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Eric
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2,625 Posts
Discussion Starter #1
So, I've been having problems with a "miss" (you can read about it in the '80-'96 forum, if you want). I've repaired several faulty parts and, still, have the problem. I think I have it narrowed down to an ignition issue, though.

When I throw the scanner on it I pass everything except the WOT test in KOER. I have done the test 4 different times and hit the gas each time. Every time I get a 77 as my only code. My truck used to pass this test a couple months ago.

What sensors/parts are responsible for telling the scanner if I goosed the gas, or, not? Why would it not be "seeing" WOT? Could this same sensor/part be causing the "miss" at cruising speeds when I try to accelerate? ICM? Some circuit in the EEC?

Thanks guys,
Eric
 

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Super Moderator
Joined
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26,089 Posts
yo Silver,

DTC 77 system failed to recognize brief WOT dynamic resistance test. Need to press gas pedal during KOER; Operator didn't execute WOT when told to during self test.

Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded

TPS, MAF (if equipped in later years), MAP and KS sensors are exercised during the brief Wide-Open Throttle (WOT) performed during the Engine Running Self-Test. The signal for the operator to perform the brief WOT is a single pulse or 10 code on the STAR Tester.

If you have a TPS, MAP or KS code in KOEO; troubleshoot those and repair until Code(s) is gone in KOEO; then try KOER and WOT (dynamic response check).
 

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Eric
Joined
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2,625 Posts
Discussion Starter #3
Thanks miesk. I get a code 11 in KOEO, though. Disconnected the battery for, about, 15 minutes and tried again. Did not get a code 77. I dunno... trucks acting crazy, lately. It's like every part decided to take a dump on me over the past month. They all seem to be original, though, so maybe it's just replacement time. Maybe the stuff's just reached its service limit.

Thanks again, man.

Eric
 

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Super Moderator
Joined
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26,089 Posts
yo Silver,

Try this;
Key On Engine Off Wiggle Test Procedure
1.Hook up a VOM or Scan Tool.
2.Turn the ignition key to the ON position.
3.For VOM, activate, deactivate and reactivate Self-Test to enter Continuous Monitor Diagnostic Test Mode (DTM). For Scan Tool, enter DTM, then enter wiggle DTM.
4.Tap, move, and wiggle the suspect sensor and/or harness to coil, ICM, DISTRIBUTOR, EEC, PCM, FUEL INJECTORS, BATTERY + & GROUNDS , IAC, TPS, ECT, EVP, IAT When a fault is detected, a Continuous Memory DTC will be stored in memory and indicated as follows:
•Check Engine (CEL) Lights
•VOM: Needle Sweep
•Transmission Control Indicator Lamp (TCIL) BLINKS

Engine Running Wiggle Test Procedure
Special Note:
•The Engine Running Wiggle Test may be activated any time the engine is running.
1.Hook up a Scan Tool as shown.
2.Key off.
3.Start the engine.
4.For VOM, activate Self-Test, deactivate and reactivate Self-Test to enter Engine Running Continuous Monitor DTM. DO NOT shut the engine off. For Scan Tool, enter DTM, then enter wiggle DTM.
5.Tap, move, and wiggle the suspect sensor and/or harness to coil, ICM, DISTRIBUTOR, EEC, PCM, FUEL INJECTORS, BATTERY + & GROUNDS , IAC, TPS, ECT, EVP, IAT. When a fault is detected, a Continuous Memory DTC will be stored in memory and indicated as follows:
•Check Engine (CEL) Lights
•VOM: Needle Sweep
•Transmission Control Indicator Lamp (TCIL)
 
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