My 4.9 wiring thread (Page 13/16)
Mickey_Moose MAY 22, 12:23 PM
added info about engine mounts to the top of the first post.

[This message has been edited by Mickey_Moose (edited 05-22-2012).]

gen2muchwork JAN 09, 02:05 PM
I have a question here.

Im attempting to run +12v switched power to the distributor, egr/ps pressure, and the trans round plug .

Do I take it from the injector feed or the ecm feed or somewhere else?

these would be the pink or pink/black ones. Maybe I just am missing something?
Reallybig JAN 09, 10:11 PM

quote
Originally posted by gen2muchwork:

I have a question here.

Im attempting to run +12v switched power to the distributor, egr/ps pressure, and the trans round plug .

Do I take it from the injector feed or the ecm feed or somewhere else?

these would be the pink or pink/black ones. Maybe I just am missing something?



I took my +12v "hot in run" power from C203 F (in the orange circle) to power the EGR and Power Steering Pressure Switch. It's the same amperage as the caddy 12v supply and I haven't had a problem yet.


The distributor coil was powered by the C500 E3 thick pink wire on the fiero, I figure it should power the Caddy distributor coil as well. Given it's guage, it must be supplying considerably more current than the C203 F could. I ran mine across the engine to the distributor from the C500.


I found this caddy ECM wiring layout quite helpfull. OK, it's for a 95, but the wiring colors are the same as are the pinouts on the ECM side. Earlier ones won't have two O2 sensors, different trans range switch etc. To bypass the power steering switch, I just jumped from BR wire to O/B.


post edited for clarity and more pictures!

[This message has been edited by Reallybig (edited 01-09-2013).]

phonedawgz JAN 09, 10:23 PM
85-88 Fieros have the ignition power wired to C500 E3. It is not fused before the connector so you should add a weatherproof fuse holder there.

Link to C203 / C500 Image
http://images.fieroforum.co...201-C500-DLC-Cru.jpg

Normally I use C203 F for the ECM and the MAF (If equipped), and the speedo buffer (if equipped)

Normally I use C203 J (INJ1) for Injector power

Normally I use C203 K for all the other power requirements. Heated O2, EVAP solenoid, Vent Solenoid, Cruise Power and Transmission Power.

[This message has been edited by phonedawgz (edited 01-10-2013).]

Reallybig JAN 09, 10:49 PM

quote
Originally posted by phonedawgz:

85-88 Fieros have the ignition power wired to C500 E3. It is not fused before the connector so you should add a weatherproof fuse holder there.

Normally I use C203 F for the ECM and the MAF (If equipped), and the speedo buffer (if equipped)

Normally I use C203 J (INJ1) for Injector power

Normally I use C203 K for all the other power requirements. Heated O2, EVAP solenoid, Vent Solenoid, Cruise Power and Transmission Power.




Phonedawgz, the caddy 4.9 injectors are powered by two seperate 10A fuses; 4 injectors per fuse. I used C203 K for one set of four and C203 J for the other set of four. Both K and J are fused at 5A each in the fiero. I didn't want to change to 10A in case they are to protect the wiring more so than the injectors. Are you not concerned that all 8 injectors on the 4.9 will be too much for the one fused C203 J wire? Do you bump up the fuse amperage?

I do have concerns that sharing the C203 F with items other than the dedicated ECM supply could draw current away from the ECM and potentially cause issues. I know that on the 4cyl fiero it is shared with the fuel injector but stands alone ECM on the V6. I'm hoping that sharing it with the EGR and PSPS won't cause me any problems....I'm probably over-thinking things as always.
Reallybig JAN 09, 11:04 PM

quote
Originally posted by phonedawgz:

85-88 Fieros have the ignition power wired to C500 E3. It is not fused before the connector so you should add a weatherproof fuse holder there.




On this wiring print, it shows that the V6 C500 E3 has a fusible link. I've got the 4cyl, so I can't confirm what it shows in this picture, but I can confirm that on the 4cyl, the pink wire from C203 E3 is NOT fused as you have stated. What Amp fuse do you recomend putting in that weatherproof fuse holder? I'm not sure what the rating is for the fusible link in this Pic.

[This message has been edited by Reallybig (edited 01-09-2013).]

gen2muchwork JAN 10, 07:14 AM
reallybig, I'm using a modified diagram similar to the 1995 you have posted. I drew in the colors I have plus the pin positions for the trans etc. Im using a late harness with early trans, but wiring the whole thing as mickeys diagrams. This makes the colors and trans wiring wacky. As a bonus I'm fairly color blind. I know my car is red though...
anyways thanks for the help.

thanks phonedawgs for the last few posts as well. seems reallybig and I are somewhere around the same wires.

I dont have it with me, but if I posted my diagram do you think you could take a look at it to double check? I seriously start to go crazy after looking at all these wires for more than a few hours at a time. I dream about wires, its weird.
lou_dias JAN 10, 01:21 PM
I'm running the TPS and temp gauge ground to E11 per here:
http://www.fieroaddiction.c.../cadero/49wire-2.jpg

This should be the top-most connector on the ECM, correct? I still get an open connection.

I'm thinking of tying the wires to B5 here: http://www.fieroaddiction.c.../cadero/49wire-1.jpg

When I ground to the chasis, it draws 12v thru the sensors and my temp reads 12v/5v higher or 2.4x higher than it should hence it pegs by 120F when ground to the chasis. I have the TPS and temp gauge on the same ground.
phonedawgz JAN 10, 02:00 PM

quote
Originally posted by Reallybig:


Phonedawgz, the caddy 4.9 injectors are powered by two seperate 10A fuses; 4 injectors per fuse. I used C203 K for one set of four and C203 J for the other set of four. Both K and J are fused at 5A each in the fiero. I didn't want to change to 10A in case they are to protect the wiring more so than the injectors. Are you not concerned that all 8 injectors on the 4.9 will be too much for the one fused C203 J wire? Do you bump up the fuse amperage?



On my swaps I use the INJ1 - C203 J for all injectors and fuse it at 10 A



quote
I do have concerns that sharing the C203 F with items other than the dedicated ECM supply could draw current away from the ECM and potentially cause issues. I know that on the 4cyl fiero it is shared with the fuel injector but stands alone ECM on the V6. I'm hoping that sharing it with the EGR and PSPS won't cause me any problems....I'm probably over-thinking things as always.



The ECM gets it's main power from the unswitched source. Put an amp meter on it and test. It only uses the switched source to sense if the ignition is on or off.


quote
Originally posted by Reallybig:

What Amp fuse do you recommend putting in that weatherproof fuse holder? I'm not sure what the rating is for the fusible link in this Pic.



20A

[This message has been edited by phonedawgz (edited 01-10-2013).]

phonedawgz JAN 10, 02:09 PM

quote
Originally posted by lou_dias:

I'm running the TPS and temp gauge ground to E11 per here:
http://www.fieroaddiction.c.../cadero/49wire-2.jpg

This should be the top-most connector on the ECM, correct? I still get an open connection.

I'm thinking of tying the wires to B5 here: http://www.fieroaddiction.c.../cadero/49wire-1.jpg



The TEMP GAUGE grounds to the engine block. I think you mean Temp Sensor. Both grounds should be essentially the same. The sensors wire directly to the ECM for ground to avoid any less than perfect grounds causing changes in the engine operation.

Are you sure you are using the correct ECM wiring diagrams for YOUR ECM? (What is your ECM SERV #?)


quote
When I ground to the chasis, it draws 12v thru the sensors and my temp reads 12v/5v higher or 2.4x higher than it should hence it pegs by 120F when ground to the chasis. I have the TPS and temp gauge on the same ground.



Something is seriously wrong with that. Chassis ground SHOULD be the same as ECM ground. If swapping from one to the other causes significant differences, you have a grounding problem.

Are you talking about scanning the ECM and reading the temp sensor, or are you talking about the reading on the gauge?

[This message has been edited by phonedawgz (edited 01-10-2013).]