Timing off, advancing 20' 95 GMC Sierra 350 cu.in.
1995 GMC Sierra P/U with a 350cu.in. Disconnected tan wire with black stripe, timing set at 0' BTC as soon as I reconnect the timing advances 20+ degrees and stays there, causing pinging, loss of power and terrible fuel milage. I've already replaced the knock sensor as well as the spark control, with no success. Any ideas would be greatly appreciated.
Re: Timing off, advancing 20' 95 GMC Sierra 350 cu.in.
I plug in est the truck will not stay running I turn dist with wire plug in now it is 6 btc now it run now it starts ??? will this hurt engine I have been trying for ever to fix fuel pump fuel filter spark plug &wire dist cap moduule pick up coil evry think egr runs an stumble an die I check T P S
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tan with a white stripe located 1 under the passenger carpet near the middle of the hump in the floorboard 2 in the engine harness near the fuse relay center may have to peel the wire loom back to find it timing at (0) btdc with connector unplugged
The timing (base), is 0 degrees before tdc. Keep in mind the timing connector must be unplugged. usually a brown wire with a black tracer, has a single connector, located under glove box, or by distributor. Thanks...
You have to disconnect the brown wire thats on the firewall. It disables the computer controlled advance and allows you to set the base timing. Disconnect SET TIMING connector (tan/black wire) located in harness close to distributor. DO NOT disconnect 4 wire connector at distributor. Thank you for using fixya and good luck, set timing is O".
You have to put the Ignition Control (IC) system in the bypass mode by disconnecting the "set timing" connector. This is a single wire sealed connector that has a tan with black striped lead. The location of the "set timing" connector with a Powertrain Control Module (PCM) controller is near the PCM connectors in the passenger compartment. Unplug connector (tan/black stripe) start engine set timing to 0 TDC, TURN OFF ENGINE, re-connect timing connector
start engine and bring to normal operating temp. unplug the base timing connector located in the distributor wiring harness tan wire with a black stripe
use a timing light and set timing to 0 degrees at idle the timing marks are on the crankshaft pulley and a tab on the timing cover with numerical indications
Note: The Timing Connector breaks out of the engine wiring harness conduit adjacent to the distributer. It is a single wire sealed connector that has a tan with black stripe lead. Note: Timing specifications are listed on the Vehicle Emissions Control Information label under the hood. Always follow the Vehicle Emissions Control Information label procedures first before using the following procedure.
PROCEDURE: Set timing under the following conditions:
Normal operating temperature.
Air cleaner installed.
Transmission in neutral.
Disconnect SET TIMING connector (tan/black wire) located in the harness close to the distributor. DO NOT disconnect the 4 wire connector at the distributor.
Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor.
Base Timing, with Manual and Automatic Transmissions: 00(TDC)
Tighten hold down and recheck the timing.
Stop the engine and connect SET TIMING connector.
Clear ECM trouble code by disconnecting ECM power source.
If the distributor hasn't been taken out, the timing can be set manually but you have to disconnect the distributor wire behind the glove box inside the cab. Tan wire with white tracer it is taped up to the a multi wire harness but is the only one with a single plug. Disconect the plug and use your timing light on the timing mark to set timing per specs. Rotate the distributor as needed to advance or retartd as required for the correct setting. tighten the dizzy clamp and plug the tan wire back together. The computer will now be fooled asd to what the base timing is and advance from there.
Contrary to popular belief, 96' and up do not have this wire. Timing has to be done with a programmable scanner.
Hope this helps.