Got a question. I've read somewhere in posts that on board computers can be reprogrammed to delete certain codes etc. I have a 94z or OBD-1. First of all..is it legal and 2nd, is this something that a back yard beginner mechanic can do ? I have an EGR situation and would like to delete DTC 32. Thanks

 

Probably not technically legal to tamper with any emissions device... As far as can any chimp do it? well maybe. Technically, it is not hard to connect and turn the test off, but stuff can go wrong during the flash process and cause the car to not start ever again until you have the PCM replaced or repaired. Just saying this because it wasn't an uncommon event when communications was lost during reprogramming. So certain precautions are taken when reprogramming and there are risks associated with it. But to answer your question, no it isn't that hard to do.

The other thing about tuning in general, is that there are a lot of guys that are computer savvy and can interface and work the software, but have no clue about what they are doing with the engines and transmissions as far as setting switches, constants, and tables. So if you knew how to tune an engine and understand fuel injection and sensor input and output, etc, then you have a reasonable chance of success. And even though tuning a computer controlled EFI car is analogous to tuning a carbed distributor car, there is way more adjustment - just more to know about due to the sophistication of the systems you have access to.

There was a guy selling a cable and software in the 'for sale' section - just be aware that LT1 Edit is pcm specific - licensed to a pcm s/n wheras Tunercat is not pcm specific in that regard and can be used in an unlimited number of pcms.

Lastly, it isn't that hard to repair egr problems except for physically doing it. They usually get all clogged up with carbon in the manifold passages or the tube from the exhaust manifold gets cracked or something. You can test the diaphragm pretty easily and see if it opens while idling the car and the car kinda stalls, but the controller only turns the solenoid on at specific times, is it is a little harder to test the solenoid. For a stock car, there is a benefit to having it, if your car is cammed, then not so much.

 

In addition to deleting the code, you also have to prvent it from setting a "system not ready" flag. Many emissions inspections will not pass you if there are a certain number of "not ready" codes.

I would note what Kevin said about deleting the EGR system, or not correcting a problem. It has no effect on performance, and can actually help reduce the tendancy for detonation (knock) when lugging the engine at low RPM in the wrong gear.

If you want to program the code out, I would recommend a mail order tuner, such as:

PCMforless

madtuner.com - Home

 

thanks for the info. My car idles and runs fine for now even with the ses light on. Question...running the engine for a two hour trip with the cooling fans running with a lit SES....do you think that can do any engine damage especially in the cold northeast weather?

 

What does the coolant temp get to in cold weather with the fans on full time? Too low and you'll be running in the cold start enrichment mode. Unlikely, but worth thinking about. What temp t'stat do you have? That will also affect where the temp is with the fans running full time.

Another consideration is the fact that the PCM will not run some diagnostics if certain other codes are set. I've never gone through the list to see which diagnostics cannot be run if DTC 32 is active. Might cover up being alerted to another problem. Of course you wouldn't know anyway if there was a new problem, since the SES light is always on.

 

The thermostat is 180. Ive run it short distances with the ses on and it didnt seem to affect the engine temp. Crazy thing is if I go on a long trip the car starts without the ses and after about 5-10 minutes of warm up the engine hesitates and the ses comes on. If I stop the car and turn off the ignition, wait a minute and restart the car the ses will not again come on for the duration of the trip. Im taking the car to another shop as the one Ive been working with cannot solve this issue. Wish me luck