You and I agree Morely I remember when he punched his cat out and it was a circus in that thread.I just have this gut feeling that something is still not right on that side.He has gone through a few O2s on that side and mabey the last one was due to silicone But he did not have any pieces of the cat to determine what really caused it to go in the first place.

I think a scan after replacing the O2 is the best thing to do first but I believe everyone should also have a baseline vacuum reading on thier intake just in case for future reference.I am wondering if he has an intake leak on that side.The scan will show yes or no...............

 

The new O2 is in and I have done a new scan... I will get it uploaded and posted pretty soon here.... aside from that - I found out that I actually opted against doing the RTV last time (the O2s come with a good enough seal with them) - so that wasn't a factor at all.


As for the new scan.... some of the log is still a bit erratic (O2 mvs dont seem much different and fuel trims are all over the place still), but the spark retard is now completely smooth (except for a few false knocks - I assume they are false). So the O2 replacement has made a difference.... Gonna go ahead and try to get the new one uploaded...


Oh - and I merely wanted to suggest injectors since the stockers have 85k and my problems have been isolated to one side... Since they are so easy on an LT1 I have been considering getting the ford blue tops and replacing them all (cheap enough peace of mind).

 

whoops - double posted... on wireless...acting weird....

 

I'm not sure I know how to do this (vacuum reading) but perhaps my father does.... I will be going back home next week for spring break... Always nice to have any tool/machine I can think of on hand... I hate being forced to do work here with limited tools...

 

New Datamaster file after the RH O2 replacement... http://www.filefactory.com/get/f.php...52ee9c298db5a8
- I never got to get any good RPM runs - but what little i do have seems to show the right curve for an LT1 (whereas the previous file didn't). Again.. I still don't know what to make of the erratic O2 mv reading and fuel trims all over the place.... During driving it sounded like I may have been getting a little bit of backfire or wanting to backfire... which would tell me that it is still lean. Will definitly have to check these other things that are being mentioned. Thanks again for any help

 

I am having the same problem Morley had playing that file back.4REGT4 if you become a supporting member you can attach files to your posts.

All you need for the Vacuum measurement is a gauge and a hose attach it to your intake where the EGR valve gets it's vacuum from as it does not work at idle anyway.I recommend getting a Mityvac it is very useful and you can bleed your brakes with it.I got mine from ebay for$30 including the attachments to bleed the brakes.

O2s will be erradic but should average around 800(at least mine do)The fuel trim is adjusted by the O2 feedback and although I can't read the file pay attention to the long term counts those are also call BLMs and should average around 128 higher is leaner lower richer.What are you seeing?

If you email me the file I can post it here for you

If you go with the FMS24# you will run a little rich(mabey) and might need an AFPR at least or a tune for them to be right.I have a set for sale in the parts section.Before you throw parts at it lets figure out for sure you need them


Also have you pulled your codes and has your SES light come on?

 

Now that I have driven it again... this last time I didn't have any problems and it didn't seem like it wanted to backfire at all.... But again it is a colder night, and I have yet to have a problem in colder temperatures... while I was getting the codes and stumbling it was almost always during a warm/hot day or coinciding with putting some gas in it (always 93 Octane Chevron)... (would a warmer day support a vacuum leak idea?) - - - - I had posted it before, but I did pull code 64 (Right O2 lean). Now the scan is clean of DTCs - - - I'll fill the tank up tomorrow and make sure that it doesn't go to heck again as it has been... That is something I can't really explain... Either way I hate all these computers... - - - I have yet to pull a plug to see if that tells me anything about the injectors....but at this point it doesn't seem to me that the injectors are any problem... Vacuum leaks sound popular in the forum so it would be interesting to know the # I'll get. My father probably has what you are talking about (or equivilent). I'll find out when I am down there...



EDIT: I plan on buying the $75 e-tuning service through PCMforless as soon as possible. Just trying to work out these bugs first. - - - When do injectors typically start to crap out anyway?? I was under the impression that it was 80k (from other things I've read). But everyone seems to think it is crazy to replace them... though the used ones sell fairly well on eBay.

 

Here are the scans

 

Unless you are still working on getting the other one up...only the old run is posted.

 

If those files are playing back right(I re installed datamaster because I could not believe what I saw you are running so lean it should blow up anytime.I mean that is the worst file I ever saw.
Mabey there is something with my version of data master that will not work with your files.So tell me the answers to my questions.
What are the L&R long term counts averaging?Same with the L&R O2s?

Here is a file of mine to compare to

 

Hmm - that is not very comforting... - But I am rather certain it isn't THAT bad.

EDIT: I still only see the one old file of mine posted...

 

I only got one zip file from you with both files in it try zipping each seperately and sending it.
The files in the zip should be try3.uni and afternewRO2.uni and both should be there.Try saving it to your desktop and open the zip file.

 

Ok - you are right. The zipped size was leading me to believe it was only the smaller one. Thanks for posting them for me. But I'm off to bed.... my fiance has been calling (nagging)...

 

Hey Morely can you describe what you see with his new file?I don't see the right side doing anything running LTs at 252right side at 142 still way lean.Going in and out of closed loop constant spark retard.Very little if any rO2 reading is that what your seeing?

 

I'm watching your "after O2 change" log as I type this.
What I'm seeing looks almost perfect. Left & right O2's are swinging together, L term & S term fuel trims are within 1-4 of each other, the duty cycles and pulse widths are matched. The only thing I see wrong is 2 knock retard spikes one at 25.5 Kpa and one at 34.3 Kpa, both were around .9v on the TPS, they wern't "bad" knocks and may just represent a poor area in the tune. you wern't accelerating or decelerating, RPM's were pretty constant, the only other difference I could see was that the RH O2 read 786 and the LH was 94.
Unless Alvin can see something in that file that I'm missing (very possible), I would say you are good to go for now. BUT, since this has been a reoccuring problem for you, I would definately log a run each week for 2-3 months to see if things are deteriorating.

<edi>Redeasysport, I must have been typing when you posted above <edit>

 

I don't get it unless I need another Datamaster program for that year I don't see anything like that.Is datamaster year specific?What were his LTs running at?I saw something like you described the first time you read his scan .

If I were hime I would take it on a 1/2 hr cruise and scan again running at different speeds and doing a couple of WOT shots.I also would do 1 a week just to be sure it is not going south.I think he has a stock tune so the knocks should not be happening IMHO.Was it going lean when they occured?

Thanks Morely what I saw scared the crap out of me.

 

Yes, you need datamaster EE to read his log. The L terms are "mostly" at 128ish, they varied from 124-134, but slowly, not radical swings like the first file.
Yes, ONE O2 went lean when the major knock(4* retard) occured..but it was the left one.
And I have to add, 4* of retard is not "major", considering it can pull up to around 11*. The knock was just a very quick spike in 2 places. I think it could just be a bad area in the factory tune, you'd be surprised at how some of them knock in a particular place. You'd rarely ever hear it because the ECM was already pulling timing. In fact, his spikes were so "narrow" I doubt he heard them, it couldn't have been more than 2 counts each time.

 

AHhh I see said the blind man.I will get the right datamaster file then.Like you said it sounds pretty much Ok at this point.I would get the baseline vacuum reading at idle now too if I were him.

 

I've heard of aftermarket exhausts causing some false knock... I don't know if that is the case, but as I've mentioned I've got flowmasters - x-pipe (replaced resonator) and gutted cats... But I also already installed an LT4 KM because of this (and I will probably add RRs in the future...) - - - Anyway - I'm not entirely sure the tuning hasn't been fiddled with - it has had many owner before me, but I do notice that it allows me to shift into any gear when the (1-4) light comes on. Does this mean someone has removed C.A.G.S? (when someone disables CAGS is the light still supposed to come on?) In which case I don't know what else could have been done... I have yet to get a response from Bryan at PCMFL, but I will probably go ahead and just buy the tune tonight - - can someone confirm that I can use tuner cat for the ALDL tuning provided by PCMforless? - - - I am just thinking that it is possible someone has already messed with the tuning (perhaps by themselves). Yet even if it was "professional" (suggesting it was tuned) - I've read that PCMFL is just about the only real good place... The 6 month unlimited re-tuning service for the ALDL program sounds real nice too... hopefully I don't go through the rest of my Trial period on Datamaster (I think I have 15 left... couldn't get it all figured out on the first few - they were wasted..).

 

Yeah - your file didn't work well for me at all - completely bizzare reading... I guess I should have recognized we have different programs. Anyway - I will see about the vacuum reading while I am down there, but I'm hoping my father has time to spray my car.. In which case I'll be prepping it and removing the rear panel (front too if I need to). I plan on making it two-tone (was the plan before I bought the car). If that happens I'll be taking some pictures for sure and posting them in some fashion...

- Again - thanks for all the help with this - - - Hopefully I'll understand how to interpret mine and other Datamaster files soon - there is a lot of information there that doesn't make much sense at first... - - - Really though - I just have nothing similar (and known to be working great) to compare it to... that would have made it easier...