Help, ignition timing!!
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Help, ignition timing!!
Here is the story 85 F-150 4.9, 5spd, 4WD. Ignition timing is not advancing. Stays at base timing no matter what. Checked the yellow wire to ignition module, conection is ok. Suspected ECU, so tried one that was know to be good. Still nothing, and yes it was the same part number ecu. Tach also doesn't work. I guessing wiring somewhere at this point. Anyone have a source for wiring diagrams, or diagnostic flow charts? I don't have anything. Or if you know what the problem may be, that would be better.
New User
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I'd say ditch the EEC IV and upgrade (or downgrade) to Duraspark II. I'll have all of my parts Saturday and will have my bronco running tip top...the wiring is all corroded and nasty on my bronco and i've removed all of the emissions so it makes more sense to just eliminate the EEC. Perhaps there are sensors that arent reading which is not letting your EEC advance the timing?
Posting Guru
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From: Right Next to U
Profile Ignition Pick-up (PIP) signal and it is relayed to the Electronic Control Assembly...... To function correctly, a Hall-Effect sensor must have voltage and a ground applied to it. If the power, ground, or signal wires are open, the sensor will not operate. If the ground is shorted on either the power wire or the signal wire also eliminates the RPM signal. No Signal means just that dead electronics.
Tuned
Joined: Oct 2003
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Here is an update. Have PIP signal, all wire continuity to PCM is ok. Have spout signal, but no change in volts regardless of RPM. Suspected that PCM is not getting signals from TPS or MAP. Checked wire continuity from both, ok to PCM. Checked voltage at TPS 11.5V. Isn't this supposed to be a 5V circuit? Checked PCM grounds, Pins 40 and 60. 40 Ohms, seems high. Run jumper from pin's 40 and 60 to ground. Recheck resistance, .3 Ohms. Thats better. Re-check voltgage to TPS, only .2volts.
PCM Toast??
PCM Toast??
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