Thanks, Pawpaw, for the link and instructions and thanks for your counsel along this road. No need to check codes at the moment. I've got no check engine lights and a truck that starts easily hot or cold, idles smoothly and has tons more power. The 2.9 will never win a drag race but I'm going up hills without downshifting and acceleration is noticeably faster. I'm very happy. We're not done yet -- I'll check timing this weekend and change a fuel filter we'd missed earlier and there's both a new idle control valve and water pump on order -- but we've got a running, driving, starting, stopping truck. That's a lot. That I've got a teen who has hung out with me on this journey, done some of the work, and learned how to drive a stick shift are HUGE bonuses. Again, thanks for your support and willingness to encourage and share knowledge.

 

Ok good feedback & to hear that youngster has hung in there with you on this resurrection, as he too will get to feel first hand, the satisfaction of results of a hands on positive trouble shooting effort.
Remember, we can have "pending" codes stored, that haven't happened often, or long enough, to have aggravated the computer to turn on the CEL, so these "pending" codes can often help focus a head scratching trouble shoot, thus can be worth extracting. Keep us posted on the additional parts replacement work & how the vehicle responds.

 

Pawpaw -- Just for grins, I decided to try to read the codes using the jumper wire and test light method. Unfortunately, I only got a steady light -- no flashes. Any idea how to interpret that? Thank you!

 

Faulty hook-up maybe. Do you have any codes in KAM thats turned the CEL on??? If not, create one that'll turn the CEL on, then Double check your wiring hook-up, check for codes again & let us know how it goes.

 

Pawpaw -- Ended up replacing the ECU with a reman unit. Not as expensive as I feared -- about $75 after I returned the core. And it was easy, too. Located behind passenger side kick panel in this era. The original unit was unable to provide a self test and could only produce a steady light. After replacing the ECU, we drove the truck 10 miles or so and all was well. No check engine light, good throttle response, no jerking or other misbehavior. Ran codes and got a 63 and a 67. I'm told the 67 is likely because I didn't have the clutch in when doing the key-on-engine-off test. 63 is low voltage from the TPS, right? It's a new TPS so thinking I probably just need to move the throttle through its full range. Our test drive was just in the neighborhood so speeds never got above 35. Of course, I'd appreciate your thoughts and counsel here.

Next up is the water pump. What was a drip is a pretty steady stream now. Again, not a surprise on a truck that sat this long. We already did the heater core, cap, and hoses so pump is just next in line.

Again, thanks for the encouragement and guidance. Both appreciated.

 

You need to make sure the A/C is Off when doing the tests. For some reason the ECM isn't happy with the TPS readings, so back probe the TPS electrical connector to make sure the replacement ECM is providing the 5volt reference to the TPS electrical connector. If it is, then make sure the replacement TPS resistance range is within specification. If all that is ok, back probe the TPS output signal return lead as you go from closed to open throttle & refer to the max / min voltage range in the link & posted in post 5. If ok at the TPS electrical connector, move to the ECM firewall connector & monitor voltage return there, to make sure there isn't a wiring problem between the TPS connector & ECM firewall connector & let us know what you find.

 

Forgot to post these TPS thoughts, If in the past someone has changed the idle control screw from factory settings, it can mess with the TPS Return voltage the ECM is seeing, so if the return low expected output voltage is at the idle, or idle shutdown position, make sure the idle screw is back in the factory position. When we switch the ignition key to Off, the solenoid is supposed to close the throttle some more so we don't get run-on when shutting the engine down, If I remember right, on my old 78 Merc 3.3L the idle stop rpm was something like 500-550 & the hot idle was something like 650-675 if my moldy grey matter remembers right. Anyway refer to your Chilton's manual for the correct setting if you come to believe, or know the idle screw has been moved. Then once properly reset, see if that affects the TPS code. More WAG thoughts for consideration, let us know what you find, as I'm being re-educated on this resurrection too!!!! lol

 

Whew! It's been interesting. Water pump is replaced with a reman unit as well as a reman ECU unit which allowed me to pull codes. Cardone water pump from ebay was under $30 and the reman ECU from Advance was under $80. I also reinstalled the original TPS and a new IAC. Previous combo was new TPS and old IAC. With the old/new combo, truck ran well, though it was clearly rich (oil smelled of gas and tail pipe emission failed the nose test, too.) Scan showed bad oxygen sensor which was frustrating since it had been recently replaced along with tons of other parts (injectors, fuel pressure regulator, fuel tank, fuel pumps, fuel filters, fuel lines, EGR, ignition module, cap, coil, wires, spark plugs ...). Replaced bad 02 sensor with a new Bosch one and all seems to be well. Ran the scanner key on, engine off and got a code 11 -- which is good -- as well as a code 34 for EGR. I'm going to let the 34 slide, at least for now. Idle is decent for a 33YO old truck with 107K and having sat for such a long time. In other words, it's not perfect but I don't expect it to be. No longer smells rich. Son got a set of KYB shocks for Christmas so those will go on next. I'll probably change the oil and filter again before too long but otherwise will just drive and enjoy it. It's got a couple of small oil leaks that I'm guessing is rear main (we did the badly leaking valve covers already). We'll leave that job until we have to do the clutch. Long road with this one and a lengthy parts list but we've got a decent little truck that's back on the road and ready for the occasional light duty haul. Plus, a good father/son project. Thanks again to this site and Pawpaw for the encouragement.

 

You two have been busy on this one, good to hear hear its resulted in a useable & satisfying vehicle to drive & that the son had a hand in seeing & making it happen. He'll likely have fond memories to pass on to his offspring.
Seeing as how the suspect rear main seal leak isn't bad so far, you might consider trying a High Mileage recipe engine oil to see if it can slow or stop it, until you pull the tranny to do the clutch work & replace the rear seal.
If you haven't already done so, check the tranny shift rail rubber plugs & if oily / leaking, check & adjust the tranny lube level without delay. If the plugs aren't leaking bad, wait until tranny removal to replace them. Even if they aren't leaking, seeing as how they're 30 years old, I'd replace them & the tranny lube when the tranny is out, as its easier to do & get right then.
More thoughts for consideration, keep us updated on how the resurrection on this vintage puppy goes.