jdemoya

For those with the experience with corvette diagnostics, I would like to know what kind of information will I get with a scanner. Some of them are inexpensive these days. How valuable will that information be to troubleshoot ignition problems, etc. Will spark timing, injector firing, etc be available with this scanner.
Thanks, JDeMoya.

93Rubie

Injector firing=no
Ignition timing=yes, ie. 36 degrees and such.

With OBDI, you WILL NOT get misfire codes, only OBDII. Even those are sketchy at best. I had a vehicle with a cyl. 1 missfire code. I suspected coil, it tested bad, I swapped to #2 cylinder and I SHOULD have seen it the code move to #2 cyl. misfire, I got P0300 instead, which is multi-cylinder misfire. Stupid, On Board Diagnostics... I replace the BAD coil I had moved to #2 and it ran fine, NEVER had a multi-cylinder misfire. Computer thought it detected one, well it was wrong.

Older OBD1 cars give you less data than newer cars. You will get basic engine data from sensor and output states-on/off. In addition to codes.

I have a cheap older Actron CP9110, it does Ford, GM, Chrysler OBDI, and Generic OBDII.

My much newer OTC Nemisys give me more engine data for all OBDI and ODBII vehicles. It can do ABS, AIR BAG, and CCM codes,data for my 93 Corvette. As well as ECM functions. I got it for 400 on ebay. They are 1200 new. It is WAY advanced for a typical car owner or even the weekend hobbyist.
I work on cars for living so I wanted a entry level professional grade scan tool.

I find them invaluable, how else do you see what the ECM is seeing? It is just a tool, NOT solution, nor is a code a soluation. It is a starting point. You have to understand what you see on the tool for it to be any worth diagnostics wise. You need to be able to pick out bad data if you see it.

jdemoya

Thank you for the information. I am still inclined to buy a scanner. Which one do you recommend? Of course not the most expensive one, he,he.
I find myself doing more repairs than I thought I would be doing so it is time to jump in.
Thanks, Jdemoya.

Cliff Harris

The cheapest and most flexible way to go is to buy a cable and hook it up to a computer (laptop preferred for obvious reasons, but I've heard of guys hooking up to a big beige box).

I use Diacom myself, but it's very expensive and they haven't updated it since I bought it in 2000.

Here are some sources for cables and software:

http://www.akmcables.com/dss.htm
http://www.aldlcable.com/
http://www.moates.net/

65Z01

About 12yrs ago I bought an AutoXray to help diagnose & tune my '88 Vette and it has served me very well.

You can use it to get a snapshot of the engine or in Monitor Mode to get a 30 sec continuous scan.

jdemoya

Thanks all for the information.
JDeMOya.

jdemoya

I don't have any codes present, the engine runs very rough and only while stepping on the gas. It will die if I let the pedal go.
If I disconnect the MAF sensor, it runs on idle though poorly.
No codes...
Jdemoya

j3studio

I'm partial to the Moates stuff, but not familiar with anybody else's (of course, my 1985's computer is dumb as a bag of rocks). I'd be willing to bet that you would get a lot more answers in the C4 Scan & Tune portion of the forum.

SunCr

I'd see if there's something for your Cell Phone first - there's an assortment of Apps for OB2 for Android and Apple, but I don't know what's out there OBD1.

You can get Sensor values and fueling with a Scanner with Closed Loop fueling probably being the more useful piece of information. However, if it runs ok with the MAF disconnected and there are no Codes, it's problematic that you need a new MAF. It's simply getting the wrong info on air flow and it's either delivering too much or too little fuel.

Cliff Harris

That sounds like you need to do a "minimum idle" adjustment. How to do that was written up many years ago by Lars Grimsrud and his article is all over the Internet. One place is here:

http://www.batee.com/corvette/dcrg/r...scuss_sim5.htm

SunCr

There is no reason for the screw to move unless someone moved it. If flow is restricted, then it needs to be cleaned. If air is getting in from somewhere else, it needs a new throttle body. There is, realistically, only one setting for one atmospheric pressure for one humidity for one temperature that works. Someone a lot brighter than me figured that out and from there, all of the variables work. The motivation to monkey with that screw eludes me.

87Blue

So where is that section of this forum?

Cliff Harris

It has been consolidated into:

https://www.corvetteforum.com/forums...erformance-48/