Ok, so I just rebuilt my 1990 F250 351W EFI and timed it 10* with the spout plug removed all appears to be correct. I put the spout connector back in, bring it up to 2500RPM and check the timing and it doesn't move. I tried going to 3000, then 3500RPM, same result. It is not advancing at all. It does throw a CEL when it is supposed to be advancing ( full throttle and RPM over 2500). Then when you let off the throttle the CEL goes off.

I haven't tried to pull any trouble codes yet... I am not sure if I can if the light is not on. I have heard mixed opinions on OBDI on whether the light has to be on and whether it stores the codes or not and whether the truck has to be running in order to get them...

The engine runs great driving around except it doesn't have a lot of power on the top end (not that I expect it since it's not advancing...)

What could be keeping it from advancing?
What IS the procedure for pulling trouble codes on OBDI?
Can anyone think of what codes I might see given what I described?

Thanks in advance for your help

 

It sounds like the SPOUT wire is broken somewhere other than the SPOUT connector, or the SPOUT connector is defective. You can test the jumper for continuity, then test for continuity between the SPOUT connector and the computer. If it is broken it's just a matter of tracking down where the break is in the harness.

See this link for how to pull codes, just leave out the test light/analog voltmeter they picture and watch the check engine light: EEC IV Self Test hookup

There's a code for a problem with the SPOUT connector, so keep your eyes open for that one.

 

Thanks for the quick response. I will check that tonight and we will see what happens...

 

Was the advance working before the rebuild and did you change anything in or on the wiring harness, the computer, or distributor?

 

I did not change anything electrical. Harness, computer and distributor are from before the rebuild. I don't know for sure if it was or not but I don't remeber a CEL at all so it leads me to believe that it was but as to what degree or anything like that I have no idea.

 

The pins in the spout plug sometimes break off so check it with a DMM.. it should be a dead short or 0 ohms.

 

May have my issue then. I checked it with the DMM and it read 10 Ohms.