redryan

while replacing the power steering belt on my '86 sr5, i shorted a long ratchet extension on the positive terminal of the battery. oops. there was a good amount of metal transfer from the extension to the positive terminal. worse, im pretty sure i had left the ignition in the on position. not running, but on. big oops.

now, the truck will start, run for a few seconds, then dies. it was running fine prior to the belt replacement oops.

ive checked all fuses and fusible links. all look ok.

i checked error codes, and was getting "6" = "no engine revolution sensor (Ne) signal to ECU or Ne value being over 1000RPM in spite of no Ne signal to ECU-defective ignitor circuit, ignitor, distributor, or ECU.

i checked resistance of pickup coil at the plug coming from the distributor, measures 165ohms--within spec.

i cleared codes by disconnecting the battery. now i get no codes, though symptoms are unchanged.

i checked the fuel pump via its test jumper, and its working. i tried starting and running with the fuel pump test jumper shorted--same symptoms--starts and dies.

at this point, im thinking ive fried either the ignitor, or the ECU.

any advice you have as to what may be causing this problem and/or how to test, or where to look for test proceedures for ecu or ignitor would be much appreciated.

abecedarian

try this- disconnect the alternator wiring and see if it runs longer than a few seconds.
may not make sense, but bear with me. if it works, it'll make sense in a bit.

iamsuperbleeder

mine does the same thing when the AFM is unplugged...

just food for thought...

abecedarian

feed me seymour, feed me.

sorry, yeah, check the afm operation too since there is a switch that activates the fuel pump once airflow has begun.
http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

redryan

ill try with alternator disconnected and report back.
if that has no effect, ill get into testing AFM.
thanks!

redryan

disconnected alternator via black 4-wire connector near ignition coil==no change. now on to AFM testing.

abecedarian

Actually, I meant to disconnect the lead from the alternator to the battery. That's my bad for not saying so.
but okay. off to the AFM

redryan

from http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml
static test results using fluke 77 DMM:
1. 102.9ohms
2. 185.0ohms
3. 284.5ohms
4. 2199ohms @ approx 80degF
5. OL=infinity

dynamic tests (same meter):
1. infinite at fully closed; 3.4ohms at not closed.
2. 104.5ohms @ fully closed; 225ohms at full open; max 550 somewhere in between.

so AFM appears within spec.

redryan

there is no wire direct from alternator to battery on my truck. it appears all alternator wiring goes through the main harness. i could pull wire(s) off the alternator...

Snotrocket

Use the jumper in your diagnostic port to check the switch inside the AFM and make sure it's turning the pump on.

It's right in that link on the 4crawler page.

redryan

if you mean the fuel pump check connector, ive used that to test that the pump is working when the key is turned on, which it is. i also used it to see if the truck would run longer with the connector jumpered, which it didnt. so i dont think my problem is fuel, i think its spark.

but i dont know.

i had been getting trouble code 6, "no engine revolution sensor (Ne) signal to ECU or Ne value being over 1000RPM in spite of no Ne signal to ECU-defective ignitor circuit, ignitor, distributor, or ECU."

since clearing codes by disconnecting negative terminal of battery i have the same 'start but not run' symptoms, but no codes.

right now im looking to find where i am losing the Ne (engine revolution) signal, whether the ignitor cicuit is not generating said signal, whether its being lost between ignitor and ecu, or whether its getting to ecu and ECU is now brain dead and doesnt recognize the Ne signal.

sound like im heading down the right road?

thanks all.

redryan

i tried again to run it with the fuel pump check connector jumpered...and...whadaya know, it runs! now im off to research what that means. any ideas?

abecedarian

faulting circuit opening relay or AFM

84sr5yoty

^^^ Yep

Most likely the circuit opening relay.

4Crawler

iTrader: (3)

It means that whatever is supposed to turn on the CO relay with the engine running is the problem. As noted above, either the coil on the CO relay or the AFM fP contact or the wiring between the two, most likely one of the latter two: