I was wondering if there were some basic mods I could make to my PROM without the feedback from a Diagnostics run? I can get the programmer and UV eraser for under $200. I plan on getting the AKM cable and a cheap used laptop, but one has to come before the other (or I just wait another month and get everything in one big bundle), but I was thinking I could make some basic safe mods that would be an improvement over stock settings and then finetune when I can diagnose the ecm. This is only if I could get feedback from this board on what type of changes could be made. I do have a gtech pro, but there isn't anywhere I could safely make quartermile runs with it (other then the local drag strip on Wednesday nights, but I don't need the gtech for that) I'm now thinking I could have bypassed the gtech and used the $150 towards a laptop and aldl cable, but that's hindsight. Anyways, I'll stop babbling now. Thoughts, opinions, criticism, et all are welcome.

 

My first question is what is your engine/ecm etc. I prefer to tune with a scan tool, but on some of the older (and slower) ecms it is of less value IMO. Though I personally would still prefer to have a scan tool to let me know whether I am rich or lean. Just my method.

But you can use other methods also (and I recommend that they should be done also as a "cross check" of the scan tool). My two most important tools (other than my Diacom) are my eyes and my ears. My eyes to see my spark plugs...you best window into whats inside the engine. Your ears to listen to the sound of your exhaust. These were the basic tools I had when I all I had was a carbed vehicle in the early 70s, and still used by myself and buddies with our motorcycles.

Here is an article on "reading spark plugs" by Bruce Plecan (aka Grumpy) http://www.diy-efi.org/gmecm/papers/plug_cuts.html

Now there are limits on how "fine" of an adjustment you can make with good old fashion tools. But then again, with a carb you basically only have idle mixture, accelerator pump and jets, (linkage if its mechanical) and with a distributor you have your base timing, vacuum and mechanical advance. You don't get the driveability, fuel economy or smoothness with a carb system, but you do get WOT performance and "reasonable" driveability with these very limited devices.

But for the fine tuning, I still like a scan tool.

Just one guy's opinion.

[This message has been edited by Glenn91L98GTA (edited January 31, 2001).]

 

For years all I used was a stop watch, and
voltmeter,
when on a really tight budget, and I temporary I used a simple 10 segment LED display of the O2. You can hunt around an build one for like $10. BUT THESE are temporary measures. It's takes lots of intelligent thinking without a scanner. AND you have to totally ignore SOTP, orther then for drivilibilty, if you read the tuning.doc at incoming DIY_EFI should help

 

Sorry, should have known to include my car. It's an 88 5.7L GTA. Current mods are a flowmaster 3" exhaust (no headers yet) and a throttlebody airfoil.

As far as checking the spark plugs, should you check them all, or is just checking one adequate, and if so, which is the easiest to get at on the 5.7? Is there even one that could bet considered easy to get to?

 

Being an old timer when spark plugs were one of the principle methods to guage your engine, I have to say ALL.

You need to see how each cylinder is firing to get an accurate determination of what is happening. You may have one "weak" cylinder which is the source of your knock retard being triggered. Also, with TPI, it is really the only way to guage an injector inbalance (or possibly a valve or rings).

One is just not enough IMO, other that to show whether you are rich/lean overall; and then that could be wrong. With all plugs you may find a few are rich, a few are lean and everything else is inbetween. You may have picked the one rich one (while the others are lean) or vice versa. One could make you come to the wrong conclusion.

FYI, some headers make the plug changing easier. I have a bad back and neck ("played" with motorcylces too long), and I find crawling under my car extremely difficult and painful. I can now get at all the plugs on the driver's side from the top and #2 and #4 from the top. Only #6 and #8 require me to go underneath because of the A/C. The day my Freon finally evaporates, I will be pulling the A/C so I can get at all of them from the top. (Or at least hope I can).


[This message has been edited by Glenn91L98GTA (edited February 02, 2001).]

 

I would probly have to say that the front drivers side plug is the easiest? Whichever cylinder number that is, i don't remember.

Brendan

------------------
1987 IROC-Z L98 350 SuperRam, Edelbrock Performer 6085 Aluminum Heads, LPE RollerCam 219/219, Crane Gold Race 1.6RR, TF 1 pc Moly Pushrods, Underdrive Pulleys, Edelbrock TPI High Flow Base Manifold, Accel 58mm TB, ADS 24#, Crane AFPR, K&N, Edelbrock TES Headers, Catco Hi Flow Cat, 3" Borla Cat-Back, Accel Cap & Rotor, MSD 8.5mm, MSD 6AL Ignition, MSD Blaster 2 Ignition Coil, Hayes Clutch, 1LE Aluminum DS, 94' Z28 Disk Rear, Wilwood Adjustable Proportioning Valve, Torsen Series 3 Posi Carrier, Precision 3.73 Gears, Southside Machine Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

Yes. Idle speed (if needed - probably not) and Torque Converter Clutch Control. The latter will provide very noticeable drivability improvements. Depending on the software you use, you may be able to bring the coolant fan(s) in sooner, too. There are probably others, but I haven't seen them with the current version of TunerCat that I am using.

------------------
'87 IROC 5.7l TPI - original owner!

 

<removed>

[This message has been edited by jRaskell (edited February 04, 2001).]