EFI: Preliminaries

PRELIMINARIES

Federal Emissions Warranty

The very first thing to check when you have driveability problems is if your five year emissions warranty has expired. If it is still in effect, you're golden! At least, you won't have to pay for fixing your car; you can take it to the dealer. But since driveability problems are difficult to solve, you may still want to learn more about diagnosing your car. This will help you understand the work done to your car (and improves your BS detector in case the service manager tries to pull a fast one).

Service Manual

If you're going to work on the car yourself, get the factory service manual:

(800) 782-4356

When I got mine, it was $30 and for the money is easily the best manual I've used. (I paid nearly twice as much for a manual that's half as good for my sister's T-Bird Super Coup.)

I believe it's very important to have the factory manual. The factory manual always contains details the aftermarket versions don't have room for. Do you really think a 3/4 inch manual that covers all Chevrolet sedans from 1985 to 1989 is going to have as much about your particular vehicle as a three inch manual that covers one model year of the platform? You're already going to save money because you're performing the labor yourself; the service manual is the wrong place to be cheap.

Scan Tool

I think the second most important thing to have is a scan tool. I have a laptop so I bought DIACOM:

Rinda Technologies Incorporated
(773) 736-6633

I got my copy directly from Rinda Technologies and it was $300. (I've heard you can buy it from retail outlets these days.) It's and definitely better than any scan tool you can buy in that price range. DIACOM comes with a converter cable that connects your parallel port to the assembly line diagnostic link (ALDL) under dash connector of your pre-1996 vehicle. It does the serial data conversion and can also put the ECM into the various test modes. Designed to run on the original IBM AT, DIACOM runs great on even the slowest laptop.

[photo] I've used a friend's Snap-on MT2500. With all the optional troubleshooting cartridges, it's better than a scan tool alone. It has numerous tests and diagnostic procedures builtin and is very comprehensive.

For OBD-II cars (1996 and newer) the AutoTap OBD-II diagnostic scanner software looks interesting. It appears to be similar to DIACOM in operation and cost ($250).

With any kind of scan tool, you can perform many of the more important diagnostic tests described in the service manual.

Vacuum Tester

The next tool you really need is a vacuum tester. This is basically a hand pump with a builtin vacuum gauge. I bought the full blown silverline automotive kit (#4000) kit for about $60 but you can get the cheaper models for around half that. A vacuum test rig is required for a number of the service manual tests and is indispensable for other investigations. Not only can you test vacuum sensors and vacuum controlled devices but you can also measure vacuum.

Digital Multimeter

One last specialty tool that comes in handy is a digital multimeter (DMM). You can use it to perform continuity tests, check for expected voltages and test sensors.

Some higher priced models can store minimum and maximum readings which is useful when testing the throttle position sensor (TPS). The unit I got has a couple of different temperature probes.

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