Is the TEC failing?

4SFED4 · founding member Joined: 25 Feb 2008 Posts: 48

4 cylinder TEC-2 running WinTEC.

Started the engine today to find it running very lean 15.X and above at idle and when trying to start off in 1st gear. Does not seem to respond to enrichments.

Switchbatt is reading 12.8 with key on and 13.2 at idle as are Inj1 and Inj3.

Fuel pump makes noise and the fuel pressure gauge on the fuel pressure regulator is reading correctly. Grounds are clean and secure.

The TEC is fully and professionally tuned, has been for years, there have been NO changes lately.

Started the car to monitor it and noticed all the sensors responding accordingly but did notice fuel flow was 0. Reflashed the TEC and it was the same. Several starts later the engine responded normally. Went for a short drive around the block and it ran just fine for 15 minutes until it stalled at a light. Restarted it and the lean condition was back. Limping home it died a few more times. Did not restart until after several attempts and I did not hear the fuel pump when it did not start. Then heard the fuel pump again and it started and ran normally to get me home. Checked voltage at the pump, switchbatt and all was nominal.

I had a TEC does something similar before and it turned out to be an internal error with the TEC itself.

Thoughts?

Ideas?

Thanks in advance,

-Brian

rb26powered74zcar · Posted: Sat Aug 16, 2008 6:34 am Post subject:

On my last Tec2, I had a simulor situation. It turned out to be the MAT sensor prong, that sticks out of the Tec unit (the tiny prong that the green connector plugs into) had corroded all the way inside the gel pack that makes it water proof, and got inside the circuitry.

If I would lift up, or push down on the green connector while the intermittent problem was happening, it would cause the MAT sensor to work or not work...

Sounds like its either that sort of problem to me, or at least a sensor/sensor related issue. Have you removed the green connectors and cleaned the prongs coming from the Tec? Mine constantly had green corrosion scale on them...
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Tec3r

4SFED4 · founding member Joined: 25 Feb 2008 Posts: 48

The TEC triggers a relay that takes power straight from the battery. I found the ground for that relay used a riveted union to the chassis and the rivet was loose enough to allow the ground wire to rotate about the eye. Hmmm. Moving it around would cause it to gain and lose contact. After removing the rivet I used a star washer and a screw and it has not failed again since then, about 60 miles. I think... (hope) that's all it was.

gwolf · Newly Aquired Joined: 12 Aug 2008 Posts: 4

Mine had a similar problem. It would work fine for a while, and then just quit, especially at idle. I spent a lot of time trying to re-tune my idle, and even advanced the timing 18 degrees manually (new location of the sensor on the crank trigger wheel). Sometimes, if the car wouldn't start, I could wiggle the long green sensor plugs, and it would work. After two trips back to Electromotive, nobody could find the problem. Electromotive insited that it was a tuning error, but couldn't supply a solution.
I finally got so frustrated I opened up the unit myself. After peeling off the potting compound, I started tracing the copper circuit pads on the circuit board, using an eye-loupe. I immediately found that 6 of the pins from the sensor connector to the circuit board were cold-soldered. I touched up those 6 connections with a small soldering iron, and the thing has run perfectly ever since.