96 PSD....Idles rough, won't rev, no power HELP!!!

[Thefarmboy21]

My buddy just aquired a 96 PSD and its running rough to say the least... It idles roughy, it revs slow and obviously doesn't have any power. BUT we have isolated a couple of the problems. The first was that the exhaust was about 75% stopped up from mud daubers nests. After we got that cleared out it sounds better and was more obvious what the problem may be. Next we started unplugging/replugging the 4 valve cover plugs until we unplugged the one that made no change....from drivers side: ran exactly the same whether it was plugged in or not. The plug doesn't look burnt, SO what might be the problem? Bad gasket? Bad relay somewhere? He did say that it blew a main fuse, so I assume that somwhere between those two injectors and that fuse, that something is burnt up or touching. Opinions....do we start by tracing the harness toward the fuse, or from the valve cover to the injectors??? Thanks!

 

[OLDBULL8]

The harness on the drives side to valve cover can be chaffed shorting out, this is a common problem. The UVCH connector under the valve cover can become partially disconnected. The EPB sensor tube to exhaust could be plugged or rusted out, sensor is on front of engine, sensor miss labled EPR in pic. The MAP sensor is very important for running smooth, that is after the filter and before turbo. Pics may not be for the 96 but should be close for sensor location. Easy to pull the drivers side valve cover, Pass side is a *****. Hope this helps.

 

[trackspeeder]

If you can get your mits on a scanner, it will help you isolate your issues.

You could have a bad plug or gasket .
The IDM could be going screwy. The PCM fuse is the same for the fuel heater. It's running, so rule that out.

Take a look at the IDM. Check it for water. 94.5- 97 are know for water logged IDM's.

 

[79jasper]

I would go ahead and just pull the valve cover.
Wire could be unplugged from a injector. Couple that with a weak injector at the same plug, could make it seem like there was no change in idle.

Oldbull, I thought the map sensor was on the firewall with a hose running to the passenger side intake runner??
(At least on obs trucks)

 

[lindstromjd]

Change your oil while you're at it, too. You literally can't do any sort of trouble-shooting on a Powerstroke unless you have good, clean oil at the proper level. Ask me why I know this... I chased a problem for a few hours until I decided to check my oil with 5,000 miles on it, and the level was low and oil quality was shot. Changed the oil, and problem went away.

 

[Thefarmboy21]

Ok, we'll do an oil change, check the IDM for moisture and pull the valve cover. We can MAYBE get a scanner, BUT will it shake any codes if the check engine light isn't on?

 

[OLDBULL8]

As far as a scanner goes, you have to have one that will read Ford codes. I don't think an OBDll will read anything.

Next we started unplugging/replugging the 4 valve cover plugs until we unplugged the one that made no change....from drivers side: ran exactly the same whether it was plugged in or not. The plug doesn't look burnt,

Since you did that, that's the place I would start first. You can change over to the single connector gasket if need be, but you will have too splice in the single connector on the harness.

You can run the engine with the VC off, see if oil spits out from each injector. Also you can inspect each connector for loose, burnt connection.

 

[Thefarmboy21]

So if oil spits out the injectors are good and/or it means they are getting electricity???

My friend has a diesel scanner and is the best diesel mechanic around....he just stays piled up, so we are trying to check all the simple things first.

 

[trackspeeder]

So if oil spits out the injectors are good and/or it means they are getting electricity???

It means the injectors are working.

 

[BigRigTech]

A buzz test would be nice, it would tell you if the injectors are trying to work or not. Usually you can pick out a bad injector by a weak sound compared to the rest.