Yet another newbie question but what is age? Is that another way of saying air fuel ration ( AFR ) because 14.7 is magic stoich number? ALso, in the scanner what spark field would I be altering the absolute, the plus or the minus.
Yet another newbie question but what is age? Is that another way of saying air fuel ration ( AFR ) because 14.7 is magic stoich number? ALso, in the scanner what spark field would I be altering the absolute, the plus or the minus.
Do the plus and minus will add to the commanded advance. I know the 4.3 had a lock dist. But the small blocks u could and would have to adjust cam retard (offset) if you didn't install it back close enough. I've never had to do a case learn once I got the cam offset set correctly. And yes I meant afr not age. Must have been spell check on my phone. Also do u have the flat dist cap? If so there are two wired that are easily crossed and if not knowing you could just put them on wrong and it will run like crap. Did that about 5 years ago when I did intake gaskets on a customers truck
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.For transmission its a 4l65e built with the monster in a box mega ss kit.
All in a 92 chevy ext cab 4x4 pickup with a 98 cab now installed with a third door!
running only e85
It is a pita to find out you don't got enough injector but if u don't got money to upgrade you can still have a good daily driver till u can get bigger. I ran out of injector on my set up and just had to keep from going wot for about 6 months till I could afford some with data.
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Let's see what the cam offset shows in the scanner and see if we can get the code to clear. I think it can only be in the range of -3 to 3 degrees. If u got more then that your not going to have success with a case learn
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Hmm well unfortunately I don't believe I am going to be able to get the cam offset readings tonight. I have to try and line up some hospice care for my Mom. Life sucks sometimes. In certain ways I am thankful I have this engine to keep my mind off things.
Anyways, I didn't want anyone to think I don't value what they have to say because believe me if I could I would be down there right now putting it back together enough to run and get that cam offset reading. But my Mom takes priority and I am sure you all understand.
Thanks again particularly Wyochimneysweep. Please keep the good advice coming. I am wittling away potential problems with each post.
No problem bud. Take care Of your mom and best wishes
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Well putting together the things I learned over the past couple days here I am leaning towards it being spark/fuel timing issue based on my cam offset being out of whack. I haven't been able to run it yet to scan it with that PID but that is what makes the most sense. Especially since I am not rock solid confident I have that distributor back exactly the way it came it. I know I am close but i could certainly be +/- 3 degrees and honestly being I did it by eye and have not done anything to correct it in the computer I kinda would be surprised if I weren't off more than +/- 3 degrees.
Being I can't do it right now, I can at least think about it still. Lets just assume my cam offset is messed up.
First of all would that give me the problems I am having? ( wideband says lean, oily plugs and gasoline smelling oil say rich ) I would think it definitely could cause all that.
Second, what exactly does the cam offset PID show?
Finally, other than taking out the distributor and reinstalling it ( in the correct position ) how else can I fix the cam offset being greater than +/- 3. Or is there something I can do through the scanner.
So being I can't get this off my mind, what exactly does that cam offset sensor do. What does the ECM do/control based off of its reading? I haven't scanned it yet but I am sure its off, maybe not too much but it must be off being there is a very small chance I plopped it in right in spec.
But now I am curious to what all is based off of its readings. I am hoping things such as spark and injector timing........
It's not a sensor but tells you the difference between the cam number 1 position and the crank reference and you turn the dist. To adjust the offset
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Hmmm well then I assume that has to effect the spark timing despite the adaptive computer adjustments right??
Would it effect fuel injector timing as well?
What happens when it is greater than +/- 2*?
Ok just to update everyone. I scanned it with cam offset PID and guess what.
-43.5*
So I would say that is definitely going to be one of my main problems and hopefully my only main problem. But as with anything I just need to keep hacking away until there is nothing left.
any tips and advice are still greatly appreciated and thanks to all who helped me out here.
By any chance, have you confirmed that you're wideband is accurate? You mentioned that all signs mechanically point to running rich while the wideband says you're absolutely lean.
With a cam offset of 43 degrees negative it's going to seem lean on the exhaust and rich on the plugs because it's not fully burning the fuel
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Hello all and thanks again for the help.
What does the cam sensor control? Is it just spark timing or is it spark and fuel timing?
Also, I cannot say for sure if my wideband is correct but I did calibrate it per the AFX instruction manual and I did the brake cleaner in a rag test and it went full rich and stayed that way for over a minute. So it seems to be working but can't say for certain.
As for fixing it, I haven't had time to do so just yet because Im so far off and because my upper intake is in the way I am going to have to pick up the distributor and move it a tooth or so before I can rotate the whole assembly enough to get it in the right place. But thats the easy part, I have to make a tool to line up the oil pump connector thing tomorrow at work. So I hope to report back Saturdayish with some good news.
Finally, I probably won't be able to offer too much advice that you guys don't already know but don't do things at night with poor lighting that require lining up two black lines on the back of your engine. Its pretty easy to trick yourself into thinking you got it "darn close"....
Last edited by knowledge; 06-14-2012 at 07:52 PM.
I sure it's for spark fuel and misfire detection as this is how the ECM knows where number 1 tdc is and times the injectors. Being as far off as you are it's throwing everything off and I don't know if it goes to batch firing injectors or if it still does one by one
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Hey Wyochinmeysweep,
That's what I was hoping to hear. Although, I popped the distributor cap off and was dismayed to see that my rotor "seemed" to be in the proper position at TDC to the 1 cyl contact on the distributor cap. However, I am not sure of that ( once again it was night ) but then I got to thinking, the rotor is supposed to be slightly before the distributor contact and I could certainly be wrong about the rotor being right with the contact is. Its dark and its tucked back behind my upper intake plus you kinda have to guess where the contact is being you can't see both the rotor and contact at the same time.
So putting the computer part aside, my mechanical spark timing is close. Meaning the rotor contact is close to the proper distributor cap contact ( at least closer to the right one than any other ones ). However, the camshaft position sensor is still way off and now the computer has no idea the rotor is basically in the correct position relative to the cap and therefore the correct contact point but it is way off relative to the body of the distributor and therefore the camshaft position sensor is way off so whatever is controlled that will be messed up. Even though the rotor is more or less correct place.
Anyways, I am glad to see that it probably controls the fuel too because if it were just the spark timing then I would be worried I had more going on than this, being the rotor is mechanically correct. I guess it would depend on how the computer does things and I suppose it might explain why I don't believe all cylinders are firing. ( new spark plugs are still white, not brown at all for 2 or 3 cylinders ) but if it controls both than it would make me much more certain this is my main problem.
This makes my head hurt just thinking about it.
Anyways, I hope to correct this tomorrow, maybe tonight if I get back home early enough. I post my updates as the happen.
Last edited by knowledge; 06-15-2012 at 05:19 PM.
Keep us updated. My red truck I overhauled was 16 degrees negative and had no power
My setup is a 356ci with a 260/268 (212/218 at .050 lift) duration cam with aluminium corvette heads and flat top pistons running 11.3 comp. ratio. with tuned port injection and vortec crank pick up and dizzy running a 411 pcm and 60lb bosch injectors, 1.6 ratio roller rockers.
Ok so here is an update with both good and bad news but more good than bad I think.
Well I finally had an evening to work on my truck and I attempted to correct my -43.5* cam offset. Which I did to a degree (terrible I know) , and it runs one hell of a lot better. The bad news is it is still out of tolerance by a ton. -24.5*.....
But its running a lot better and for the first time I am pretty confident all 8 cylinders are combusting consistently. It was also much much smoother and generally working like it should. Still rough and the 02 sensors were up in the 8 and 9 hundreds more often than not. However my wideband was pretty good, high 12s to low 14s. I just hope going from -24.5* to 0* +/- 2* does half as good as going from -43.5* to 24.5* and Ill be on the road by the end of the week.
Its going to rain for the next 24 hours so I won't be able to give another update until Tuesday or Wednesday.
Damn weather!!!!
Here is the log file from tonight as well as one from before to compare. I was dumping so much fuel down my exhaust when thought I could get away with putting my wideband sensor in place of one of my 02 sensors. Well it dumped so much unburnt fuel down my exhaust my cats were red hot
Well I got the distributor to within +/- 1* and its running great.
Need to adjust the valves and deal with a slightly rough idle but I should be driving it on the road shortly
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