GNX dash installed, now have problems!

[mazdatech78]

I just got my car running after a months of engine and trans work. During that time I installed an AVC GNX dash w/ VDO gauges. I got the instructions from Tom at gnxdash.com and followed them to a tee. During cam break-in I noticed some problems.

1st The tach doesnt work. After doing some searches on the board I found that VDO tachs need the unit from caspers to work. I just want to double-check that I have this connected correctly. The instructions say to connect the tach wire to the white wire of the auxillary harness off the cluster. Is this right?

2nd My SES light flashes very fast and my scanmaster doesnt work anymore. The scanmaster powers up (screen says 2.1 on engine start) but then doesnt display anything. Im just wondering if anything that was changed during this dash install could cause this?

Any info would be greatly appreicated due to the fact that im not going to be able to tune this pig w/o my scanmaster. Thanks in advance.

James

 

[ES1]

I would check the connections for SM as that has been a problem for me when when it acted like you described.
I think a flashing SES means the chip is not set right or it might be an ECM problem.
I would recheck all grounds.
On the VDO tach, I have one that I did not have to anything extra to get it to work. Tach is about 3 years old. It is set for the 6?

 

[rodman99999]

I had a VDO tach on my '85 GN that worked perfectly, without any other pieces needed. Made certain it was set for a 6, and hooked it to the white RPM take-off wire (next to the alternator, green connector).

 

[ajt86]

yeah a flashing SES light is a poor connection at the chip. did you swap your chip at the rebuild? take it out of the ecm, check all the pins and reinstall.

 

[GNut]

Definitely not dash related!!
The tach not working depends on how old the tach is. VDO "Used To" modify them at the factory for use with a GN's Ignition. They don't do this service anymore and all new tach must use one of Casper's convertors. You can use the white feed wire from the auxillary harness or run a wire all the way out to the dianostic plug up near the a/c compressor (green plug with nothing hooked to it). I had a flashing SES once, definitely Chip related.

Tom Houser
Performance Instruments
www.gnxdash.com

 

[mazdatech78]

I took the chip back out and and reinstalled it. The SES light no longer flashes. The problem with the scanmaster was the ground at the turbo bracket. I recleaned and added a star washer and everthing is all good. As for the tach, I dont know how old it is. I am going to run a wire from the tach straight to the green connector. If it still doesnt work ill call up Caspers and get the converter.

James