Electronic spark advance seems on strike

Tiny
KA9INE
  • MEMBER
  • 1992 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 260,000 MILES
Why won't truck accelerate and why does it now sift 500 to 1000 rpm higher than normal?
I replaced fuel pump and when I went to start truck it ran for about 20 seconds and died, it did that three times and then would'nt start anymore. I towed it to shop. They said it was the dist. When I got it back it ran but I had no power, shifting is now about 1000 rpms higher than it should be, power locks no longer work, and if the truck even sees an incline it starts slowing down. Before changing fuel pump the engine ran great. My scan tool said the ECM was in limp mode but the engine never ran better. Now, after reman dist. Ha sbeen installed (by shop)I I get code 42 Electronic sparks advance and ECM in limp mode. I installed a reman ECM last Thursday but I still have no acceleration above 30 mph. I sure could use another opinion, that is if any of this makes sense to ya. Thanx
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Monday, January 31st, 2011 AT 6:14 AM

8 Replies

Tiny
RASMATAZ
  • MEMBER
Probably the distributor wasn't stabbed in right or the EST wire wasn't disconnect when doing the ignition timing adjustment
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Monday, January 31st, 2011 AT 7:40 AM
Tiny
KA9INE
  • MEMBER
When I went to pick up truck the repair order said that they set timing at 2 deg adv. Which brought the idle up to about 900 and the cat. Converter plug ( about 2 inches in dia.) Had been popped out. I had to seal that hole due to noise and I asked them to set timimg to 0 deg. He said he does that alot, to try to make for chain stretch. So when he reluctently agreed to reset it he disconnected a brown wire connector on firewall, pass. Side, right at corner of engine. But he disconnected it while engine was running. Isn't that a no no?
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Monday, January 31st, 2011 AT 7:58 AM
Tiny
RASMATAZ
  • MEMBER
The EST wire is Tan and Black. Its okay if he's adjusting the ignition timing. Once adjustment is done and plug back in-the computer controls the timing advance
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Monday, January 31st, 2011 AT 9:28 AM
Tiny
KA9INE
  • MEMBER
I agree. So now we're back to my original problem and question which has to do with lack of power
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Monday, January 31st, 2011 AT 9:46 AM
Tiny
RASMATAZ
  • MEMBER
Hesitating/lacking acceleration

Could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it and keep testing.
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Monday, January 31st, 2011 AT 9:55 AM
Tiny
KA9INE
  • MEMBER
I have a snap on scan tool and have had it connected while driving. From what I've read and what I see on screen it appearsthings are normal. You would'nt happen to have operating specs so as to compare with scan tool real time numbers?
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Monday, January 31st, 2011 AT 10:08 AM
Tiny
KA9INE
  • MEMBER
Would ya know why its not shifting at the proper rpm under normal acceleration?
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Monday, January 31st, 2011 AT 10:12 AM
Tiny
KA9INE
  • MEMBER
I replaced the O2, now I get code 42 Electronic Spark Timing, can ya assist me?
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Wednesday, February 2nd, 2011 AT 11:29 PM

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