tusairon1

I've got an 87 vette that had a cracked block. I had a 350 short block already rebuilt, bored .30 with flat top pistons. 212@.50 or .214@.50 flat tap cam. I had the 113 heads redone put long tube headers on with a 2400 stall. I eliminated air pump, ran true duel exhaust with no cat. Changed the o2 sensor to a 4 wire. I sent the chip to be reprogrammed and installed it. My problem is! It is running rich at idle. when your trying to drive at a steady speed it acts like its running out of gas. Press on the throttle a little and it takes off. It will do this until the SES light comes on! Then it runs like a dream. I don't know how to check the code when the light is on or how to data log. Please tell me what to do! Every time I shut the car off the computer resets.

tusairon1

I also cannot find the connecter under the dash for the diagnostic plug or to check the code it is throwing.

cumbercr

The connector is under the dash just to the right of the steering wheel. It's rectangular shaped, about 2 inches wide and has 12 pins. Use a paper clip or wire to connect the two upper right hand pins together. Turn the key on. The check engine light should blink. It should first show a Code 12. It will blink once (1) then pause and blink twice (2). The code 12 will be displayed 3 times. The blinks that come after that are the fault codes. For instance, Code 21 will blink twice, pause and blink once. Each fault code will be displayed 3 times. When all codes have been displayed it will repeat code 12.

tusairon1

Found the plug. stuffed up in the wiring behind the radio all tangled up. Remounted it where it belongs. I'll check those codes tomorrow night and post what I find out. Thanks for the help.

C409

..... FYI ... flat top pistons + 58cc heads = lots of compression = busy knock sensor ...............

JackDidley

You need to be datalogging ASAP.

tusairon1

My machinist said the flat tops would bump it up to about 10:25 to 1. I'm running 93 octane. I'm way behind on all this computer and sensors stuff.

tusairon1

I know nothing about datalogging either. Trying to figure it out. I ordered a cable from aldlcables.com. Hoping it comes with info on what to do.

tusairon1

I connected the 2 upper right pins together with a jumper wire and it just keeps blinking once then twice.

vetteoz

12 ;No codes stored

http://www.corvettephotographs.com/c4vettes/codes.htm

vetteoz

You need datalogging software
Datamaster gives you 20 free logs before you have to buy

Download and install this file for your '87
http://www.mastertune.net/software/D...M-32-setup.exe

This Datamaster guide is for a turbo truck
http://powertuneplus.com/syclone/tunersguide_dm.shtm
( some items shown don't apply to our cars )
but it shows you what the datalog lets you see when you play back the recording

tusairon1

Well I got the cable and logged a file. what program do I use to play back a uni file? I used Data Master 32 version 4.0.1

vl5150

You can do the playback through Datamaster as well.

I think your initial problem is your changes are way outside a normal engine so it's going to take lots of logging, chip burning, more logging, chip burning, etc to get your rig where it needs to be. One and done chip isn't going to cut it. I used the Moates Auto Tune and highly recommend it.

Go you have an adjustable fuel pressure regular? What's your fuel pressure? Did you increase the injectors? Lots of reasons in play to give you performance problems at this point.

When you do the UNI playback open the histogram and click L-term counts to get a good idea of what's going on.

l98tpi

A) Do you have a heated Oxygen Sensor?

B) Probably need to get a dyno tune.

MrWillys

Unless you race your car on a dyno, learn to tune on your own. keep up the datalogging and tuning. money Cannot buy knowledge.

JackDidley

You are the best tuner for your car.