I HAVE A 94 Z. YESTERDAY I WAS GOING TO A CAR SHOW AND AFTER FILING UP WITH 93 OCTANE, I GOT ON THE ROAD. AFTER AROUND 3O MINS. RUNNING AT 70-80 ISH CAR WAS DOING FINE. I CAME TO A TOLL BOOTH. I SLOWED DOWN AND THE CAR WAS HESSITATING, BACKFIRING, RUNNING SUPER ROUGH.ALMOST STALLED.

insteed of just chaning parts i'd like to know whats wrong.

what is a good scan tool so i can pull my own codes?

 

Here's a "draft" version of a writeup that will eventually end up on my website... should answer your question:

===================
D - R - A - F - T

GUIDE TO SCANNERS FOR 4TH GEN F-BODYS

There is a fairly rigid dividing line between OBD-1 (1993-1995) and OBD-II (1996/1997) hardware and software. Unless specifically stated, products will only operate in one system, not in both.

Further complicating this is the fact that the 1993 and 1994 models have a 12-pin “OBD-I” ALDL connector underneath the dashboard, near your right knee. 1996 and 1997 models logically have a 16-pin OBD-II ALDL connector in the same location. But, the 1995 models, while equipped with an OBD-I computer (PCM – or powertrain control module), have a 16-pin OBD-II connector. This means that when you buy a scanner, or a laptop connector for a 1995, you must verify that it can be supplied with the OBD-II connector, with pin locations specific to the 1995. There are “urban legend” stories about some dual-cat 1995 models being equipped with OBD-II PCM’s, but no one I know has ever found one. The 1995 “California emissions” option A4 cars are equipped with dual cats, but the PCM’s are OBD-I (and they are not rated 10HP higher than the single-cat “49-state” cars.)

A “scanner” can be a valuable tool… allowing you to identify the DTC (diagnostic trouble codes) that can be set in you PCM, and to view in real time the values for many of the sensors and actuators in the engine. Most “scanners” will not access the body control module (BCM) or the ABS control system. Most scanners can only read the sensors or PCM values, not change them.

For some info on what you can read with many scanners, and how to interpret this data, look at my “ScanMaster” writeup, linked below.

http://members.aol.com/InjuneerZZ/ScanMast.htm

For the mother load of all links related to the computer:
http://www.bfranker.badz28.com/fbody/links.htm#PCM

Another site with excellent info and links relating to scanners is AKM Electronics:
http://www.akmcables.com/




OBD-I: HARDWARE

§ AutoXray
http://www.autoxray.com/index.htm
http://www.autoxray.com/scanners.htm

GM OBD-I Scanner ($200 list/$175 at auto chain stores) - Reads trouble codes and sensors. Records 29 seconds of data. Will work on many GM vehicles, from mid-1980's. This is a good portable unit, small enough to hand-hold while driving, but the LCD display makes it sort of hard to read in anything but bright light.


§ ScanMaster LT1 - $250 from Ramchargers or T. Byrne Motorsports.

Performance oriented unit. This one is small enough to mount on the steering column, or in the A/C vent on a Z28. Bright LED display makes it easy to read. Default display is O2 mV's and knock retard. When you go WOT, it will record the minimum O2 level and the maximum knock retard, and the MPH at which each happened. As soon as you go WOT again, the new data overwrites the old.

While driving, can be sequenced through about 20 sensor and PCM value displays. It will only display one sensor reading at a time, and does not record anything other than the O2 and retard for a single WOT pass. One of the displays in the sequence it for trouble codes, and it will display all active and stored codes in a sequence. Always nice to have it read "--" for this one…..).

All features work for 1994 and 1995 only. Will NOT work on 1993 F-Body. Will work on 96/97, but will not display OBD-II trouble codes.


§ Actron CP9001 ($35):
http://www.sunpro.com/cgi-bin/web_st...=2781372_28269

The "GM Code Scanner" is nothing more than a switch in a box, that shorts the ALDL pins together. This will ONLY work on 1993 F-Bodys, and you do not need a "scanner" to do it. All you need is a paper clip. Do NOT buy this for your 1994 or 1995. It will NOT work.


§ Actron CP9110 ($220)
http://www.actron.com/cgi-bin/web_st...d=4322814_4845


§ Snap-On:
See "OBD-II" for Snap-On products.


§ OTC Tech-series
These are the GM service tools. See "OBD-II" for these products.



OBD-I: SOFTWARE
(Obviously, works best with a laptop. Requires an interface cable…. See AKM Electronics link, at bottom)


§ Diacom
http://www.rinda.com/auto/auto.htm

Old-fashioned DOS software… advantage is it works with many GM cars from about 1985. Not much else to recommend this one. Just remember, it won "Popular Mechanics" Design & Engineering award in 1991 (!!!) and hasn't been updated much since. They even spell the name of the product wrong ("DIATOM") on their website - duhhhhh)

Diacom ($279) - Codes and sensors, real time display.

Diacom Plus ($579) - As above, but adds data recording, graphing.


§ TTS Datamaster (free download - 20 run limit, cable $125; software license + cable $219)
http://www.ttspowersystems.com/

This is the Cadillac of the scan software, for OBD-I. Version available for 1993 F-Body.

I do have a question on the accuracy of the fuel injector duty cycle that is calculated within the Datamaster software. It appears to calculate a number that is too high. This needs to be investigated.


§ pcmcomm - bundled with LT1_Edit for OBD-I.
http://www.carputing.com/

Add $50 for data logging capability.


§ FreeScan (free download)
http://www.andywhittaker.com/ecu/ecu_software.htm

I have seen posts that indicate that although there is a "93" version listed for FreeScan, it will not work with 93's. I have not been able to verify this, so proceed with caution if you have a 93.

 

3 cheers for Freescan.

 

injuneer. da#n you know some ****. thanks alot .i'm ordering a scanmaster today and trying out free scan in the meantime.
thanks again