My idea: S52 sensor for temp gauge/ temp sensor for computer (need opinion)

[omar85]

since my s52 only has that one 4 prong connector in the head for both temp gauge and the temp signal to the computer i was thinking of a solution.

I am using a 94 harness that of course uses 2 separate 2-prong connectors.

why not cut the 2 separate connectors off on the 94 harness and solder the wires to a 4-prong female connector from an obd2 harness. I would then be able to use the stock obd2 4-prong sensor on my obd1 harness.

I would obviously match the wires so that the signals are sent to the correct place and then just ground the grounds manually to the head.

i hope this all makes sense

The only reason i am making this thread is because i haven't heard of anyone doing this and it seems like a lot less of a headache then some of the alternatives i have read. Does anyone know a reason this will not work or know for sure that it can be done before i start cutting?

[Van Westervelt]

Your temp gauge will read wrong. You need to use an e30 temp sensor for the gauge cluster to read accurately. And I am not sure but I think there is a difference in the obd2 temp sensor and the obd1 sensor in the range that it sends to the dme.

Do it right. Tap the head and put the new sensors in.

[erik325i]

I believe that would work in an e36. Some company makes an adapter that does just that, but it doesn't work in the e30 from what I read.

[e30s52]

Yeah turner does and if you buy it for the e30 they wont return your money.

Ask me how I know.

[Jean]

Turner won't even return your calls... F them.

[e30s52]

Or email/reg. mail but they did answer my phone call when I was asking about cams. Then they got really busy and the salesman told me he would call me back.

[omar85]

Your temp gauge will read wrong. You need to use an e30 temp sensor for the gauge cluster to read accurately. And I am not sure but I think there is a difference in the obd2 temp sensor and the obd1 sensor in the range that it sends to the dme.

Do it right. Tap the head and put the new sensors in.

are you saying this from experience or what you have read?

i know the e30 gauge temp sensor does not thread in to the head without re tapping it but will the stock e36 temp for the dme bolt right in?

[Fidhle007]

The E30 sensor is a single wire sensor while the E36 sensor needs two. It's easy on an M/S50 because there are already two ports and the E30 sensor bolts right in but on the OBDII heads there's only one port, which is why you'd need to duplicate it for the second one.

[MIKe30]

The E30 sensor is a single wire sensor while the E36 sensor needs two. It's easy on an M/S50 because there are already two ports and the E30 sensor bolts right in but on the OBDII heads there's only one port, which is why you'd need to duplicate it for the second one.

early s52's have 2 :mrgreen:


quick question, is your second port slightly larger than the first port all the way at the front of the motor? Right now I have 3 holes there. First is for coolant temp switch, 2nd is plugged up (i'm assuming used to be for second obd1 sensor), and third is a connector to pass coolant on to tb.


I just bought the obd2 double switch sensor. About to buy the m20 brown top sender. Need to know which hole the m20 sender will fit into (slightly larger plugged up one?) so I can know which part to order for 3rd and final hole (if I need the plug or the connector). There is a 2 day wait time from dealer for both.

Any thoughts?

[jakeb]

The dme sensor goes in the first hole, m20/e30 sensor in the second (plugged in your case), and TB outlet in the 3rd hole. This is goes from the front of the engine back.

My S52 also had the second hole there with a plug....very nice.

[7pilot]

are you saying this from experience or what you have read?

i know the e30 gauge temp sensor does not thread in to the head without re tapping it but will the stock e36 temp for the dme bolt right in?

The sensor is calibrated for the E36 OBD2 gauge.
The correct OBD 1 sensors won't bolt into the S52 cylinder head.
The rear most port on the S52 head that supplies coolant for the throttle body heating circuit will accept an unmodified OBD1 Coolant temp sensor.

m

[omar85]

The sensor is calibrated for the E36 OBD2 gauge.
The correct OBD 1 sensors won't bolt into the S52 cylinder head.
The rear most port on the S52 head that supplies coolant for the throttle body heating circuit will accept an unmodified OBD1 Coolant temp sensor.

m

ok so i can take out the TB coolant supply and plug in my brown sensor for the gauge. then ill just plug off the other coolant line. no problems with that right?

so my question is will the obd1 e36 temp sensor for the dme bolt in to the hole provided for the obd2 temp sensor???

[MIKe30]

ok so i can take out the TB coolant supply and plug in my brown sensor for the gauge. then ill just plug off the other coolant line. no problems with that right?

so my question is will the obd1 e36 temp sensor for the dme bolt in to the hole provided for the obd2 temp sensor???

If by brown sensor you mean the m20 one for the gauge cluster, no. According to jakeb, the m20 brown top fits into the second hole - which is larger than the 1st and 3rd, so it will not fit in the tb coolant supply hole.

14 & 15 are smaller than 13. m20 brown top goes in spot 13 according to jakeb.

Somebody correct this if I'm wrong please!!

[Van Westervelt]

he has an obd2 head, so these ports (what you are calling port 13) doesnt exist, yet. I am not sure on the thread pitch size on the obd2 dual sensor port. It may fit either the obd1 temp sensor, or the e30 gauge sensor. I am running an obd1 head, and it threads right in, so someone with the obd2 head would have to chime in. All the other swaps I have toys with were all obd1 heads.

[atldohc]

its been a while but i have an s52. there was no threads on my head that were the same size as the e30 gauge sensor. i ended up drilling and tapping one of the holes to match the sensor. in retrospect i probably shouldve just ground the sensor down and tapped it to match the threads in the cylinder head. i have read of somebody else doing it this way. better to modify a 10 dollar part in my opinion but its too late now. anyways i did a good job on it and expect to never have any problems with it