OTC 2000 not reading info on '81

[dhattey]

I've been fighting retarded timing on my '81 Monte Carlo turbo coupe. Folks on this board suggested a scan tool, I scored an OTC 2000 for $40 on ebay.

Unit came with a 3-way cartridge and manual, plus a GM cartridge with no manual. Both seem to work and to communicate with the engine computer (no check engine light when connected, "no data" on screen when disconnected). But no data shows - everything shows fixed numbers (mostly zeros). So not much help troubleshooting the car!

Anyone seen this before? Any suggestions?
thanks in advance
Dave

 

[charlief1]

The early puters don't always read properly. Do you have it hooked up to a 12 volt power source from the lighter socket or battery? The early ones need it to read right.

 

[dhattey]

Yup, its plugged in - OTC doesn't light up unless it is plugged in to lighter socket. Funny part is it knows its getting a data stream - if i unplug the diagnostic connector under the dash the OTC says "no data" on either module. But the values don't change - most are zero, the temp reads 186 on one cartridge and 367 on the other and doesn't ever change. MAP and Baro read 0, ox reads 0. Higher mode numbers return "unused".

Original problem is the computer/ESC retards the timing heavily whenever the 4 pin connector is plugged into the distributor - hot or cold. Car barely runs with it connected, disconnect the 4 pin and it runs enough to drive it but no boost to speak of (probably good since no knock protection either).

I thought it was a sensor, have changed knock senser, MAP, Baro and Ox. I didn't know these early computers could even be scanned, got the suggestion here and found the OTC with a '81 diagnostic connector adapter. Computer is running as its making data stream to OTC and if the diag is jumpered flashes out error codes (none there).

Ideas?
thanks!

 

[TurboDave]

You sure you got it setup properly to the vehicle you're trying to read? There's setup steps you go through to match the vehicle.

 

[dhattey]

Yup, read the book on the 3-way cartridge and followed it to the letter. And followed the prompts on the straight GM cartridge to enter VIN digits. Both seemed to respond properly.
thanks!

 

[charlief1]

I had a simular problem with an early tune port firebird at work one day. It turned out the plug was messed up on the cord. We had 3 and no one remembered why and I ended up with 1 of the bad ones. After an hour one of the guys said something and I just about hit him.

 

[Freddie's Buick]

I've been fighting retarded timing on my '81 Monte Carlo turbo coupe. Folks on this board suggested a scan tool, I scored an OTC 2000 for $40 on ebay.

Unit came with a 3-way cartridge and manual, plus a GM cartridge with no manual. Both seem to work and to communicate with the engine computer (no check engine light when connected, "no data" on screen when disconnected). But no data shows - everything shows fixed numbers (mostly zeros). So not much help troubleshooting the car!

Anyone seen this before? Any suggestions?
thanks in advance
Dave

It won't work without the grey adapter it should of came with. The cartridge is fine but it is mostly for 82' on up computers. The 1981 is not compatible with the OTC-2000 w/o the adapter.

I have one so I know what you are going through. I got lucky back in the early days of the forum. One of the guys had a OTC-2000 but for the later ECM's and had the adapter which he did'nt need. He passed it on to me. Nice people here on this forum. :biggrin:

Hope you score one to complete your OTC moniter.

 

[dhattey]

Good news is the one i bought came with the grey adapter - so it sees the data stream and puts the ECM in test (check engine light goes out). Bad news is it just doesn't get any info out of it - all modes show zeros or numbers that never change.

One new piece of info - if i go back to the menus and tell it to pull the error codes it says "reading" and stays there - tried it twice, my patience ran out after 5 or 6 minutes each time and i power cycled the box the first time, then the second time i pulled the data cable - and it went to "no data".

If i jumper the diagnostic connecter it flashses codes on the check engine light (no codes, just the all ok sequence).

thanks for the feedback, this spark any more ideas?