timing

kb3jhp · #1 10-29-2006, 01:02 AM

i was told my cam timing is off i have a 96 bravada and it has been pinging bad so i had my teacher scan it and he said the cam timeing was off.
i no that a jumped timeing chain can do this but it is makeing no noise.
would a worn out dist gear do this since the cam postion senser is in the dist.
also can the dist be turned on a 96 vin w and if so could that do it it was -8 off and should be 0

sreve · #2 10-29-2006, 09:25 AM

0 is optimum it won't complain if you get it within + or - 2
it is quite common for the composite distributors to have so much shaft play
i can't belive they still run. check the dist.
you will need a scan tool to dial it in. at 8 one tooth is probably too much if so i have run a 3\8 bit thru the hold down to dial it in. if you do this make sure it's squared up right before you tighten the hold down bolt.

534BC · #3 10-29-2006, 09:26 AM

It does sound like a worn out timing chain, but I can't really see it causing the pinging.

If the coil is on the pass side above the valve cover and the dist cap has the wires coing out the sides (left and right sides) then it uses a fixed distributor housing and the timing is controlled by the computer thingy.

MT-2500 · #4 10-29-2006, 11:44 AM

Quote:

Originally Posted by kb3jhp

i was told my cam timing is off i have a 96 bravada and it has been pinging bad so i had my teacher scan it and he said the cam timeing was off.
i no that a jumped timeing chain can do this but it is makeing no noise.
would a worn out dist gear do this since the cam postion senser is in the dist.
also can the dist be turned on a 96 vin w and if so could that do it it was -8 off and should be 0

The cam retard/offset/dist timing has nothing to do with the engine timing or timing chain.
The engine timing is set by the camshaft sensor.

It centers the rotor tip to the dist plug wire prong/terminal.

Some dist can be turned and some can not.
As Serve said you can drill the hold down clamp a little on the unadjustable ones to get the dist to turn a little.
Whe setting the came retard offset you will have to raise the engine over 1000 rpm for the pcm to pick up the new seting.
MT

534BC · #5 10-29-2006, 11:54 AM

Can you guys elaborate on here the cam senor is and how it works?

Also where are you geting the -8 from?

How does a scanner know the cam is offset? What inputs is it using? Thanks for helping me to understand. I'd like to check mine because sounds very much like what I'm experiencing.

MT-2500 · #6 10-29-2006, 12:07 PM

Quote:

Originally Posted by 534BC

Can you guys elaborate on here the cam senor is and how it works?

Also where are you geting the -8 from?

How does a scanner know the cam is offset? What inputs is it using? Thanks for helping me to understand. I'd like to check mine because sounds very much like what I'm experiencing.

On that on the cam sensor is in the dist.

The - 0r + setting on the cam retard is the dist position.
Or the position that the rotor is in when the dist fires.
It centers the rotor to fire dead on with the dist cap plug wire prong/terminial.
The dist needs turned to set or change the cam retard setting.

If it is off the rotor fires before or after going by the dist cap terminial.
That is where it gets the - or +
Dead on it shows a 0 setting.
If before or after it shows - or + or before or after.

It should be as close as -2 or +2 or the pcm will set a code on it.
But 0 or dead on is better.

The scanner gets the reading from the crankshaft and the dist camshaft sensors.
They have to be timed together to get a perfect 0 reading on it.
Hard to explain but hope this helps.

MT

534BC · #7 10-30-2006, 11:12 AM

Yep, I think I got ya. I apparently cannot read that "cam position" with my cheap lap-top software.

What doe it take to read it? I am willing spend some more money on more sofisticated software in order to check it.

MT-2500 · #8 10-30-2006, 12:35 PM

Quote:

Originally Posted by 534BC

Yep, I think I got ya. I apparently cannot read that "cam position" with my cheap lap-top software.

What doe it take to read it? I am willing spend some more money on more sofisticated software in order to check it.

A snapon MT-2500 is one of the best all around but expensive.
here is a link you might check out.

http://autoenginuity.com/

534BC · #9 10-30-2006, 01:01 PM

The auto-enginuity is one of the softwares I am looking at, but which is the particular test or sensor that will give me the cam offset?

Or is it ONLY a code? If it's a code I think my freebie would do that. I'd like to check mine and see what it is even though I do not have a trouble code.

And thanks for the help too.

kb3jhp · #10 10-30-2006, 04:36 PM

it did not send a code it is just off by -8 and is running crappy. this also controls fuel curve doesent it

MT-2500 · #11 10-30-2006, 05:27 PM

Quote:

Originally Posted by 534BC

The auto-enginuity is one of the softwares I am looking at, but which is the particular test or sensor that will give me the cam offset?

Or is it ONLY a code? If it's a code I think my freebie would do that. I'd like to check mine and see what it is even though I do not have a trouble code.

And thanks for the help too.

If off very much it should/but not always set a code.
The cam offset reading can be found in the engine sensor data readings.
Different scanners may have it in different sections of the reading.
But any of the that can read the engine data should read it.
But may not show up on just OBD11 readings.
You will need a engine capable scanner.
Good Luck
MT

kb3jhp · #12 10-30-2006, 06:56 PM

ye my school has a mac scanner that shows it and is of by -8 i am going to replace the dist cap roter pick up and hope for the best i post back if it works

MT-2500 · #13 10-30-2006, 07:21 PM

Quote:

Originally Posted by kb3jhp

ye my school has a mac scanner that shows it and is of by -8 i am going to replace the dist cap roter pick up and hope for the best i post back if it works

10-4
Look at the old cap and see if it has been firing on one side of plug terminal.
Replace it with a AC-Delco cap and rotor they work the best.
And if it does not bring it back to normal if the non adjustable dist you may need to slot the the dist hold down clamp a little to turn the dist enought to set it.
But on the pinging part make sure the egr valve is working good.
Good luck and let us know how it goes.
MT

534BC · #14 10-31-2006, 12:01 PM

Must be my free software, It senses only rpm, timing, map, o2volts, shorttrim, longtrim, speed, closed/open loop, tps, air temp, coolant temp, fuel status, obd conformation and load.

I have 8 pages of sensor readings, but only 1 page is active, As I look thru the other 7 pages of readings I do not see any that look like "cam offset"

When shopping for software what is it called? maybe "cam offset" I suppose it could also be that my vehicle will not support this reading also?

MT-2500 · #15 10-31-2006, 02:26 PM

Quote:

Originally Posted by 534BC

Must be my free software, It senses only rpm, timing, map, o2volts, shorttrim, longtrim, speed, closed/open loop, tps, air temp, coolant temp, fuel status, obd conformation and load.

I have 8 pages of sensor readings, but only 1 page is active, As I look thru the other 7 pages of readings I do not see any that look like "cam offset"

When shopping for software what is it called? maybe "cam offset" I suppose it could also be that my vehicle will not support this reading also?

It is actually called crankshaft/camshaft position sensor correlation.
The engine specific code for it is P1345
All of the engines that have it the pcm/vcm supports it.
But not all scanners will read it.
I am not sure that OBD11 suports the reading of it.
I always get it from the engine specific data or engine data capable scanner.
Even on a snap on scanner it is sometimes only shows up on engine missfire data readings.
Good luck MT.

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