Set timing on the 7.3 IDI when injection pump housing removed [Archive] -

: Set timing on the 7.3 IDI when injection pump housing removed

03-30-2008, 02:25 PM
This is what worked on my 1990 Ford F350 dually w/ a 7.3 Navistar rebuilt engine when I stupidly removed the injector pump housing and pump without marking the gear location first:damnit

I read a lot of Threads on this and other Forums.:thanks:

What was most helpful in general was:


I suggest reading thru this and looking at the pictures carefully to start with:popcorn:

Then, consider the following which worked for me ......

First, if you have never timed a diesel engine before you will need two people. Assuming your engine was running fine BEFORE you removed the pump and housing, the following should bring your timing back to where it was ......

Determine the correct firing order for your engine.

Pull the injector lines from the pump and the injectors and set asides carefully.

Remove all the glow plugs and set aside carefully.

Have someone familiar with checking compression on the top of the engine.

Using a 1/2" drive ratchet and a deep 15/16" socket, turn CLOCKWISE on the crank below

Try and locate TDC of the correct cylinder w/ the timing marks lined up by feeling for the compression stroke above at the glow plug hole of the correct cylinder (it my case it was #1). There should be a push of air out of the glow plug hole as you approach TDC.

Next, check you have the CORRECT cylinder at TDC w/ the timing marks lined up below by checking the firing order of the remaining cylinders in the same manner at the glow plug openings (checking for the rush of air). You are trying to confirm that you had the timing marks lined up when the correct cylinder was at TDC.

This was the ONLY way I got my engine running. We tried mirrors, a dental pick, a lighted scope, thin reflective metal, various lights and NEVER did find the mark.

Once you are sure you are lined up on your timing marks w/ the correct cylinder at TDC, you are ready to install the injector pump housing:Thumbup:

My count from the 'Y' mark on the injector pump gear was 17 teeth up from each side until the teeth disappeared into the housing.

I carefully counted up the same number of teeth from this mark and made a mark directly in line w/ the injector pump dowel pin to the housing.

The dowel pin was in the four o'clock position.

I then 'dry fit' the housing to the block several times before I
got the 'feel' correct I was comfortable with.

Then I applied RTV Super Blue and installed the housing, checking that
the dowel pin matched my mark on the housing.

I installed the glow plugs first and then the injector lines.
(This is a good time to replace your glow plugs when the
access is relatively easy).:Thumbup:

Make sure you prime the filter and pump before starting.

Make sure you have fully charged batteries.

Also, do not crank for more than 30 seconds at a time or you
may burn up your starter.