1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay

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Offline ZoomZooki

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1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay
« on: June 13, 2017, 03:56:30 PM »
Okay, I have a "new to me" 1995 Geo Tracker 4x4 16-Valve Multi-port Fuel Injection (MPI EFI).

The thing will run fine if I put a jumper wire across the Pink/Black wire and the Blue/Black wire at the Green Fuel pump relay connector.  The relay is good because I tested it using a good relay from my other tracker.

The issue is, I'm not getting power to the Fuel Pump Relay.  This is the Pink wire A5 on the ECU.  I check the Black/White wire and it does have a good ground, but I do not have 12v at on the Pink wire with key run or start.  This wire (according to the wiring diagram) is supposed to get power from A5 on the computer.

So, I opened up the ECU and everything looks good.  Nothing black, no bad caps.  So I'm wondering if I have a bad computer, or if there is something else that can cause the ECU to "NOT" supply 12v to the Fuel Pump relay when the key is on.   ???




1994 Geo Tracker 4x4 5-Speed 1.6L 8v

Offline BRD HNTR

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Re: 1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay
« Reply #1 on: June 15, 2017, 08:25:10 AM »
The pink wire on C2-5 is a computer ground to pull the relay in.  The computer only grounds the relay for a few seconds unless it senses that the motor is running.  If computer is not grounding it, it would have 12 volts on it.  When it is grounded The current flowing through the relay closes the relay.
The BLK/WHT wireshould have 12 volts.  It comes from the line feeding the main relay relay.
93 Tracker,XL7 springs & 1" raised spring pads in front with YJ springs in back, home built bumpers rear & front (w/winch), 2" x 4" rock tubes,  ARB front & rear, converted Sami rear to IFS, 33x12.5x15  aluminum rims, roll cage, 2.7L w/5 speed auto.

Offline ZoomZooki

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Re: 1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay
« Reply #2 on: June 19, 2017, 06:15:44 PM »
Yes that was my bad, I was looking at it backwards.  The Black/White wire does have 12V with key on, but the Pink wire is not getting grounded.  I opened the ECU and checked the Transistor leading to Pink wire.   It's Q113 (Transistor Part number CE1F3P)  I looked up the data sheet and it's an NPN transistor with built in resistors and diodes.   I took it out and tested, and yup it's bad...  There are a few of these on the board, and the others test good.

Waiting on new transistor, I'll let you know how it goes.
1994 Geo Tracker 4x4 5-Speed 1.6L 8v

Offline BRD HNTR

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Re: 1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay
« Reply #3 on: June 20, 2017, 06:54:21 AM »
Shouldn't be hard getting the transistor, and installing isn't as hard as pulling them.  So you should be back on the road (with it working correctly) shortly.
Good work.  Here are you?
93 Tracker,XL7 springs & 1" raised spring pads in front with YJ springs in back, home built bumpers rear & front (w/winch), 2" x 4" rock tubes,  ARB front & rear, converted Sami rear to IFS, 33x12.5x15  aluminum rims, roll cage, 2.7L w/5 speed auto.

Offline sidekickyc

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Re: 1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay
« Reply #4 on: June 20, 2017, 03:57:45 PM »
BRD HNTR, Good one, sounds like you nailed that one! Hope he comes back on that ,after the fix.

Offline BRD HNTR

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Re: 1995 Geo Tracker 16-Valve EFI No Power to Fuel Pump Relay
« Reply #5 on: June 21, 2017, 06:09:25 AM »
Shouldn't be hard getting the transistor, and installing isn't as hard as pulling them.  So you should be back on the road (with it working correctly) shortly.
Good work.  Here are you?
I was asking "Where are you?"  My phone likes go auto correct incorrectly.
93 Tracker,XL7 springs & 1" raised spring pads in front with YJ springs in back, home built bumpers rear & front (w/winch), 2" x 4" rock tubes,  ARB front & rear, converted Sami rear to IFS, 33x12.5x15  aluminum rims, roll cage, 2.7L w/5 speed auto.