coolant temperature sensor info and XAT screwed me

[95lstegman]

BTW, all of the following is in regards to the coolant temperature sensor that feeds to the ECU, not the temperature indicator sender which drives the needle in the dash.

i've searched and i've talked to my local SR shops (XAT and Enjuku) and everybody seems to agree that in order to get the car running properly, a JDM Redtop coolant temperature sensor is required. XAT said that they've had mixed results with USDM KA sensors. i went to XAT to get the very last of their stock of the JDM CTS and what do you know, they told me they'd be open Jan 02 2006, but nobody was there. another guy with S15 SR + S13 5-speed into S14a trailered in from jacksonville, and me and him both go screwed b/c XAT was never open. we both were told they'd be open and apparently we were lied to. thanks, guys.

anyways, i went to the nissan dealership and found that the CTS is the same for all pre-OBD-II 240SX's 1989-1996. so i figured that if the KA24E, KA24DE/S13 and KA24DE/S14 all shared the sensor, the Silvia/180SX w/ SR20DET probably shared it as well. i didn't check if Z32's use it as well, but i would guess it's likely.

i know i was told the results were mixed, but i bought the sensor straight from the dealership for $25, installed it [with a little trouble because my 19mm deep socket apparently isn't that deep], and it's been running in tip-top shape since. thanks for nothing, XAT, and to the rest of you, good luck. when this sensor goes it's a beeotch, running really poorly once warmed up, ultra-rich, missing all over the place and lacking a lot of power.

[SpeedRacer1]

Yeah the coolant temp sensor and coolant sensor for the cluster are the same on the S13 SR20DET's and S13 KA's.

[efrain240sx]

, and to the rest of you, good luck. when this sensor goes it's a beeotch, running really poorly once warmed up, ultra-rich, missing all over the place and lacking a lot of power

tell me about it, damn stock sr cts gave out ran like **** put one a old ka that I had laying around ran better for like to weeks but know its back to runing like ****. got to get a new one i guess

[95lstegman]

Yeah the coolant temp sensor and coolant sensor for the cluster are the same on the S13 SR20DET's and S13 KA's.

no, i said explicitly that we're talking about the CTS, which drives the ECU, not the instrument cluster.

and to efrain, i bought mine new from Nissan and today i got the motor nice and hot from some hard driving and now it's back to the same crap it was doing, although not quite as bad as before. i'm going to put in a NISMO thermostat and hope that it never gets to warm up, thus solving the problem. it's okay at light loads most of the time, but it seems like the ECU is retarding the ignition timing a lot when i get on it much. it doesn't make popping sounds like misfiring would; it sounds normal but feels extremely sluggish. and sometimes it does just misfire like mad. and when i hit the clutch, the engine speed falls like a rock down to ~300rpm, then pops back to 1200rpm or so then stabilizes from there after bouncing back and forth a few times between 300 and 1200. sometimes it actually dies if i don't catch it.

this is really pissing me off. i hope the NISMO thermostat fixes all this. it's been about 2 weeks since this car went at least 24 hours without needing repairs/money.

[S13240]

Yeah the coolant temp sensor and coolant sensor for the cluster are the same on the S13 SR20DET's and S13 KA's.

This man knows what he's talking about, they are interchangeable. I know because I am using ka sensors on my blacktop.

[SpeedRacer1]

Yeah the coolant temp sensor and coolant sensor for the cluster are the same on the S13 SR20DET's and S13 KA's.

no, i said explicitly that we're talking about the CTS, which drives the ECU, not the instrument cluster.

Yeah the coolant temp sensor and coolant sensor for the cluster are the same on the S13 SR20DET's and S13 KA's.

illiterate...?

[SpeedRacer1]

Thermostat wont fix anything. The engine will still reach warm up, it has to, the oil needs to heat up to lube properly.

Check the ECU codes, have timing checked, TPS adjustment. Those are the proper steps.

[95lstegman]

sorry about that, man. i don't know where my brain was.

anyways, this all started when i changed the heater core lines. the heater works now but i've been having this problem. i figured that if the engine was running wierd only when it got all the way up to temperature, i would just keep it from getting there. it didn't work. so i decided in a fit of despair to reset the ECU, and voila! i'm rockin' my super rice hunter again! suh-weeeeet! this was after Enjuku tried to get me to buy into the "fact" that i "need" to buy a $400 new OEM SR wiring harness and pay the additional $150 to have it professionally converted, plus installation, and then they would problem solve from there. don't get me wrong; i love those guys [most of the time]. but BS like that is what makes me always come here after getting an opinion from them and/or XAT. Enjuku also told me that the fat O2 sensors were from redtops and the skinny ones were from blacktops. and therefore the previous owner of my SR when it was in Japan must have swapped over to the "newer" skinny type for some reason. okaaaaaaayy guys . . . sure . . .

[SpeedRacer1]

Redtop = thin O2 sensorBlacktop = fat O2 sensor

Good to see the car is running again. Did you see if there were any codes being thrown?

[95lstegman]

i can't. no CEL in the dash, and my E5 ECU has no light on it. i WISH it did. i actually did begin to figure it out. here's what i know:1) when i run the radiator fan, it messes up as described above. when i turn it off and reset the ECU by removing the fuse for 30sec, it's fine until i run it again.2) if i let the temp needle get more than a tiny bit above the second dot while the car is sitting still, and let it sit for a few minutes, the temp won't go up, but it will start to spew white, sweet smoke out the tailpipe (burning coolant). when i start moving again, it stops smoking immediately.3) my coolant looks funny, but i know it needs a flush b/c i used that red coolant a while back and it made a royal mess out of my coolant system. i drained it a few days ago and refilled with the green stuff, but i didn't flush it.4) my thermostat is out b/c i'm afraid that esp. with no fan, it will get and stay hot and blow white smoke all the time.5) it runs great right now even with no thermostat, and gets gas mileage around 23mpg or so with just 3" exhaust/DP and a broken O2 sensor.

any body got a guess? Enjuku wants me to buy a $550 new OEM SR harness converted by them and then work from there at their electrical problem solving rate of $85/hr. FU** NO! this all started when i put in new heater core hoses. never had a problem before that.

[SpeedRacer1]

Was the harness a redtop harness?

[efrain240sx]

[QUOTE=SpeedRacer1]Was the harness a redtop harness?[/QUOTE

those it make a difference if its a red top harness on a black top arent they the same. I ask because im having the same problem and I have a red top harness on my blk top and it was conv. by me. I thought that maybe it was a bad cts & o2. my ecu also dosent have a LED for codes but I used 2 different ecus from my friends and it reads 55= ok and i also ran the car whit the ecus and it runs the same. also my car does back fire like crazy i bean told that a 2 foot flame comes out.

[SpeedRacer1]

The main difference between the redtop and early blacktop harness is the O2 sensor wiring.

[efrain240sx]

The main difference between the redtop and early blacktop harness is the O2 sensor wiring.

how are they different plugs or wire location becuase the plug on the harness maches whit the fet o2 of my blk top

[SpeedRacer1]

The wiring at the ECU is different between the redtop and early blacktop. The O2 sensor has 3 wires. One wire is the power wire and it comes from a 12 volt source. The other two wires are at the ECU. The white wire is in the same place on the two ECU's. But the other wire (brown/yellow) goes into different places on the ECU. So whenever you crossuse the ECU's and harness's the O2 sensor is not working properly.

[Neil]

When I lenghtened the wires for my 02 sensor, I accidentally had a fiber of the sheidling touching the sense wire and it was grounding out the voltage the O2 sensor was putting out. The ECU was running open loop because of this and it was crazy rich and smelled pungent but boosted ok. Then I found out I had a bad TPS, cuz it was filled with water. It was reading randomly which was my random idle issue. Fixed the O2 wire, got a new O2 sensor (fat, blacktop, got a '96 300zx-t piece) anyway cuz i roasted the original with the bad mixture for 100 miles, got a new TPS and set it, and now everything's 100%.

Try tightening your BOV a little at a time, it could be staying open somewhat at idle till it sees boosts again and shuts.

Also if you want, I still have the TPS that had water in it. I ground off the plastic casing above the potentiometer and got all the water out and then it worked perfectly. I can ship it to you if you want to test it out.