Well I tried to take advantage of the nice day here to run some errands but was stopped by a stupid check engine light. About 4 months ago I got codes 173 and 311. Replaced a bad HEGO with a new motorcraft one and cleared codes. All was good until today. Ran diagnostics and got 172:HEGO indicates always running lean. Along with that I got 211:PIP circuit failure, and 311 again:thermactor air system inoperative. 173 before was a running rich condition. Now it's lean. Checked pressure at rail and at idle I read 38psi. Any ideas?

 

I guess my real question is what does PIP circuit failure mean and how is it fixed, and what can cause a lean condition?

 

http://i1214.photobucket.com/albums/...11pipstall.jpg


That's from my personal archives...lol Should help somewhat..


If you need anymore diagrams...Lemme know..

 

Sorry if I seem dumb here but what exactly is the diagram saying to do?

 

From what I gathered from it....It's saying to splice a wire and use some sort of foil around it...

But don't go clipping wires! Till you KNOW what's going on...

 

Ok I will see if I can find any more info...

 

Another note I want to add is the 172 was KOEO and the 211,311 were KOER.

 

Fuel Injection Technical Library

 

Thanks for the last link. I'm getting the 172 in KOEO in the cm. Any ideas on why that is there? And I have read a pip circuit issue can cause a lean condition?

 

Evan, in what order are these codes appearing? Which are KOEO, which are CM, and which are KOER?

Ford lists them with the most-critical first; deal with that and ignore everything else; clear codes and begin testing again.

THIS SITE tells what the PIP is. A sudden failure of that component will leave you dead on the side of the road, the pickup inside your distributor may be on its way out.

They can be tested with an ohm meter but it generally requires distributor removal unless you've got special connectors for testing purposes. Do a Google on testing your PIP and see whatchya find.

BTW I wouldn't go hacking the harness and applying tin foil to things based only on a random picture you see on an Internet forum that doesn't also have a complete explanation as to what is being depicted and why and in which situations it might useful to do.

 

Flashes/codes go as following:
KOEO: 111, 111, delay, 172
KOER: 211, 311

I wasn't planning on messing with anything till I knew what the issue is.

 

Ok so I went out to check the PIP voltage to the TFI. The website guide I found said its a blue/white wire but my TFI doesn't have a blue wire running to it. Which wire is it? Its a fender mounted unit by the way.

 

OK, here is my line of thinking....

KOEO passes just fine. All it's doing is ensuring it can talk to all the sensors and they're all giving values within specifications.

The 172 is from memory, it means the computer detected a situation reported by an O2 sensor within the past 80 (I think) run cycles.

You say you've replaced an O2 sensor, do you have multiples?



OK, next thing....

The engine-running test is reporting problems with the distributor pickup module. That concerns me.

It's more complicated than this (read that fueulinjection page for a better description of how it all works) but the distributor pickup instructs the module to fire the coil at the right times. If the PIP is initiating coil firing at the wrong times - or not at all - then I could understand how this could cause lean/rich conditions reported by an O2 sensor.

Assuming you have only one O2 sensor and it is presumed to be operating correctly and all your wiring & electrical connections are in good shape (no butt connectors or wire nuts or anything), then I'd be looking at the same wiring at the distributor (which contains the PIP sensor) and check for broken or frayed insulation, etc.

Then, the less expensive route involves some diagnostic work on that sensor in there, they can be tested with an ohm meter (google around to figure out what your specs should be). But doing this can be a PITA unless you have special connectors & wiring.

If the test shows the PIP to be faulty, replacing it is even more of a PITA as it requires a gear puller to remove the armature.

The easier & faster route is far more expensive - replace the distributor, probably with the ignition module at the same time.

But, before you do any of that, do some research and see if there have been any TSBs issued for your truck related to the ignition components. FTE has a TSB lookup thing that's marginally useful but it's better than nothing and you might find something with it.

You might also ping that steve83 guy who's username is written on that picture, but I don't know if he's a user here on FTE or someplace else. If you can get a hold of him, ask him some questions as to what that image is referring to.

The 311 is referring to the smog pump/air injection system, I'll bet somebody disabled it (and maybe other emissions-related things) thinking they're making things better and will get more power out of the engine.

That's the route I'd probably be taking if it were my truck....

 

I believe the PIP signal has always been Pin #1 on the module but don't take my word for it.

I think Chilton/Haynes books have some halfway-decent diagnostic steps in them.

 

My truck only has one O2 sensor. I checked all the wiring for it before replacing it with a new Motorcraft one about 1000mi ago.
I would rather diagnose the issue as well. Mainly because with my picky ways with this truck, I would only replace it with a Motorcraft one and I dont have $300.
And as for the 311, we have had the truck since '98 so I dont think it has been messed with...

This is the page on testing that I was referencing:
SBFTech.com TFI Module/Hall Sensor Testing Procedure