'87 350 TBI, custom application, looking to go bare-bones

[Mrgto68]

Hey Dave,
there was definitely a slight learning curve with that software, but figured it out pretty quickly :-)

I'm not able to drive the rig around right now, however I was able to get it up to operation temperature and recorded some data.

I attached the data file.

Thanks Again!

-Mike

[sturgillbd]

It appears to be open loop at idle. What is the 4 letter designation on the chip in the computer? Some of the early 7747's had open loop idle. You probably need to use a heated O2 sensor with this setup and idle can be tuned. May have to change the chip to a later calibration. The computer can be modified to accept the flash type chip and you can get stuff to burn your own chip or get someone on here to burn one for you.

[Mrgto68]

It's definitely open loop at idle. I haven't looked at the chip yet, I'll do some research and figure out where to find it. I've read several places about using a heated O2 sensor, what's the benefit installing one?

[dave w]

Hey Dave,
there was definitely a slight learning curve with that software, but figured it out pretty quickly :-)

I'm not able to drive the rig around right now, however I was able to get it up to operation temperature and recorded some data.

I attached the data file.

Thanks Again!

-Mike

Congrats on figuring out TunerPro RT.

The single wire O2 sensor is using the heat from the exhaust gases only to maintain the minimum operating temperature for the O2 sensor to work correctly. Often the exhaust gases are not hot enough for the single wire O2 sensor to maintain the minimum operating temperature for the O2 sensor work correctly.

A three wire O2 sensor has a heating element to maintain the correct operating temperature of the O2 sensor.

dave w

[Mrgto68]

Ok, makes total sense.

I just placed an order for the ACDelco AFS74 and the three wire harness adapter. Should have it installed by tomorrow evening.

I noticed that I was getting a VSS error. When I installed the new ECM Wiring Harness, I don't remember if I hooked up VSS connector.

Where would I begin looking for the VSS wire connection on a 1987 R30 350TBI?

This is freaking awesome, Thank you all, seriously. I've been a classic car guy working on GM motors since around the age of 16, 34 years of tuning Carburetors.. the whole TBI / ECM thing is recently new to me, started when I went to the 2015 SEMA show out here in Vegas and first saw the Fi-tech drop in "fuel injection" system. Was blown away by the technology and immediately purchased one for my '68 GTO. I will NEVER touch another Dinosaur Carburetor ever again lol...

[1project2many]

The heated O2 will not cause closed loop idle if you have an open loop idle calibration.
If you are using the engine in an off-road application there is no need to use an O2 sensor or to restrict yourself to 14.7:1 AFR.
I would suggest installing a check engine light, or at least a convenient connector where a light could be installed. You currently have no feedback to indicate a problem detected by the ecm. You also have no way to view "flash codes" which can be obtained with a simple jumper wire.

[mecanicus]

I would connect the heated o² sensor like dave w said. This way the sensor reaches its working temperature much faster and will hold the temperature on near idle as well. When engine is running in closed loop , it is running efficiently and smoother. For your VSS problem have a look for a used DRAC module and only connect this to your ecm. For your wiring problems, we need the exact number on your ecm,there are wiring diagrams according to the ecm here on the forum.And install a SES light for safety.
try this adx file and have a look to dashboards, there are different views.

When I read your earlier posts again, i realized that you have a complete FITECH system bought and mounted. I fear in this case you have to ask at fitech for a wiring diagramm and if you can connect heated O2 sensor and DRAC. Wiring diagrams here on the forum will not work!

[S.O.B.B.]

If ur using 7747 there is a post under 1227747 wiring question.I think it may have the info u seek.I searched drac wire diagram and the second last on the list is that post.hth

[PlayingWithTBI]

I ran across this link which may help in your wiring/troubleshooting...

https://www.gmt400.com/threads/88-95...manuals.43575/

[Mrgto68]

If ur using 7747 there is a post under 1227747 wiring question.I think it may have the info u seek.I searched drac wire diagram and the second last on the list is that post.hth

Hey thanks for the info, I did a search and wasn't sure If I landed on the same thread you were referring, can you post the link?

[Mrgto68]

I would connect the heated o² sensor like dave w said. This way the sensor reaches its working temperature much faster and will hold the temperature on near idle as well. When engine is running in closed loop , it is running efficiently and smoother. For your VSS problem have a look for a used DRAC module and only connect this to your ecm. For your wiring problems, we need the exact number on your ecm,there are wiring diagrams according to the ecm here on the forum.And install a SES light for safety.
try this adx file and have a look to dashboards, there are different views.

When I read your earlier posts again, i realized that you have a complete FITECH system bought and mounted. I fear in this case you have to ask at fitech for a wiring diagramm and if you can connect heated O2 sensor and DRAC. Wiring diagrams here on the forum will not work!

Hey Thanks Buddy.

The Fitech system is on my '68 GTO. the info I'm gathering here is for a 1987 R30 350TBI which I'm using as a base vehicle for a custom fabricated vehicle. I relocated the entire driver controls and have since done away with all the dash components and gauges. When I purchased the new ECM wire harness there were a few plugs that were not run, ie: VSS and TCC.