oct 2007
Posts: 3,147
Fuel injectors

I had a diesel mechanic on board yesterday and he showed me how to check my injectors to see if they are working properly.

**All that was required was a wrench and a rag or blue paper towels.

To check them you crack open the injector with the wrench and listen to the sound of the motor.

The towels is to collect the diesel fuel that will spurt out when you loosen the injector nut

there is a*noticeably difference in the sound of the engine.

If the injector is bad there will be no change.

This was for a Cat 3208. *Is it the same for most diesels.

SD
skipperdude is offline   Reply With Quote
Old 06-17-2011, 09:06 AM   #2
Member
 
Marsh Rat's Avatar
 
City: Onancock Creek,VA
Vessel Name: Tracinda's Treasure
Vessel Model: Pearson 43 Motor Yacht
Join Date: Jun 2011
Posts: 21
RE: Fuel injectors

That works well for most older diesel engines. Not so much on the newer common rail electronic injectors. When you loosen the fuel line to the injector your are shutting off the fuel to that cylinder. Like pulling the spark plug wire off of a gas engine. That cylinder stops firing while the fuel is shut off.
But this doesn't always let you know if your injectors are good or bad. If you have poor compression on that cylinder for any reason you might not notice and change in the sound or smoothness of the engine.
Marsh Rat is offline   Reply With Quote
Old 06-17-2011, 09:11 AM   #3
JD
Guru
 
JD's Avatar
 
City: New Bern NC
Vessel Name: Stella Di Mare
Vessel Model: Mainship 34t
Join Date: Apr 2010
Posts: 1,702
RE: Fuel injectors

Quote:
skipperdude wrote:
I had a diesel mechanic on board yesterday and he showed me how to check my injectors to see if they are working properly.

**All that was required was a wrench and a rag or blue paper towels.

To check them you crack open the injector with the wrench and listen to the sound of the motor.

The towels is to collect the diesel fuel that will spurt out when you loosen the injector nut

there is a*noticeably difference in the sound of the engine.

If the injector is bad there will be no change.

This was for a Cat 3208. *Is it the same for most diesels.

SD
Skip,

That is how*one checks to see*if they are working true enough.* But that is not how they are checked to see if they are working correctly.* They need to be pulled and the pop off pressure is checked as is the spray pattern.* Working is one thing working correctly is another matter.* The cook at Waffle House will feed you but the Chef at a fine restaurant will amaze you.* Unfortunately engines need to be amazed to operate correctly.

I'm not being critical just explaining the difference.
JD is offline   Reply With Quote
Old 06-17-2011, 09:30 AM   #4
Guru
 
skipperdude's Avatar
 
City: Whittier AK
Vessel Name: Apache II
Vessel Model: 1974 Donald Jones
Join Date: Oct 2007
Posts: 3,147
RE: Fuel injectors

Yeah, I didnt mean to say it will give you a full report on the condition of the injectors.

Some Mechanics are less than truthfull when it comes to a job.

But if someone tells you you need new injectors this is a way to check for yourself.*

*It is what a mechanic will do to check them.

SD

*
skipperdude is offline   Reply With Quote
Old 06-17-2011, 10:34 AM   #5
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 22,553
RE: Fuel injectors

Happily with the 3208 removing the injectors to have them checked is fast and really EZ..

In FL the local shop wanted $5 each just to bench test them and $65 to $80 each if they needed a rebuild , depending on what was shot.

More happiness is it is probably the easiest of all to time the injection.

Back off a bolt or two, insert a pin , or drill bit through a hole into the block, lock it up, remove pin.

Wish it were that EZ on DD's.
FF is offline   Reply With Quote
Old 06-17-2011, 11:56 AM   #6
Guru
 
jleonard's Avatar
 
Join Date: Jun 2008
Posts: 5,037
RE: Fuel injectors

"But if someone tells you you need new injectors this is a way to check for yourself.*

*It is what a mechanic will do to check them."

Sorry I can't agree with this either.

This is how a mechanic will diagnose to find a faulty injector. An injector that is so faulty it will not function properly at idle.

Many (or possibly most) times when an injector starts to degrade, it will spray a poor pattern or*fire at the improper time due to*pop pressure degredation**or leak after shutdown (and contaminate the oil).

Your mechanic prbably didn't mean it to be taken literally. True enough this procedure is similar to pulling a spark plug wire on a gasser, but it not the way to find if an injector is performing properly.
jleonard is offline   Reply With Quote
Old 06-17-2011, 02:06 PM   #7
Guru
 
Arctic Traveller's Avatar
 
City: Juneau Alaska
Vessel Name: Arctic Traveller
Vessel Model: Defever 49 RPH
Join Date: Oct 2007
Posts: 607
RE: Fuel injectors

Quote:
jleonard wrote:Your mechanic prbably didn't mean it to be taken literally. True enough this procedure is similar to pulling a spark plug wire on a gasser, but it not the way to find if an injector is performing properly.
*What it is best at is discovering which cylinder is not firing right when you have a rough running engine to begin with.* When you find one that makes no difference with the line cracked open or not, you have found at least the cylinder that's misfiring.* Could be the injector, or something all together different.* I used that method a couple years ago to discover that I had a valve adjusting screw that had lost it's hardface, and was wearing rapidly resulting in a loose valve.* I knew it was running poorly, but not which cylinder.* Cracking the lines told me................Arctic Traveller
Arctic Traveller is offline   Reply With Quote
Old 06-17-2011, 02:34 PM   #8
Guru
 
skipperdude's Avatar
 
City: Whittier AK
Vessel Name: Apache II
Vessel Model: 1974 Donald Jones
Join Date: Oct 2007
Posts: 3,147
Fuel injectors

Quote:
jleonard wrote:
"But if someone tells you you need new injectors this is a way to check for yourself.*

*It is what a mechanic will do to check them."

Sorry I can't agree with this either.

This is how a mechanic will diagnose to find a faulty injector. An injector that is so faulty it will not function properly at idle.

Many (or possibly most) times when an injector starts to degrade, it will spray a poor pattern or*fire at the improper time due to*pop pressure degradation**or leak after shutdown (and contaminate the oil).

Your mechanic probably didn't mean it to be taken literally. True enough this procedure is similar to pulling a spark plug wire on a Gasser, but it not the way to find if an injector is performing properly.
*Well*I had one mechanic that was hard up looking for work.

*He told me I needed new injectors I got a second opinion and watched and learned as he checked the injectors. No fault was found.

I agree it is not a definitive test but it will tell you if there is a problem that needs more attention

SD


-- Edited by skipperdude on Friday 17th of June 2011 03:41:20 PM
skipperdude is offline   Reply With Quote
Old 06-22-2011, 08:20 AM   #9
JD
Guru
 
JD's Avatar
 
City: New Bern NC
Vessel Name: Stella Di Mare
Vessel Model: Mainship 34t
Join Date: Apr 2010
Posts: 1,702
RE: Fuel injectors

Quote:
Arctic Traveller wrote:jleonard wrote:Your mechanic prbably didn't mean it to be taken literally. True enough this procedure is similar to pulling a spark plug wire on a gasser, but it not the way to find if an injector is performing properly.
*What it is best at is discovering which cylinder is not firing right when you have a rough running engine to begin with.* When you find one that makes no difference with the line cracked open or not, you have found at least the cylinder that's misfiring.* Could be the injector, or something all together different.* I used that method a couple years ago to discover that I had a valve adjusting screw that had lost it's hardface, and was wearing rapidly resulting in a loose valve.* I knew it was running poorly, but not which cylinder.* Cracking the lines told me................Arctic Traveller

*Exactly you may have found the problem cylinder but not the problem per say.* Move the injector to a good cylinder and the good injector to the bad cylinder.* If the problem follows the injector you know it is the injector, if the problem stays put the cylinder has other problems and a compression check is in order.
JD is offline   Reply With Quote
Old 06-22-2011, 08:22 AM   #10
JD
Guru
 
JD's Avatar
 
City: New Bern NC
Vessel Name: Stella Di Mare
Vessel Model: Mainship 34t
Join Date: Apr 2010
Posts: 1,702
RE: Fuel injectors

Quote:
skipperdude wrote:
*Well*I had one mechanic that was hard up looking for work.

*He told me I needed new injectors I got a second opinion and watched and learned as he checked the injectors. No fault was found.
Now you know why he was hard up looking for work.* Thief comes to mind.*
JD is offline   Reply With Quote
Old 06-22-2011, 08:48 AM   #11
Guru
 
skipperdude's Avatar
 
City: Whittier AK
Vessel Name: Apache II
Vessel Model: 1974 Donald Jones
Join Date: Oct 2007
Posts: 3,147
RE: Fuel injectors

Roger that.

That is the jest of the thread. If someone tells you you need this or that. Nothing wrong with a second opinion and learning what to look for as a tell tale sign of injector problems can give you an edge.

There is enough things I need my boat bucks for.

SD
skipperdude is offline   Reply With Quote
Old 06-26-2011, 06:31 AM   #12
Guru
 
Forkliftt's Avatar
 
City: Diberville Mississippi
Vessel Name: KnotDoneYet
Vessel Model: 1983 42' Present Sundeck
Join Date: Oct 2007
Posts: 2,450
RE: Fuel injectors

Quote:
skipperdude wrote:


Roger that.

That is the jest of the thread. If someone tells you you need this or that. Nothing wrong with a second opinion and learning what to look for as a tell tale sign of injector problems can give you an edge.

There is enough things I need my boat bucks for.

SD
Good point. And I like the way the mechanic "proved" the injectors were fine. A good mechanic should always be able to prove his case if you ask him to.
Forkliftt is offline   Reply With Quote
Old 06-28-2011, 10:35 AM   #13
Senior Member
 
ralphyost's Avatar
 
City: Cape Coral FL
Vessel Name: Say GoodBye
Vessel Model: 21 Mako
Join Date: Oct 2007
Posts: 261
RE: Fuel injectors

Skipper Dude -

As the others have already said, there is a LOT more to the story than what that "mechanic" told you. He neglected to tell you about pop pressure, spray pattern, carbon build up, etc.

I pulled all my injectors last winter on my 1982 Lehman 120....had 6500 hours on it.

What I found was the bleed off line was INCORRECTLY attached to the injectors by some "mechanic" before me. See here to know what I am talking about

http://tinyurl.com/2868qbo

The bleed off tube was crooked when mated up to several injectors. THe pictures show it. You can see how the bolt head is cocked and not flat to the bleed off tube ring. The screws that hold the bleed off tube into the injectors were CROSS THREADED !!!! What a NUCKLEHEAD that "mechanic" was ! So the bleed off tube was NOT holding the bleed off fuel as it was supposed to.

Took them all to a shop to be tested and rebuilt if needed. Shop calls me and says "Yeah they needed to be rebuilt because the threads were crossed and the nozzles were all crapped up. BUT they are all popping at the correct pressure."

So I ask them how they know what the correct pressure is, because they didnt know what engine they come from. Turns out the rebuilder looked them up in book to get the pop pressure. BUT, his looked up pop pressure was only 2/3 of what the Lehman book said it should be ! So I tell him NO! Set the pop pressure at what my Lehman manual says it should be (and I told him the correct pressure).

*

So be careful when dealing with "mechanics" and I especially shutter when boaters use the term "had it done by a professional".

R.
ralphyost is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ford Lehman Fuel Injectors MVDarlin Ocean Alexander 25 05-21-2018 12:46 AM
1978 34' - dip fuel tanks to measure fuel? meridian Marlow - Mainship 6 10-14-2011 10:52 AM
Fuel gauge for hard to get at fuel tanks on a 1980's Trader 39 Trawler Yacht Ian Streten Electrical and Electronics & Navigation 11 08-26-2011 03:20 AM
Fuel Injectors Wannabe Power Systems 10 09-15-2010 02:39 PM

» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 06:21 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012