Bubbajones_ya

I posted a while back about an issues I had that started around when I added octane booster to my tank. I thought it was completely unrelated to this issue, but seemed very coincidental to the cause of my issues. Anyways...


Currently I'm having a bad drive-ability issue with ONE of the symptoms being fuse #9 blowing. The problems with the vehicle happen right when this fuse blows (probably not because it blows, but they happen simultaneously). The problems are:

- Fuse #9 blows so I lose all my gauges (they are digital)
- The Camaro starts to stumble heavily like it's intermittently loosing spark to the coil. The whole time it's driving like this, fuse #9 will keep blowing.
- The car starts to overheat (I didn't know how bad until today.)

I've been noticing this the past week of driving trying to pinpoint what it is. At first I thought it was purely an electrical issue (after getting rid of the bad gas from the octane booster) that something was shorting out and just causing me to lose my gauges. However it always starts to stumble and drive poorly when this happens. It also seemed to be a little hotter than normal when I'd throw in a new fuse to check my temperature, but wasn't sure if it was just the gauge reading wrong.

Anyways the fuse blew again today after a few hours of driving both highway and city. The car was driving great the whole time before this. I drove about 4 miles back to my girlfriends place and was going to check the temperature with an infrared gun.

When I popped the hood, the car was so hot that coolant was spitting out of the radiator cap while it was on. The infrared gun read 260 on the intake manifold. The car was running perfectly fine and around 215 before any of this happened.

Whatever issue this is, it makes the vehicle overheat very quickly, run very poorly, and blows fuse #9. With the car being that hot, I can see it run poorly for sure, but it starts to run poorly immediately when fuse #9 blows, so I don't think the drive-ability issue is heat related (at least initially.)





Does anyone have any ideas what this may be? I'm a little worried the engine may have been damaged with it getting as hot as it did today. I'm kinda at a loss of what to check because this is an intermittent problem. It will be driving great, then terrible all of a sudden. Sometimes it drives great the whole day, other times it will constantly give me trouble.

I'm thinking potentially with it getting as hot as it does quickly, something is causing the car to run very lean when the fuse blows, but I don't really know what. If that's the case, then I don't know how that can be an intermittent problem.


Anyways, any advice and suggestions would be greatly appreciated!

Bubbajones_ya

I just went outside to try and do some troubleshooting after letting it sit for a while. The circuit breaker I put in place of the fuse keeps tripping after I turn the ignition on (the engine doesn't have to be running, just the ignition on.)

I went and checked the exhaust manifolds temps after about a minute of idling.

the middle two (6 and 4 as well as 3 and 5) seem to be about 100 degrees hotter than the outer manifold tubes. I don't know if this is normal for warmup on a TBI, but it's what I noticed. The temps were mid 300s on the middle tubes and about 200 to a little under on the outer tubes.

RBob

iTrader: (1)

OK, I take it that fuse #9 is the GAGES fuse, as it powers the dash. If so that fuse is run all over the place, including the EGR solenoid. I mention that one in particular as bad EGR control will cause an engine to run poorly.

The attached image is from the '92 FSM, but should or nearly be the same as your '91.

RBob.

Bubbajones_ya

Thank you RBob for the response and advice! Fuse 9 is for the gages yes!

I'm going to take a close look at all the wiring that you posted when I get a chance as well. I did manage to get the car home yesterday which was good!

This may be completely unrelated to the issue as well, but I figured I'd post it just in case it may mean anything. I was doing some more troubleshooting yesterday (like unplugging the vapor cansiter, egr and air solenoid plugs) to see if the circuit breaker I put in place of fuse 9 would still trip. It was still tripping with each of those unplugged.

I then took off the fuel cap, and a bunch of air rushed out (it usually does I think it's building too much pressure in the tank.) Right after taking that off, the circuit breaker stopped tripping and the car ran normally... Maybe too high of fuel tank pressure is causing part of the symptoms I have, but that seems like a far off guess.

I still am thinking something is causing my car to run lean with how quickly it got hot (and it almost wasn't driveable.)


Anyways I'll check that circuit as best I can over these next few days to see if I can come up with something. I'll also try and see if there is a way I can prevent so much pressure building up in the fuel tank if (by the far off chance) that may have something to do with part of my issues. Thanks again for the response!

Bubbajones_ya

Alright, I think I've actually come across a very logical solution to my problem.

I feel like a complete IDIOT if this is it, but that's fine if I get my car fixed!

There are two things that I think contributed (and I hope are the only things when I get around to fully fixing them.) First, the side post battery terminals could not get connected well enough to make a consistent connection. The bolt itself was tight into the battery, but the cable wasn't able to be tight enough on the bolt going into the battery. The positive battery cable covering was black and brown with small traces of it's original red coloring left due to overheating. The smaller gauge wire that ran to the positive junction post was cracked and splitting from heat, and some of the wires leading off the post were discolored.

I purchased two new side post positive battery cables to put in place of my original one. Instead of using the smaller gauge wire that goes to the junction post, I put in a very short positive battery cable. With two cables off the positive post, the cables were able to be tightened sufficiently so that there was a good connection on that end finally. I also replaced the wring ends with 10 gauge wire that were damaged on the other side of the positive junction post.

The second issues (that most likely caused the problem):

I had my secondary fan wired to the air system wiring (smog stuff is removed but I used the wiring for a switch 12v ignition source for the fan relay) which is connected to fuse #9.

I checked over that wiring several times before and didn't see anything wrong with it. However, after replacing my fan controller yesterday, I noticed a hidden red wire that was also connected to that that I missed the last three times I was probing and checking the wires. I completely forgot I wired up my heated o2 sensor to that as well (since I couldn't find a way through the firewall when I wired it up.)

Sure enough, I traced that wire back and it has been grounding out on the exhaust. This would definitely make the fuse blow. Fuse 9 controls the speed sensor, and I had the oxygen sensor hooked up to this circuit as well. I don't know how much an effect this would have on fueling, but potentially having the oxygen sensor ground out may have played a role in lean fueling of the car when it got super hot.

I decided I'm going to wire in two switches for the fans as well so I can manually turn them on apart from being temperature sensor controlled. I found that my stock fan wiring relay and relay connector are pretty badly discolored (maybe stemming from the bad positive wire connection) so I need to solder in a new connection there. My blower motor fan relay and connector are also burnt up so those need replacing as well. I'm guessing this could have stemmed from the positive battery connection also.


Thankfully, I found a small stock access panel about the size of a half dollar that just popped off from the firewall. This made it easy to drill a small hole and put a rubber grommet in place. Now that I have this, I'm going to wire my O2 sensor and fan switches up through the dash sometime today.

I really believe this is going to fix the issue for good so I'm hopeful. I was so upset yesterday when after replacing my fan controller and positive battery cables that I still was having the issue that I may have hit my windshield a little too hard with my fist.

That's okay though, I was going to replace it as soon as I could anyways... I just have to do that now before driving because I don't think it's legal to drive with the windshield in the shape it is now!