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I have a 1998 Olds Bravada 4.3 Vortec. After changing the head gaskets, plugs, wires, rotor and cap, I am getting a 1345A fault code. The engine runs and performs as before the repair, but the dash light comes on. The cam is read from the distributor, and suggests that it is off, but moving it one notch or gear either way will not start the engine. The scan tool says it is 17 degrees off, but the engine willonly run in that position. A professional mechanic spent two hours on it and could not resolve the crank-cam correlation problem. I am hoping some one has run into this before and has a fix.??

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When removing the head gaskets, was the crank moved in either direction, even a tiny amount? It has to be something minor by my reasoning if the engine cranks and starts easily, idles smoothly, accelerates smoothly with the customary amount of power, and runs down the road just fine, then it isn't timing no mater what the degree correlation indicates.
Cars are new, and then they start being not new, and every factory part begins aging at the same time and as consumables like plugs, wires, caps, and rotors wear, the computer is constantly making hundreds of little adjustments to maintain the engine's performance to as nearly-new as it can. So a car gets used to its parts and it actually has a degree of symbiosis with them, and when some human gets in there and starts replacing all kinds of parts, all at once, the computer basically does several double-takes; these new readings aren't possible! Yesterday they were X...today they're...WAY OFF. Something must be broken! Error Code P1435!
Now, you've changed a lot of the parts that can throw that code. But there are several others that can be responsible for it, because the computer can't adjust the wear out of parts so widely separated in age...maybe as much as 200kMi. So you need to check these things if they've not already been checked:

• A loose CMP sensor causing a variance in the sensor signal
• Excessive free play in the timing chain and gear assembly
• Incorrectly installed distributor - 1 tooth off in either advance or retard positions
• A loose distributor rotor on the distributor shaft
• A loose or missing distributor hold down bolt

You also need to check timing chain tensioner assembly not just chain play, and if you need a chain, you need gears, and if you need gears, you need a tensior assembly. And check for any shims that were in the distributor that may have got left off, and if you did everything you said but didn't completely rebuild the distributor, do that. You need all your parts on the same page in 'life' to make things easier for the computer. For the PCM to settle in, quit complaining, and start getting used to these new parts, it is going to require several engine cycles to monitor the input and compare to the factory presets. Even after everything is right, it might still throw the code for a few days. Two hours not NEARLY enough diagnostic time.

And you ultimately may have to get the PCM reflashed.

Posted on Apr 16, 2017

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  • Cars & Trucks Master
  • 12,124 Answers

Diagnostic Aids
Check for the following items:
• A loose CMP sensor causing a variance in the sensor signal
• Excessive free play in the timing chain and gear assembly
• An incorrectly installed distributor--1 tooth off in either the advance or the retard position
• A loose distributor rotor on the distributor shaft
• A loose or missing distributor hold down bolt
Step
Action
Value(s)
Yes
No
1
Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and Failure Records for reference. The control module's data is deleted once the Clear Info function is used.
Did you perform the Powertrain On-Board Diagnostic (OBD) YES - YES - System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check
2
Install the scan tool.
Start the engine.
Monitor the engine speed with a scan tool.
Does the engine speed fluctuate (up to twice the desired RPM)?
--
YES - Go to Step 3
NO - Go to Step 4
3
Replace the crankshaft position sensor. Refer to Crankshaft Position Sensor Replacement .
Is the action complete?
--
Go to Step 9
--
4
Perform the Camshaft Retard Offset test procedure as follows:
Install the scan tool.
Start the engine.
Important: The camshaft retard reading will not be accurate below 1000 RPM.
Raise the engine speed to the first specified value.
Monitor the camshaft retard with the scan tool.
Is the camshaft retard reading within the second specified value?
1000 RPM
-5° to -17°
Go to Step 5
Go to Step 6
5
Note the camshaft retard reading from the previous step.
Raise the engine speed to the first specified value.
Does the camshaft retard reading change more than the second specified value?
2000 RPM

Go to Step 6
Go to Diagnostic Aids
6
With the engine at operating temperature and the engine OFF perform the following procedure:
Remove the distributor cap.
Grasp the distributor rotor and gently attempt to rotate the rotor.
Does the rotor turn on the distributor shaft?
--
Go to Step 8
Go to Step 7
7
Check for proper installation of the distributor.
Refer to Distributor Installation in Engine Mechanical. Repair as necessary.
Did you find a problem?
--
Go to Step 9
Go to Diagnostic Aids
8
Replace the distributor. Refer to Distributor Removal in Engine Electrical.
Is the action complete?
--
Go to Step 9
--
9
Using the scan tool, clear the DTCs.
Start the engine.
Allow the engine to idle until the engine reaches normal operating temperature.
Select DTC and the Specific DTC function.
Enter the DTC number which was set.
Operate the vehicle, with the Conditions for Setting this DTC, until the scan tool indicates the diagnostic Ran.
Does the scan tool indicate the diagnostic Passed?
--
Go to Step 10
Go to Step 2
10
Does the scan tool display any additional undiagnosed DTCs?
--
Go to the applicable DTC table
System OK

Posted on Apr 16, 2017

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My problem was solved when I repaired my 4 wd activation dash switch. The switch was contacting on 2WD & 4HI at the same time. The front differential activation is vacuum activated possibly creating a tug of war that didn't actually engage it but drained off vacuum from the engine? A theory at best but stumbbled across it because I knew the switch wasn't working properly I repaired it and low and behold rough idle disappeared and all is good for 3 weeks running.

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SOURCE: 02 GMC Sierra 4.3 V6 P1345

Well that sounds like a tough one , But here is a site worth checking out . Several mechanics use this it to help out people like your self that are frustrated and are getting P #$%$# off ! Good luck

http://www.obd-codes.com/forums/search.php?search_id=active_topics

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SOURCE: 2001 Galant ES-V6 DTC is P0304 - Cylinder #4 misfire

look for weak valve springs.

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SOURCE: 1996 Honda Accord Rough Idle Even After tune up

Perform a valve clearance inspection and adjust if necessary. Tight or sticking valves will cause a misfire or rough running concern. Note: Perform valve adjustment when the engine is stone cold. 4cyl: INT 0.26mm EXH: 0.30mm (V6 engine are hydraulic and no adjust necessary.) Also check for a sticking or stuck open EGR valve. For diagnostic purposes only: Remove the EGR valve. Place a business card over the EGR passage and bolt the EGR valve back on. This plugs the EGR ports and if the misfire goes away the EGR valve is partially stuck open and is defective.
Check for low fuel pressure. Check for low compression. Check cam timing. Check for a weak ignition coil. Also don't over look the possibility of worn or broken engine mounts which cause excessive engine movement and engine vibration. -hope this helps

Posted on Mar 05, 2010

  • 834 Answers

SOURCE: Rebuilt my 454 engine, installed distributor with

The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these procedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on TDC. (Top Dead Center) This "Static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at TDC.

1. Place the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing (usually has a #6 for 6 cylinder engines or a #8 for 8 cylinder engines) indicating the number one TDC alignment position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one TDC alignment mark or notch that is on the distributor housing, if it is not then loosen up the distributor and turn the distributor until the ignition rotor is pointing to and aligned with the TDC alignment mark or notch on the distributor housing and then tighten down the distributor, the engine should now be "Static" timed. (The more precise that you are aligning the TDC alignment mark with the ignition rotor the better the engine will run, and it will be less likely that there will be a camshaft to crankshaft correlation problem)

If the distributor can not be turned enough to align the ignition rotor with the number one TDC alignment mark on the distributor housing, or the distributor does not set properly and will not allow the installation of the spark plug wires then the distributor is not installed correctly and is most likely a tooth off and it will need to be re-installed correctly. (The distributor should set like it is shown in the firing order diagram when it is properly installed)

Here is a firing order diagram to also help assist you.




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Posted on Oct 25, 2010

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