My 4.9 EFI is driving me batty. It starts up and runs (a bit doggy but runs) and usually if I am just going to one place and then back home it is fine. However if I have to make a second stop, when I come out and try to start it, it fires, but as if it is getting way to much fuel. It stumbles and stalls and then when I attempt to re-start it, acts like it is completely flooded. I have put it in two auto shops for this problem but neither was able to fix the problem.

Lately, it still starts right up the first time but acts flooded and won't start everywhere I go. I came out of the parts store one day and it did that and they put the code reader on it and said it was the Crank Shaft Positioning Sensor. But the other parts guy said that can't be what it is. That when they go, they just go. No intermittent stuff.

Has anyone else had one behave this way before?

 

You know they say the same thing about the older IGN boxes, they just go!
Well I have seen on my own cars the box go bad when driving down the road, let it cool off and it will start again and run till it gets hot again.


I would say if the code reader said it was a bad crank sensor I would start there.
As above I can see it heating up/heat soak when sitting and causing issues.


BTW I was going to ask what does the computer codes say?
Dave ----

 

Do the OBD-II versions have a crank position sensor? I may be wrong, but I think the "crank position sensor" is the pickup in the distributor, i.e. the PIP.

They can go bad intermittently and usually symptoms occur when it's warm, i.e. you made a second stop and the engine had a chance to heatsoak a bit. The computer uses the PIP signal for the initial spark timing when you start it. May if doesn't get the signal & doesn't fire the sparkplugs but still fires the injectors it gets flooded?

Can you post the code?

FWIW I went through the trouble of buying a PIP and installing it but in hindsight I'd just spend the $70 on a new Spectra unit. It wasn't much cheaper to just replace the PIP and you need a press for the distributor gear.

Here's a link to a testing procedure to check your ignition system. I'd try to test it when the engine is hot to increase your chance of seeing an intermittent fault.

http://easyautodiagnostics.com/ford/...module-tests-1

Edit: I fixed the link.

 

Thanks for the reply

I was just going by what the parts store guy said when he checked it in their parking lot. He didn't give me the actual code, just looked it up and said it was the crank position sensor. I can get it read again though and get the actual code.

by "a new Spectra unit" do you mean the whole distributor?

 

Yes, I meant a new distributor.

Is your truck OBD-2? I've poked around the internet and it seems you might have a real crankshaft position sensor.

If I were you I'd get the codes run again and see what they are, and I'd try to confirm if you have a crankshaft position sensor. You should be able to see it on the front of your engine if it's there.

 

I'm not sure if it is an OBD-2 or not. I can find out though. I had the engine completely replaced with a crate motor about 40,000 miles ago. I've been dealing with this problem for about that last 20,000 of that too.
I will have the codes re-ran and see if the parts guy can confirm it does actually have a crankshaft position sensor. I'd have no idea what i was looking for.

This stuff is exactly the reason that my other vehicle runs a VW 1600 air cooled engine, without so much as a single sensor or vacuum line on it. I can keep that running smoothly myself.

 

Here's a good thread for you: https://www.ford-trucks.com/forums/1...rk-advice.html

Seems as though the crank position sensor doesn't affect how the truck runs. The diagnosis on the thread I linked was PIP.

Check it out & see if it makes sense for your problem.

 

From what I can make of it, it seems like it could be the PIP. I vaguely recall once upon a time having problems with a pick up coil in the distributor. Once the engine heated up, it would start breaking down it's output and causing starting as well as running problems. I had it replaced and things were better for a time. I think it was this truck that happened with.
At any rate, i took your advice and just ordered a new RichPorter FD08 (a.k.a. Spectra FD08) distributor a few minutes ago. It will be here by the 26th so I guess I'll see if that does any good. I'll post back to let you know.
Thanks again for the input, and the links.

 

Nice, I hope it works for you.

I replaced my PIP sensor because I kept getting a 'SPOUT open' code. New PIP and didn't get the code anymore. (I knew the code was wrong because I verified SPOUT continuity.)

 

Well, I installed the new distributor this evening. In about 10 minutes. (literally) No pulling the #1 spark plug to feel for the compression stroke and then getting it up on Top Dead Center, or any of that.

I just unscrewed the cap pulled it up out of the way, stuck a piece of masking tape on some rigid cable housing that ran past the distributor and marked where the rotor was pointing on the tape with a sharpie pen.

Then I unplugged the electrical plug, unbolted the retainer lock down bolt, and pulled the distributor right up and out of the engine.

Paying attention to where the rotor pointed once the gear was free, I just turned the new distributor's rotor to the same position and slid the new distributor right down into the engine block.

Once all the way down, the rotor was pointing right at my mark on the tape. I then bolted the retainer clamp bolt back in, Plugged in the wiring harness. and slid the old cap and wires right back down onto the new distributor and tightened the screws.

Then I totally stunned and shocked myself, by turning the key to the start position. and standing there with my jaw dropped as it fired immediately and dropped into the smoothest sweetest idle I've heard out of it ever.

I tightened the retainer bolt down right there where the distributor had landed when i slid it in, closed the hood and took it around the block in amazement.

I don't know yet if it fixed the starting problem I started this post describing yet, but it sure made a difference in the way it runs when it is running. I guess I'll find out if it starts after stopping at a few places when I take it to run errands tomorrow.

I'll let you know what the verdict is if I ever get back.

 

That's awesome!

 

Well I drove it around and stopped at 5 different places, and it fired right back up every time I came out to leave.

It did stumble a little on the road but I think that's another issue all together. I also need to follow all of the vacuum lines out, i know it has a couple of leaks.

But so far so good as far as it starting back up. So thanks for all the info and the links. Hopefully it will continue starting.