Secondary issue

[Troglodyte]

Lo all, been browsing these boards for years now, but first time posting.

In any case, I'm about to so some extensive work in my 93ATX 130k. I'm going to redo all the gaskets on the upper half, plug well seals, intake, valve, the works, as well as put new cams in. I noticed 2 things last week that I would like to see about while I have the car apart.

1st. The secondaries are not opening at 3750ish like they always have. I cannot tell whether they are stuck open all the time or just simply are not opening. Could they be stuck closed due to buildup? Hit me with anything you can think of.

2nd. When I have the climate control on vent the temp gets as high as the "N" in town and sits between the "A" and the "L" on the highway. However, if I put the climate to anything else (Panel/Floor/Def) the temp moves to the top of the "A" and sits there irregardless of how or where I drive?

Any suggestions? TIA.

 

[Sho-Driver]

1st. The secondaries are not opening at 3750ish like they always have. I cannot tell whether they are stuck open all the time or just simply are not opening. Could they be stuck closed due to buildup? Hit me with anything you can think of.

You can check to see if your secondaries are sticking open by having someone turn on the car while looking at the secondaries. You should see them close when vacuum is applied. If you reach around the back and disconnect the vacuum line, they should open back up.

If you do not have a chip, your secondaries should be opening at 3950 RPM.

2nd. When I have the climate control on vent the temp gets as high as the "N" in town and sits between the "A" and the "L" on the highway. However, if I put the climate to anything else (Panel/Floor/Def) the temp moves to the top of the "A" and sits there irregardless of how or where I drive?

Any suggestions? TIA.

I am ALMOST POSITIVE your ECT is bad. This is the temperature sensor for the computer and is located just to the right of the thermostat.

 

[Troglodyte]

Okey, 3950 sounds correct, must have "fat-fingered" the 7.. I'll take a peek tonite when I wake up. I'll have my wife start her up while I tinker.

It wouldn't surprise me if the ECT is bad (nothing surprises me anymore with this car ), but I had that changed out about 6 months ago, hmmm. I'll change that out as well again, just because I have another for some reason.

Total aside... 10 years with this SHO has left me with a LOT of "spare" parts..

 

[Yamaha V6]

There are 2 sensors...

The Engine Coolant Temp Sender is to control the gauge (only). Typically this sender fails to the low side, showing lower than normal temps, and the gauge rarely if ever goes above horizontal, even when the engine's roasting hot.

The Engine Coolant Temp SENSOR is what feeds the PCM, and has nothing to do with the gauge. Both are located near the thermostat. The sender has one wire attached, the sensor has a multi-wire connector on it.

If you're on Defrost or AC, the cooling fan's supposed to be coming on, because the AC compressor's kicking in. First, ensure the radiator fan's kicking on when it's supposed to.

 

[Troglodyte]

The fan does appear to come on when it's supposed to. I also just remembered that when on the highway, the gauge does rise (about a needle's-width) to the bottom of the "M".

 

[Sho-Driver]

Just to add a little and reiterate what Fred said.

If the car is cooling down in the defrost/ac/floor/etc, the fan is supposed to come on to make the condenser work. If you are warming up during city driving and while stopped, most likely the fan is delayed due to a bad ECT. Driving at a constant speed above 40mph will cool the radiator in place of the fan.

I bet if you were to pull off your radiator cap with a cool motor, start and let warm up, your coolant will be boiling.

The ECT is a $16 at Auto Zone and requires a 1" deep well socket to remove/replace. With as many miles as you have, I do not doubt it could have failed. My first one failed at less than 60k miles.

Located on block:

<front of car>Gauge sender --- T-stat --- ECT (computer sensor) <rear of car)

 

[Troglodyte]

I may as well replace all 3 items as I have them and they are right there. I'll just wait to do so until I get all my parts in. I'm going to have to drain the coolant anyway to change out the water pump here in a couple of weeks when I have time.