So I pulled the smog pump and associated gear off of my 91 d150 tbi and lo and behold the engine refused to start up. It seems to be fueling correctly at start up but it has a weak orange spark. I checked for broken connections/wires around the distributor first with no luck. Then I replaced the coil (at 14.00 why not i figured) and the Hall effect pickup in the distributor (the test given in Haynes did not seem to work and at 25.00 again why not) and still no start. I've looked for bad grounds, ect, ect and am at my wits end to the cause of this because the truck ran fine up to the point i pulled the smog pump. Any suggestions or starting points would be appreciated.

 

Have you figured it out yet?

I have a '91 D150 V6. I yanked my smog pump and related junk before I rebuilt the motor about a year ago. I plugged the holes in the exhaust manifolds and removed the back pipe and cut the pipe from the cat and sealed it. I left the O2 sensor in the downpipe and it is still plugged into the harness.

In my situation, I felt like the gas was not going to the throttle body (see my thread) but I definately want to know if the smog delete could be the culprit.