experts in reading PCM data?

[Craig 94 TA GT]

I was finally able to get a cable to the laptop...and used Freescan to try and diagnose my problems. However, I have no idea what all the figures mean, and if they are on par, etc. As far as my problems go, it stumbles a slight bit (sometimes) at idle, and the problem seems to increase a whole lot when the A/C is on. And as far as top end, it stumbles past 4800 PRM and makes a large popping noise at 5400 RPM. I'll try to get a WOT run later. The file attached is in Excel txt format. Anyways, if anyone can shed some light on the values or read my current ones, I would greatly appreciate it. Thanks in advance.

[Kevin - Blown 95 TA]

Well, that data is hard to look at, but there's nothing that I can see that stands out as problematic. The only thing that is a little off is your Left BLM which is 141 and later 133, when the Right BLM stays at 128. This means that the left side is adding fuel to compensate for a slight long term lean condition possibly due to a vacuum leak, intake leak, or possibly exhaust leak on the left side. You can also see that the left bank of injectors is a little longer pulsewidth (average) than the right which is the extra fuel. It seems to get better when it goes to 133, which isn't too far off from 128. It is all within the corrections that the PCM can provide, and you can see the integrators (short term corrections)are normal. You can also see that the O2 sensors are both switching normally in the .100-.800V range. Temp & idle, tps voltage, etc all look normal, no spark retard.

[Craig 94 TA GT]

Thanks for the info Kevin. I do have the intake oil leak and am going to fix it sooner or later. So I guess that may be causing my low end stumble. I just hope that's also the cause of the motor to sputter at 4900+ RPMs.

[Kevin - Blown 95 TA]

Thanks for the info Kevin. I do have the intake oil leak and am going to fix it sooner or later. So I guess that may be causing my low end stumble. I just hope that's also the cause of the motor to sputter at 4900+ RPMs.

I don't know about that - you might have an issue with valve springs, opti, wires, plugs etc...

[Craig 94 TA GT]

The opti, plugs, wires, entire fuel system are new. I'll probably end up changing a lot of the valvetrain when I repair the intake leak. Probably LT4 valve springs, LT4 or Crane SA 1.6 RRs. Would you know how much the valve covers need to be modified for them to fit? Also, would it be ok to replace the lifters, as well, or do they already have grooves or valleys that are worn with the cam after 106k miles? I'm afraid that new lifters wouldn't work well without replacing the cam. Thanks a lot for the info.

[Kevin - Blown 95 TA]

You might or might not have to do anything to your stock valve covers. Mine worked without any changes, but some guys have had to trim the supports to clear the rockers. I eventually went to plastics which are more roomy and are rumoured to absorb noise better than the steel ones.

The lifters are probably fine, and it is probably best to keep them with the cam, even if they are rollers. I'm sure plenty of guys have reused their roller lifters with new cams since they don't get worn the same as flat ones. When I did my cam, I put in some Crane lifters which bleed down a little more than stock. Besides not pumping up at high rpm, they have the added benefit of bleeding off a little at low rpm which gives a little less lift when you are just driving around town.

[Injuneer]

When you save your file in FreeScan, is it possible to save it in ".csv" format? That will allow virtually anyone with Excel to study your file, manipulate the data, etc. It takes me about 15 minutes just to format a .csv file, and add the formulas that I use to analyze some of the data. Then save it in .xls format. But it makes it a lot easier to study the numbers.

You also might want to look over my online scanner writeup, for some guidance on interpreting the data.

ScanMaster

[Craig 94 TA GT]

Sorry about that Fred...the xls file is here: http://s94938520.onlinehome.us/data/idle_run.xls
Thanks for the link to the info on what the data means...I will study it thoroughly.

Kevin, as far as the lifters go...I agree with you. I would think that these are "mated" with the cam, especially since they have 106k miles. If I were to get different ones, I don't know what would happen...although some have said that there should be virtually no wear since the lifters are roller...
So the current pushrods are OK to reuse unless I get non self-aligning RRs, right? Then I would need hardened pushrods with guideplates? Which would you recommend for an internally stock motor (and probably will always be internally stock). Do any have more/less clearance issues? Thanks again...

[Kevin - Blown 95 TA]

Yeah, you're OK with stock pushrods, but aftermarket ones are cheap, so you could get stiffer ones, hardened, and better than stock, even w/o guide plates. Otherwise just wait until you do a cam and get them then. probably not as important as valve springs - a lot of people overlook those cause they're a pain to do. IMHO, a guy with a stock car can see a performance gain from nothing other than replacing the springs. I'd dress the ends too.

[Craig 94 TA GT]

Thanks again for the reply Kevin...I wanted to quickly ask if I would need to replace the valve seals too? Also, if I replace the valve springs, is there a simple tool to keep the valve from falling into the cylinder? Or would I have to get a compressor, hook it up to the spark plug hole and compress the cylinder? And using hardened pushrods are ok with the stock lifters/cam + 1.6 RRs and LT4 valve springs?

I'll also add a new file of the PCM data...one thing I noticed is that the left BLM raises quickly after it warms up, but it seems to even out a bit later. Then it seems to go back even again. Is this still a sign of a vacuum leak? Also, the IAC is 99 during cold idle, which seems a bit high according to Fred's document. Is this normal? Thanks a lot for your time and help...
[EDIT]
Sorry, I forgot to include the file link, dummy me. http://s94938520.onlinehome.us/data/first_run.xls