Howell FI CEL and code recovery

[thescot]

Figured I throw this out before I call Howell or try to find a diagnostic means to pull codes. This is the first CJ with FI so Im not sure what to expect really. Its always started normally however seemingly way to rich as it blubbers like a heavy choke till its run a few minutes. I head down the street which is mostly downhill and at the bottom stop sigh as I push the clutch in it typically idles down so low I think its gonna stall but never has. Friday as I was coming home from work which is 30 miles of 50mph plus and the CEL comes on and then goes off about 10 miles later while cruising along. Sat when I fire it up I get a constant light when the key is turned on, which is normal,then as I crank it goes out briefly and comes back on as it fires up like a single flash code. Howell says its a must to have NO voltage drop as you crank it over if the ECM isnt wired correctly and will ump its memory every time its started until wired correctly to a constant hot once key is on. Its been some 10 years since the Howell was installed and I cant see anything changing far as wiring goes.The tags on their harness are not legible so reading whats what is a no go. The only thing I can offer was it was getting low on fuel and maybe pressure dropped but even at that the FI has so few sensors it would never know if the tank was dry, a cat was installed,the vapor canister was screwy etc,etc. All it reads is a 02 sensor, map, and one temp sensor and 12 volts pretty much, if Im not mistaken. Id surely be interested in hearing any others experiences with the FI system.

 

[Old Dog]

I've had mine for 6 years now with no problems, although I did have to change the o2 sensor once.
Have you jumped the ALDL to check for codes? If not I'd start there. Also make sure it's going into closed loop mode after it warms up.

 

[thescot]

How can I verify it in closed loop after its warmed up?

 

[Torxhead]

To verify closed loop, the oxy sensor has to be putting out voltage between .1 and .9 volts at a variable rate while the engine is running. I have also had to replace the oxy sensor.

 

[Old Dog]

You check it in "field service mode" which means jumping the A and B terminals of the ALDL with the engine running and driving at a steady speed. when the sensor is cold (open loop) the service engine light will flash at a rate of 2.5 times a second. In closed loop (sensor warm) it will flash at a rate of 1 time per second.

 

[thescot]

Thank you, I'll see what that does. If Im not getting closed loop what is this indicating, a bad 02 sensor?

 

[Old Dog]

yes, chances are good that would be the problem.

 

[thescot]

Thanks Guys, think I swap out the sensor regardless, its the original from way back and their cheap enough.