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?
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.
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.
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.
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?
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?
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.
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.
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.
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).
so should i try jumpering my oil pressure wires that go to the FP relay and see what happens?
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.
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 AND when i do a continuity test to C203 pin P, it goes to pin GF6.
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?
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 (Fiero ECM) - 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?
Yes. But not all manual transmission cars had a shift light -- so this wire may not be present in your car.
quote
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.
No. Pin A on the C203 is NOT connected to the serial data circuit. This is the shift lamp wire (if present). On the 7730 ECM, pin GF6 is for TCC/Shift light control. And you would connect this pin on the 7730 ECM to pin A of the C203 only if you have a manual trans and a shift lamp. If you have an auto, this wire coming from GF6 goes to the transmission.
quote
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 AND when i do a continuity test to C203 pin P, it goes to pin GF6.
im confused on getting a shift lamp now.
First thing you need to do is verify pin GF6 of the 7730 ECM is connected ONLY TO pin A of the Fiero C203 connector and nothing else ONLY IF you have a manual transmission. If you have an automatic, this wire gets connected to the automatic transmission electrical connector.
Second thing you need to do is verify pin BA9 of the 7730 ECM is connected ONLY TO pin M of the ALDL connector.
Pin P of the Fiero C203 connector gets connected directly to the automatic transmission electrical connector (purple wire) and NOT the ECM. If you do not have an automatic transmission, then this wire gets connected to NOTHING.
I am still in the process of gathering parts for my conversion.
Now, I was told (when I tried to order it) that the EGR connector pigtail "PT301" is not available from ACDelco. Is that true? It's still listed on their website... What were you guys using? An aftermarket "Standard" or similar brand, or used from the recycler?
I agree, that would be the easiest route if I was living in the US. However, I am stuck in Europe :-( Over here US cars in junkyards are scarce to say the least. And I got the EGR valve from eBay, but sadly without a pigtail. Stupid me assumed that if a pigtail is listed at acdelco.com that it is available for purchase and not just displayed for teasing prospective buyers. Oh well.
I agree, that would be the easiest route if I was living in the US. However, I am stuck in Europe :-( Over here US cars in junkyards are scarce to say the least. And I got the EGR valve from eBay, but sadly without a pigtail. Stupid me assumed that if a pigtail is listed at acdelco.com that it is available for purchase and not just displayed for teasing prospective buyers. Oh well.
Best regards,
Oliver
I have an extra digital EGR pigtail I will give you for free if you pay for shipping. Email me at sp1@gmtuners.com with your shipping address and I'll get you a shipping cost.
well after comparing my harness to the one merlot originally had on the car and the one i got from bubbajuju, mine seems to be a bit off on the wiring. and possibly threw me off on all of this. my harness is said to be from a 86 v6 4spd. from CANADA. so maybe that had something to do with it. but that pin A C203 / ALDL pin M / BA9 wire had a factory splice in it.
both my pin P and pin A on the C203 were wrong. they were swapped. i got it like that.
The ignition module on DIS engines will produce spark as long as it is getting power and a valid crank sensor signal, even with the ECM disconnected. If you are not getting spark on a DIS engine, there are only 3 possible problems:
-Bad crank sensor or bad wiring between the crank sensor and module -No power getting to the ign module -Bad ign module or bad coils (but all 3 coils would have to be bad for the unit to produce no spark at all with a good module which is unlikely)
NOTE: Early DIS modules did have a relatively high failure rate.
Darth, sent you a pm about using a substitute for the 1227730 ecm on a 3x00 engine. You're more knowledgeable about it than I am, just want your opinion before ditching the 7730 and using something from megasquirt.
what are some DIS troubleshooting steps? i know the most obvious, check for power, ground, and that the crank position sensor is plugged in. what other things are there to do to check each system on the DIS system? i read this :
Here is a little trick that will literally show you if a DIS ignition module and its crankshaft sensor circuit are working: connect a halogen headlamp to the spade terminals that mate the DIS module to the coils. A headlamp is recommended here because it puts more of a load on the module than a test lamp. If the headlamp flashes when the engine is cranked, the DIS module and crankshaft position sensor circuit are functioning. Therefore, the problem is in the coils.
If the headlamp does not flash, or there is no voltage to the module or coil pack when the engine is cranked, the problem is most likely in the crankshaft sensor circuit. On most vehicles, a bad crank position sensor will usually set a fault code, so use a scan tool to check for a code. Or, check the crank sensor itself.
Magnetic crank sensors can be tested by unplugging the electrical connector and checking resistance between the appropriate terminals. If resistance is not within specs, the sensor is bad and needs to be replaced.
Magnetic crank position sensors produce an alternating current when the engine is cranked so a voltage output check is another test that can be performed. With the sensor connected, read the output voltage across the appropriate module terminals while cranking the engine. If you see at least 20 mV on the AC scale, the sensor is good, meaning the fault is probably in the module. If the output voltage is low, remove the sensor and inspect the end of it for rust or debris (magnetic sensors will attract iron and steel particles). Clean the sensor, reinstall it and test again. Make sure it has the proper air gap (if adjustable) because the spacing between the end of the sensor and the reluctor wheel or notches in the crankshaft will affect sensor output voltage. If the air gap is correct and output is still low, replace the sensor.
Hall effect crankshaft position sensors typically have three terminals; one for current feed, one for ground and one for the output signal. The sensor must have voltage and ground to produce a signal, so check these terminals first with an analog voltmeter. Sensor output can be checked by unplugging the DIS module and cranking the engine to see if the sensor produces a voltage signal. The voltmeter needle should jump each time a shutter blade passes through the Hall effect switch. If observed on an oscilloscope, you should see a square waveform. No signal would tell you the sensor has failed.
so thats to test and determin if the ICM and coils are working or not and the CKP sensor? what things should i check comming from the ECM in the 5 pin harness to determin if it is working or not? and does anyone know the resistance specs of a 3100/3400 CKP sensor? or the specs of things that should be at each wire on the ICM connectors?
i know the wires from the CKP are POS( hi ) and NEG ( low ), but what should that voltage rating be? is it that 20mV in the reading above speaks of?
my tach does move. so does that mean that the ICM is working?
what are some DIS troubleshooting steps? i know the most obvious, check for power, ground, and that the crank position sensor is plugged in. what other things are there to do to check each system on the DIS system? i read this :
so thats to test and determin if the ICM and coils are working or not and the CKP sensor? what things should i check comming from the ECM in the 5 pin harness to determin if it is working or not? and does anyone know the resistance specs of a 3100/3400 CKP sensor? or the specs of things that should be at each wire on the ICM connectors?
i know the wires from the CKP are POS( hi ) and NEG ( low ), but what should that voltage rating be? is it that 20mV in the reading above speaks of?
my tach does move. so does that mean that the ICM is working?
The crank sensor can only properly be checked using a lab waveform scope. You can check it with a digital volt-ohm meter, but all you will see are voltage pulses when the engine is cranking over; and you won't be able to see exactly what kind of signal the crank sensor is putting out (nor the number of these pulses in relation to crankshaft revolutions).
If you are getting a tach signal while cranking, then my guess is the ignition module is at least getting a crank sensor signal as well as power and ground. But without the proper test equipment, there is no way to know for sure what is going on.
If this were my car and I was using a used DIS module from a donor engine that was in unknown condition, I would probably try another DIS module at this point and see if that fixes the problem.
the DIS ICM and crank sensor i have on the car are the same ones that were on there when it ran last. only thing ive changed was the 7730 conversion harness. i had to build a new one due to the last one kept blowing the injector fuses. that last harness was a mess.
what things should i check other than that are connections from the ecm to the DIS ------------------ 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 My Fiero Fuel Economy Videos of My GT Google Videos of My GT
[This message has been edited by americasfuture2k (edited 12-24-2008).]
the DIS ICM and crank sensor i have on the car are the same ones that were on there when it ran last. only thing ive changed was the 7730 conversion harness. i had to build a new one due to the last one kept blowing the injector fuses. that last harness was a mess.
what things should i check other than that are connections from the ecm to the DIS
As I stated before, the DIS module will fire the coils even if the ECM is not connected to it. So if you are not getting spark, then you have a problem with the DIS module, power/ground supply to the DIS module, coils, wiring between the DIS module and crank sensor, or crank sensor. That is all that can be wrong in a no-spark situation. Now if you are running an external crank trigger on this engine, then your problem could be there.
Having said that, I suppose if something was wired up incorrectly between the ECM and the DIS module, it COULD prevent the coils from firing. So another thing you should try is to disconnect the ECM from the DIS module and see if you get spark. Of course depending on how something was incorrectly wired up, it could have fried the ignition module.
one thing I don't like too much about the 730 conversion is the need to rewire the VSS and add a resistor/capacitor to the wiring harness. So I did some research, and well, I may have found a way to eliminate this and wire the VSS input to the "old" VSS wire the stock ECM used.
Here's my thoughts:
The 87/88 Fiero used a P4 ECM as well, and the input circuitry of that ECM (see image below -> red circle) is virtually identical to the input circuitry of the '730 (rest of the image). The only difference is, instead of using the B10 VSS input with the additional components and wire it to the VSS sensor (as described in Darth Fiero's original plans), one can use the C6 VSS input on the '730 instead, and wire it to the VSS output of the Fiero's speedometer, like the stock ECM setup. The internal ECM signal "OUT4" is used to switch between the two alternative inputs. This way the VSS wire can be moved from the old connector to the new connector just like all the other pins without additional hassle and it would make the swap easier.
To make the '730 use the "old" VSS input instead of the other one, one byte in the MEMCAL must be changed though: the address $804F (ROM offset $004F) should have bit 4 set, i.e. change the byte from (for example) $00 to $10. That should be all. The only drawback is the ECM VSS outputs can't be used with this solution, so whoever wants to add a digital cruise must use an 88 speedo to supply the 4000ppm VSS pulses.
Now, all this reasoning comes from study of the mask source code and comparison of the schematics of the 730 with the Fiero V6 and L4 ECMs, this has yet to be verified. My 730 conversion is still on hold with my V6's engine being down with a bad water pump, but maybe someone will find this helpful or interesting and would like to try this out.
What do you guys think?
Best regards,
Oliver
------------------ Visit my website: www.fieros.de for lots of technical and other Fiero related information
On my 7730 instructions I do not see any call for a resistor/capacitor. I see splice BB9 (VSS Low) into terminal R of the C203 and splice BB10 (VSS High) into terminal G of the C203. For my digital cruise I ran a wire from BB11 (VSS 4000 PPM Out) to pin K on the digital cruise module. As far as I can tell it all works just fine.
[This message has been edited by Hudini (edited 12-28-2008).]
Right, I misunderstood that part, I thought that circuit was needed for the conversion.
Still, the alternative solution would save cutting and splicing on the VSS wires, just moving the old VSS pin to the new connector. Best part is, the solutions are not mutually exclusive - i.e. if this works, you can start out by using the 2000ppm VSS input, and if I ever want to do the digital cruise and use the circuitry inside the ECM, you can still use the 4000ppm VSS input to drive the 4000ppm/2000ppm outputs of the ECM, and select in software which one the ECM should use (since they're identical it shouldn matter unless the speedo is broken).
In any case, when the time has come to do my conversion, I'll give that a try.
Best regards,
Oliver
[This message has been edited by fieroluke (edited 12-30-2008).]
ive found something that has probably caused my car not to fire up. involving the DIS 7730 conversion. darth, pm me if you would like to know this if you dont already, so it can be corrected if you see it necessary. i dont want to say anything that will make you look bad. your a great helpful person. last thing i want to do is make you look bad.
ive found something that has probably caused my car not to fire up. involving the DIS 7730 conversion. darth, pm me if you would like to know this if you dont already, so it can be corrected if you see it necessary. i dont want to say anything that will make you look bad. your a great helpful person. last thing i want to do is make you look bad.
Please post here in the thread what you found. If I made a mistake, all I can say is it happens to the best of us. I would rather get the issue resolved vs. trying to cover up a mistake I made just to save face.
merlot pointed out to me on the DIS connections, on the 2 pin plug, the ground, pin a, says to connect to engine ground but in the beretta 7730 diagram, it shows it connecting to BA12. thats the only one i can see off the top of my head, ill let you know more as i go along. that could be whats causing my not firing up issue. im tired....
merlot pointed out to me on the DIS connections, on the 2 pin plug, the ground, pin a, says to connect to engine ground but in the beretta 7730 diagram, it shows it connecting to BA12. thats the only one i can see off the top of my head, ill let you know more as i go along. that could be whats causing my not firing up issue. im tired....
BA12 terminal on the 7730 ECM is a ground input to the ECM. This MUST be connected to engine ground. However, my 1992 Beretta diagrams ALSO show the DIS pin A (2-pin connector) connecting to ECM terminal BA12; so it must be an error in the wiring diagram (because on another page of the diagram, it shows BA12 connecting to engine block ground). In any case, the DIS module pin A as well as ECM terminal BA12 must both be connected to engine block ground. My wiring instruction sheet tells you to wire it all up in this way.
hmm, i didnt have anything in BA12 from what i remember. more rookie mistakes. i fail as an electronic tech. oh well, you live you learn. sometimes the hard way.
hmm, i didnt have anything in BA12 from what i remember. more rookie mistakes. i fail as an electronic tech. oh well, you live you learn. sometimes the hard way.
Don't be hard on yourself. If wiring were easy, cavemen could do it.
my 7730 w/DIS conversion also didnt fire right away due to a wiring ommision.....and I am a wiring genius & electronics guy..... took almost 2 weeks to find what I missed......lousy ground wire....grrrrrr
Step-by-step instructions would be so nice. Anyone out there brave enough to write a set of instructions and parts needed to complete this project; after all, most of us have 2.8's sitting in the back of our cars - we too want to make them "[act] like a new engine found in today's new cars!"
------------------ 1986 GT Fiero Owner & Enthusiast For Fiero updates, visit my site and don't forget visit our google ad sponsors http://educatorstop15.com/fieropage.htm
hurts my ego since i am an electronic tech for the navy. i have a question on a pin. 
