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2G Camshaft Sensor Keeps Failing

Posted by Tyler’s_DSM, Nov 11, 2019

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  1. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
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    Joined Dec 26, 2018
    Elwood, Indiana
    So my last two posts were about a crank but no start, after listening to a guy from STMTuned saying it was most likely spark plugs then having my mechanic from my job look at it telling my fuel filter, as well replacing fuel pump and a few other things car still did not start. I kept thinking it was the cam sensor, finally bought a brand new one from Orielly's. It was $73 from Import Direct. Replaced sensor car started with no hesitation. I was happy.... for a few days. Had a coolant leak, fixed it and then car ran perfect besides cold start idle. Idle would jump to 1500 and sit for a few seconds then go to 500 and almost seemed like car would die then went to 1000 and when car was warmed up, it ran fine. About five days later go out to start car around 6:30 and it was like 35 degrees out. Car wouldn't start, just cranking like it did in the first place. Now I doubt it could be from the brand new sensor, so I'm thinking maybe the connector has a piece of dirt, wiring is bad, or ecu is causing this to keep a sensor from working. Anyone had this issue before, everything else is perfect, timing, compression, fuel, spark, air. Could it be a dirty connector that needs cleaned? Bad wiring? Bad ECU? How can I check to see what it could be, or is there a way to simulate with the sensor by cleaning sensor or warming or cooling sensor out of car then reinstall? I'm clueless at this point.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  2. kenuwine4g63

    kenuwine4g63 Proven Member

    461
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    Joined May 26, 2009
    Charlotte, North Carolina
    Check your coolant temp sensor. Especially when its cold out and your having inconsistent cranking issues during whether change.
     
    kenuwine4g63

    390  0

    1995 Mitsubishi Eclipse GST
    000.0 whp · 000.0 lb/ft · 2G DSM
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    streetraceboi and TSiAWD666 like this.
  3. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
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    Joined Dec 26, 2018
    Elwood, Indiana
    That’s the first thing I replaced when this happened four weeks ago. So I know it’s not the coolant sensor. I just got a replacement cam sensor today for free so I’ll see how many days the car runs again before it happens again
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  4. TSiAWD666

    TSiAWD666 Freelancer

    2,153
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    Joined Aug 15, 2003
    Herndon, Virginia
    Check the coolant temp sensor wiring especially near the harness for the sensor itswlf. The location and type of insulation on the wiring leads to shrinkage and degradation due to all the heat, exposing the wiring and making it very easy to break. Really look at that wiring and make sure it's fully intact.
     

    Road Race Build 14K  12  371

    1999 Mitsubishi Eclipse GSX
    377 whp · 416 lb/ft · 2G DSM
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  5. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
    9
    Joined Dec 26, 2018
    Elwood, Indiana
    That’s the first thing I looked it around four weeks ago when car didn’t start. the sensor and wiring looked good. After that I checked everything else plus replacing wires, plugs, fuel pump and filter, coolant temp sensor for ecu and checked for fuel, spark, timing, compression and all checked out to be perfect. Replaced CAS and fired right up. Now car won’t start again after finally fixing it about five days ago. Yesterday I replaced CAS again and car fired right up again. So I’ll check the coolant sensors and wiring to them once again. But I think my problem lies with the cam sensor and either wiring is bad, ecu is bad, maybe the trigger plate inside the housing it causing damage to the sensor? Or maybe the connector is shorted out? Or dirty inside? I have no clue. I haven’t thrown a single code at all.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  6. TSiAWD666

    TSiAWD666 Freelancer

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    Herndon, Virginia
    I might buy pigtails from Ohm Racing for the cam and coolant sensors just in case and splice them in to rule them out.

    Also since it's right there, make sure your PTU harness is snug and snapped in. Since you're playing with the cam sensor you may be nudging it and that might be your issue. I had that happen to me once, I had the harness plugged in and the car would drive fine, yet what I didn't know was it wasn't locked (i.e. no click when plugging it into the ptu), and it just suddenly worked its way loose one day enough to loose connectivity. At a glance you'd never know because it looked plugged in. Turns out the orange gasket inside had bunched up inside the harness and made it really hard to push the harness fully onto the ptu. Once I fixed that and locked it in place everything was good again.
     

    Road Race Build 14K  12  371

    1999 Mitsubishi Eclipse GSX
    377 whp · 416 lb/ft · 2G DSM
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    kenuwine4g63 likes this.
  7. kenuwine4g63

    kenuwine4g63 Proven Member

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    Joined May 26, 2009
    Charlotte, North Carolina
    Which cam sensor are you running for them to be failing like they are, supposedly?
     
    kenuwine4g63

    390  0

    1995 Mitsubishi Eclipse GST
    000.0 whp · 000.0 lb/ft · 2G DSM
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  8. Tyler’s_DSM

    Tyler’s_DSM Proven Member

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    Joined Dec 26, 2018
    Elwood, Indiana
    If I remember right where the PTU is located which is behind the middle of the fuel rail? If so I have never bumped nor touched that sensor and the other day I did make sure it was all the way down and locked and it was. I’m starting to think maybe I have a leaky cam seal which is getting oil on the sensor and it’s losing its magnetic play to the two blades/teeth on the actually gear inside the sensor housing. I’ll try and wipe excess oil off and see. It kinda makes sense to me because the OEM sensor was covered in oil quite a bit and the brand new one was obviously not so that’s why it starts and runs fine until it gets oil on it? Idk if that’s possible but at this point anything is possible haha. I’ll see if that does the trick if so I guess I need a new seal. I have heard of this happening on another car my grandpa worked on before.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  9. Tyler’s_DSM

    Tyler’s_DSM Proven Member

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    Joined Dec 26, 2018
    Elwood, Indiana
    As stated above I believe it’s called import direct from oreillys. Now each sensor is brand new and sealed so no one else has returned either one. I doubt it has anything to do with the brand at this point. Yes ik autopart stores don’t sell the best quality but it’ll get the job done most of the time from experience. I’ve had issues with autozone duralast parts but never with oriellys so far.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  10. kenuwine4g63

    kenuwine4g63 Proven Member

    461
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    Joined May 26, 2009
    Charlotte, North Carolina
    No not the brand. Which type. 1g, 2ga or 2gb?
     
    kenuwine4g63

    390  0

    1995 Mitsubishi Eclipse GST
    000.0 whp · 000.0 lb/ft · 2G DSM
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  11. TSiAWD666

    TSiAWD666 Freelancer

    2,153
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    Joined Aug 15, 2003
    Herndon, Virginia
    Having oil on the camshaft position sensor is totally normal and a red herring here.
     

    Road Race Build 14K  12  371

    1999 Mitsubishi Eclipse GSX
    377 whp · 416 lb/ft · 2G DSM
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  12. streetraceboi

    streetraceboi Proven Member

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    Joined Sep 4, 2002
    San Antonio, Texas
    Sounds like Coolant Temp Sensor symptons. Youd be surprised how many "New" parts we had returned that were defective when I worked at an auto parts store.
     
  13. Tyler’s_DSM

    Tyler’s_DSM Proven Member

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    Joined Dec 26, 2018
    Elwood, Indiana
    It is the stock setup for the sensor for a 98 gs-t. Not sure which 2g one that would be that you said. Could ut be the connector and if so how do I test it to see?
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  14. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
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    Joined Dec 26, 2018
    Elwood, Indiana
    But my sensor is brand new for coolant for the ecu. And each time I replace cam sensor it starts up no hesitation, I replaced sensor a few days ago again and started car up while it was 17 degrees out in the morning. But after four to five days the cam sensor goes out and if I replace it again it'll start without any issues and run perfect for a few days until this happens again.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  15. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
    9
    Joined Dec 26, 2018
    Elwood, Indiana
    Okay, well I'll try and get pics of both wiring to connectors of both sensors tomorrow and see if you guys think it looks any good, I'll order the pigtails off ohm racing anyways but what is the best way to splice them, I feel like soldering them would be a challenge with how much the harness has almost no slack and the tight area to work in with even the intake piping out of the way.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  16. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
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    Joined Dec 26, 2018
    Elwood, Indiana
    So I went ahead and just got the pics tonight of wiring. It all looks decent to me. I went ahead and put key in car and checked connector with multimeter on the cam sensor. Well I got 3.5 volts then started to wiggle connector around and went to 11.7 to less than 1 volt. So I’m guessing my connector itself has loose wiring going to it or something cuz the wires themselves look good. I ordered a pigtail off ohmracing. Now what’s the best way to connect them? Crimp connectors and some high quality electrical tape? Soldering and tape? I just feel like getting a soldering gun and solder in there would be difficult cuz the harness has almost no slack. Even getting the intake pipe out of the way I don’t feel like it’ll help much either? So what would be the best way?
     

    Attached Files:

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
    Loading...
  17. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
    9
    Joined Dec 26, 2018
    Elwood, Indiana
    I posted pics of wiring I ordered pigtail for cam sensor. What’s best way to connect the new pigtail? My other post with the pics I said how connector as I tested it would jump up and down voltage so I assume it’s just the cam sensor connector itself. But I bought the pigtail off ohmracing. I’m just wondering how is the connector I guess getting shorted out and jumping voltage, yet every time I get a new sensor put in the car starts? So would that mean if connector is shorted out is it causing the new sensors I’ve put in to be no good? Cuz car started perfect with a brand new sensor but after a few days car won’t start at all. So I assume it’s the connector but what I’m wondering if car ran good on a good sensor then would it short out the sensor and cause it to fail and be no good or do you think the sensors should be good? Or should I just get another new sensor after I replace pigtail? Sorry for long post.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  18. TSiAWD666

    TSiAWD666 Freelancer

    2,153
    565
    Joined Aug 15, 2003
    Herndon, Virginia
    I am not sure why your readings jumped around. If you were making poor contact I can see that being the cause but is that your testing method or the wiring or harness I don't know. I would check our the harness for any weird splices and redo them if there are any . Also would hurt to check the wiring for this sensor near the ECU.

    The best method for splicing is using 3M metal butt connectors, not solder. Solder is brittle and inflexible and can get broken easily. You also want some 3 to 1 heat shrink tubing that is adhesive lined. You will need a good crimper for these kinds of connectors, and for the tubing ideally a heat gun but you can get away with a pilot lighter if you're careful.

    Butt splices:

    Inexpensive crimping tool: https://www.amazon.com/gp/aw/d/B0195VXA10?psc=1&ref=ppx_pop_mob_b_asin_title
     

    Road Race Build 14K  12  371

    1999 Mitsubishi Eclipse GSX
    377 whp · 416 lb/ft · 2G DSM
    Loading...
  19. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
    9
    Joined Dec 26, 2018
    Elwood, Indiana
    I just probed them with regular multimeter probes and stuck them in as far as possible without bending or breaking anything. And just holding the connector still it wasn’t at twelve volts. I’ll try agin tmr with a paper clip and alligator clamps. But it makes sense thought of the connector isn’t holding a proper 12 volts and that’s what causing a brand new sensor to fail just after a few days. I think I’m not good with electrical. Where does it plug into the ecu? I’ll check that but I’m not sure where it’s located around ecu and where’s it connected to at.
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
    Loading...
  20. Tyler’s_DSM

    Tyler’s_DSM Proven Member

    30
    9
    Joined Dec 26, 2018
    Elwood, Indiana
    Well I said screw it and just proved them again tonight with paper clips and well cam sensor has a constant 11.7 volts and coolant temp sensor that goes to ecu I got a constant 4.7. I wiggles connectors around. So you were right On the way I probed them the first time around. But if I got a constant voltage I would assume it can’t be the wiring or ecu then? Right? I did notice the coolant temp connector when clicked on sensor it has 1/8” of pkay back and fourth. The cam sensor has about 1/16” of play back and forth on sensor. So could it be the connectors are just not making proper contact. I’ll have my girlfriend crank car over tmr while I hold both connectors on sensors tightly and see if she fires up. If so I know it’s the connection of the connectors to sensors. And if it still doesn’t turn over. Then I’m confused on why I can use a brand new sensor and it’ll let car start and run no issues for five days then the car will not start again. I’m still not throwing any codes so idek at this point
     

    Street Build 160  1

    1998 Mitsubishi Eclipse GST
    fwd · automatic · 2G DSM
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  21. TSiAWD666

    TSiAWD666 Freelancer

    2,153
    565
    Joined Aug 15, 2003
    Herndon, Virginia
    If something screwy with either plug then messing with them can "fix" the connection but over time just work itself loose enough to loose signal to the ECU. When you put in a new sensor you have to re-seat the harness so I can totally see this happening then.

    As for ECU wiring, yes it still can be wiring if there's some intermittent disconnection/short. I know this firsthand because after 18 years of ownership I suddenly had a weird sputtering problem only on right hand turns that just started in the middle of a track session. Turns out the crank sensor wire near the ecu was literally hand twisted together by the previous owner and these "splices" were wrapped in electrical tape hiding them (and I never thought to check as up to now I'd never had a weird crank sensor issue). I suspect recent handling of the ECU wiring caused these hand twisted connections to pull loose but only on right hand turns. You just never know what a previous idiot owner may have done unless you inspect it yourself.

    I attached a pinout diagram of the ECU which helps identifying where these wires go. While you've verified power at least sometimes is connected, you have to worry about consistent ground as well as the signal wire from the cam sensor. Cam sensor signal wire to the ECU is pin 88 on B-56, and coolant temp (the black with white stripe wire to the sensor) goes to pin 83. I believe the ground wire for the coolant sensor line connects into pin 92 (but don't quote me on that) if you want to check its continuity.
     

    Attached Files:

    Road Race Build 14K  12  371

    1999 Mitsubishi Eclipse GSX
    377 whp · 416 lb/ft · 2G DSM
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