1997 Suburban trouble codes P340, P1345, P0300

[TURBOPOWERED68]

1997 Suburban 350 4X4 gave 3 Codes in the following order:
1. P0340:Cam Position Sensor A bank, 1 Ckt Malfunction
2. P1345: CKP/CMP Correlation
3. P0300: Random/Multiple Cylinder Misfire detected, mod $10

Just got the truck
it had both heads cracked So we installed 2 new heads and now it runs worst then when it had the cracked heads on.
HELP

 

[Daniel Jost]

that random cyl misfire may be coming from a bad cap and rotor those are known to do that i would try replacing the cap and rotor no matter what if you didnt since you bought the truck. maybe even a set of good wires wouldnt hurt

,Dan

 

[Daniel Jost]

also was it between the cyl cracks? that can be caused from spark arc across the cylinders do to bad wires.

 

[TURBOPOWERED68]

Thanks for the reply

The engine ran very smooth before the heads whir pulled out.
The cap and rotor look like new and so do the wires. And since it ran smooth I put them back on.

But I guess something could have gone wrong during handling them So I’ll pick up all 3 of them new today and try to get them on in the next few days.

If you have any new ideas please post them up.
My (mechanics) skills run out as soon as the new part is installed.

BTW it did get new plugs with the new heads

 

[charlie]

I own a 98 tahoe and those fault codes are more than likely caused by the distributor not being reset after you replaced the heads , you need a scan tool capable of putting the computer into the mode to set timing cannot be done without a scan tool , if you dont have one take it somewhere and have the timing set , should correct your problem.

 

[TURBOPOWERED68]

I am using an Actron CP9185 scan tool I looked read the 10K page booklet and its note specific on anything.

Supposing I had the Scantool of your choice- What are the step by step instructions I must follow to reset the timing on this truck.
Thanks for your help.

I tried - This connecting the plug on the distributor and then setting the timing using a timing light but the closer I set the timing to the damper the worst the truck gets.


BTW-i replace the wires,cap and rotor and no change.

 

[gunslinger]

You can't set timing on that truck with a timing light. You need a scan tool to set camshaft retard offset.

Don't think of it as a distributor, think of it as a cam sensor.

From ALLDATA:

TEST PROCEDURE
The ignition timing cannot be adjusted. The distributor may need adjusting to prevent crossfire. To insure proper alignment of the distributor, perform the following:

1. With the ignition OFF, install a scan tool to the DLC.
2. Start the engine and bring to normal operating temperature. IMPORTANT: Cam Retard Offset reading will not be accurate below 1000 RPM.
3. Increase engine speed to 1000 RPM.
4. Monitor the Cam Retard Offset.
5. If the Cam Retard indicates a value of 0°+/-2°, the distributor is properly adjusted.
6. If the Cam Retard does not indicate 0°+/-2°, the distributor must be adjusted.

ADJUSTING PROCEDURE

1. With the engine OFF, slightly loosen the distributor hold down bolt. IMPORTANT: Cam Retard Offset reading will not be accurate below 1000 RPM.
2. Start the engine and raise engine speed to 1000 RPM.
3. Using a scan tool monitor Cam Retard Offset.
4. Rotate the distributor as follows:

4.1. To compensate for a negative reading, rotate the distributor in the counterclockwise direction.
4.2. To compensate for a positive reading, rotate the distributor in the clockwise direction.

5. Repeat step 4 until 0°+/-2°, is obtained.
6. Turn the ignition OFF.
7. Tighten the distributor hold-down bolt to 3 Nm (25 lb. ft.).
8. Start the engine, raise engine speed to 1000 RPM and recheck Camshaft Retard Offset.

 

[chopped39]

I am using an Actron CP9185 scan tool I looked read the 10K page booklet and its note specific on anything.

Supposing I had the Scantool of your choice- What are the step by step instructions I must follow to reset the timing on this truck.
Thanks for your help.

I tried - This connecting the plug on the distributor and then setting the timing using a timing light but the closer I set the timing to the damper the worst the truck gets.


BTW-i replace the wires,cap and rotor and no change.

look at the rear base of the distributor with a small mirror.There is a white marker line that goes down the holddown part of the dist and on to the intake manifold. line the marks up and see how it runs. if you had it right on number one when the dist was installed timing should be right on.the 340 code was from the cam sensor being disconnected. dont worry about the 300 till the timing is set . good luck

 

[TURBOPOWERED68]

thanks guys i'll give this a shot this week end and let you know how it goes.
David

 

[TURBOPOWERED68]

OK guys the scantool shows 16* of advance at 1000 rpm.
I will try to get to it tonight I will move the distributor back ONE tooth at a time and see what happens.