What is the sensor on the lower intake next to where the upper meets?

[Jack B]

Is this the temp sensor for the fan? I have a ported intake being shipped so figured I'd get new parts while I have it apart. In advance, Thanks for the reply Mike...LOL

[Meotchh]

Sounds like you are referring to the knock sensor. You got pics?

[Jack B]

I don't Meotchh but the nut take's a 1 1/8 inch wrench and it looks almost like a bolt welded onto an electrical connectors. This is on an '86 intake. The nut is quite large and the sensor faces the firewall. BTW - your avatars are hilarius

[Jack B]

I do now 4247

[MikeFleming]

That is the knock sensor. There is only one mounting position on the in-line manifold, points straight down near runenr #4 (rear most).

For the in-line, it MUST go in the hole that points rearwards. NOT the hole that points towards the LF shock tower.

[Jack B]

So this can be left disconnected if I listen for any signs of detonation? Just reading the steps to increase performance on TF & forced4 sites. Thanks

[MikeFleming]

So this can be left disconnected if I listen for any signs of detonation? Just reading the steps to increase performance on TF & forced4 sites. Thanks More accurate is if you have another method to make sure there is no detonation (octane, good tune, enough fuel, not too aggressive on timing & boost, etc.).

In some cases by the time you hear it - IF you do hear it - it's too late already.

I recall a time a couple decades back when I had practiced my launches in my relatively new, all-stock 84 SVO as I had a trip planned to LA Country Raceway to get some 1/4 mile times. So I worked out my launch style listening to the engine, tires, and "feel" of the car against a stop watch.

Then when I got to the strip, the first car that lined up next to me was a 8-second dragster with open headers. So all that practice of listening to the sounds and feel of the car went out the window! My car was vibrating so much just from the noise of the car next to me I couldn't tell if the engine was even running. Totally flying on instrument control.

[Jack B]

Ok, I'll just leave the knock sensor connected. Got another question. Got my new ported lower and my old one off. My old lower has a large coolant sensor. The new one doesn't. Looks to have an air charge sensor instead. What do I do about not having the coolant sensor? Do I need to drill and tap the lower and install the sensor? Or can I omit it? I assume I can just keep the air charge sensor to plug the hole. I have no connector for it. 427542764277

[SVOBoyd]

I believe that coolant sensor controls the fan (I'm not sure why Ford used three coolant temperature sensors; one for the EEC, one for the fan, and one for the temp gauge?) I guess you could delete it but you would have to find another way to turn the fan on.

[Jack B]

Thanks Boyd. I was thinking about switching over to a dual fan setup when I replace my radiator. Was going to install a seperate fan controller in the process.

We are not that far apart. Do you go to any of the First State Mustangs shows?

[MikeFleming]

Your first two pics of post #8 show the later, 2-wire coolant fan temp switch. it goes into the center passage on the lower intake where the coolant goes. Note the coolant crud. It needs to have a sealant on it to prevent coolant [pressure] leaks. It uses a tapered pipe thread so using a sealant means less torque required to seal.

The third pic in post #8 above shows the air temp sensor - as used on the LA-series of EECs (87/88 TC). It has a small surface area thermistor that is exposed to the airflow in the intake runner going to cylinder #3. Another tapered pipe thread but this one seals intake side vacuum/boost leaks. This is not needed if you're not running an LA-series EEC (and optional if you are) - but you will need to plug the hole if you don't install the sensor.

[Jack B]

Thanks Mike. I think that confirms I either need to tap the lower or add an external fan controller. I am running a LA3 but obviously need my fan to operate properly. For the price of a new switch, I'll probably just do the external unit.

[TheSVOTrust]

Jack

Don't be a "he man woman hater" on that Knock sensor !!
(I want to say the torque is UNDER 10inch pounds)

Mark

[Jack B]

Thanks Mark. I will be stopping by your spot on Saturday at Carlisle next weekend.

[SVOBoyd]

Jack No I didn't know about the First State Mustangs show, pm me when one is coming up and we will meet up. Isn't Lincoln Univ on Rt 1 close to Philly? Sounds like we are doing the same thing I am swapping out my stock upper and lower for a gutted upper and knife edged lower.

[Jack B]

Update: I got everything back together and tested. I was able to swap out the ported lower (very cool of the seller!). Replaced all the sensors/sending units while it was apart. Also, new t-stat and housing while the coolant was drained down. Added an Autometer FP gauge on the rail. My gauges and fan are working better than before.

Next up: Full 3" exhaust going on June 20th!

[Meotchh]

Good deal.

Sounds like you found yourself a good guy to buy parts from there. Let us know how the new exhaust works out.