1996 4.3 Timing issue
#31
01-18-2018, 03:01 PM
I do have the Dash Command. I did purchase the pids, around 10 bucks if I remember correctly. I used it to set the cam retard and it worked great. I opened up the slot also.
A few months later I still had a small hiccup even after all the things I did to it. I believe my issues could be tranny related now. I replaced the whole distributor just for the heck of it. That didn't correct the issue either. Still have it but haven't been to a transmission shop either...lol.
Long story short, the cam retard works with the pids I purchased.
Good luck
A few months later I still had a small hiccup even after all the things I did to it. I believe my issues could be tranny related now. I replaced the whole distributor just for the heck of it. That didn't correct the issue either. Still have it but haven't been to a transmission shop either...lol.
Long story short, the cam retard works with the pids I purchased.
Good luck
#32
01-18-2018, 04:36 PM
Jacked_72 I checked my timing advance using Torque and my values are all positive. Don't know what is going on with your setup. Can you screen cap your negative timing values in Dash Command and/or Toque for me?
#34
01-18-2018, 04:44 PM
Originally Posted by jacked_72
Sorry for frustrating you, certainly not my intent. I'm seeing the same negative readings in Torque as I saw on my corded OBD scanner. I saw the same negative readings with DashCommand, but I want to look again before I lead you astray. It was cold last night and I did'n't spend a lot of time with DashCommand, but I recall thinking that perhaps its values were are derived differently from the others and then being disappointed that they were not different. I know I don't need the enhanced PiDS to see the timing, but I saw from some of your screen shots that there is an IAC PID. That is definitely one I'd like to have a look at as I believe that could be at the root of the fuel trim issue. I'm not fixating on the timing issue, but it just seems that its significantly different from the norm -- i.e., positive values rather than negative. Anyway, here's the link to the other forum. https://www.garagejournal.com/forum/...ight=jacked_72 You'll have to join to see the thread but its a good forum and lots of useful information. As you will see, I got the fairly typical internet responses. All the information in the world seems to be on the internet. The tricky part is finding the information that is accurate. And everybody is an expert. I got many posts about rotating the distributor and cutting the slot in to the hold down clamp. You're the first guy that seems to have any idea how the sensors work. Trust me, I'm not trying to do anything but have you help me.
Yes, this is not my daily driver. I've had it since November and put a lot of weekends and nights into it. Its hard to believe that a car with so few miles can have so many issues.
Yes, this is not my daily driver. I've had it since November and put a lot of weekends and nights into it. Its hard to believe that a car with so few miles can have so many issues.
Of course everyone is an expert. I have been wrong before, and I will be wrong again - but I seldom give up and I have been pretty successful. But to me things have to make sense - and the timing and IAC as problems causing these codes just doesn't make sense to me. If IAC is open to far then the engine runs faster (not leaner) - If it's too far closed, then the engine runs slow (not richer) - if it's unsteady, then so is the idle. Note sure exactly what your problem is at this point, but if you stick with us we will get it fixed. It's much more difficult when the vehicle diagnosis is done remotely, but this all has become pretty interesting to me - so I'm game if you are.
Last edited by LesMyer; 01-18-2018 at 04:56 PM.
#36
01-18-2018, 09:36 PM
I see where your claim of the negative spark advance is coming from. Very strange unless PID is not correct for you vehicle. But you said with a hand held scanner too!
Is your S10 (pickup IIRC) a LU6 (vin X) or a L35 (Vin W)? 8th digit.
Also here's some interesting info for you.
I have factory info that says 1996/1997 fuel trims are in "counts". Ideal is 128 counts. But that is for L35
1998+ L35 fuel trims are in %. Ideal is "0".
So it seems the PIDs for the 1996/97 might be significantly different. looking into this further.
In the meantime attached is the factory diagnostic chart for P0171 in a 1996 S10 to consider. (Yeah I know I said not the IAC)
Is your S10 (pickup IIRC) a LU6 (vin X) or a L35 (Vin W)? 8th digit.
Also here's some interesting info for you.
I have factory info that says 1996/1997 fuel trims are in "counts". Ideal is 128 counts. But that is for L35
1998+ L35 fuel trims are in %. Ideal is "0".
So it seems the PIDs for the 1996/97 might be significantly different. looking into this further.
In the meantime attached is the factory diagnostic chart for P0171 in a 1996 S10 to consider. (Yeah I know I said not the IAC)
Last edited by LesMyer; 01-18-2018 at 09:49 PM.
#37
01-19-2018, 08:48 AM
Thanks Les. It is a VIN X vehicle. I researched the "counts" thing versus the percentage of fuel trim earlier. I found a chart somewhere that compared the two and I believe that 128 counts was equal to 0%. From what I read, "counts" was GM's way of calculating the trims. It appears not to have caught on and the world went with the percentage measurement. I suppose that if the ECU is putting out "counts" and DashCommand is looking for percentages, that could make the fuel trim readings look odd, but I don't think it would explain the CEL turning on as the its an apples to apples issue for the ECU.
I'm glad that you see what I'm seeing on the timing. It may have nothing to do with nothing, but it is really a head scratcher.
I'll have time to work on it this weekend, so if you've got any suggestions as to things to check, please let me know. I plan to play with the IAC and double check that the distributor is in right.
I'm glad that you see what I'm seeing on the timing. It may have nothing to do with nothing, but it is really a head scratcher.
I'll have time to work on it this weekend, so if you've got any suggestions as to things to check, please let me know. I plan to play with the IAC and double check that the distributor is in right.
#38
01-19-2018, 10:41 AM
Originally Posted by Lesmyer
Yeah, let me read the entire story.
So I guess I must agree with you that the question regarding negative timing remains a smoking gun. I think that must be answered, if you are to trust the FT values. If one is goofy, I think the other could be as well.
What we don't know is if the timing PID in both of your scanners is the wrong one for your 1996, or if there is actually something wrong with your system. I really hope we can get Graveyard to fire up Dash Command on his 1996 and actually read his Timing Advance with the Generic OBD2 PID and also tell us if a separate GM timing advance PID might exist in Dash Command for the 1996 (separate does not exist for my 2001).
Also, you can try the two PIDS that are in Torque Pro and see if there is any difference. There is a [GM] Spark Advance PID in Torque Pro, as well as the Generic OBD2 Timing Advance PID. Enhanced PIDs don't always work as they could be for a specific vehicle or year range of vehicles.
That would hopefully give us some answers.
Last edited by LesMyer; 01-19-2018 at 10:55 AM.
