I have been having some cold start issues so decided to have a scanner put on the old girl to see what's going on. At 65 degrees the other day, still had a hard time starting after sitting for 2 days.

Glow plug test shows no faults with the Snap-on scanner. Previously, I manually ohmed out the glow plugs and they test good. I've been thru this system 3 times, so the basic "your glow plugs aren't working" response doesn't apply here.

The buzz test shows that I have a weak solenoid on cylinder #5. But the contribution test shows this cylinder to be putting out the power needed.

The contribution test does show that cylinder #3 is not putting out the power though.

I have taken off the ipr and cleaned and inspected. The icp isn't leaking oil and doesn't help starting if unplugged.

I plan on replacing the #3 injector due to no power output, but seeing the injector on #5 is putting out, would a solenoid be the fix for the weak buzz test?

The ole girl has 270,000 miles on her and I know the best case scenario would be to replace all the injectors. Sorry to say that this isn't an option right now, but I do need to keep her running right. These 2 issues were the only problems seen with the Snap-on scanner. IHOP pressure was good and such.

Only problem was that I had to drive 150 miles towing over 3000 lbs to do this test. The test was not when the problems exist, when it's cold.

Thanks for any and all replies or suggestions.

 

if short on cash then i would do only those two injectors that you said was messing up...scott

 

With the #5 cylinder, It produced a weak buzz test, but the contribution test showed that cylinder putting out the recommended power.

I'm thinking just a new solenoid instead of an entire injector.
What's your thoughts on this?

 

you could do that...dont know how good you are at taking apart injectors..but take your time and take lots of pics....scott

 

All superduty 7.3 engines have a problem with the under valve cover harness connectors backing out of valve cover gasket due to heated oil causing lock tab to sag. Glow plugs don't get enough amps and injectors will malfunction as well. Remove your valve covers and push the connectors in and repeat buzz test to see if injectors clean up. Also glow plug relay should be replaced every year due to contacts getting carbon buildup on contact surfaces. Remember, glow plugs pull 180-200 amps, so when relay disconnects, a massive arc occurs. Ford sells a plastic tab to shim up locktab on harness connector to prevent backing out. Give it a try 1st before replacing any injectors.