crank sensor

langwilliams

Registered User
What are the symptoms of a bad crank position sensor and any tips for changing it? thanks for the patients with this newbe....
 
I had the similar car. When my car was warm and I would make stop and I would come back and start it, It wouldn't start. All the signs and peoples advice lead me to the cam sensor. I figured since I am gonna change the cam sensor I might as well change the crank sensor. I no longer have any cranking or misfire problems. Hope this helps.. Just my 0.02 cents
:)
 
I think the biggest indicator of a bad crank sensor is having the orange upshift light on while cranking the engine to start it. And of course it not starting at all. If your cam sensor is bad, it will start one out of every 3 or 4 times you try. Im replacing mine right now, and have it off waiting for a new one. I dont think it would be that easy with the balancer in place, so plan on pulling that off. Also might want to make sure it wasnt your balancer that took out the crank sensor. They are a high fail item now that they are old. Also make sure you have the tiny socket for the sensor bolts, I forget the size, but its tiny. :)
 
if it backfires maybe its flooded(wet plugs) bad wires or bad cam sensor or bad harmonic balancer if crank sensor was bad it wouldnt fire at all
 
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Crank or cam?

I have simular symptoms but one includes having the tach bottom out when the car will begin to shut off, and it will stay bottomed out if and when I am able to get the car started again. Sometimes I won't be able to start it back up until I wait long while, maybe till it cools off. What do you guys think? Is it the crankshaft? Also, what's involved in replacing it with removing the HB and all? I've got the book, but advise is always welcome. Thanks!
 
What year is your car. 94/95 have different crank sensors than the early models. If you own a '93 and like to shop at AutoZone tell them your car is a '92 or earlier for the crank sensor. For some reason they have the 94/95 version listed for the 93MY. You can replace the crank sensor without pulling the crank dampener. It's a bit of a pain, but doable. The only tool that you'll need that you might not have is a 5.5mm or 7/32 socket.

Are you getting a check engine light? Have you scanned for codes at all? Does you crank dampener and or pulley have a wobble when the engine is turning over? Are all of the crank pulley bolts in place (including the large center bolt)? Are you getting spark and fuel pressure?
 
'90 SC auto. Engine lights hasn't come on. I haven't scanned for codes since I don't have a light on. Haven't noticed any wobble to the pulley. Am planning on doing the fuel pressure check before anything else. If the crank is bad, the car won't start? Is the tach attached to the crank? That was one of my indications that it might have to do with the crank. Somebody in one of the previous forums had mentioned an indication of the orange upshift light being on while cranking the engine. I haven't had that. In fact I just turned it on to see if it would do that and didn't notice it. She's running great right now but give it several minutes or so especially driving, she'll either cut off or start shuttering really bad reving up & down at really low rpms. When that happens I would have to turn it off and then attempt to restart it. If and when it did start up, the tachometer would stay bottomed out for the rest of the drive. I can't figure it out and was hoping you guys could before I start taking this whole engine apart trying to figure it out myself. Thanks for any advice you can give!
 
Justin,
You problem sounds more like a cam sensor or DIS module. You need to scan for codes. Just because the light isn't on doesn't mean there aren't codes in there. Scan for KOEO and KOER codes.
 
Will do. I've never done that before but I've got both Haynes and Chilton Books and they have the different trouble codes in it and I just have to find the time to sit down and read how to do it. Does running the codes require any special equipment? This is a self-test, right? I know with dodge vehicles you just turn the key on 3 x's and then it start blinking codes to at w/the engine light. I think it's almost worth taking it to my mechanic and having them run the diagnostics on it. If I can only find out what it is, I can fix/replace it myself. What are those codes you said, KOEO and KOER, and how do I find them? Again, thanks so much!
 
KOEO (Key On Engine Off), KOER (Key On Engine Running). Both are outlined inthe Haynes manual in the emissions section. You can set it up the same as they show but instead of putting the analog voltmeter in there just run the jumper wire that they show, get in and turn the key to "On". The codes will start blinking at you.
 
Okay. So I'm trying to find where it is I connect the jump wire. Again, I haven't done this before, sry. I think I've located the self-test on the passenger side, right? It's called the EEC Test and is black and plastic rectangular. Also located beside simular but grey part called ARC/EVO Test. Am I on the right track? (Hope I'm not wearing out your patience! LOL!) So, I connected a jumper wire to pin 2, the Signal return pin on the larger connector and then to the STI (located just below) but couldn't get any readings on the engine light. Thinking I may have it in the wrong pin, I tried the other two but no luck. The diagram in haynes looks a little different from the connector I'm looking at, at least from what I can tell. Do you know what color wires are going into the SIG Return pin that I need to connect the jumper wire to? And how long after turning the key to the "on" position does it take to get readings from the light?

sry for all the q's! Just tryin to learn...Thanks! :)
 
If the Haynes pic doesn't make sense then try doing a search on google for ford eec-iv code reading or on here for code reading. I know I've posted the link to a site that shows how a couple of times. EEC TEST plug is the one you want. It might take a few seconds for the codes to come up. After you turn the key to on it should trip a few relays and turn the engine fan on and off. Good luck.
 
Well, I did a search and this site came up first:http://www.35ththunderbirdregistry.org/Tips/EECSelfTest.htm which helped. I followed the directions and got the jumper wire in the right pin, turn the key to "on" and waited for codes, but didn't get any. I waited for about a minute. Also didn't noticed the fan come. I did get her started so I can get her to regular operating temps as instructed in the Haynes but then she died out on me like 7 minutes later. Still no luck doing the test though. I'm stumped. One question I did have though was about the upshift light. 7birdslater stated earlier that having the upshift light on while starting engine is a big indicator of a bad crankshaft sensor. I did notice that this morning as I was trying to restart her after she cut off. What do you think? I still haven't done the fuel pressure check as I am waiting to borrow a fuel pressure gauge from a mechanic friend. I did notice that I can hear the pump coming on when I turn the key, but I could not hear it when the engine cut off and I turned the key again. I'm still wondering if it's the fuel pump now.
 
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Upshift light while cranking means no crank position is being recieved by the ECM. It will not give any spark when this condition exists. Mine was intermittant and sometimes the car would start, but ran really bad and would die like yours. Mine was weird, right after I soaked the engine with water, it started right up. I also didnt get any codes in the ECM for this condition.
If your not getting any codes, either you dont have the jumper in good enough, Jumper in the wrong pins, you have a wiring fault somewhere, you didnt turn the key to run, your check engine light is burned out, or something worse... your computer could be heat soaked and failed. Your fan relays should click, and the fan come on and at the very least you should get a system pass. If you have a test light or volt meter, the 35th registry tells you what pins you can stick that on to get the codes also.

Edit: after re reading your post, you might want to look at your ignition switch....
 
Ran codes finally

Just now got a chance to mess with my SC. Borrowed a computer and ran my KOEO codes and came up with these following codes:

14 C - Profile Ignition pickup circuit fault
19 - don't know if it was continuous memory (C) or Ignition on (O) but haynes has it as C: Distributorless Ignition Cylinder Identification circuit failure or O: Failure in EEC reference voltage (??).
95 O, C - Fuel Pump circuit open, ECA to motor.

I'm not sure what to do now. I was pretty certain that it was the crank sensor, but based on these codes, there is no indication of that being it. But, correct me if I'm wrong, looking through the codes in the book, I didn't see anything regarding the crank sensor anyways and was wondering if that would even be detected through a diagnostics test. Based on these codes listed, does anyone have any advise for me? I've never done a diagnosis before and am kinda new at this. Any help would be great! Thanks!!
 
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