Troubles with 1HZ Injector pump...

Howdy folks, hows things?

If I can pick your brain for a bit?

Got the trusty 80 series TOJO ('91). Only thing is that the injector pump is making a loud throaty 'diesely' sound and power & economy are down. The motor misses when running on my main tank but doesnt miss on the sub tank, even though it still has that diesely sound. Obviously air has gotten into the IP. When i fix the suspected leaky fuel line/ air problem in the main tank fuel line, will that fix my problem do you think? or will i need to recondition/ fix or buy a new IP?

If i do need a new IP, any1 know where to get a good deal on a ghood 2nd hand IP?

Any thoughts will be appreciated.


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Reply By: happytravelers - Friday, May 14, 2010 at 20:45

Friday, May 14, 2010 at 20:45
How would you be able to hear the injector pump over the sound of the engine? If you were able to define it as an injector pump noise it would mean it's got serious problems. If the engine misses on one tank and not the other the chances are that tank has either got contaminated fuel or there is an air leak in the fuel line between the main tank and the switching solenoid which is located near the chassis cross member forward of the sub tank. The first step would be to check your fuel filter for contaminants.
AnswerID: 416706

Reply By: Member - Barnray (NSW) - Friday, May 14, 2010 at 21:15

Friday, May 14, 2010 at 21:15
Suggest you find a Diesel mechanic before you spend a couple of thousand. Barnray
AnswerID: 416712

Reply By: Member - Stuart P (WA) - Friday, May 14, 2010 at 21:22

Friday, May 14, 2010 at 21:22
it may also be a blocked injector.
AnswerID: 416715

Reply By: racinrob - Saturday, May 15, 2010 at 11:23

Saturday, May 15, 2010 at 11:23
Run a fuel line, (gravity feed) directly into the pump, this will tell you if the problem is the pump or the filter(s) fuel lines or tank, it's a matter of tracking down the problem by by passing different components.
Be aware there is a small acorn filter on the fuel pick-up line in the main tank that can get blocked by sediment etc, it happened to me and took awhile to track down.

AnswerID: 416761

Follow Up By: Rowen - Tuesday, May 18, 2010 at 10:10

Tuesday, May 18, 2010 at 10:10
Howdy Rob, cheers for your reply.

I better check that small acorn filter out. Can you tell me where to find it (actuualy in the main tank?) & how to get to it etc?


FollowupID: 687212

Follow Up By: racinrob - Tuesday, May 18, 2010 at 13:40

Tuesday, May 18, 2010 at 13:40
G'day Rowen, the acorn filter that caused me so much grief is on the end of the fuel pick-up in the main tank. My HZ is a tray back and the floor plate inside the cab only gave me access to the fuel gauge sender unit so I had to drop the whole tank out to get to it, no easy task ! To do this I jacked the vehicle up via the chassis rails to fully extend the rear springs and tail shaft, undo the tank straps and wriggle the tank out and you'll find where the fuel line enters the tank, pull that off and on the end of the fuel line is the acorn filter, while you're at it you can flush out the tank too !
Not known by many and not even mentioned in the work-shop manual there is a tiny mesh filter in the body of the injector pump, remove the fuel line into the pump then flatten the end of a piece of wire and bend at 90deg and gentle fish it out, it's a lot easier to do this before you drop the tank, see if it works.
In my previous post I said to feed fuel directly into the pump, do that via a container sitting on top of the engine and run a fuel line straight to the pump, if it runs without a problem you know your blockage is back down the line somewhere, it's a matter of elimination. Have fun and let me know how you go !

FollowupID: 687240

Follow Up By: Rowen - Tuesday, May 18, 2010 at 15:08

Tuesday, May 18, 2010 at 15:08
Howdy Rob...

Cheers again for that.

The IP is making an awefull 'throaty' noise from both fuel lines (it misses on the main tank line but not the sub tank line) & its lacking power/ economy so its got to be the IP right? Still, I will check by doing the direct fuel feed to the pump. maybe its worth doing/ checking the tappets too?

I've got the rear drawers fitted in the back of my wagon, so I will be dropping the tank out too i will suspect to access the accorn filter. whats best to use to flush the tank out with?

I can get a good secondhand IP for ~$270 without too many klicks on it, so as my IP has 550 klicks on it, i might aswell. I will replace the seals etc. Can I pull the replacement IP apart for a clean/ service before i put it on?

so the mesh filter is not far up the fuel line in the IP? is it easy to fish out is it?

Cheers again

FollowupID: 687253

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