TeddFoxx

So spent the day under the hood of my 91 5.0.

Changed the radiator out along with the thermostat and hoses.

Also took the throttle body off to clean it and put on a new IAC and TPS.

Replaced all the spark plugs, wires and new cap and rotor.

New pcv valve as well

While I was in there I took apart the air box to replace the filter and found the thing full of old oil and the crank case filter looked like it had been in there since 91. So wiped that all up and cleaned it up. Changed the filter.

So upon spark plug removal they all looked good except number 8. I'm attaching a picture to see what you guys think. But I think I've got a bad injector. I'll be testing them as soon as I can.

So on my test drive, noticed the truck not driving the same. The Rpms are way up and it wouldn't shift into OD. I'm thinking the TPS sensor is not set in there right and putting out in correct voltages....will also be testing as soon as I can.

Just wanted to get you guys thoughts on the situation at hand.

Thanks!

qdeezie

This all sounds PCV related. What brand is the new PCV? If it's not Motorcraft, there's your problem.

Also you'll need to set your TPS. It's a must do.

But the brand of PCV truly matters.

qdeezie

After you install your new Motorcraft PCV, (assuming your new one isn't), you'll need to clean the tube that goes to the air box and install a new breather filter in the air box.

In thinking about it more, before anything else, do the Motorcraft PCV first and assess your truck afterwards.

TeddFoxx

Yes the new PCV valve is motorcraft.

I installed a new crank case filter and air filter in the airbox.

I have not metered the TPS as of yet.

fltdriver

When you installed the TPS, you put it in then rotated until the mounting holes lined up and it was facing the same direction as the original? The inserting then rotating of the TPS is critical in it's ability to properly function.

TeddFoxx

My friend did that part but we did read about it first.

I just metered the TPS. Here are my results. KOEO

Orange to black wire- 5.04V

Green to black- 1.06v closed and 4.56v WOT

Green to black resistance unplugged- .964kOhms closed and 3.862KOhms WOT

I just have a craftsman digital meter. My pockets aren't deep enough for a fluke

Thoughts?

fltdriver

I believe closed should be .9-.97 when plugged in.

Go back through and check to make sure that you have all connectors plugged in, can't tell you how many times something gets forgotten and causes people headaches.

Chris_1

iTrader: (1)

Idle does sound like possibly TPS. That spark plug is fouled. Could be a bad plug, bad wire, or leaking valve seal.
Or as dqueezie said it could be PCV related. If the PCV is working properly, oil shouldn't migrate up the intake hose to the airbox. It's actually supposed to suck air from there. Maybe check all the PCV lines etc and the port at the intake to make sure there's no blockage. Inoperable PCV system causes pressure to build in the crankcase, lifter galley and rocker areas and it ends up pushing it's way out somewhere.

Aktech

Cylinder 7 and 8 are subject to cross fire with the cheaper caps and wires so make sure the wires are ran the preferred way. You can ohm test the wires also.

TeddFoxx

I'm thinking the injector on 8 is done. It was the only plug that looked like that. Also when pulling the wire with the engine running we had no change. Cap, and wires are motorcraft. Rotor was a bwd. New motorcraft coil, iac, and TPS.