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| ECM upgrade (1227730) for stock 2.8 (Page 81/107) |
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Hudini
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NOV 08, 11:40 PM
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YE13 is fuel pump voltage to the ECM. This wire is spliced into terminal L (Tan/White wire) of the C203 connector. This is how the ECM senses the voltage going to the fuel pump. The other question: I don't know why the ECM isn't sending out voltage to close the relay. It needs pulses from the ICM to fire the injectors but the fuel pump should be powered up and running. Maybe check the ECM grounds? Does the car run with the fuel pump powered through the aldl connector?
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americasfuture2k
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NOV 09, 12:23 PM
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ohhh, i will check that conection. the car sputters when i force it on, it needs new plugs. badly. just cant afford any till uncle sam pays me for my outstanding service. ------------------
First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones 
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Darth Fiero
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NOV 09, 03:40 PM
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| quote | Originally posted by americasfuture2k:
i just swapped ECM's and still the same thing.
my fuses are good. ive tested the fuel pump relay turn on wire from the ECM and it reads nothing. its that grn/wht wire coming from the ECM to the FP relay.
the datalog doesnt show anything when 12v is applied to pin G on the ALDL. or....wait, come to think of it, i didnt apply any voltage to the aldl since i was logging through the aldl. tomarrow in the daylight i will try this and see what comes of it.
but one question, how would a good/bad fuse, or power applied to the FP itself by bypassing the relay effect what is shown on the datalog for the power on the FP? and why am i not getting any power on the grn/wht wire that goes to the FP relay coil? i know in order for a coil to energize, it needs power(+) and ground (-). my ground is good.
that APU1 is a pretty amazing and useful tool. emulates, logs, live tunes, burns and reads.
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The ECM sends 12v + power out to the Fuel Pump Relay to turn it on (one side of the relay's control coil). The other side of the control coil is connected to engine ground (be sure to check/verify this).
When you first key on the ignition, the ECM should ALWAYS turn on the fuel pump relay for 2 seconds. This is called FUEL PUMP PRIME. If it does not, then you either have an ECM issue, wiring issue, or blown fuse somewhere.
After the fuel pump prime period, the ECM will only command the fuel pump relay on again when it sees reference pulses from the distributor/crank sensor (when engine is turning over or running) or until you key off the ignition for 10 seconds and then turn it back on (which will activate the fuel pump prime again). If the ECM is not commanding the fuel pump relay on during engine cranking, then the ECM is not receiving a distributor reference pulse.
NOTE: I have come across some bad ECMs in my time where the fuel pump relay output driver was bad. So if you verify your wiring is correct and your ECM is turning the FP on during key-on prime. If your wiring checks out good and the ECM is not turning the fuel pump on during key-on prime, then you could very well have a bad ECM.
OTHER INFO: In OE Fiero wiring, power supply to the fuel pump relay comes from the fuse box (under dash) thru the C203 connector (orange wire) then goes out to the fuel pump relay. The relay output for the fuel pump comes back into the car on the tan/white wire thru the C203 connector then passes out thru the bulkhead with the harness that travels out to the C500 connector where it splits off to that 3 way connector in front of the engine that runs down to the fuel tank. I have come across a couple Fieros that had poor fuel pump wiring connections at the C203 connector; some melted, some corroded. So make sure you check your TWO fuel pump circuits that run thru the C203 connector and make sure you don't have problems there.
The OE Fiero oil pressure switch (if present) acts as a backup/bypass for the fuel pump relay. Once oil pressure rises above approx 7psi, the switch will close and supply power to the fuel pump. The oil press. switch ties into the fuel pump wiring at the fuel pump relay. Having low oil pressure WILL NOT disable the fuel pump operation UNLESS your fuel pump relay is not working properly.
OE Fiero relays are not weather sealed, instead they are packed with a sticky grease compound GM used as a sealer. This sealer is not perfect and I have seen MANY bad relays in the Fieros I have worked on (water/moisture gets inside and corrodes the contacts of the relays). In all of my swaps I replace the factory Fiero relays with modern GM weather-sealed units to prevent this problem. Since I do this I also remove the oil pressure switch from the fuel pump wiring circuit since it really isn't needed.
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Pyrthian
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NOV 10, 09:46 AM
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I know its probably somewhere in this thread - but - getting kinda long to browse thru - so:
wideband O2
does the 7730 support it? if so - does the 7730 'just use it' - or does a new chip need to be made?
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Darth Fiero
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NOV 10, 12:20 PM
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| quote | Originally posted by Pyrthian:
I know its probably somewhere in this thread - but - getting kinda long to browse thru - so:
wideband O2
does the 7730 support it? if so - does the 7730 'just use it' - or does a new chip need to be made?
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All GM ECMs are designed to work only with a narrow band O2 sensor input. Some wideband O2 sensor controllers have a narrow band output (0-1v) which can be used for this.
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americasfuture2k
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NOV 10, 06:46 PM
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so pin "B" on the C203 has power. its hot at all times. tested the fuel pump fuse and its hot at all times as well. is it supposed to be like that or no? and i think my c203 has some wires not right on it. the c203 connector and the in car connector of that c203 has different colored wires on some of it. ------------------
First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
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Darth Fiero
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NOV 10, 08:46 PM
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| quote | Originally posted by americasfuture2k:
so pin "B" on the C203 has power. its hot at all times. tested the fuel pump fuse and its hot at all times as well. is it supposed to be like that or no? and i think my c203 has some wires not right on it. the c203 connector and the in car connector of that c203 has different colored wires on some of it.
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Yes the fuel pump fuse in the fusebox as well as the wiring circuit passing thru terminal B of the C203 connector is supposed to be hot at all times. The other fuel pump circuit (terminal L, tan/wht wire) is only hot when the fuel pump relay and/or oil pressure switch is closed (fuel pump should be running when this is hot).
-ryan
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americasfuture2k
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NOV 10, 11:37 PM
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so should i try jumpering my oil pressure wires that go to the FP relay and see what happens? ------------------
First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones
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Darth Fiero
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NOV 11, 12:48 PM
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| quote | Originally posted by americasfuture2k:
so should i try jumpering my oil pressure wires that go to the FP relay and see what happens?
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If you do that your fuel pump should run. If the pump runs when you do this, but the pump does not run when you turn the ignition on and/or crank the engine, then you have to check the ECM, FP relay, and FP wiring circuits.
If you jump the oil pressure switch wiring and the fuel pump does not run, then you need to check the FP wiring circuits.
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americasfuture2k
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NOV 11, 09:45 PM
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ok, so i am doing a very thorough check on my harness. and checking again and again to make very sure i got everything right. ive already found some mistakes  hurts my ego since i am an electronic tech for the navy. i have a question on a pin.
A7 - tan/blk - TCC / Shift Lamp control - move to - GF6
the TCC only applies to the auto. and shift lamp is for the getrag. should i move the mentioned above wire to the shift lamp pin on the C203? pin A?
but pin A on the C203 goes to BA9 which is the serial data and on the C203 pin A is the shift lamp control.
on the C203 pin P is the TCC Brake Switch feed.
when i do a continuity test to C203 pin A, it goes to pin BA9 AND pin M on the ALDL
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when i do a continuity test to C203 pin P, it goes to pin GF6.
im confused on getting a shift lamp now.
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D8 - dk grn - egr diagnostic switch, pin C at egr - move to - GE8 - coolant fan control, connect fan temp sw wire to this circuit
i am missing this wire. i have the dk grn/wht wire going from the fiero specific coolant switch to the C500 then into the car.
do i need to connect that dk/wht wire to the dk green wire in GE8? or is it ok as is? or did i screw something up?
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BA5 - gry - 5v ref - connect to A/C pressure sensor terminal B
what is terminal B and what A/C pressure sensor?
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BB5 - blk - sensor ground - splice into existing wire to supply ground ref to A/C pressure sensor terminal A
again, what is terminal A and what A/C pressure sensor?
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First LX9 Fiero GT, 1987
If you can't fix it with a hammer, you've got an electrical problem
Fiero's are people too. We pay just as much attention to them, if not more than our loved ones [This message has been edited by americasfuture2k (edited 11-11-2008).]
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