The Mule rides again (sort of) - pics.

[Sinister Fiero]

Cool. I'll give it a shot. Anything you'd recommend for a replacement? Silver sharpie?

The cylinder numbers for each coil position should be molded into the ignition module and should be visible even with the coils installed. So why do you need numbers printed on the coils? I think it looks better without them.

[The Dark Side of Will]

Pretty much just to make it idiot proof for me when I have to pull plug wires or disconnect the ignition module to swing the engine down.
I didn't realize the cylinder numbers were molded into the module. They're pretty subtle, though. Thanks for pointing that out.

[The Dark Side of Will]

I've been discussing some things with WCapman out of Mississippi. He's the guy who found the engine-only chip for the OBDI Caddy computer.

He's rewiring his entire car to operate high current loads with relays rather than directly with switches. Everything in my car works, and I'm not motivated enough to rewire the entire thing. However, I did think that it could be good to include a rear fuse box when I rework my engine compartment harness later this year.

The circuitousness of the Fiero electrical system has always amazed me. GM could have taken POUNDS of copper out of the car if they had included front and rear fuse boxes rather than requiring everything to go through a single fuse box inside the passenger compartment. The crank wire in total is probably over 20 feet long, when it could be 2 feet long with a relay. The rear lights go through a C500 pin that is a few inches from the battery negative post and the main body ground in order to ground inside the passenger compartment via G202 on the center console next to C203.

The ignition power wire coming through the C500 could be used to operate a high current relay that would then supply all the engine compartment needs. It would feed the ECM IGN fuse and the INJ1 and INJ2 fuses, which would be relocated to a rear fuse panel. With a little trickery, a similar relay could be used for the rear lights.

[Series8217]

I've been discussing some things with WCapman out of Mississippi. He's the guy who found the engine-only chip for the OBDI Caddy computer.

He's rewiring his entire car to operate high current loads with relays rather than directly with switches. Everything in my car works, and I'm not motivated enough to rewire the entire thing. However, I did think that it could be good to include a rear fuse box when I rework my engine compartment harness later this year.

The circuitousness of the Fiero electrical system has always amazed me. GM could have taken POUNDS of copper out of the car if they had included front and rear fuse boxes rather than requiring everything to go through a single fuse box inside the passenger compartment. The crank wire in total is probably over 20 feet long, when it could be 2 feet long with a relay. The rear lights go through a C500 pin that is a few inches from the battery negative post and the main body ground in order to ground inside the passenger compartment via G202 on the center console next to C203.

The ignition power wire coming through the C500 could be used to operate a high current relay that would then supply all the engine compartment needs. It would feed the ECM IGN fuse and the INJ1 and INJ2 fuses, which would be relocated to a rear fuse panel. With a little trickery, a similar relay could be used for the rear lights.

This is something I've wanted to do for awhile as well. The Fiero's wiring harness has voltage drops exceeding 2 volts at high current stuff like the headlights, blower fan, etc.

[The Dark Side of Will]

I hadn't measured high current loads, but I don't doubt that at all.
OTOH... those devices "work", although probably not optimally. The Fiero's electrical architecture is almost exactly the same in the components present and circuit design as everything else GM built in that era. The oddball "in-synch with lights off, out-of-synch with lights on" front turn signal behavior dates back to the '60's. The only difference between everything else GM built and the Fiero were the wire lengths.
That being said, there was a guy on the 6000 list or A-body forum (don't remember which) who rewired his headlights to run off a relay and claimed he could SEE a difference in illumination.

The crank wire goes from a ring terminal at the battery junction block through a fusible link to a terminal pair (not going through C500) to the ignition switch contacts to another terminal pair to another terminal pair to the clutch switch contacts to another terminal pair to the C500 to a ring terminal on the starter solenoid.
So there are 5 terminal pairs, two switches, two ring terminals and a fusible link in that circuit.
The headlight wire goes from ring terminal through a fusible link to a terminal pair through the tail fuse to another terminal pair through another terminal pair through a circuit breaker through the light switch contacts to another terminal pair to another terminal pair through the dimmer switch contacts to another terminal pair to C100 to a terminal pair to the filament. So the headlights have EIGHT terminal pairs, THREE switches, a circuit breaker, a fuse, a fusible link (THREE current protection devices) and a ring terminal in the circuit.

Yikes... I'd never sat down to add all that up before. Going to a relay system would reduce the crank circuit to two ring terminals, two terminal pairs and relay contacts. The headlights would drop to one ring terminal, three terminal pairs, relay contacts and over-current protection of some sort. There's probably a protective relay on the market that could be used in lieu of a fuse or circuit breaker without adding any more contacts to the circuit.
The headlights don't need TRIPLE over-current protection.

[The Dark Side of Will]

I've had some *weird* electrical problems that were contributing to the hot/no-restart condition. I reseated C500 and C203, but the problems persisted.

My volt meter and oil pressure gauge would waver, sometimes in synch with electrical loads on the car, like the turn signals.

When the turn signal was on, the volt meter would drop and stay down as long as a light was illuminated.
When the hazards were on, the volt meter would flicker when the lights came on, but not stay down.
When I turned the parking lights on, the volt meter would flicker, but not stay down.

The hazards and parking lights are on different fuses and fusible links than the turn signals. In the end, the commonality among the electrical problems was fusible link A and the ignition switch. I removed the ignition switch yesterday and took it apart to inspect it. There was wear and erosion on all the contacts. The original grease was black with wear particles. That makes the best argument I've seen for relay-based power distribution.

I'll replace the ignition switch and see if that makes these issues go away.

[Series8217]

I've had some *weird* electrical problems that were contributing to the hot/no-restart condition. I reseated C500 and C203, but the problems persisted.

My volt meter and oil pressure gauge would waver, sometimes in synch with electrical loads on the car, like the turn signals.

When the turn signal was on, the volt meter would drop and stay down as long as a light was illuminated.
When the hazards were on, the volt meter would flicker when the lights came on, but not stay down.
When I turned the parking lights on, the volt meter would flicker, but not stay down.

The hazards and parking lights are on different fuses and fusible links than the turn signals. In the end, the commonality among the electrical problems was fusible link A and the ignition switch. I removed the ignition switch yesterday and took it apart to inspect it. There was wear and erosion on all the contacts. The original grease was black with wear particles. That makes the best argument I've seen for relay-based power distribution.

I'll replace the ignition switch and see if that makes these issues go away.

I have the same problem. The turn signals will even make the engine RPM change slightly when they turn on. Turning on the HVAC fan at full blast can even stall the engine. I never thought about looking at the ignition switch... the cars didn't do this new so corrosion there makes sense.

[The Dark Side of Will]

It's well protected from corrosion... But the contacts are subject to mechanical wear from the sliding action and erosion from the combination of sliding and high current loads.

[Series8217]

It's well protected from corrosion... But the contacts are subject to mechanical wear from the sliding action and erosion from the combination of sliding and high current loads.

Oh, I misread "erosion" as "corrosion". Wear shouldn't be a problem, it keeps refreshing the surface (wearing off the oxide layer) so resistance should stay low unless the contacts are worn thin.

Did you check the fusible links for corrosion?

[The Dark Side of Will]

I manipulated the fusible links (the remaining ones are still at the engine compartment junction block) extensively and didn't see anything in the gauges.

For hazards and parking lights, the volt meter would flicker as I turned them on, but then recover almost immediately as the regulator in the alternator upped current output to maintain system voltage.
With the turn signals, the volt meter would flick down and stay down until the light turned off. This indicates that the circuit is dropping voltage between the alternator and the volt meter. As the oil pressure gauge is effectively a variable voltage divider, changing the rail voltage powering it changes the reading, so the oil pressure gauge reacts to changes in rail voltage also.
The water temp gauge is a variable voltage divider also, but the coolant temp sender has a resistance from low to 1400 (or more) ohms, while the oil pressure sender is a 0-90 ohm sender. While both gauges react to changes in rail voltage, the water temp gauges reactions are not visible. The fuel gauge has too much damping to show quick reactions the way the oil pressure gauge can.

[The Dark Side of Will]

Found out there was an AC Delco parts house nearby... picked up a new ignition switch for $16!

[The Dark Side of Will]

http://forums.corner-carvers.com/showpo ... ostcount=2

Interesting discussion of wide band O2 sensors

http://www.ecm-co.com/

[AkursedX]

My Fiero used an NGK AFX wideband and I was quite happy with it. The only issue with it is that it is though to find a place to mount the box.

[The Dark Side of Will]

New ignition switch cured most of the electrical weirdness. However, one problem remained. The engine would cut out for a split second periodically, sometimes several times rapidly in succession... sometimes it would stay cut out for several seconds before kicking back in. I drove down to my dad's place this morning and dealt with 4 or 5 episodes of this behavior, while the car drove fine for the remainder of the trip. I hunched that I had a high-resistance ground and that the ICM was dropping off-line causing the cut-outs.

When I arrived at my dad's place, I unbolted my main ground that connects the engine to the battery. The large cable to the battery was fine, but the small wire from the harness had only a couple of strands left. The ground lug came right off in my hand as I examined the formerly almost broken wire. I guess that was my problem...
The cleaning lady has hidden the heavy duty ground lugs that I KNOW I have around here...

[Aaron]

The cleaning lady has hidden the heavy duty ground lugs that I KNOW I have around here...

I bet you put them somewhere special so you wouldn't forget them. I do that with every car part I can't find.

[The Dark Side of Will]

I also finished tweaking the heat heat shield for the under-pan exhaust pipe. It fits with 1/16"-1/8" each way to the oil pan or the exhaust pipe. It's at the fab shop getting mounting tabs welded onto it right now... I forgot to snap a photo before I left it there.

However, to get that close fit, I had to take down the small stiffening rib/huge casting flash ridge that ran right through the middle of heat shield area (pictured is an extra oil pan I practiced on before I worked on the one in the car):

[The Dark Side of Will]

The cleaning lady has hidden the heavy duty ground lugs that I KNOW I have around here...

I bet you put them somewhere special so you wouldn't forget them. I do that with every car part I can't find.

I *DID* have them in a specific place where I could find them before the cleaning lady moved things.

[The Dark Side of Will]

Found them last Thursday night... *NOW* they're in with the rest of my electrical terminals and such.

May need to rerework both of the ground loops that I just reworked in order to include some shrink tube as a strain relief.

Heat shield is still at the fab shop.

[The Dark Side of Will]

After fixing the engine grounds, I found that the body ground had deteriorated also. I'm using the split negative battery cable from the original Caddy application. One side goes to the engine, one to the body. The body connection had gotten rusty. I cleaned it up, greased with anti-seize and punched in a slightly larger self-tapping screw. It works great again. My voltage and oil pressure indications went up and my windows got faster.

It's having an intermittent miss across a variety of operating conditions, though. I'm wondering if one of my NOS coils is succumbing to simple age. I need to put some serious effort into getting Torque to log KR and misfire counts so I can see which cylinder(s) it is and then see if it moves when I swap coils.

[The Dark Side of Will]

I had a breakthrough with Torque

From the torque home screen touch the action button for settings, scroll down and touch "Manage Extra PIDs/Sensors". From the "Manage custom OBD2 PIDs" screen touch the action button for the menu and select "Add predefined set".

Options show for:
Chrysler/Dodge/Jeep/Mercedes
Ford (Incl PowerStroke)
Other
Pontiac / GM / Opel / Vauxhall
Toyota Prius (Gen. II)
Toyota Prius (Gen. III)

I selected Pontiac/GM and immediately had a list of the data points I'd been missing.

So.... operator error, as usual.

Code: Select all

Name              PID   
Knock Retard           2211a6
Injector pulse width 1 221193
...                    ...
IPW 8                  22119a

Misfire 1 History      221201
...                    ...
Misfire 4 History      221204
Misfire 1 Current      221205
...                    ...
Misfire 4 Current      221208

Misfire 5 Current      2211ea
...                    ...
Misfire 8 Current      2211ed

Misfire 5 History      2211f8
...                    ...
Misfire 8 History      2211fb

Which agress with Ryan's below:

Knock Retard: 2211a6

Misfire Cyl.1 Current: 221205
Misfire Cyl.1 History: 221201
Misfire Cyl.2 Current: 221206
Misfire Cyl.2 History: 221202
Misfire Cyl.3 Current: 221207
Misfire Cyl.3 History: 221203
Misfire Cyl.4 Current: 221208
Misfire Cyl.4 History: 221204
Misfire Cyl.5 Current: 2211ea
Misfire Cyl.5 History: 2211f8
Misfire Cyl.6 Current: 2211eb
Misfire Cyl.6 History: 2211f9
Misfire Cyl.7 Current: 2211ec
Misfire Cyl.7 History: 2211fa
Misfire Cyl.8 Current: 2211ed
Misfire Cyl.8 History: 2211fb

I'm running TorquePro v1.6.58
I'm running TorqueScan v1.5

By adding the IPW's and misfire counters to my log, I'm at one sweep about every 3 seconds which is getting a bit low-res. I took a couple short trips Wednesday evening, one 350 samples and one 338.

I'm definitely getting junk data for injector pulse widths... they start at zero for a few dozen rows, eventually 5 out of the 8 are constant -3.92156863

It looks like I'm getting junk data for the misfire counts and history also.
The misfire count is mostly 0, but has a few -1's. Summing across my 350 samples, #8 has -1; #'s 1, 3 & 4 have -2 and #2 has -3.
However, the misfire history is mostly 0 with a few -1's or -257's. Summing across my 350 samples, #'s 2 & 8 have -258, #3 is -259, #7 is -262 and #5 is -514.
In order to accumulate 257 misfires of one cylinder in my 3 second sample rate, the engine would have to turn 514 revolutions in 3.06 seconds, which is 10,078 RPM... obviously junk data.

Also getting a whole lot of zeros for KR, but that could be because of the previous difficulty with the OBDI knock sensor on the dyno and the fact that the local tuner turned down the knock sensor sensitivity to compensate.