I have a '97 PowerStroke 7.3 liter with 9 codes on it, the major ones are cam pos. sensor, crank sensor, and tps. I think one might have also been mass airflow also, but I'm not sure, I had my friend use his computer scanner 'cause mine blows and I wrote them down but lost the paper. If anyone could help me even locate and tell me how I can tell if they're bad, I would greatly appreciate it. I love my truck and hate to see it running this way. Some symptoms are bad transmission shifts (hard/rough, NO SLIPPAGE though), and when it starts it sounds like it's choking, like a person with a bad cough. Like, "UgagaUgagaUgagaUgaga." Oh, yeah, the O/D lights blinking, that *****er.

 

Welcome to FTE. What was your buddy using to pull the codes? The Cam sensor and Crank sensor are the same thing. It does take a special reader to get the codes from a 7.3. Even the free scans at the parts stores are pretty much worthless.

If you've got a CPS issue, stop by Ford and spend the $25 for a new one from them. Don't waste your money on the ones from the parts stores. For the other issues and O/D light, I'd think the VSS would be suspect. It's usually less than $20 at Napa or your local parts store.

CPS change instructions are here http://www.guzzle7pt3.com/cps.php
The VSS is the sensor on top of the rear diff. Wipe the dirt from around it, remove one bolt, unplug wire, and pull the sensor.

 

I got the CPS recalled actually and I'm not sure what kind of computer scanner my friend used, but I did try my one from autozone and it said it passed. It definitely shouldn't have. Those things are crap, and my buddy's a local mechanic. Also, I have checked the VSS also, it didn't seem to be broken, but I'll check it again, and I thought the speedometer usually goes bad when they do and mine seems to work fine, so I think that might be ruled out.

 

You're right about the autozone scans. You're also right about the speedo usually acting up with a VSS issue, but it's hard to say for sure when you start dealing with sensors and computer stuff.

There's also a couple of sensors on the E4OD, but something should be throwing a code if it's a sensor issue. Sometimes a dirty VSS can cause strange things.

A TPS code can also cause the symptoms you described, but it would probably be helpful if you could post all the codes you're buddy found so we'd have a better idea of which way to go next.

 

Welcome to FTE

Sounds like the scanner used to pull those codes is not compatible with a diesel. They do not have a Crank Position Sensor (CKP) or a Mass Air Flow (MAF) sensor. Maybe you have them confused with the CPS or MAP sensor (Manifold Absolute Pressure).

The VSS is actually a Rear Antilock Brake Sensor (RABS). It sends a signal to both the ABS module and the PSOM (Programmable Speedometer Odometer Module).
The speedo might still work when the signal gets fouled but will cause the OD light to flash. The hard shifts are caused by the trans protecting itself. The hydraulic pressures are increased to stop clutch slippage.
Do what F350 says, remove it from the top of the rear diff and clean off the crud.......re-install, it's magnetic and will collect the fine particles suspended in the diff fluid. The particles will foul the signal.

The sound you described may be the EBPV hanging (Exhaust Back Pressure Valve. You can unplug it permanently.....not really needed. It's used to speed up engine warm up times during cold weather. Look here:
https://www.ford-trucks.com/forums/8...e-out-why.html

Post the codes and you'll get better guesses

 

They all start with the PO or P0 and the numbers are:
*122 TPS
*123 TPS
198 Oil Temp.
221
*344 Cam. Pos. Sensor (Circuit Intermittent)
470 Exhaust Press.
472 Exhaust Press.
*603 Internal Control KAM
708

I wrote down everything I have on the paper, my buddy told me the starred ones are the most important, let me know what you guys think. I also just installed a brand new starter and relay and the truck won't turn over without me like jumping the relay, I'm thinking this is a safety thing in the computer so I don't damage it anymore. Just another damn symptom.

 

Here's my best guess at the one that's causing your trouble:
P0708 Transmission Range Sensor (TR) Circuit High Input,
This will cause the engine to run very bad and the no-crank condition you have......Neutral Safety switch.
It's on the driver side of the trans. Shift cable is hooked to it.
It may just need to be re-adjusted vs. replacing it.

______________________
You may have old codes stored because you said the CPS was replaced and you still have a CPS code (P0344).
Now that you have them written down you need to reset the PCM and see which ones return.
I would disconnect the batteries for the reset vs. just erasing them with the scanner.
Come back here and post the ones that return.

These are the ones that will cause it to run poorly:
P0198 Engine Oil Temp sensor out of range high (EOT).
These are all TPS related: It will cause many problems and is very expensive to replace.
It's on the Accelerator pedal in the cab. It can be removed and cleaned if necessary.
P0122
P0123
P0221

BTW:
P0603 is not critical. It is common for trucks with a chip or if the batteries have been recently disconnected.
P0470 & P0472 EBP sensor may not be critical it controls the EBPV. When it fails the PCM ignores it and just doesn't allow the EBPV to operate.

 

THANK YOU! I think that is it, I was messing around with it and it started perfect the o/d light went off, but it won't shift unless I do it manually and only to 2nd. I will replace it probably today, just in case the old one does it again. I'll post again if it starts again.

 

Okay, I need some help again. Big surprise, there. The check engine light and o/d are not on at the moment and I'm sure both lights are good, but it is still not shifting right, I re-adjusted the neutral safety switch and that seems to have fixed the majority of my problems, but when I step on the fuel pedal it revs up to 3,000+ without shifting. I can get it to shift if I let off the gas a little bit, but it will not shift like it should. Any ideas?

 

I'd start by checking the transmission fluid level. A buddy of mine had that problem 6 quarts later it started shifting normal again. LOL

 

Have you checked the electrical connector on the TRS. It may have corroded/bent/broken terminals or water intrusion.
If it looks ok then you need a new TRS IMO....they do wear out.

 

I was going to replace the sensor part, but I can even get the thing off, the bolt is pretty rusted, I have to go buy some PB Blaster or WD40, cause I can't find the 3 bottles we have of it. The connector piece also seems okay, but the clip that probably holds it nice and tight on there is broken, I'm guessing that's bad, maybe not. And I'm pretty sure the transmission fluid is good, but I will check it.

 

I was also thinking of the TPS, just wondering what you'd think of that, its got the codes for it and all the symptoms I found for that going bad match. You think it's worth it to fix for the 40 bucks?

 

Yep, the busted clip may have let water in it an shorted out the TRS.
The trans fluid couldn't have caused your no start condition but it can't hurt to check.

The replacement TPS is very expensive +/- $300.
The $40 piece is after-market.... probably won't work. Some do some won't. They usually cause more trouble than they fix.
You can try and clean it as best you can....clean & adjust the IVS too while you're at it. (Idle Validation Switch)

My bet is still with the TRS.
Keep us posted

 

You seem to know what you're talking about, so I have to get that sensor off and replace it, sounds like, and I guess a whole new connector piece, also. Correct.