need some help!

**Jon114** · 03-21-2015, 10:20 AM

Ok so i just did the shbox tests on my 95 camaro. the readings i got at the icm harness were( terminal A: 11.52. Terminal D: 10.59 and Terminal B was from 1-5 while cranking). Question is, my car has been having an ongoing missfire/ stumble and backfire thats only gotten worse the few times ive drove the car and this morning shut off twice after about 5 minutes of running. I was thinking it was the opti. Talked to popo and he gave me the great advice of doing the tests before i wasted anymore money. According to shbox's tests, im right where i need to be. so what else could be causing the car to act like that. It runs great at wot and runs like shit most of the time at a cruising speed/rpm. has anyone else had similar problems or any advice? Anything would be helpful as of this point. Haha.

**Jon114** · 03-21-2015, 10:38 AM

Also, i tested the opti harness. i got for pin A: 5.07 Pin B: 5.06 Pin C: 10.81 and Pin D was 37 ohms.

**95ImpySS** · 03-21-2015, 02:54 PM

Originally Posted by Jon114

Also, i tested the opti harness. i got for pin A: 5.07 Pin B: 5.06 Pin C: 10.81 and Pin D was 37 ohms.

This test was done on the engine harness with the key on right? The 10.81 volt reading is a little odd to me unless the battery was discharged. Could you do another test and and also measure the voltage at the battery? A fully charged battery should read around 12.5 volts. If your getting a 2 volt drop through the harness you may have other issues.

Do you have access to an old style analog volt meter? If so you can hook it up to your opti wires and watch the to see if the needle drops when the car stalls out. I would measure on the low resolution side of the opti.

**Jon114** · 03-21-2015, 04:34 PM

Yea the battery did confuse me so i tested it again. Same thing. but i did have the car scanned today again. I got a code 41 est electronic spark timing? Also, out of nowhere, The battery died??? I did notice that my opti short harness clip that latches the plug onto the opti was broke. So ive ordered a new harness today. You think that could be a cause??