Iroc n roll

Ok, I just straightened out my "gauges not working" problem. It was a blown fuse which I had over looked . But now I have a new problem. When I replaced the fuse, the SES light and gauges came on but then went out. I go to check the fuse, sure enough, it's blown. Why is my gauge fuse blowing? Here's a little more backround. I just rebuilt the motor. It had a 10 amp fuse which was working until as long as I can remember. When I replaced it I didn't have a 10 so I used 15 and it blew that too. What can I do? Also I just found that my temp sensor (not CTS) is not connected, could that be causing this? I'm having trouble hooking it back up too. The wire has seperaed completely from the sensor...do I need a new one?

Vader

Blowing fuses?!

I'll bet that makes the fuse happy. I blew a seal once, but the walrus got jealous...

Anyway...

Your GAGE fuse should be a 10A. According to what I can see on the schematics for your '85, the GAGE fuse does power the MAF burnoff module (piggybacked to the ECM) but not the CTS. However, the GAGE fused circuit also powers and protects several other devices, including the A.I.R. Port and Divert solenoids, EVAP canister Purge solenoid, brake power switch for the TCC lockup relay (and the relay itself), the "SES" lamp (MIL), and the EGR solenoid. If you have a manual transmission, the TCC is obviously not connected, but the GAGE circuit also consists of the "SHIFT" lamp and first gear sensing switch.

Good luck on sorting those out. Try disconnecting and metering one of those items at a time. And stop blowing fuses, or the WeatherPack connectors are going to start talking behind your back....

Iroc n roll

LOL....well what can I say, I needed the money. Actually I can clear part of this mess up a bit immediately. EVAP, EGR, and AIR is already gone, out of the car for a while, so unless these connectors are grounding out somewhere I can take them out of the running. Also, just to be sure, I'm not talking about the CTS (Coolant Temperature Sensor), I'm talking about the temp gauge sensor (located in driver's side head) thats disconnected. So being as this is gauge related I'm starting to think this might be the cause of my woes....but I can't reconnect the damn wire!!


PS When I'm talking about head, please realize....no pun intended

Iroc n roll

Ok, I reconnected the temp sensor, and the fuse still blows. I even disconnected the two single weather packs that go to the + battery terminal (for the ECM power and volt gauge I believe), and the fuse still blows. I don't have AIR, EVAP, EGR, or any of that other stuff...save the TCC. So is that my problem? What else could it be? Is there maybe a ground that I hooked up that I should have just kept loose?

Vader

Grounds should be grounded, so that shouldn't be an overcurrent issue.

Try removing the TCC relay. IIRC, it should be in the swing-out "Convenience Center" under the dash in the driver's foot well area.

If that doesn't solve the fuse-munching, try disconnecting the MAF burnoff module.

And even though you don't have solenoids for the EGR, EVAP, and AIR valves, the wiring still exists and may be a problem. For your sanity's sake, I hope not.

Iroc n roll

Is the "Convenience Center" basically where the fuse box is under the panel? I sure hope it's that too. I have a feeling I'm going to be very angry with this car in the following weeks.

felo72

I've been there, done that. It took me forever to find the problem, finally I sat down with a Hayes manual and ran every wire that was connected to the gauge panel fuse. Don't drive the car when it's dark, because the buzzer stays on when the lights are on, and believe me, it's quite annoying. Anyway, what Vader said is some great information (by the way if you haven't learned it by now, he's the man!).

Anyway, look at the wires at the starter. There are three wires on one terminal, if any one of them are touching the block it's going to cause the fuse to blow. Also, check the coil, that too has voltage going back to the instrument panel because of the tachometer.

When I was tracking down the problem, I had the computer disconnected, the dash all tore apart and dissconnected, the MAF relays, distributor, cruise control, and air pump all disconnected and I still blew a fuse every time I turned the ignition.

Let us know how you make out.

Iroc n roll

Thanks for the info. Do you guys think that if I have a bad ground somewhere in a related system that it would cause this?

RB83L69

No, it can't really be a bad ground. That would cause something not to work, from current being unable to flow. You have the opposite problem: one too many grounds, one where it's not supposed to be. You're looking for a pinched wire, or melted, or some piece that has 12V on it touching the chassis, or something like that.

Iroc n roll

I'm ressurrecting this one from the dead. Can you guys give me "idiot" directions to the TCC relay and Maf burnoff? The burnoff is on the drivers side fierwall right?

Vader

U-Roc,

Your '85 is a little different. The big yellow strap-on (D/A converter and MAF control module) on the back of the ECM is for the MAF functions. The relays may still be mounted remotely, but I'm not positive they are on your firewall. This is the layout for an '86:



And this is the schematic for yout '85 ('870 ECM):

Vader

And if you want to isolate the TCC relay, disconnect the purple wire from the brake pedal switch, and follow it to the relay (or just leave it unplugged). The TCC relay is inside the passenger compartment, and I thought it was on the Convenience center.



Again, your '85 may be different. You can still take it out of th ecircuit by disconnecting the purple wire at teh brake switch.

Iroc n roll

I think I am about at my wits end with this stuff. The TCC checks out ok, I checked the wires at the starter, AIR, EVAP, EGR, distributer, all over that damn engine bay and nothing. I saw some frayed wires and fixed them....still nothing...no burnt, frayed, or joined wires. I'm not exactly sure where that burnoff is so I guess solving that is my next effort. BTW..i heard something about the cigarette lighter also fusing to the GAGE fuse...is this true? Where else can I look. I've also already pulled the gauge cluster to check that off the list as well. And does anyone know how i can check wires under the hood with a multimeter to see if they are the culprits or not?

felo72

Did you try looking at the wires going to the starter? If those touch and ground out each other, it'll cause the cluster to blow. I had the same problem and the starter was the culprit for me.

Vader

U Roc,

The cigar lighter is on the 20A "ACC" fuse with the horn and interior lighting. Have you looked at teh back side of the fuse panel itself. I had a '94 that had some shorted bussing in the fuse panel - just a thought...

Iroc n roll

I pulled the wires from the distrubuter today and the coil....still blows the fuse. I'll check the fuse box tomorrow. The wires to the starter look good but they go through this little tube so I can't tell if maybe there is a problem in there. Does anyone know how I can check those wires with a multimeter? Would I be able to check them at all since the fuse is blown and there is no power running to them. Also I don't know if this is related, but it seems like the fuse is only tight on one side, like the connector only touches the hot side. What would happen if only one side of the fuse touched?

Iroc n roll

Should driveability be affected at all without this fuse (other than no gauges except speedo)? Remeber most of that stuff is removed already for me. I'll just have no TC lockup, will anything else be affected? Is there any other place I can look for shorts in the system?

Iroc n roll

Ok, here's the update. Here's an 85 schematic for the gauge fuse. I'm going to disconnect the C207 connector tomorrow to eliminate those possibilities. Then from there its only a few more things. However, I don't see those starter wires anywhere. I'm only blowing the gauge fuse....is that what happened to you? Could they be in the circuit somehow? This is shows everything that could blow that fuse.....right?

Iroc n roll

Ok, i can't post it but its here

http://www.geocities.com/vtcamaro/Wire-Diagrams.html

Go to the 7th photo for "fuse block details" (it's in the first column).

Iroc n roll

Here we go:

Iroc n roll

bump

Vader

U-Roc,

Yeah, that's the same schematic I have. C207 should eliminate a lot of wiring and possibilities.

As for checking the wiring with a multimeter, check the circuit with the fuse removed and the meter set on a resistance scale. Check resistance to ground as you connect and disconeect relays, loads, etc. Anything that has a resistance below 8-10 ohms should be an automatic red flag, and given the nature of the loads connected, anything below 15-20 ohms is pretty suspect. Most relays and instrument lamps should be at or above 35 ohms.

Iroc n roll

I unplugged the C207 connector, turned the key to the on position and I SAW GAUGES!!! The volt meter went up and my tach "zero'd". I pull the fuse and its ok. So, now the elimination of the culprits. If my car was an 87 I could cut the wire running to the C207 and forget about it since there is no MAF relay, but since I have the MAF relay I need to find another way to edit that stuff out. Just as a re-cap, I have none of the systems below (EVAP, AIR, EGR) with the exception of the MAF burnoff relay. However the wiring is in tact for all systems. I want to eliminate these things from my wiring harness (with the exception of the MAF burnoff of course). Also, below is a picture of my driver's side back corner of my engine bay. Which one is the MAF burnoff relay so I can unplug it to see if its at fault?

felo72

That looks like your CTS and Fuel Pump relay.

Vader

U-Rock,

Awright, buddy! NOW we're getting somewhere.

BTW - I think Felo meant "ESC" and FP relay...

Your '85 will have the MAF function relays stuck to the back of your ECM, not out on the firewall like newer cars.



See all them purty wires? It's in there... Never having had one open, I'm not sure how servicable the relays are. Even if they're soldered to a circuit card, you should be able to replace them. I may have a line on a source if you strike out.

And even though you may not have the devices, if you still have the EVAP, A.I.R. and EGR relays and solenoids (and their wiring) you may not have completely eliminated those possibilities. If you have a connector from a relay hanging loose, that might be a real potential problem if the connector somehow grounded.

Iroc n roll

Oh boy......it must be HITHEREHITHEREHITHEREHITHEREHITHERE fool's again. Dirk....you're HITHERE funny man. "HITHERE".....lol. My next mission is going to be to scrounge around and start cutting out the wires HITHERE don't use to prevent further problems. HITHERE think splice S175 or somthing like that ties all of this stuff together. HITHERE'l try and eliminate what HITHERE can there. But first HITHERE want to check the MAf burnoff. So will unplugging that connector take it out of the circuit and prove its guilt or innocence? It feels good to finally be getting somewhere.

felo72

Oops, sorry, I meant ESC, thanks for correcting me.

Vader

Felo,

We knew what you meant.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

U-Rock,

Instead of going to all the trouble of altering your harness to prevent shorting, you might want to simply install the corrugated plastic tubing as protection for the wiring, and tie them into position so they don't just swing about, risking damage. If you ever want to go back to EFI, you'll have all the wiring intact. If not, it will still be out of the way and secured, and will probably save you some labor in gutting all the wires. You don't know where all the splices are, and removing wiring that may be necessary could be an issue. I'm still guessing that you will find a problem with a device rather than the wires themselves.

Iroc n roll

Back to EFI? I'm still running EFI. Now that I look at the picture again...can I even unplug that connector the the relay or is it fixed in there?

Iroc n roll

PROBLEM SOLVED!!!!!!! Man I feel like an idiot and you guys are going to kill me when you gear what it is. Remember the first post months ago when I said I had just rebuilt the motor. Well, I was flipping through a 1987 FSM wiring supplement (that my friend MarkOlc was gracious enough to lend me) and I saw that in back of the engine was a connector for the EGR vacuum something or other. I had remembered seeing one male connector un-pluged as I was finishing up the rebuild, with a female connector near by so I decided to hook it up. Well, there was my fatal mistake. I remembered about this today and went out to disconnect it. I did and put a new fuse in and PRESTO! working gauges. And my car runs great now that it has MAF function back (it was stumbling and running rich). So finally a happy ending. Moral of the story.....Don't plug in ANYTHING unless you know what it is for.

Vader

Persistence pays...

Imagine what it would have cost to have a shop do all the troubleshooting. You could probably get two new Z06 for the labor bill.

EDIT: But you DID do it alone.

Iroc n roll

Exactly. Thanks guys! I wouldn't have been able to do it alone!