Engine Cutting Out

[tayto]

sounds like you don't have equipment to data log? if not try to jumper the terminals of the CTS together. start engine, within ~30 seconds you should get a code 14. If you do, the wiring to ecu should be ok and the sensor is most likely at fault.

TBI codes explained with troubleshooting flow charts:
http://www.gearhead-efi.com/gearhead...c/TBIcodes.pdf

[srgould41]

Hmmm. I like that idea as an extra troubleshooting step. I do have data logging capability as well as chip burning. I will try the idea you suggested though. Seems worth a shot just to prove I am getting what I expect. I'll probably try both open and closed to trigger each error.

On a positive note, I guess, I just finished testing the wires. I could not detect any issues in either the CTS or ICM wires. Wiggled like crazy everywhere I could and no change in continuity. Ordered a new CTS. ICM should be here Thursday. Ordered both the D1943A and the Police version D1984A. The D1943A will go in my onboard spares bin.

sounds like you don't have equipment to data log? if not try to jumper the terminals of the CTS together. start engine, within ~30 seconds you should get a code 14. If you do, the wiring to ecu should be ok and the sensor is most likely at fault.

TBI codes explained with troubleshooting flow charts:
http://www.gearhead-efi.com/gearhead...c/TBIcodes.pdf

[tayto]

D1984A is the "369" module
D1945A is the "048" module

369 is the one to get. apparently gm discontinued the 048, so i've always wonder if both Delco numbers are the same module but never had the time to check with a timing light.

if you datalog just follow the troubleshooting flow chart in the pdf. my method is if you only have a paper clip in your tool box...

EDIT: aside from regular tune up items, I usually consider the CTS part of a "tune up" item for TBI. usually for my own vehicle or if someone brings me something that has been neglected or not running right. Also consider the same for the O2 sensor, I usually upgrade to a heated O2 at this time.

[srgould41]

Thank you for the info.

D1984A is the "395" module
D1945A is the "048" module

395 is the one to get. apparently gm discontinued the 048, so i've always wonder if both Delco numbers are the same module but never had the time to check with a timing light.

if you datalog just follow the troubleshooting flow chart in the pdf. my method is if you only have a paper clip in your tool box...

EDIT: aside from regular tune up items, I usually consider the CTS part of a "tune up" item for TBI. usually for my own vehicle or if someone brings me something that has been neglected or not running right. Also consider the same for the O2 sensor, I usually upgrade to a heated O2 at this time.

[brian617]

The CTS is a common failure for a TBI engine. The cutting out you are experiencing is the huge amount off fuel being adding intermittently as the PCM sees an engine temp of -40* when the sensor fails. It is enough added fuel to stall the engine and cause the issues you are having. Ignition cut out issues are usually followed by exhaust backfire.

[srgould41]

I have experienced the engine backfire as the ICM failed. Didn't know what it was at the time.

Ran the experiment today, unplugged the CTS and the engine stalled and would not restart. Jumpering it seemed to run fine. Both cases threw the correct error code. Since I already ordered the ICM and CTS I'll swap both parts.

The CTS is a common failure for a TBI engine. The cutting out you are experiencing is the huge amount off fuel being adding intermittently as the PCM sees an engine temp of -40* when the sensor fails. It is enough added fuel to stall the engine and cause the issues you are having. Ignition cut out issues are usually followed by exhaust backfire.

[tayto]

jumpering the connector and the vehicle running better is a good sign. I haven't seen this problem personally in over 10 years. as i stated before it is part of my TBI tuneup "recipe".

i made a mistake it's a 369 not 395. check what module you have currently. 048 will pull 6* of timing by 5000 rpm. 369 will add 2* by 3600. on a stock motor you should notice an improvement going to a 369 module. if you tune the timing tables it shouldn't matter what module you use.