wjiroc86

I am having a problem with my 89 RS TBI 305, back about a month or so ago I put on some headers and let my friend put on the right one, well he wasnt paying attention and broke a sensor, i have no clue what this sensor is called, but it has one wire connector and appears to be in a coolant passage, if someone can tell me what this sensor is called i would really appreciate it... i have looked at almost every thread on this site that has to do with any kind of sensor and no luck yet...

Thanks

drowning in tbi

Is it in the cyl head or on the lower part of the block? What color is the wire?

wjiroc86

cyl head, and the wire is black

rallysport383

Got any pics? I believe it might be the temperature switch that controls your fan.

tony_cogliandro

iTrader: (3)

here is the wiring diagram for a 90 camaro with tpi - it is color coded and might help you out. there are a number of sensors over there and you cant really rely on the wiring colors as they appear not to be consistent within the same model years, must less different years. that is why gm is in trouble. for 70.00 per hour the uaw did not think they were paid enough to only use the wiring that was supposed to be used and at times grabbed anything that was handy, or fed the wrong wire into the harness making machine.
i attached a pdf file so you should be able to make it as big as you want to be able to read it. if you cant then go onto adobe.com and download the free acrobat 9.0 reader. keep the diagram on your computer you will need it again.

ok i was not paying attention its a 305 tbi - darn its too early. here is the diagram for that. i just left the other one here incase someone else needs it.
i think you have vin F but i am enclosing both F and E. use the one you need and keep the others, you may want to get a tpi for a 350, or put tpi on your 305.

wjiroc86

I dont have a camera right now

ownor

iTrader: (5)

not sure but i thought the 88-up engines all had fan schedules programmed into the ecm without a fan switch. my 84 TA used to have one and it is indeed located in the pass. side cyl head.
another option would be the ESC Knock Sensor which is located in the lower portion of the block on passenger block, but this one is for sure a one-wire switch. i broke that one two when i wanted to fully drain my block

drowning in tbi

The knock sensor should be on the lower part of the block. This should be a temp sensor OR fan switch.

wjiroc86

Hey tony, where can i find a wiring schematic for an 89 tbi? thanks again for all the input from you guys...

tony_cogliandro

iTrader: (3)

if you look on the E diagram there are a numbr of solid black wires.
the throttle position sensor is black but i think that it is in the other worng position.
there is one to the Mat sensor that is black, which is what is may be.
there is a coolant sensor that also has a black wire and it could be that too.
why dont you get the number off of the sensor and look it up on the net?
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this be the place - http://www2.wiring-diagram.com/
they will download it at a website, send you the link and you can down load it. put is someplace safe, and back it up.
get the full diagram with everything on it, not the cheap one. dont have them rush - it will get to you in less than a day. they just send you the link.
it is a great investment.

wjiroc86

Thats a pretty cool website thanks again, if its the fan switch, im running aftermarket jegs fans on a switch and relay nothing to do with the sensor, so is this sensor important if im not using the factory fan harness, or would this tell the car that i dont have fans running or something and run horrible, because it is.

melsplace6

most likely the anti-knock sensor. It retards your timing if it detects a problem.

tony_cogliandro

iTrader: (3)

your ecm need the information, if you are using an ecm. so yes it is important because it changes the setting as the operating environment changes. even if you have an aftermarket chip it might disconnect certain features, like smog, but it still needs the imput to change things to run at top performance.
its like you trying to move around without your ears or eyes or ability to touch and feel. you can do it with one of those missing, but not as well as you can with everything working properly.
yes the computer needs the imput.

wjiroc86

Thanks man, you helped me alot, damn computers, im leaning way toward putting my 350 in there with a carb =], not because it makes more power or anything like that though, just because this tbi is almost always messed up, shes broke down in the driveway right now...

naf

iTrader: (7)

If the wire in question is indeed going to the temperature switch in the pass side head and you are controlling the fans some other way, then it is not needed. The ECM reads temperature from the Coolant Temperature Sensor (CTS) that should be installed on the water neck. The CTS is a two-wire sensor
as opposed to the single wire fan temp switch (or the opposite side single wire temp sensor for the instrument guage). Yes, three different temp senders but only the CTS provides input to the ECM.

Oh I have to add that if you're controlling the fans manually and not with an alternate temp sensor somewhere, I really have to recommend retaining additional control with this temp switch. There's no reason you can't do both and having the temp switch still connected could save your motor one day.

wjiroc86

Thank you for the advice, i appreciate it, I got another problem though now, i keep loosing control modules, even the one i just bought from jegs in a new distributer, i dont know whats going on, the car runs nasty in high rpm's when its running it cuts out really bad, and about two or three weeks ago i lost the brand new one and a couple of days ago i lost the original one, any ideas from anyone???

It wont start at all now, could that be the knock sensor? and would that mess up a control module???

RFmaster

Bad coil

//RF

wjiroc86

I bought that when I bought the distributer, and I even tested it with original that worked when I took it off, and another one that was on my dads truck, I think I might have it figured out now, I took the new distributer out and it was rubbing and grinding a little bit when the car was running so it took out the first CM and then I had the original distibuter back in and it fried a control module to, but when I looked at it the two wires from the control module where both cracked in the same place right at metal so they probably grounded out... Now im sending my new distributer that was defective back to jegs and when they send me a new one I hope it works right...

zapeee

can anyone tell me where the knock sensor is supposed to go on a mkIV big block? i think it should be on the block above the oil pan near the starter, but the new one wont thread into the hole there, and i dont know where the original went.
i'm also wondering if anyone knows if there is a difference between the big block and small block throttle bodies- they look the same and take the same gaskets.

buttroq

pass. side is coolant fan switch on head, on block is knock sensor, dvr side head is a coolant temp sensor