Did some more data logging.

I found that my Ignition Timing Advance is bouncing around between 10º and 19º at idle. This seems like a lot of fluctuation to me, is this normal?

Attached is a picture of the data I logged (click on attachment to view full size). This data was taken over a period of about a minute (on intervals of about 2-3 seconds).

As you can see, idle speed is not constant and varies from about 590 to 630 rpm. This is the reason I am logging data (to resolve a funny idle issue).

Could this be a bad Cam Position Sensor? I replaced the timing chain with a new double roller timing chain about 6-8 months ago (noticed an overall improvement). No loose timing chain noise now.

Could it be a PCM issue?

Any input would be appreciated.

Thanks,
Chris

 

id pull the timing cover just to be sure.....it may be new, but all parts have potential to be defects.......

 

Dont have to pull the timing cover to check the chain. (although, Not sure which method is actually easier.....)

Pull the dist cap, turn the engine slowly backwards until the rotor starts to move. (having someone help is going to be a requirement on this motor......) Mark the damper, and the timing cover....... then, turn the engine forward until the rotor starts to move. See how far the engine has turned. That is the amount of slop in the chain. Anything under 10 degrees is ok. With a new timing set, should be less than three.

 

That's fine for ignition timing at idle. The" fuel sync" is the one affected by the timing chain. The pcm does ignition timing and will adjust it on the fly for air temp, barometric pressure, coolant temp, throttle position, etc., etc. You and your tuner question, LOL. You're like a kid with a new toy!

 

That is normal for the timing to bounce around like that at idle!!?!?! Holy cow. Are you sure about that Aim?

Yes, I have been having fun with my new logger... the only problem is, I don't know how to interpret any of the info it gives me!!! Any signal that isn't perfectly stable makes me think something is wrong. Luckily there are some patient people on DF.

Maybe I will get blocked for asking too many simple questions.

HeyYou, 95Ram360, I have actually done that test before. It is how I determined my old chain was bad (had 11º slop). I will try to get it done this week. I still need to look under the cap too (to check the condition).

Unfortunately I am a little short on time these days... if only I could play with my truck all day.

Any of you guys running an aftermarket timing chain tensioner? I thought I saw one on one of the sites... of course I didn't see it until after I had done my timing chain.

Thanks for the input guys,
Chris

 

Isn't that how it usually goes though? When I did mine (over the course of four days.....), I just put in a good double roller timing set. The factory set lasted 165000 miles..... I figger if I can get another 165K out of it, I will be happy.

 

Yes, ignition timing gets pushed and pulled a lot, as the O2 sensors tell the PCM to richen/lean out the mixture to maintain the proper A/F ratio for fuel economy purposes.

Lots of guys at bionicdodge.com run those tensioners and recommend them. I know www.manciniracing.com sells them.

 

Yeah, that is the tensioner I was talking about... I wish I had have found it before I did my chain. Seems like cheap insurance.

Thanks for the input everyone.

Cheers,
Chris