I've finally crossed out the fuel system as the culprit for the issue at large. After resealing the fuel bowl, my 97 F350 OBS STILL starts rough. It takes a longer time to turn over, and when it does, it sounds like it's misfiring really bad at first, then brings itself to a normal purr. Starter is a year old, and checked out good, fuel system is clean all the way to the heads. What else am I looking for?

 

Bad glow plugs. Ohm them out to find the bad ones. Measure voltage from the GP side of the regulator to ensure its good also.

 

Is there a voltage regulator for the glow plugs? I cant get more than a week or two before I am down a glow plug or two on my 95

 

If you're burning out gp's in a couple weeks then I'd say your GPR is staying on

 

Found them. 2 and 6 were burned out. Replaced all 8 with a set of motorcrafts, and she's running like new now. I can finally move on to more "fun" projects, like installing this coolant filter...

 

Or he has Autolites in it.

 

The dash GP light goes out and the alt gauge goes up at the same time so I am pretty sure that GP are not staying on. Have used both Ford and aftermarket glow plugs with the same result.

 

jump the GPR for 30 seconds and then start it, if it starts easier then you may have PCM issue

if using block heater and start nice then there is a issue with controlling GPR

 

Crank it then let the gp's turn off and check the GPR with a meter to see if voltage is still passing through

 

Both of these are signs of a bad GPR. Not a pcm issue

 

Plugging in the block heater for a few hours is how I start it now. After a few hours it starts right up and is good for the day. Truck is not a daily driver but still it would be nice to fix this problem.

Thanks for the help, I will check the GPR

 

Glow plug relay, there's an upgrade made by Stancor? That supposly is better, maybe someone with part # chimes in.

 

Thanks for that. I googled and found the Stancor relay. 586-902 part # I believe. Should be better as it is a much larger relay. Ordering that upgrade today.