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Thread: TW Sensor!

  1. #1
    DX User plasmadis's Avatar
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    TW Sensor!

    Ah, good evening my fellow 3geezers. Gather around and let me tell you the story of the mysterious TW sensor. Some of you may have already heard of this guy, but for those of you who haven't, this should be valuable information for you.

    Take a look at your EFI engine, and you'll see two sensors above the distributor, under this thing with two vacuum hoses coming out of it. The one on the left, with a green plug, is a temperature sensor. It simply controls when the cooling fan goes on and off, when the car is off. Right next to it, on the right, with a beige plug, is the more important TW sensor. Some places will call it a ECT (engine coolant temperature) sensor, or just a temperature sensor. This guy is likely to give you a lot of grief.

    Having trouble starting? Does it just crank and crank? Does it act like it floods? Does it feel like sometimes your car runs like shit, rough acceleration and idle? Well, first thing to check is your main relay, the solder points could be loose. But that's a whole other story, just Google "main relay site:3geez.com" to read all about it. At first that's what I thought my prob was, so I resoldered the relay, only to find it sorta fixed what was wrong, so after some poking around, I narrowed it down to the TW sensor.

    Well, I was a complete moron and didn't bother to check what code the ECU LED was throwing. Sure enough, it was blinking 6 times, indicating the ECT sensor was bad.

    Now, here's where things get tricky. You'll prob like be like "Well, ima just head down to Kragen and grab one". When I did Google "TW sensor site:3geez.com" I even found ppl here saying they'd just pick up at Kragen. Uh-uh.

    Kragen will sell you this guy:
    http://www.partsamerica.com/ProductD...pe=290&PTSet=A

    You can even ask them and they'll be like "Oh yeah, temperature sensor? Yeah that's the guy." NO! THIS IS WRONG! They'll sell you the one on the LEFT, with the GREEN PLUG. This just controls the fan and won't do shit for your car running like shit. So you'll go back and be like "Uhh, I need the OTHER temperature sensor", and they'll be like "Nah mang, that's the only one I got mang". As far as they know, there is only one temperature sensor they got for our cars. They dunno shit.

    So I called around. Autozone, Pep Boys. They only have that one too. Shit. Sure I can find one online, but it comes from back east, takes a week, and I need one now because I'm tired of my car running like crap and being a bitch to start.

    BTW, the TW sensor does a great deal, I've found. It's what tells the ECU how much gas to give the engine, based on its temperature. If the engine is cold, it'll give it more gas, and if it's hot, vice versa. This is especially important when starting. With a bad TW sensor, the ECU thinks the engine is always cold, so it'll give it too much gas, you'll sit there cranking and cranking, and the engine floods. This happened to me once, leaving me stranded in a grocery store parking lot (BTW, this is also a symptom of a bad main relay, which I also then fixed). So, a temporary solution, which I found here on the site, is the "paperclip method", haha. Just stick a cut paperclip in the TW sensor plug. This gives a closed circuit to the ECU from the sensor plug, making it think the engine is always warm, so it won't give it too much gas. This saves you from flooding it, however, it makes starting a bitch, as you gotta give it just the right amount of gas as you crank it, then rev it a little before it'll idle properly. If you don't, then it dies, since the ECU doesn't really know what to do. Man, it was like I had a carbed 3gee again! Those damn carbs! :p

    Anyway, I just decided to hit up the dealer. Capitol Honda here in San Jo knew exactly what I was talking about, pulled up the Honda part number, but then they didn't have it in stock. No! But wait, he was kind enough to tell me the Honda on Stevens Creek had it. What a guy!

    And here it is, the guy that saved me from these past 2 weeks of grief:

    Ouch! 40 bucks!

    Here are the old sensors:

    The bigger one is the sensors that controls the fan, the green plugged one, the wrong one Kragen sold me. It was working fine, but I went ahead and put in the new one anyway.

    And here are my shiny new sensors installed:

    Yay!

    And thus concludes my adventures with these damn sensors. The car runs like a champ now, starts like it's brand new, just cranks over about three times (rrr, rrr, rrr), and vrooooom it's goin. Also acceleration and idling feel a lot smoother. As someone on here said, "it feels like a new car".

    Change your TW sensor, you'll be glad you did!

    plasmadis



  2. #2

    LX-incredible's Avatar
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    Re: TW Sensor!

    Good info.
    88 LX-i coupe auto (241K DD), 88 LX-i coupe 5-speed, 89 SE-i coupe auto.
    Quote Originally Posted by stat1K View Post
    who is tim and where can i get naughty pictures of him?
    CARDONE SUCKS.

  3. #3
    3Geez Veteran MessyHonda's Avatar
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    Re: TW Sensor!

    dude....i need to change those as well as the temperature gauge in the rad....my fans dont turn on at all...so i had to wire them....they run all the time now. so both sensors were 41 bucks? i get mechanic discount at honda.....so hope it gets the job done.

    1989 Honda Accord LX-i
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    Redzone tuned

  4. #4
    DX User plasmadis's Avatar
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    Re: TW Sensor!

    Just the TW sensor cost me 41 bucks from the Honda dealer. :p The other sensor is the one for the fans, the one I got from Kragen, for 23 bucks.

    If you're having a prob with the fans turning on, it might also be the fan relay, which is in the engine compartment fuse box.

    plasmadis

  5. #5
    2.0Si User
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    Re: TW Sensor!

    Lil idea i always had was put a pot between the output of that sensor and the ECU and you got crude fuel control.




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  6. #6
    LXi User coope's Avatar
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    Re: TW Sensor!

    man my light was cumming on and it is hard to start sometimes it's like it was out of gas or sumthing i had replaced fuel filters and such thanx will get rite on that thank God for u !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  7. #7

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    Re: TW Sensor!

    If I'm not mistaken, it appears that Autozone sells the TW sensor: part number SU4006.

    Thanks for posting this - you probably saved me from buying the wrong one (I think my TW sensor needs replacing too).
    Last edited by redaztec; 06-28-2007 at 08:14 PM.

  8. #8

    carotman's Avatar
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    Re: TW Sensor!

    Some 3geez don't have that green sensor there. It's there if you have the fan delay control module.



    Notice how the thermostat housing has a blank hole where the fan sensor is supposed to be.

  9. #9


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    Re: TW Sensor!

    I started having trouble with the TW sensor about 2 weeks before it got so bad that I was afraid to turn the engine off away from home. I ordered it from the Honda dealer and ended up changing it out in the dealer's parking lot. I'd advise people to just get a new one now, because sooner or later it's gonna go. Same for the main relay, although it's a PITA to install.

  10. #10
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    Re: TW Sensor!

    I don't live within 200 miles of a dealer and the only parts store that had a clue and could get one was napa.They knew what i was looking for and it
    is just like the one in the pic above.Mark

  11. #11
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    Re: TW Sensor!

    Can someone confirm this?

    Is this part that Rockauto sells for $15 the infamous TW sensor that may be causing my erratic idle and non-starting issues?

    Quote Originally Posted by redaztec View Post
    If I'm not mistaken, it appears that Autozone sells the TW sensor: part number SU4006.

    Thanks for posting this - you probably saved me from buying the wrong one (I think my TW sensor needs replacing too).

  12. #12


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    Re: TW Sensor!

    Ya know, I know some of you guys make it a point of principle never to go near the Honda dealer. But really, a quick stop there, even if they had to order it, would get you one in a day or two.

    Amusing story plasmadis.

  13. #13
    LX User stephensimmons's Avatar
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    Re: TW Sensor!

    Quote Originally Posted by w261w261 View Post
    Ya know, I know some of you guys make it a point of principle never to go near the Honda dealer. But really, a quick stop there, even if they had to order it, would get you one in a day or two.

    Amusing story plasmadis.
    Some of them rather spend $20 on something that will work then to spend $40 on something that will solve all their problems.

  14. #14
    LX User stephensimmons's Avatar
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    Re: TW Sensor!

    Quote Originally Posted by Harrison_Bergeron View Post
    Can someone confirm this?

    Is this part that Rockauto sells for $15 the infamous TW sensor that may be causing my erratic idle and non-starting issues?
    Ill almost bet you my next pay check that it isnt.
    Last edited by stephensimmons; 03-26-2010 at 06:56 PM.

  15. #15
    LX User Bluntman's Avatar
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    Re: TW Sensor!

    Quote Originally Posted by Harrison_Bergeron View Post
    Can someone confirm this?

    Is this part that Rockauto sells for $15 the infamous TW sensor that may be causing my erratic idle and non-starting issues?
    TW sensor stands for Thermal Water or Temperature water sensor, so it is called ECT sensor ( engine coolant temperature sensor) when you ask or look up parts on sites other than dealer. Honda just calls it TW sensor. As for idle it could be a bad IACV ( Idle Air Control Valve). 88-89 have this valve. I had a bad one, was idling a small bit bad on start up, tried cleaning it first but that didn't get it, so I bought a new one and idles like new. These will not always throw a code.
    Last edited by Bluntman; 03-26-2010 at 06:43 PM.
    My '66' GT I built. My first Hot Rod magazine Cover "Summer 85". I've had it for 32 years, since I was 18. It's a trailer queen. 289 Hi-po, t-10 Toploader 4speed, 9 inch rearend.

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    LX User Bluntman's Avatar
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    Re: TW Sensor!

    Here is a NAPA parts list I use to get NAPA part numbers.
    http://www.dmauto.com/web/dmauto/catalog/
    My '66' GT I built. My first Hot Rod magazine Cover "Summer 85". I've had it for 32 years, since I was 18. It's a trailer queen. 289 Hi-po, t-10 Toploader 4speed, 9 inch rearend.

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    Re: TW Sensor!

    I forgot the link:

    http://www.rockauto.com/catalog/moreinfo.php?pk=945853

    Quote Originally Posted by Harrison_Bergeron View Post
    Can someone confirm this?

    Is this part that Rockauto sells for $15 the infamous TW sensor that may be causing my erratic idle and non-starting issues?
    I have compiled a list of all the things that may cause my issues based on 3geez info:
    IACV
    TW Sensor
    Vacuum Advance
    Main Relay (my starting issues seem more like the ones caused by the TW flooding the engine on a cold start)
    Transmission shift sensor(was in the manual, my idle drops almost to stalling when put in gear)

    I think I may have multiple idle/starting issues, but the TW seems like a likely culprit from what I've read. I plan to clean the IACV tomorrow.

  18. #18
    LX User Bluntman's Avatar
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    Re: TW Sensor!

    Quote Originally Posted by Harrison_Bergeron View Post
    I forgot the link:

    http://www.rockauto.com/catalog/moreinfo.php?pk=945853



    I think I may have multiple idle/starting issues, but the TW seems like a likely culprit from what I've read. I plan to clean the IACV tomorrow.
    Yes on both, but cleaning the IACV does not always work on these vehicles, you may want a new one later.
    Last edited by Bluntman; 03-26-2010 at 07:24 PM.
    My '66' GT I built. My first Hot Rod magazine Cover "Summer 85". I've had it for 32 years, since I was 18. It's a trailer queen. 289 Hi-po, t-10 Toploader 4speed, 9 inch rearend.

  19. #19

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    Re: TW Sensor!

    Quote Originally Posted by Harrison_Bergeron View Post
    That is the TW Sensor, but you really should buy the Beck Arnley part for $21 and not some off-brand thing. If it's failing, it will usually start throwing codes so yours is probably good enough not to cause huge problems. Why don't you describe your symptoms in a new thread?
    Dr_Snooz

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  20. #20
    DX User rohwer's Avatar
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    Re: TW Sensor!

    This thread appears to sum up the issues that I am having as well. I already rebuilt, then replaced the IACV. New spark plugs and wires. Things worked better for a few weeks, but now it takes 20 min to start the car. I just ordered a new TW sensor. I hope it takes care of the problem. Thank for the great info.

  21. #21
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    89 Accord fans do not turn on even with A/C running

    Ok, it always seems like one thing after another with this 89 Lxi. Was driving to work this AM, and when I got close to work I noticed the Temp gauge was pegged. Ive done the, turn on A/C on to verify Driver side fan works, which it did when I first tested it when I got to work. Now A/C is blowing warm, when it was cold as all get out Yesterday. I jump the fan relay under the hood, and the passenger, (cooling) fan does engage. My last Accord, an 86 did the same thing @ about the same mileage. I hooked up a switch to the fan realy to turn the cooling fan on when needed.

    I pulled the plug to the green connector on the thermostat assembly, & noticed oxidation inside the plug. I cleaned it out as best I could. Maybe need new plug. However, when I jumped the plug wire side to make a voltage connection, nothing happened, no fans. @ least I can jump the fan relay and get me home from work, but any ideas @ this point? Why would a fan issue all of a sudden cause my A/C to blow hot overnight? Do I need a Fan switch or what?

    Thank you for any ideas on where to troubleshoot this.

  22. #22

    carotman's Avatar
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    Re: TW Sensor!

    Do you have voltage at the plug?

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