ka24de obdI crank sensor myth vs fact?

[HapaxLegomonon]

So on my 95 s14 I'm getting a crank sensor code.*Here's the deal:

1. I keep seeing post of ppl arguing rather or not the obdI crank sensor is in the dizzy or not. Is it that crank and cam sensor are the same thing? Or, I see two different codes in the book for crank sensors and is there another location for a second sensor which is not on the trans bell housing but mounted near the starter? When I look up parts, I keeps seeing the same one which mounts to the bell housing on later models for mine but I keep seeing ppl say that it's nonexistent on 95 and earlier ka's.

Can somebody straighten this out for me? I need facts, not assumptions.

I will dismount the starter my self and check soon enough when I change my mounts this week. However, if there are two crank sensors, which code goes to the dizzy, which goes to the other? There's about a $200-$250 price difference in the dizzy replacement vs the sensor I keep seeing when I do a parts search.

2. I keep seeing ppl saying that the crank sensor only detects a misfire however, I'm not getting any misfire code, only code 82 for the crank sensor aaand I read a sensor guid which states specifically that bad crank sensor does in fact create a misfire. When I clear everything, my random misfire goes away but once the misfire comes back, still no code for that, only for the crank sensor, code 82, not the other crank code.

Who's got real facts? I keep getting running upon contadictory answers in other ppls threads so I created an account specifically for this question. It'd be nice to clear the air on this.

[l adam l]

What ecu do you have? Can you connect an obd2 scan tool on the passenger side and read codes? I have a 1995 240sx se and I did in fact have a sensor mounted on the bell housing.

[HapaxLegomonon]

I have a 3c. I looked it up to make sure that it was obdI because I read where the obdII ecu will cause issues on the 95 and lower 240's but I did notice as I was hooking up an indash earlier that I do have what seems to be an obdII connection on the driver side. Regardless I've just been reading the ecu by the light flashes on the back. I just installed motor/trans mounts yesterday but still haven't pulled the starter to see if there is a sensor beside it. Going to get on it within the next day or two though because with new mounts I'm still reading a bad crank sensor code. I picked this s14 up a few months ago from a guy that went to a few drift events in it and has done some rewiring on a few things. I'm using as a track/dd my self so I'm pretty much just figuring out everything he's done as I go and it could have something to do with his work. Tbh it seems though that someone hay have had it before he did and rly put some efforts into a build and I think it may have been gutted then he got it and gave up so here I am w it. Either way, I love these things so I'm going to keep on w it. I'll post again after I figure out what's up on a sensor near the starter or not.

[2.5T_/<ouki]

I have a 1995 OBD1 S14 as well and know for a fact that the CRANK angle sensor is on the bellhousing, regardless of auto or manual. I've never heard of another crank sensor near the starter. The CAM angle sensor is located in the dizzy on the s14's. Was your car previously auto? Sounds like previous owner did auto to manual conversion and used S13 transmission.

I recently did auto to manual conversion on my S14 as well and used s13 transmission, however I did drill out the hole for the crank angle sensor. Look at my post, scroll down.

http://zilvia.net/f/showpost.php?p=6063597&postcount=7

[Agamemnon]

All S14's have the Crank sensor regardless of which OBD protocol they have. If your trans bell housing is missing the hole, then it's an S13 trans.

The sensor in the distributor is for monitoring the cams.

[HapaxLegomonon]

Awesome info.. I don't think it was previously an automatic however I do recall now that the guy I purchased from said that he bought a shell and dropped the same year engine in but never said anything on the transmission, which is definitely from an s13 from what you're saying. I just assumed that since it was obdI that it wouldn't have a crank sensor like the s13 trans and considered it normal w/out even considering if he got a different year transmission. So basically, I just need to install the sensor on the bell housing and possibly check out how to wire it up.

Just out of curiosity though, anyone know if that means s13's are w/out crank sensor? I found it strange that crank would be measured where cam is or even that it would be a 2in1 type of deal but I'm not auto engineer so I guess It's possible.

[2.5T_/<ouki]

Originally Posted by HapaxLegomonon

Awesome info.. I don't think it was previously an automatic however I do recall now that the guy I purchased from said that he bought a shell and dropped the same year engine in but never said anything on the transmission, which is definitely from an s13 from what you're saying. I just assumed that since it was obdI that it wouldn't have a crank sensor like the s13 trans and considered it normal w/out even considering if he got a different year transmission. So basically, I just need to install the sensor on the bell housing and possibly check out how to wire it up.

Just out of curiosity though, anyone know if that means s13's are w/out crank sensor? I found it strange that crank would be measured where cam is or even that it would be a 2in1 type of deal but I'm not auto engineer so I guess It's possible.

The CPS (crank position sensor) is NOT needed for running the car, however it is ONLY needed/used for detecting misfire/emissions on OBD2 equipped S14's. If you have an S14 than your lower tranny harness should already have the pigtail/connected; more than likely it's tucked away somewhere, so no need to wire it up, just plug it in IF you want to add it.

I still think you're confused.

[HapaxLegomonon]

Well you would be correct sir. Tbh I'm trying to pinpoint a sloppy iddle for a few seconds after throttle release along with hesitation @ 4,000rmps that happens only in gear and after 1st gear which I hear is fairly common yet haven't seen anybody post a resolution to. I read a list of each sensor and what they do, to pinpoint my issue which says misfire could be from bad crank sensor and 4grand issue from bad knock sensor. I'm actually running without my #2 o2 sensor or a trans harness in general w 3" exhaust, no cat because emissions aren't checked where I live. The codes I'm getting are for crank and #o2 as it should right now but that is all I'm getting. Now, everyone says rear o2 and crank aren't need to run and I run however my ecu is adjusting timing so much that no matter how I adjusted my distributor, timing changes according to my light but the rmps change very little if at all. However I have to advance my distributor all the way to run properly and still get the 4grand issue. I've done engine mounts, knock sensor, installed a thermostat where it previously was ran w/out. I've checked vac lines, fuel pump, fuel pressure, compression new plugs. At this point I'm at either doing my plug wires, distributor or trying to Iinstall those sendors and seeing what happens.

If you have any ideals, let me know...

[2.5T_/<ouki]

Originally Posted by HapaxLegomonon

Well you would be correct sir. Tbh I'm trying to pinpoint a sloppy iddle for a few seconds after throttle release along with hesitation @ 4,000rmps that happens only in gear and after 1st gear which I hear is fairly common yet haven't seen anybody post a resolution to. I read a list of each sensor and what they do, to pinpoint my issue which says misfire could be from bad crank sensor and 4grand issue from bad knock sensor. I'm actually running without my #2 o2 sensor or a trans harness in general w 3" exhaust, no cat because emissions aren't checked where I live. The codes I'm getting are for crank and #o2 as it should right now but that is all I'm getting. Now, everyone says rear o2 and crank aren't need to run and I run however my ecu is adjusting timing so much that no matter how I adjusted my distributor, timing changes according to my light but the rmps change very little if at all. However I have to advance my distributor all the way to run properly and still get the 4grand issue. I've done engine mounts, knock sensor, installed a thermostat where it previously was ran w/out. I've checked vac lines, fuel pump, fuel pressure, compression new plugs. At this point I'm at either doing my plug wires, distributor or trying to Iinstall those sendors and seeing what happens.

If you have any ideals, let me know...

Check your MAF. Rear o2 is only for emissions and has absolutely nothing to do with how your car runs or behaves.

[HapaxLegomonon]

Okay so I just cleaned the piss out of my maf and found the tps voltage was way off as well. When I set my timing it had a way different range and the engine sounded/ran way better. Made me grin because I'm sure this is it. I'd not seen anyone w this issue adjust the tps though I'm sure there is a thread I didn't find where somebody posted it as a solution if this is it. I'm also pretty sure I had a compounded problem from multiple issues but either way, I get to test it out in a few hours so I'll post on the results.

[HapaxLegomonon]

You're right... maf was acting funny butttt it's because there was an s13 coolant temperature sensor where I need and s14 sensor. Ecu wasn't saying anything as the sensor wasn't bad just wrong, causing maf to act funny as well w no codes thrown because it was good as well. Hope this helps some ppl because I've seen ppl do a ton of different things having the same issue, wasting a ton of cash w no resolve. I didn't pinpoint this until I started hitting everything with a volt meter. If you're going diy i definitely suggest learning to use a volt meter and getting a repair manual. Since I for some reason need a moderator to approve my comments to my own issue this probably isn't going to help anybody because my last comment wasn't posted and neither will this so I'm starting a new thread just to get the info out there and under the title of the actual issue I had since this thread go a little off topic anyways... probably posting my findings on other sites as well so ppl know how badly the s13 coolant temperature sensor can mess w th e s14. As I said, no codes thrown, I had to use a volt meter so basically w/out that and knowledge of what each sensor would read, I would've never figured out the issue.

[HapaxLegomonon]

Okay so I checked the mafs with a voltmeter. It was all out of whack, not bad. It read fine while the car was on and engine off. With engine running read higher than normal voltage signal at idle yet reacted fine to throttle. So something was obviously throwing it off initially as it functioned as it should. I did some research and the previous owner had an s13 coolant temperature sensor where this is an s14, causing it to send wrong info to the mafs as the s13/s14 coolant temperature sensor are NOT compatible with one another's ecu and cause the engine to opporate/run strangely yet not throw codes because nothing is wrong w the coolant temp sensor or maf. Without a voltmeter or knowledge of what sensors act which way electronically, I would've NEVER figured this out. I hope this helps others out who run into this issue. I've seen a lot of posts where ppl have spent tons of time and money trying to fix the same issue yet don't show if they've resolved the issue, replacing maf, ignition parts, fuel system parts ect.. and a lot of ppl say maf but nothing on cts.

If you're having an issue w no codes from the ecu GET A VOLTMETER, OBTAIN INFO ON HOW YOUR SENSORS ACT AND WHAT THEY SHOULD READ AND TEST THEM. A little common sense and knowing what relates or runs inline with what can save a LOT of time and money wasted.