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Chevy Base timing disconnect wire
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mr+brakes
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Dec 25, 2012, 9:57 AM
Post #1 of 18
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Chevy Base timing disconnect wire
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I need to find the wire to disconnect to set base timing on a 2000 chevy K3500 with a 5.7.
On earlier models of chevy there is one brown wire that gets separated to set to base timing without computer taking control. Does the 2000 chevy K3500 have the same aspects to set base timing?
If so where is the wire located in the 2000 chevy K3500 to disconnect to set the base timing?
Help! Does anyone have location to this wire needed to disconnect to set the base timing on a 2000 K3500 5.7?
On engines after 1980 GM required a base timing set before computer is set to control engine.
(This post was edited by mr+brakes on Dec 25, 2012, 9:58 AM)
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Hammer Time
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Dec 25, 2012, 10:02 AM
Post #2 of 18
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Re: Chevy Base timing disconnect wire
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You cannot adjust the timing in that engine.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
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Dec 25, 2012, 10:16 AM
Post #3 of 18
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Re: Chevy Base timing disconnect wire
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Not sure how much anyone will be around today but found this and could be wrong. Timing is not adjustable as HT said but putting distributor back in if out is an issue.
This is what I found with no assurance of accuracy.................
4.3L, 5.0L, 5.7L And 7.4L Engines
Timing Disturbed
- Remove the No. 1 cylinder spark plug. Turn the engine using a socket wrench on the large bolt on the front of the crankshaft pulley. Place a finger near the No. 1 spark plug hole and turn the crankshaft until the piston reaches Top Dead Center (TDC). As the engine approaches TDC, you will feel air being expelled through the No. 1 cylinder spark plug hole. The timing mark on the crankshaft pulley should now be aligned with the 0 mark on the timing scale. If the position is not being met, turn the engine another full turn (360 degrees). Once the engines position is correct, install the spark plug.
NOTE Before installation, position the rotor so it points to the No. 2 terminal on the cap. As the distributor is lowered into the engine, the rotor will rotate clockwise and stop at the No. 1 terminal. This is the desired position.
- Turn the rotor so that it will point to the No. 1 terminal of the distributor cap when it is fully seated in the engine.
- Install or connect the following:
NOTE If the distributor will not seat completely in the engine, remove the distributor and align the groove on the top of the oil pump drive shaft with a long screwdriver to match the tab on the bottom of the distributor shaft. Reinstall the distributor.
Distributor. It may be necessary to turn the rotor a little in either direction, in order to engage the gears.
- Tap the starter a few times to ensure that the oil pump shaft is mated to the distributor shaft.
- Bring the engine to TDC again and check that the rotor is pointed toward the No. 1 terminal of the cap. If the marks are all aligned.
- Install or connect the following:
Hold-down bolt and tighten Cap and fasten the mounting screws Electrical connections and the spark plug wires
T
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Hammer Time
Ultimate Carjunky
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Dec 25, 2012, 10:22 AM
Post #4 of 18
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Re: Chevy Base timing disconnect wire
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If you move this distributor in any way, you are going to need a very expensive scan tool to get it set again or it will run terrible and set a P1345 code. There is no reason to ever touch this distributor unless it is being removed for some reason.
The procedure Tom gave is only to get it close enough to start. The scan tool will be required to set it correctly.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Dec 25, 2012, 10:23 AM)
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mr+brakes
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Dec 25, 2012, 8:46 PM
Post #5 of 18
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Re: Chevy Base timing disconnect wire
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Distributor had been removed, so in this case your saying timing is done with a scan tool? I know that on earlier models that the base timing was set by disconnection of one wire that engaged computer and a timing light was used to set base timing at zero.
So when did the timing light become obsolete timing the 5.7 engine?
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Tom Greenleaf
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Dec 25, 2012, 8:56 PM
Post #6 of 18
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Re: Chevy Base timing disconnect wire
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Timing light! Pretty sure for GM about when HEI ignitions ended. Could still use it to see if a plug wire has spark going thru it. What prompted you to touch the distributor to begin with? - T
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Sidom
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Dec 25, 2012, 9:14 PM
Post #7 of 18
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Re: Chevy Base timing disconnect wire
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Almost 20 years ago.....
Not sure where the mark came from but I've noticed a white mark on the dist base & manifold on a lot of them. If you line the 2 up after the dist has been installed corrected you may get lucky......If it has a mark, you'll need a mirror to line it up
If you get it to far out, you'll turn a light on & set a code as HT has indicated
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mr+brakes
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Dec 26, 2012, 5:55 AM
Post #9 of 18
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Re: Chevy Base timing disconnect wire
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Timing has to be adjustable in order to set the base timing, otherwise the computer has no way to be accurate control of timing.
I have other GM trucks the timing is set by disconnection of one wire to set base timing, A 2000 chevy does not have coil pack, where timing is not an issue when a coil pack is used.
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Hammer Time
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Dec 26, 2012, 5:59 AM
Post #10 of 18
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Re: Chevy Base timing disconnect wire
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You know, I really have no patience for people that ask for help from professionals and then want to debate the information. I'm telling you that the ignition timing IS NOT ADJUSTABLE. If you want to debate that, I don't have time for you nonsense.
I'm going to say this one time, Any vehicle that uses a crank sensor has no means to change the base timing.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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mr+brakes
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Dec 26, 2012, 6:35 AM
Post #11 of 18
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Re: Chevy Base timing disconnect wire
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Gm still had base timing adjustable except when a coil pack is used. I personally found that base timing is adjustable by disconnection of one wire, which is usually brown to disengage computer to set the base timing.
Not in all vehicles is in the same location is this wire found. I had even done timing on vans where it has the same wire to disconnect to set the base timing not using a coil pack.
I've retired due to my age and forgotten allot but still know base timing is very important in order for the computer to function properly.
I may not be able to keep up with everything since I'm retired but I know GM did not eliminate the need to set the base timing on engines without coil pack.
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nickwarner
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Dec 26, 2012, 6:49 AM
Post #13 of 18
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Re: Chevy Base timing disconnect wire
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You're still thinking about this like the distributors you used to work on. This is nothing whatsoever like it. From the outside it looks like one. If you don't get this installed back to EXACTLY where it was when you pulled it you WILL have a code, it WILL run like crap and you CANNOT do a single thing to help that with a timing light at all. HT has explained that to you several times. You have to have a high-end scan tool to fix this and the knowledge to use it if you get this wrong. Ignore the advice at your own peril, maybe it'll run enough to get to a shop and pay someone to undo this. Or its going there on a wrecker. All of us here have made plenty of money with our scan tools because of someone who was convinced that this wasn't true and they could adjust it themselves with a timing light. When they tried to do it and failed it ends up in our bays and gets done right.
Things have changed on cars. We did away with bias-ply tires. We invented ABS. Radios play music from satellites. And your timing isn't adjustable in any way shape or form.
Its your truck, do what you want with it at your own peril.
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Discretesignals
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Dec 26, 2012, 7:09 AM
Post #15 of 18
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Re: Chevy Base timing disconnect wire
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Base ignition timing isn't adjustable on that set up because the crank sensor is fixed on the front of the engine. The engine computer gets base ignition timing from the crank sensor and not the distributor cam sensor.
As HT stated the computer uses the cam sensor in the distributor to figure out when number one is top dead center on the compression stroke, so it can synchronize fuel injection. When you turn the distributor, your changing the cam sensor signal timing in relation to the crank sensor signal timing. Another words instead of changing base ignition timing by rotating the distributor your changing injection timing.
That explains why when you disconnect the crank sensor on that engine it won't start, because the computer doesn't know when to start the firing sequence.
If you don't believe us, connect your timing light to number one and point it down on the balancer while turning the distributor. You'll understand.
Just because it has a distributor doesn't always mean the base timing is adjustable. Dodge &Jeep have distributors on their engines (318,360,4.0L early) but the crank sensor is down by the flywheel, so base ignition timing isn't adjustable on them either.
On older HEI systems, the ignition module got the crank position from the sensor in the distributor. The ignition module controlled base ignition timing, but the engine computer was able to modify the base ignition timing through an EST circuit after the engine got running. Disconnecting the EST circuit (tan/black wire) caused the ignition module to revert back to base ignition timing mode, so you could adjust the base ignition timing by rotating the distributor.
(This post was edited by Discretesignals on Dec 26, 2012, 7:56 AM)
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mr+brakes
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Dec 26, 2012, 9:50 PM
Post #16 of 18
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Re: Chevy Base timing disconnect wire
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Problem solved with wiring. Issue found in the wiring.
Have A Nice Day
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Hammer Time
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Dec 27, 2012, 4:07 AM
Post #17 of 18
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Re: Chevy Base timing disconnect wire
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Yep, plug wires in the wrong order won't run too good.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Discretesignals
Ultimate Carjunky
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Dec 27, 2012, 8:43 AM
Post #18 of 18
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Re: Chevy Base timing disconnect wire
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What was the issue with the wiring? If it was plug wires being switched, that is a common mistake.
It's funny we were never told any symptoms. You should still have the offset checked with a scan tool. If the cam sync is off, it can cause engine damage. Just some FYI.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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