Trace I.D. 1990 eprom

[BIRDCLAWTSi]

I have a 1990 Eprom ecu, I have been having some strange issues with this ecu,

I have a strange unstable TPS issue, It will fluctuate +/- roughly 5%, Say you are at 20% TPS, It will fluctuate between say 17 to 23%, Car bucks, Wideband going crazy. This is intermittent...

I can't ground the ecu case, It feels like rev limiter, Or fuel cut at like 1500-2k rpm. Also intermittent...

I have a strange reading on the logger as well (mmcd), have to jump two wires at datalink, Pins 10 and 12, Otherwise readings cut in and out and get serial comm error.

I have tried the stock chip, Burned chip, and the ostrich, all with same results.

I removed the board, and found a broken trace, Repaired the trace, But found something that didnt look quite right, Maybe it is, But I have nothing to compare it to, Maybe someone can identify this for me.

I should also mention that i am running this in a 93, With pins 6 and 14 switched.

Here is a picture of the traces in question. The small red circle on the left is the trace I repaired, The big red circle on the right with the small red circles on the inside are the two solder traces attaching the upright board to the small resistor...I don't know if the solder should be touching the upright board...I appreciate any insight. Thanks, Dave.

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[rts91tsi]

Both of those pins from IC 110 should be connected to C25.

Pin 1 of IC 110 is connected through R16 and CM 105 is tied to pin 110 of connector C-59.

Pin 2 of IC 110 is connected to the ECU's grounds both chassis and sensor from the applicable pins of C-59 and C-61 connectors.

http://www.dsmlink.com/images/forums/1GECUPinout.pdf

Although difficult to tell with all of the components installed, I can't see how any of the repairs that you made would cause a funky TPS reading since the TPS circuit is on the opposite side of the PCB, and it's circuit path leads to IC101, as well as some of the other analog inputs from C-61.

Check your wiring for the TPS circuit to make sure it is in specs, and it probably wouldn't hurt to test the TPS too.

Try also checking continuity and resistance on pin 63(MFI Relay Control) from C-60 to pin 4 of IC 110, which could be causing the intermittent bucking issue.

 

[BIRDCLAWTSi]

\ Thanks for the reply, It turned out to be a bad capacitor SIP, under the heat sync. One of the legs was dissolved from past cap leakage. I replaced the sip, car has not acted up in 2 days. So far so good. Thanks to Dave Mertz at ecmtuning.