Analyze my Datalog. . .tell me what's causing this

[Italian LX]

Originally Posted by 86GT

Have you changed the EEC out?

Yeah, I guess I forgot to add that in there... I'll edit my post and add it in.

[86GT]

humm, let me think about it a while......

[Italian LX]

Originally Posted by 86GT

What a bout a loose connection on the TFI to EEC. Look at pin 16, 36, 56. Make sure there is no corision and so forth. I would slao check the shield wire. It is supposed to be grounded.

I concentrated a lot of my "loose wire testing" around the distributor/TFI module with no luck. I've tugged and tapped on the TFI itself with no luck in reproducing the problem. I have also inpected the EEC connection when I swapped computers, but didn't notice anything unusual.

What really throws me off is why the ECT drops down and slowly climbs back up.

I thought it could be the ECT sensor dropping out and some how causing the EEC to do weird stuff with the timing. I tried pulling the connector while the motor was running, but the datalog just shows the ECT staying at the same position it was in. I bought a new sensor to try, but I haven't put it on yet.

[Italian LX]

Originally Posted by 86GT

humm, let me think about it a while......

Take your time. . . I've been thinking about it for half a year now and still haven't come up with anything.

[86GT]

I just replaced my ECT too. Do not buy the cheap plastic one. They tend to go bad after a year. I have gone through two of them already. I now have the original Borg Warner version.

Another food for thought, If the EEC power relay was on the fritz then it could cause what you are seeing. Since you are monitoring the EEC while this is happening, the EEC loses power, but the Tweecer plugged into the laptop is supplying the minimum voltage. The PC will not be able to supply the full current and things begin to drop off.

[Italian LX]

Originally Posted by 86GT

I just replaced my ECT too. Do not buy the cheap plastic one. They tend to go bad after a year. I have gone through two of them already. I now have the original Borg Warner version.

The one I bought cost $20 at AAP. Thanks for the tip; I'll check and see what brand it is.

Originally Posted by 86GT

Another food for thought. . .

Hey, I'm grasping straws, so I appreciate any direction that you can point me in.... no matter how far fetched it may seem.

Originally Posted by 86GT

. . . If the EEC power relay was on the fritz then it could cause what you are seeing. Since you are monitoring the EEC while this is happening, the EEC loses power, but the Tweecer plugged into the laptop is supplying the minimum voltage. The PC will not be able to supply the full current and things begin to drop off.

This has also happened without the laptop hooked up. It's also weird that the ACT stays normal while the ECT fluctuates.

I've got a DataQ that I can tap into the EEC power circuits. I can use it to datalog in the WinDaq software -- that way, I can see if the power relay maybe causing an issue.

[86GT]

Another thing to check would be the MAP sensor. There is a spark multiplier associated with it. If the BP is real low it applies a multiplier of 0. Anything multiplied by 0 is 0.

Maybe, Maybe

[Italian LX]

Originally Posted by 86GT

Another thing to check would be the MAP sensor. There is a spark multiplier associated with it. If the BP is real low it applies a multiplier of 0. Anything multiplied by 0 is 0.

Maybe, Maybe

Definitely worth a try. I'll just add Barometric pressure to my datalogging and see what it does next time it cuts out.

[Wicked]

I don't remember, does the ECT and distributor harness run through the same leg of the engine harness. Maybe there is a loose wire as you said.

Also, kinda off the wall, but my Cobra would do the same thing when I first put my switchable chip in. The switch was not fully secure and would bounce around and the ignition would cut out for a split second over bumps. Only occured 2 or 3 times but it was an easy catch. I know you don't have a chip, but maybe your Tweecer wiring or connection.

[Italian LX]

Originally Posted by Wicked

I don't remember, does the ECT and distributor harness run through the same leg of the engine harness. Maybe there is a loose wire as you said.

Nope, the ECT, ACT, TPS, Injectors, etc. are on the injector wiring harness. The TFI, SPOUT, etc. go back to the CPU wiring harness.

Originally Posted by Wicked

Also, kinda off the wall, but my Cobra would do the same thing when I first put my switchable chip in. The switch was not fully secure and would bounce around and the ignition would cut out for a split second over bumps. Only occured 2 or 3 times but it was an easy catch. I know you don't have a chip, but maybe your Tweecer wiring or connection.

Well, the TwEECer basically ressembles a chip on the J3 port and it does have an RJ11 connector on both it and the selector switch. However, as mentioned in one of my pervious posts, I have replaced all that with new and the problem still exists.