CamaroUK

I did the TB bypass mod earlier today, while I had the coolant drained I put my old 180* thermostat back in for the coming winter months.

Everything went to plan other than having coolant overflow out of the radiator fill point whilst trying to bleed the system.

After I was done I ran the car until warm to check there were no leaks. Everything was fine.

3 hours later I decide to take the car for a road test to see how things went, I started the car up and the first thing I noticed is that the windshield vent was blowing very weak when I went to switch it on, the dash lights and headlights also seemed a little dim. The dash voltmeter was in the red! a few seconds later the ABS INOP light came on and stayed on until I switched off.

I checked in the engine bay for anything that looked out of place, nothing. Then the volts picked up to where the needle normally sits. I went for a drive and the volt needle was drifting up and down and really sank when I booted it.

What did I do wrong?

My first thought is that there was coolant on the alt drive belt, but it seems to be spinning ok, and its not like theres any load on the alt with just the headlights and dash vents on? I don't remember spilling any coolant other than when the rad overflowed.

Severous01

sounds like you got the alt wet. you'll likely have to replace it. i dont think once you run it with water in it that you can go back to the way it was....it shorts out stuff inside.

try taking the battery terminals off the bat and cleaning them. could be that you have just hit the limit with corrosion at the same time you did the work.

Dtimekw

Check the battery voltage with the car off. Should be above 12volts, start the engine and let idle, battery voltage should be over 12.5volts with no acc on (lights, AC etc..) rev up the engine and the volts should increase to over 13 volts. If they do, bring it back to idle, note the voltage and turn on headlights, and AC, voltage will drop but shouldn't go down under 12 volts. This checks your charging system. The voltages will vary a bit with the age of the batt and alternator but what you are really looking for is an increase in volts as you rev up the motor. If you make these checks, post the results and we can go from there. Hope this helps.

CamaroUK

Hmmm, I'll do the voltage tests tomorrow. As far as I know, the battery and alternator are the originals and the car is a 1995.

Any idea as to why I'm seeing the ABS INOP light? I knew the tb bypass would cause me trouble.

Thanks for the replies.

Dtimekw

Not sure about the ABS INOP light, maybe a low voltage condition is throwing it up. Just a guess, but for now, I'd go after the dim lights and weak vent.

shoebox

Low system voltage will cause the ABS INOP to light.

SS RRR

It does? What stuff? Perhaps I should avoid power washing my engine bay from now on!

CamaroUK

I've just been under the bonnet with a multimeter.

With the car off the battery voltage was just over 12 volts.
With the car started and at idle, the voltage was still just over 12, this was also confirmed by the dash voltmeter being in the red again.

Revving the engine made no difference to the voltage.

The all of a sudden it picks up to 14 volts at idle and the dash voltmeter was were it should be. I switched on the A/C, rear defogger and the headlights and the voltage starts to fluctuate between 14 and 12. I could even hear the engine noise changing as the voltage changed. Then it seemed to start to settle at 14 again.

Is my alternator dying?

Chevycobb

probably. mine went once I would turn on the vent and all my dash lights went off. replaced alt and all was fine. Most parts stores can test it for you for free

shoebox

Clean and check all your major grounds and power connections for tightness. Plus, the little wire that is on the back of the alternator. If it does not make connection, your alternator will not charge.

CamaroUK

I tightened the battery terminals, the positive was a little loose. I rubbed the loop connector in the little red connection box with emery paper. Whilst inspecting the large red cable on the back of the alternator I noticed a small connector which was not properly plugged in on the back of the alternator. I pushed it back in and now evertything seems to be fine.

Are you refering to the small connector that I found loose?

Mtrhds94Z

Yes, that connector out or loose, would make it not charge.. it should be OK now..

shoebox

Yep.

1FstFormulaV8

I have had an ABS INOP light on for quite sometime now without thinking anything of it. Until now. I went out and tested my voltage.

Battery: Ign. Off. 12.5V
Battery: Car running. 14.39V

Battery: With as many accessories running as I can. (Headlights, interior lights, heater on high, defroster, radio) 13.7V

I am kinda stumped here. I don't have any dimming issues. My interior volt gauge ALWAYS reads above 13! Could just me being paranoid about it. Or it could be legit. Any suggestions?

One little detail. My light ABS INOP light blinks. It does not stay solid.

CamaroUK

I can only assume that I must have knocked the connector loose whilst moving the wire loom about thats by the steam pipe during my tb bypass mod. It can't have been in properly in the first place because it has a clip on it to hold it in place when pushed right in. Maybe it would have become a problem sooner or later anyway.

Oh well, I guess its sorted now, thanks for your advice everyone!



Maybe one of the sensors in the rear end has become defective. I think there are 3 in total? Do a forum search to find out where exactly they are.