Hello,

Recently bought a 1993 F150 5.0 with 255,000 miles for cheap. Truck ran, drove and stopped, but barely. I am fairly inexperienced with cars, and have never worked on an OBD1 vehicle, so please excuse anything that might be obvious.

Worked on it for a couple weeks, and have got it down to three codes. At this point, truck starts pretty easy, but sometimes stumbles and misses at idle. Truck will correct the miss by revving a bit after a few seconds.

117 - Low ECT voltage. I have replaced ECT, and since replaced it with the original I took out of the truck after finding that the replacement was garbage. Resistance on original ECT was within range at cold, haven't tested at operating temp yet. Will do so tomorrow. Voltage was about 2.4 cold while running, and about .8 at operating temp. Connector has been cleaned, and wiring harness has been examined as far as I can (runs underneath a bunch of stuff a few inches back) and, as far as I can tell, there are no damaged wires. Code can be cleared and will be back within a few miles of driving.

217 - overheat. I think this is due to the ECT reporting a low voltage. I have verified the temp sender to be working, and have checked engine temp at thermostat housing with temp gun. Never seen it above 200, and temp gauge never gets above the "o" in normal. These codes always appear together, never seen one without the other.

Also got a code for insufficient EGR movement - forget the exact code, hasn't thrown it in a couple days. Cleaned the connector on top of EGR, and replaced a broken vacuum line. Even still, threw the code again. When applying vacuum to the EGR, truck stumbles and runs rough, but I've never been able to get it to die. I know if it doesn't respond at all, that's indicative of a stuck valve - what about if I can't get it to die?

Also, truck has an E4OD. Threw an excessive torque converter slippage code, and was shifting pretty rough, so I decided to drop the pan, change the fluid and filter. Fluid was BLACK. Looked like old oil. No large chunks, but magnet in the pan was covered in shavings. I drained the TC as well. Replaced with MaxLife ATF. Truck shifts better now, but gets funky around 3rd. It will delay shifting into 3rd, and then hard shift. Not crazy hard, but overly firm when compared to other gears. Every now and then, it'll slip into 3rd rather than a hard shift. Other gears are fine, OD works fine, and downshifts from 4 to 3 are usually okay (sometimes funky, but nothing like the upshifts).

Any advice? High mileage truck that's seen some abuse, so I understand it wont be perfect. But I like to tinker, and would eventually like to be able to tow with this truck.

Thanks!

 

Code 217 for a 93 5.0?
No such varmint
Better double check your code check procedure
* I'd do the pinpoint tests in the PCED for the code 117 and measure the voltage from the ECT
.64V is a damn hot ECT, and will turn on the electric fans on vehicles equipped with them
At 80 degrees that ECT should be around 2.8 volts
At 180 degrees it will be around .8v
At 200 degrees it will be around .6

 

Thanks for reply.

Ill look into the codes again - possibly i miscounted the blinks, although i did count "217" both times it cycled through. I assume these are all 3 digit codes, right?

Not sure exactly what PCED is, Google didn't turn up much specific. But went through and measured resistance cold and at operating temp, verified KOEO voltage at harness, and measured voltage at cold and operating temp.







Ill grab codes again and check procedure, and will report back.

 

Well, looks like I probably counted the separator code single flash. The code is 172, not 117. Not sure how i missed the extra 2 flashes at the end the last time. Didn't throw any other codes after a 10 mile drive, although that could change.

Truck has some rotted places in exhaust, and I've yet to run new vacuum lines (I've fixed what I've seen broken, but old lines are so brittle I think new is the way to go), so possibility there's a vacuum leak somewhere. I read that can cause this code, or a bad o2 sensor.

 

With a code 172, running rich, I would look more into fuel injectors, O2 sensor or regulator. If it was a lean code, then I would chase vacuum leaks. It doesn’t hurt to replace the vacuum lines though! Buy a 20’ roll, extra never hurts!

 

Thanks!

Looking around, I'm seeing code 172 as a lean code. Computer might be compensating for it and actually running rich, but that's just what the internet says.

Regardless, I started today by replacing the vacuum canister and all the vacuum lines i could find under the hood. Vacuum canister had a hole rotted into it, replaced it with a universal plastic ball reservoir. Hooked up all the necessary things with new vacuum line, and capped off some of the smog vacuum lines that run behind the engine.

In the process, discovered that the canister purge valve was disconnected and left open. The T is broken off on one side - i imagine that when the solenoid opens, that would be a significant leak into the throttle body. For now, I left the solenoid plugged in, and capped off the line going to the throttle body. I also capped off the evap canister line that had been cut.

Drove it around, and somehow didn't notice a significant difference after doing all that. It did take significantly longer to throw the 172 code. But it still did.

Came home, and cleaned up the grounds beneath the kick panels in the cabin, and as many grounds as I could find in the engine bay. Only had time tonight to let it sit and idle, not for an actual drive, but it idled significantly smoother after cleaning the grounds up - before, it would miss, shake, and sputter so bad that it would have thrown a cup of water off the engine. Now, it isn't perfect, but its smooth enough to function as a dining room table in a pinch. Looking forward to a test drive tomorrow - maybe it was a simple ground issue.

If it throws a code again tomorrow, I'll start looking at injectors, pump and solenoid.

 

Even if it doesn’t fix the code, it’s running better and necessary! Progress is always good!

 

Got a cheap smoke machine today - using it to find vacuum leaks. Found two on my ranger, and found a total of three on this F150 - a small leak out of the EGR valve, a small leak from the bottom of the throttle body, around the TPS, and a huge leak from underneath the plenum. Turns out, some idjit pulled the PCV elbow out and didn't bother to plug the elbow or the port in the engine. Plugged the PCV back in, and no longer have an audible vacuum leak. No more intest exhaust smell in the cabin either, go figure. Going to order a motorcraft TPS and a TB gasket, and swap the TPS while I'm cleaning the TB and changing the gasket. Got a feeling old TPS may be bad, given some hesitation and shifting issues.

Have yet to dig into fuel system.

 

Worth is money to get one? I’ve contemplated getting one.

 

I think so. I got this one off Amazon for $40, plus a bottle of baby oil. Comes with some plugs for blocking off the throttle body, connectors for the vehicle battery, and a single fuse. Metal housing, doesn't weigh much. Works pretty well as far as I can tell. Who knows if it'll last long-term, but we'll see.

Ill tell you this - as someone whos not very experienced tracking down vacuum leaks, I likely wouldn't have found any of the leaks i found without stumbling upon them while doing other stuff- i would have found the PCV issue eventually, and I may have inadvertently fixed the TB leak when I cleaned it. The leaks on my ranger i had literally no clue about - just threw it on there out of curiosity.

Probably a good tool to have, if not an absolute necessity.

 

Thanks! I’ll have to get one at some point then…

 

Good tools are worth their cost. My smoke tester was around $1k back in the day. It's worth every penny. You will know if you have a leak or not. Works well with vacuum operated climate control systems too. If you can get one for $40 [and it works] it would be worth it, even if it only worked one time.

Throttle shafts leak. Unless it's a huge leak, they don't really cause a lean code. It would be the last part I would replace if I was chasing leaks.

 

Agreed! Hoping to get more than one use out of mine, but definitely worth $40.

Yeah, one of the leaks on my ranger was from the throttle body as well. Asking around, seems common.

That said, I did pick up a TPS and a TB gasket today. Cleaned the throttle body (it was pretty bad), and replaced TPS. Found a spot on black wire of original TPS that had no insulation - wire harness had been tucked so tightly under TB I had no way to get at it until TB was unbolted and lifted up.

After replacement, truck drives better. Less transmission weirdness, smoother shifting, less hesitation, more sensitive throttle... pretty much improvements all around. Still some weirdness with 3rd gear, but could just be high mileage trans things. Could also be normal automatic things - i daily a standard, and have owned a CVT car for years. Haven't driven a normal auto since I was a teen, and even then, it was a little camry. Not exactly sure what a normal E4OD feels like.

But, point is, its much improved. You can drive down the road at 55 with your foot barely on the pedal, with the engine nearly at idle. Before, it took some effort to maintain speed. I think old TPS had a flat spot at the top of throttle.

Seems like truck idles higher, now - not sure of RPM, no tach on this one. I did try unplugging IAC and restarting the engine, and it idled much slower but ran very poorly. Missed a lot. If i unplugged IAC while engine is running, nothing happened. IAC has been cleaned - might it be safe to assume this IAC is bad?

Still throwing lean code, and got a new code today during KOER test - 411. Might also point to IAC? Not sure why I didn't get that code prior to today. Maybe IAC just bit the dust or something. Also got a 311 code, but i have all vacuum lines plugged to thermactor. Was told that was the way to go, so plugged them off and sent it.

 

Did you clean the IAC while you had it off? It food you leave it on while cleaning it?

Improvement!

 

I took it off and cleaned it when I first got the truck and was having such a bad miss at idle. Didn't make a difference... but I guess it its bad, doesn't matter if its clean or not.