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New TFI module (gray) from Ford, parts guy at the dealer said it was recently updated/superseded (bought it in 2014)
New ignition coil (Borg-Warner/Lordco)
EGR from a '94 F150 302
3G Alternator swap (came out of 90's Taurus)
Replaced my tach-less dash with one that had a tach, came out of a truck that was a bit older than mine
High pressure fuel pump (Carter)
Everything else is original
Symptoms:
Truck will randomly stall. This can happen while driving, stopped at a light, even at highway speeds of 100km/h +
As long as truck is moving I can cycle the key back and forth to "on" and the momentum will start the engine up again instantly
I have tried pulling codes with my OBD1 tool. I hear the pump relay click and pumps come on, but that is it, no codes, no response what-so-ever after that pump relay clicks on and off.
Usually when the truck stalls it is instantaneous. Almost As if the key has been turned to "off" yet the radio and HVAC continue to run without any hiccup
If I try to start the engine with the starter it will crank considerably longer than usual to start
Recently while driving I was able to catch it trying to stall. I saw my revs start dropping and struggle to stay up. Hitting the gas didn't seem to raise the revs at all and it stalled after a few seconds (rather than instantaneously)
The final thing at the end that stays lit until key off concerns me, but let's ignore that for now...
KOEO and CM will each flash their codes *twice*; there is a "long pause" (5s?) between KOEO & CM.
KOEO tests only the basic integrity & operational ability of the sensors at that precise moment in time; CM - Continuous Memory - is where "stored codes" are placed - what it remembers about the last N driving cycles (where N is 30 or some such) and this is what you should be looking at.
If KOEO is ok at the time but it remembers 23 in CM, it should report:
1s 1s
pause of a few seconds
1s 1s
pause of several seconds
2s 3s
2s 3s
I forget what officially gets jumped; myself, I only jumper the single-wire gray connector to ground, this starts the sequence but I look at blinkenlights on the dash and forget what wires to connect a testlamp to... that book explains it, tough; see if you can read that stuff....
"fast codes/flicker", 11, 11, pause..., one flash, pause..., 11, 11
KOER:
Engine is warm
Start truck
4 flashes (V8)
Single flash
Code 41
Code 34
Flash once for goose test, GOOSE IT (not more than 3500rpm)
Code 41
Code 34
Code 41: Heated Oxygen Sensor circuit indicates system lean, right side
Code 34: EGR valve pressure transducer/position sensor voltage above closed limit
(this has nothing to do with TPS, correct?)
I forgot to mention I did change my EGR valve with a newer/shinier one off of a '94 302
I have tried disconnecting the EGR before and the truck still stalls same as noted in OP.
Just tested my egr. It's got about 3200 ohms fully closed and about 230 ohms when fully opened. Haynes manual says around 5000 ohms closed and around 100 ohms fully open.
Last time I drove the truck with this EGR/EVP connected it stalled 1 time withing a 10km drive, and twice on the way back home.
Going to the bone yard today to see if I can find an EVP that tests closer to 5000 ohms fully closed and 100 ohms fully closed. For now, my old EVP is connected, but vacuum line is removed from the EGR and capped off.
Also: My reference voltage tested perfect at 5.02V!
I picked an EVP from the boneyard for $5. Called lordco yesterday and they don't have any o2 sensors in stock but will have one by Monday.
Both the drive to the boneyard with EGR vacuum line disconnected and the drive back with my 'new' EVP sensor and EGR functioning went on without a hitch!
Well as luck would have it, after going through the KOER tests in my backyard, I shut the engine off after the test and my truck would not start afterwards.
Went to the boneyard and picked up a newish looking distributor from a 1988 Crown Victoria w/ TFI module
I put my recently purchased Motorcraft TFI on the Vic's distributor and installed it in my truck. Still no start lol. After not even a year my brand new Motorcraft TFI had taken a $%^&.
Maybe because the old dist it was on looked like this:
I have the O2 sensor, but haven't change it yet since its a bit of a pain to get at, probably will have to buy a special wrench/socket.
Haven't had it stall randomly yet though!
And thanks for your insight on this issue ctubutis! Misery loves company lmao
And thanks for your insight on this issue ctubutis! Misery loves company lmao
Heh.
It might be kinda painful at the start while you're learning the OBD-I stuff but you'll find it's really helpful once you understand how it all works and you let the computer help you figure out what's wrong.
Looking at your distributor, that connector looks really bad and it wouldn't surprise me if your problem is right there. IIRC that's the crankshaft position sensor that the module plugs into, a critical component of your ignition.
All these names make it so much easier to find replacements.
Aye...
It is just a Hall Effect sensor, Ford installed them initially in the distributors before later moving them to the crankshaft down by the timing case cover. But they all operate the same way and perform the same job in exactly the same manner.
