Thread: Removal of mechanical injection pump from a diesel engine

Firstly, the timing would be specified by the manufacturer to deliver the best compromise between power, torque, fuel economy, engine life, and emissions, whilst taking into consideration the peak leverage point, time it takes to deliver the fuel, and the expected rpm at the peak torque point.

The later models may have retarded the timing to reduce emissions or sometimes to improve fuel efficiency but at the expense of power.

You can advance the timing a few degrees to get more power, but this can be at the expense of more smoke and you don’t want to inject far too early.

A good tuner should be able to tweak the timing.

Originally Posted by Pedro_The_Swift

What are the timing requirements before pump removal?


I have a sticking throttle at first full throttle application of the day, when the bus is at operating temp it doesnt happen. The single bit of electronics inside the pump is working properly, the linkages and exterior attachment point all return as they should.
The engine returns to idle when shut down with the key.

When you say you have a sticky throttle, with the mechanical throttle linkages back to the pedal disconnected, from a cold start does the pump throttle stick open when you rev it at the injector pump (by hand).

Have you been able to observe exactly where it is sticking open?

Maybe something is binding up internally within the pump and it just needs a good cleaner put through it.

From conversation with Tandy's ( at bus pickup) he had to exit the engine bay quite quickly and run for the ignition when he duplicated the stick,, so I'd say the pump throttle returns to idle..
Not adverse to running some form of cleaner, it will have to mix in 200 odd litres of diesel though..

I ASSUME diesel injector cleaner will work on injector pumps... ?


This engine has had new injectors installed within the last two years...
I wonder if its the same cause...

Hear good things about this stuff, but who'd know? DiscoDB seems to find data sheets on most things.

Originally Posted by Pedro_The_Swift

I ASSUME diesel injector cleaner will work on injector pumps... ?


This engine has had new injectors installed within the last two years...
I wonder if its the same cause...

Or try one that really works.

Injector Cleaner - Diesel Injector & Fuel Injector Cleaner

Originally Posted by Tins

Hear good things about this stuff, but who'd know? DiscoDB seems to find data sheets on most things.

Let’s just say I like to understand what makes some of these products “special”.

First up the Nulon Diesel Injector Cleaner is your typical kerosene based cleaner with some naphtha solvent. For 200L you would add 300ml. From a value for money point of view it is fairly low cost to try.

The Cost Effective CRD Fuel Enhancer product is interesting in that it is >90% base oil (like found in two stroke oil) with a small dose of naphtha solvent (<5%), a small dose of naphthalene (<1%), and a small dose of phosphoric acid (<1%). To me it reads like a two stroke oil but added at lower doses. Can not work why it is so “special” beyond being like dosing with a good quality two stroke oil - which by all accounts does work.

Another option which also gets good reviews may be Cost Effectives FTC Decarbonizer which is >60% naphtha solvent with some anti-fungal agents. You would start with a double dose of 250ml for 200L.

The other product to also consider is to give the system a shock treatment of Fuel Doctor (add 1L for 200L fuel, then repeat). Fuel Doctor is an ethanol based fuel treatment with alcohol cleaning agents to dissolve any contaminants and remove carbon and gum build up. Probably a good idea if the vehicle has been sitting unused for extended periods in the past.

Many of these products do have a whiff of snake oil about them, but if they are based on good cleaning agents it hard to see how they can’t offer some benefits. Compared to the cost of removing and stripping down the fuel injector pump I would be giving these a go. Probably starting with Fuel Doctor first, then FTC Decarbonizer and Nulon Diesel Injector Cleaner.

Originally Posted by V8Ian

Or try one that really works.

Injector Cleaner - Diesel Injector & Fuel Injector Cleaner

Certainly no harm trying and also gets good reviews.

Cleanpower is a detergent based fuel treatment, so very minimal hazardous chemicals added - just a small dose of naphtha solvent and some Tetraethylenepentamine added. A double dose only needs 50ml to treat 200L of fuel.

I have a bottle of this which I am yet to try for myself. You can also buy with 2 bottles of FTC Decarbonizer and comes with the Ezypor dispenser which makes getting the right dose of FTC easy.

Engine Decarbonizer Pack - Cost Effective Maintenance

I do use FTC myself - more as a preventative cleaner, but can’t say I have noticed any change and do still get the occasional sticky turbo actuator fault, so will be trying a two stroke oil after a go with Cleanpower.