3400 head swap, no rear sensor hole?

[dnalbach]

I'm getting close to done with the 3400 head/intake swap on my 95 Olds wagon and I notice that there is no hole in the driver side rear cylinder head for a little sensor that was there on my old 3100 heads. I've not been able to find out in any of the diagrams what this sensor is. Does anyone here know? It's just a little green gasket in the plug if that helps, and sits down near the crossover pipe. How do compensate for not being able to use this sensor? I assume the car is going to throw a code for it. Will it affect performance?

[1988GTU]

I think the hole is in the LIM not the head. Keep looking, it should be there.

[dnalbach]

No, I checked the old heads, it's in the head slightly above the head bolt on the driver side of the rear head. The sensor would stick out at a 45 degree angle from there. The new 3400 heads I got manufactured in 2001 do not have this threaded hole for the sensor, it's just solid there.

Wait, are you suggesting that the sensor hole in the 3400 engine is in the LIM instead of the heads?

[bszopi]

The old 3100s had the signal wire and sender for the gauge cluster temp gauge mounted in the rear head. The 3400s and newer 3100s have both temp senders integrated into a single unit now, which is mounted in the LIM. So no, you won't get any codes, but you also won't have a reading on the dash until you get the new sensor, new connector, and do some wire splicing.

[dnalbach]

Ah, so that's the one that gets spliced! Thanks Brad! I read about that somewhere else and didn't make the connection.

[Azrael]

The sensor you need is part number 213-815 from ACDelco or GM#: 10096181 (GM# might be different in the US). You can grab a spare 3x00 TPS connector from a junkyard since it'll connect to the new coolant sensor.

[3100 MPFI]

I did that new sensor to my Cutlass Supreme, and it works just fine.

You can get the sensor from a 1996 Pontiac Grand Prix with the 3100. Get a TPS plug. Wire it up so that the old coolant wire goes into the center wire (I know they are in a circle, but 2 are like side-by-side, and one is on top. Hook the gauges wire up to the top one).

If you do this, it will all work fine.

[Daguse5853Z]

or couldn't you just pull the drain plug out of the side of the block and just screw the sensor in there? you have to lengthen the green wire a foot or so but it beats pulling your intake back apart and splicing a new plug in. i originally went to the single coolant sensor but than I went back to the two wire and just ran the sensor in place of that plug like i said earlier. the plug is on both sides of the engine block so your options are open.

[dnalbach]

Daguse5853Z, is the sensor a direct fit for the drain plugs, or did you have to modify it?

[PCGUY112887]

I did that new sensor to my Cutlass Supreme, and it works just fine.

You can get the sensor from a 1996 Pontiac Grand Prix with the 3100. Get a TPS plug. Wire it up so that the old coolant wire goes into the center wire (I know they are in a circle, but 2 are like side-by-side, and one is on top. Hook the gauges wire up to the top one).

If you do this, it will all work fine.

Are you saying that the sensor used in a 96 3100 works the same way 00+ setups work? I'm putting 00+ 3400 top end on my 96 3100 and am trying to figure out for sure how the whole temp sensor plan is going to work.

[torq455]

or drill and tap a hole in the head like the stock one, and screw in the sensor.

[Daguse5853Z]

Yeah the sensor will thread right into the hole for the drain plug. why drill and tap anything when you just have to extend one wire?