Timing Off, Heater Core, and Blower Motor Resistor Issues

[Black91SHO]

In my very well maintained '91 MTX, I've been having issues with blower motors. They keep going bad very quickly.

Then today, two more problems popped up.

1. The timing is suddenly off (I'm hearing some pre-detonation at really low RPMs when I give it a lot of gas. Also, there's low power all through the RPM band, and the engine doesn't sound smooth like usual).

2. The heater core is blowing water vapor up on my windshield.

I'm guessing the heater core sprung a leak, but do you think it could've have leaked onto the blower motor resistor and killed it?

As for the timing, what on earth would cause something like that? I'm confused by that one.

Any ideas?

 

[zoomlater]

For the timing issue, did you already pull the codes

 

[rubydist]

The heater core or heater hose leaking will result in a sweet smell of antifreeze, distinctly not "water" - is that what you are getting?

The timing could be off if the timing belt has stretched or the tensioner has gotten loose. The tensioner being loose is more likely, in my experience. You have to get all the covers off to confirm what is up, so you might as well just change the belt while you are in there.

 

[sperold]

The resistor for the blower motor usually fails in a mode that allows the full speed setting to work.

The blower motor does not fail all that often, but the blessing is they are inexpensive and easy to install as they are readily accessable.

The heater core leak is the biggest heart break. Usually is it just vapour that escapes from the crack and fogs up your windshield. If liquid is escaping, it will find its way onto your floor mats. Failures like this are usually associated with disturbing the heater core rubber hoses in the engine compartment, but not always.
Changing the core requires dropping the heater box under the dash, which means disconnecting the AC lines as a starter.

Make sure your spout connectors have not been removed for whatever reason. That is the little connector that sets your timing to 10 degrees and keeps it there and is removed to pass inspection test and to set timing, among other things.

 

[Black91SHO]

Rubydist,

I've had issues where the timing is thrown off by another issue, but I forget what can cause that. Something with a sensor throwing off the computer's timing.

Didn't pull codes but I will today hopefully.

 

[rubydist]

the timing can be off due to the spout connector missing as sperold points out above, but that will not cause ping because it locks timing at 10* advanced.

 

[Black91SHO]

Thanks for the replies.

I hope the timing belt didn't jump a tooth. Maybe a cam sensor went bad--just remembered that's what effects timing considerably since the timing reads off of it for the ignition. I've had some weird issues with crank sensors causing timing issues, too, if I remember correctly.

Yeah, the heater core springing a leak sucks, but I'm kind of used to it now (I've owned 6 or 7 SHOs--it's pretty bad when you lose count. lol). The aftermarket heater cores are really crappy and usually only last a couple of years from what I hear and from my own experience.

I'll let TexanTony deal with it. Ain't nobody got time for that!

 

[sperold]

I once bought a SHO and drove it 250 miles home without an issue. When I changed the coolant, within a day or two, it was pretty dark and strange looking; the water pump would leak a puddle 6 inches in diameter if I stood idle for more than a few minutes. Turns out I had been duped on this one.

It was all being held together with stop-leak, and the heater worked great before the change in coolant.

At the risk of hearing shrieks of horror from other members, I would suggest a high end stop leak product before I dropped the heater box. That stuff plugged a pretty big leak, and in its own way, was quite impressive.

In the end, I changed the water pump, just like you will change the core. But for now, you could give it a try, as I am sure your core leak is nothing compared to the water pump.

I am not a proponent of magic in a bottle, and would never have tried this stuff on my own. But I will say that the experience changed my opinion of additives, as the car cooled the same, the heater was the same, and there was no downside to all that stuff circulating in the cooling system.

 

[Black91SHO]

Thanks. Not a bad suggestion. I may try that.

Turns out my car has a poltergeist. On the way down to the shop, the windshield wipers would turn on and off and spray the windshield randomly.

When I first got the car, I had problems with it because someone had had the genius idea of splicing into the wiring harness so they could put a gen 2 starter on the car. Turns out, evil spirits of the dead attach to the car when that happens and start haunting the electronics. Imagine that.

The wires kept shorting out making us think it was a crack position sensor until we finally figured out it was the splice job. We reversed all of the electrical splicing and got it back to stock, but we apparently haven't yet tracked down all of the gremlins it caused. I imagine we'll be more thorough this time if we end up pulling the dash. Can't remember if it's an old or new heater core on this one (I get the mechanic issues on my cars mixed up sometimes). That'll decide if I use the Stop Leak or not.

Thanks again.