Software
The box next to the configuation line said 5 and was flashing red. I changed the baud rate and the position of the resistor and the box turned green and had a twenty in it. Oddly enough the idle changed and smoothed out.
I tried to syncronize the TBIs using a manometer. When I did nthis on my truck 1991 GMC I did not block off the air inlet to the IAC. but it worked. So do I need to block the IAC?
The car idles high 900/1000 RPM and has trouble warm starting. The injectors dripple. When I shoot starting fluid in to the TBI throats it fires right up and runs okay.
The car still has its original TBI and fuels pressure regulators. Should I change the regulators
Sorry for the long post. I thought that all of these may be related.
Thank you all
The ECM spits out a series of hexadecimal numbers. They are a list of parameters that the ECM is seeing, such as RPM, coolant temperature, spark advance, etc. You need the correct data definition file that matches your setup. That includes whether the trans is manual or automatic and the rear axle ratio. Otherwise it's just a jumble of numbers that the software tries to interpret.
If you have the wrong data definition file you will get wacko results like -2.26 volts for TPS.
[EDIT]: The reason is that it is actually looking at the value of some other parameter and trying to interpret it as a voltage. [/EDIT]
I suspect your coolant temperature sensor is sending bad info to the ECM. If the ECM thinks the coolant is cold it will richen the mixture and raise the RPM. You'll need to get your software working correctly to find out what temperature the ECM is seeing.
Last edited by Cliff Harris; Jun 11, 2013 at 12:57 AM. Reason: Added clarifying verbiage.
The ECM spits out a series of hexadecimal numbers. They are a list of parameters that the ECM is seeing, such as RPM, coolant temperature, spark advance, etc. You need the correct data definition file that matches your setup. That includes whether the trans is manual or automatic and the rear axle ratio. Otherwise it's just a jumble of numbers that the software tries to interpret.
If you have the wrong data definition file you will get wacko results like -2.26 volts for TPS.
I suspect your coolant temperature sensor is sending bad info to the ECM. If the ECM thinks the coolant is cold it will richen the mixture and raise the RPM. You'll need to get your software working correctly to find out what temperature the ECM is seeing.
I would like to have a decision tree on how to troubleshoot the system.
I sent away for a manual on disc it has not appeared yet.
Like what tells what what. ECM/IAC/TPS injectors on.
When you turn on a TPI the injectors squirt. Should the TBI do the same?
Thank you
Joe
I suspect the TBI does something similar.









