Injection pump rebuild

[mauro12]

Hi guys , in a few weeks I’m going to send my injection pump to have it rebuilt and finally solve the rich running condition but I wanted to ask you something .
Once you set the pump and the engine at the correct timing , you connect all wires and cables , is there any procedure to follow to adjust the mixture ? I guess you have to set the perfect idle spot and that’s all, am I right ? You have to set again the ignition timing maybe ?
No other procedures to make ?

[Pawel66]

Mauro, with my limited experience I managed to tune the car this way:
1. Mixture adjustment at idle (just to have my car with proper idle, not stalling, etc.)
2. Mixture adjustment across rpm range
3. Mixture adjustment at idle again (as the point 2 adjustment changed the point 1 adjustment as well)
4. Warm up cycle

For point 1 and 3 I used:
Linkage Tour from our Technical Manual. As mixture measurement I used split linkage test initially, then I bought Gunson gas meter.

For point 2 adjustment I used:
General info on FIP adjustments that we have in Technical Manual and on the Forum
- location and operation of main adjuster
- location and function of Barometric compensator shims
- made strategic decision if to use BC shims for adjustment or the main adjuster - I chose the main adjuster, fitted 2mm of shims and did not touch shims again
- as measurement I used the colour of the spark plugs in essence (Gunson gasmeter would not work well, these values should be measured under load)

For point 4: just the oval shims adjustment and Gunson and Members advise.

In the meantime I spotted issue of my FIP delivering fuel in a wrong way, so I had it calibrated in the FIP shop.

If I were you, I would check if I have a shop who could try to tune my injection system on the car before I would send the FIP for rebuild. If there is no such shop, I would see if I can try to tune it myself or with a a help of a mechanic and this forum.

Yes, for tuning the car you have to have ignition timing done, valve clearances done all the FIP components working (BC, WRD) as well as CSV working/not leaking. Otherwise any tuning attempts do not make sense.

Today we have an excellent tool under Fuel Injection section the Fuel Injection system simulator that is very helpful and has all the info in one place.

[Cees Klumper]

To your last question Mauro, the ignition timing is 'autonomous' meaning whatever is done to the injection pump settings/condition, the ignition timing is not affected. It should be set properly before any adjustments to the fuel/air, and should not need any touching once set properly.

[mauro12]

Thank you guys,
Tuning the injection pump in place didn’t bring any good results . The mixture is very rich and I have to replace the spark plugs too often because they get too black and covered by soot.
I decided to send to oldtimer Technick, Hans fritzsche in Germany and hopefully he will solve this problem .
I’ve checked everything I could during these years , including valve adjustment, csv , linkages and everything is almost perfect . Such a huge rich mixture cannot depend on a sloppy linkage or from a shim under the BC.
I guess some internal seals of the pump just failed and gas is flowing and mixing with the engine oil .

[wwheeler]

As it has been said, these pumps wear to the rich side. At some point, they are beyond DIY tweaking and a full rebuild is the only way to bring them back into specs.

[mauro12]

Guys, in general when you get back your new and overhauled injection pump from the rebuilder , are there any procedure to follow to set the idle mixture ? Do I have to expect some stalls in the engine mixture or some general problems? Just put the pump back on the correct timing and everything should be fine ?

[Pawel66]

You will have to properly time it. Timing instructions are in the Tech Manual.

[wwheeler]

It must be installed with the correct timing as Pawell said. You will also have to bleed the injectors and so forth. You generally will have to adjust the idle mix. You may also have to adjust the full range but only very slightly. You need to check that the air shuts off at the WRD at the proper temperature. You may also have to add or remove oval shims on the WRD housing to adjust the cold running mixture. Other than that, it should be set correctly. Again, these should only be very minor tweaks.

You will want to double check the throttle linkage set up as the lever on the IP may have been reset during the rebuild. 

[Shvegel]

Waalace,
I am trying to think why they would richen over time?  Mine was rich before I rebuilt it as well but in retrospect There really isn't anything internal to the pump that would cause this except maybe the springs in the governor.  I wonder if we are missing something like the warm up thermostat or barometric compensator somehow drifting off spec? It is a displacement pump so the pump section itself isn't really going to drift toward more fuel over time.  In fact it "should" drift to less fuel over time if there is any leakage or wear on the cam and followers.

What sucks about having a pump rebuilt is it is basically a clean, change gaskets and adjust barring any plunger / barrel (Piston / cylinder) wear.  Both styles of delivery valve (outlet check) are not available as of a few months ago and very few of the other hard parts are an issue.

I have a spare 24Y pump for my car and had started building a test stand to set my pump up on after I rebuilt it but then decided to have Hans at H and R set it up.  Maybe when I get time I will finish my stand, dig out the test sheet and see what I can figure out.

[su8pack1]

A few years ago when I got mine back from a complete rebuild, ($2,500) and replacing all injectors, it was just plug and play. Just follow the timing instructions as mentioned above and you should be fine. I was replacing the plugs every few hundred miles and soot out the exhaust. I tried everything else before biting the bullet and sending off the pump for a rebuild. Running like new ever since.

[Pawel66]

Waalace,
I am trying to think why they would richen over time?  Mine was rich before I rebuilt it as well but in retrospect There really isn't anything internal to the pump that would cause this except maybe the springs in the governor.  I wonder if we are missing something like the warm up thermostat or barometric compensator somehow drifting off spec? It is a displacement pump so the pump section itself isn't really going to drift toward more fuel over time.  In fact it "should" drift to less fuel over time if there is any leakage or wear on the cam and followers.

What sucks about having a pump rebuilt is it is basically a clean, change gaskets and adjust barring any plunger / barrel (Piston / cylinder) wear.  Both styles of delivery valve (outlet check) are not available as of a few months ago and very few of the other hard parts are an issue.

I have a spare 24Y pump for my car and had started building a test stand to set my pump up on after I rebuilt it but then decided to have Hans at H and R set it up.  Maybe when I get time I will finish my stand, dig out the test sheet and see what I can figure out.

What about the 3D cam wear?

[wwheeler]

Not sure why they go rich, but I remember it was discussed years ago. I think people much more knowledgeable and experienced than I commented on that. I just remember that it is a good thing they go rich because going severely lean is bad news for an engine. It does also seem that the majority of people who get their pumps rebuilt do so because of an excessively rich condition that seems unsolvable. 

[Shvegel]

Pawel,
I have had maybe 6 apart and never saw much wear other than a few spots where the later cars with fuel cut off had worn due to the stylus being run into the cam when the fuel cut off solenoid was energized.  My pump had more wear on the stylus than the cam so I replaced it.

 The more I think about it I bet the springs in the Governor get weak.  It makes the most sense.

[Pawel66]

Ok, thank you!