TWO UNKNOWNS... (Page 1/2)
eti engineer JUN 15, 02:43 PM
As most of you know, I have had my Fiero out of commission for some time. I am finally putting the engine back together. I thought I had taken enough pictures of everything to ensure I was putting everything back together in the same manner it came apart. So far, things have gone well.

The company that put my engine together apparently didn't put all the external hardware back in the block and one head. I have two threaded holes for which I don't have pictures. i need help in identifying these. The first one, I would assume is for the oil pressure sensor since it is located next to the oil filter. I apparently need to order one of these.

The second threaded hole is in the front head of the engine when it is installed. The same hole in the rear head has a plug in it. Rather than my spending a lot of time researching this, I thought I would ask in here, since there is a ton or two of knowledge here. BTW, the car is a 1988.

Thanks in advance for any help.



[This message has been edited by eti engineer (edited 06-15-2021).]

Will JUN 15, 03:19 PM
Since your engine is an '88, you should have a tubular part that installs to that hole by the filter and puts the oil pressure sender up near the belt where you can access it for replacement from the top rather than having to get under the car to do it. Not sure what that says about what GM thought of their oil pressure senders...

The second photo is the location for the coolant temp sensor, but it should be on the rear head on the driver's side... so they put the heads on the "wrong" bank. Just swap the plug from the "rear" head to the "front" head.... use teflon tape to seal the threads.

Are you re-doing the wiring? There's also a three wire CTS that can drive your dash gauge as well. That means you only need one sensor instead of two and your gauge and computer are reading from the same point on the engine.

[This message has been edited by Will (edited 06-15-2021).]

Patrick JUN 15, 03:35 PM

quote
Originally posted by Will:

Since your engine is an '88, you should have a tubular part that installs to that hole by the filter and puts the oil pressure sender up near the belt where you can access it for replacement from the top rather than having to get under the car to do it.



Will, was it just the earlier years then where relocation of the oil pressure sender was based on whether or not the car had A/C?
theogre JUN 15, 04:32 PM
OP sender...
See my Cave, Oil Sensor for TSB covering this.
Basically Use standard ⅛" and ¼" pipe fitting to move it so rain etc can get to the plug.
Mertipack plugs are better the most but seals will let water in when constantly get soaked.

other likely part of heater loop.
See my Cave, Heater
I have little data for 88 V6 so don't know if uses meter output port.
Should be an output to heater core.
Standard metal hose barb w/ pipe threads on other side would works but soften shape edges on the barb side or can cut thru the rubber hose.

But Note If heater flows too much coolant... can cause radiator and t-stant "problems."
IF has to restrict flow, pull the barb and braise a washer in the barb. Solder may fail over time because big heat cycles can crack many solders.

OE T-stat can be a "problem" too even w/o that. See my Cave, Thermostat

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Will JUN 15, 06:13 PM

quote
Originally posted by Patrick:

Will, was it just the earlier years then where relocation of the oil pressure sender was based on whether or not the car had A/C?



Did cars without A/C have the sender down by the filter?
Will JUN 15, 06:14 PM

quote
Originally posted by theogre:

other likely part of heater loop.
See my Cave, Heater
I have little data for 88 V6 so don't know if uses meter output port.
Should be an output to heater core.
Standard metal hose barb w/ pipe threads on other side would works but soften shape edges on the barb side or can cut thru the rubber hose.

But Note If heater flows too much coolant... can cause radiator and t-stant "problems."
IF has to restrict flow, pull the barb and braise a washer in the barb. Solder may fail over time because big heat cycles can crack many solders.

OE T-stat can be a "problem" too even w/o that. See my Cave, Thermostat




The corner of the head is definitely the CTS. It is not the heater.
Patrick JUN 15, 06:36 PM

quote
Originally posted by Will:

Did cars without A/C have the sender down by the filter?



I believe so.

cvxjet JUN 15, 06:52 PM
My 85 SE V6 (AC-less) had the oil pressure sensor mounted down by the oil filter.
eti engineer JUN 15, 06:56 PM

quote
Originally posted by Patrick:

I believe so.



So should I just plug this opening? My car has AC. I think that when they hot tanked the block they left a few things out after rebuilding. I didn't notice that the opening by the oil filter was open until I spun the oil pump with a drill to check and see if everything was lubing as it should. Next thing I know, I had oil on the garage floor.

Thanks for the comeback...
eti engineer JUN 15, 07:00 PM

quote
Originally posted by Will:


The corner of the head is definitely the CTS. It is not the heater.



Thanks. I thought that it was, but wasn't sure. My car is an '88 with AC, but I am not even going to re-install the compressor. I will leave the lines intact and plugged, but here in CA, with little to no humidity, there is no need for it with the T-tops off. I thought that they had put the heads on opposite sides from where they were before. I didn't see where it would matter as long as I can re-route the wiring for the temp sensor. Do you know where the fan switch is located?