#1
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97 Maxima starting problem w/ bad crank sensor (ref)
This problem goes back months but I think I'm getting closer to a solution. Basically when I bought this 97 Maxima, it's harmonic balancer (crankshaft pulley) had come apart and damaged the crankshaft position sensor (REF) below it. It rubbed through the outer casing, exposing the copper core beneath it. When I tested it with an ohm meter it indicated an open circuit with no conductivity between the two prongs.
Originally the car would eventually start after a long crank....The service manual indicated that with a bad CPS (REF) the engine needed to go through two complete revolutions before the 2nd crank sensor (POS) would read it and start the engine. This is exactly how it behaved and the other CPS (POS) tested out fine. Ironically after buying a new CPS (REF) from Autozone the car would then intermittently either start right up or go through long cranking which now included misfiring which, over time, eventually fouled the plugs. Thinking maybe I bought a defective part from Autozone (even though resistence values were correct) I then went to a local junkyard and took a factory original off the same year car. This sensor behaved the same way as the one from Autozone. As soon as I re-installed the original damaged sensor the car would go back to starting after one long crank but never misfire in the process! I also heard that the problem may be bad engine grounds between the mating surface of the engine and transmission so I added a jumper ground wire to bridge the engine and trans. I cleaned all other engine ground connections from the battery and also the starter. I even ran a ground wire directly from the battery to the 10 mm bolt on the CPS, thinking that might help, but none of this made a difference. I just don't understand why with new, seemingly good crank sensors, I get intermittent perfect starts (1 or 2 seconds) and horrible long starting (with misfires) while with the bad sensor there are no misfires but just one long crank to start it. I'm now wondering if (1) the car's computer (ECM) could be defective, (2) if I still have an engine ground problem or (3) if I simply had the misfortune of buying two bad crank sensors (REF). If anyone has a suggestion I would greatly appreciate it, since I've been trying to figure this one out for months, spending many hours going through all related threads. |
#2
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did you test your power circuit. there may be other body ground connections. refer to engine control manual from page EC-300.
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#3
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My long cranking problem was solved by replacing the CPS (POS) sensor at the junction of the transmission and engine. The sensor always ohmed out fine; my shop had to put a scope on it to find the issue. Replaced it about 2.5 years ago and it has been starting fine ever since. Good luck.
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1997 Maxima SE, 5 speed, dark green with tan leather, 235K+ miles and still going strong. |
#4
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Yes I replaced the CPS (pos) as well but it didn't make a difference. In fact since the engine starts right up after making it's two complete revolutions, that's telling me that the CPS (pos) is doing it's job because the service manual said the computer would need to read the CPS (pos) after two revs. if the CPS (ref) was defective and that's just what happens. Thanks for the suggestion though. Tom
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#5
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'did you test your power circuit. there may be other body ground connections. refer to engine control manual from page EC-300.'
I'm not sure what you mean by the engine control manual page EC-300. Is that something I can find online? When I refered to the ECM in my post I meant the computer (engine control module). When I tested both wires to the CPS (ref) I found good ground on one and resistance on the other. I also checked these wires with the ignition on and w/engine running and found no voltage present. I believe it works by magnetic induction only and never requires current from the battery. If I am wrong I hope someone will let me know because that could really narrow down the problem. Thanks, Tom |
#6
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Factory service manuals (loose leaf) are found in Knowledgebase section. You can download it here for free. Engine management issues such as yours are found in Engine Control manual. Browse thru it and see what other manuals are available for your vehicle. In thread #4 you speak of service manual so you are working off some type of repair manual, Haynes or Chilton maybe.
It seemed to me you have identified the problem but you reason your way out of fixing the problem by convincing yourself you don't need power source cuz the sensor works by magnetic induction. That may be true but you just can't pluck magnetic field out of thin air, or can you. Magnetic field is created when electrical current is applied to a device. So refer to manual for reference voltage value on power, ground and signal wires. |
#7
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Couple more Qs: Did the misfires only occur while starting, or continue while car was running? Was there any correlation between long starts and cold vs warm engine? Failure of the sensor which provides coolant temp to the ECU can also cause messed up starts.
Have you had any work done which required separating the engine and transmission, like a clutch replacement? These cars are extremely sensitive to havinga good ground there - it is absolutly necessary to clean up the mating surfaces and that doesn't always get done well. |
#8
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Quote:
From what I read this CPS (ref) does not have current going to it. Additionally I stopped by the dealers' service department today and he confirmed that. He also said the timing could be off a bit even though I told him it runs perfect once it starts. I checked the timing when I got home and that looks good. If I don't figure this out in a day or two more I'll probably take in to them and explain all I've done so far. They charge $110 for the first hour and hopefully will be able to diagnose the problem. I could also pick up a used ECU online and plug that in but the service dept. said I'd have to have them program it for another $110. The computer I'm looking at has the exact same #s and the production date will match my car, so I'm wondering if it really needs to be programed? |
#9
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Quote:
The car runs perfect once started and the intermittent starting problem doesn't seem to be temperature related. Right now I put the defective original sensor back in, so one long crank ALWAYS starts the car WITH NO MISFIRE at all. As soon as I install either of my other two CPS (ref) sensors it goes back to either starting right up or bad mifires with long cranking. At least with the former I'm not fouling the plugs...I've lost count how many times I've had them out to clean off the carbon....PS Yes I did replace the plugs with platinium NGKs. |
#10
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bobflood, you got me thinking about something.
My 95 Maxima went through a time where it would take a lot longer to crank than normal, especially after sitting for a while (over night). It progressively got worse and since I couldn't figure it out, took it to a mechanic friend who diagnosed it as the ignition switch. He replaced it and that seemed to correct the problem. However, just this week, I noticed that on occasion, it seems to take longer than it should, not like last time though but time will tell if it gets that bad again. Makes me think I may have a CPS going bad or at least flaky...... I just bought my daughter's 97 Max from her so at least now I have a car I can swap parts on before actually having to go buy one. As for the OP, the 97 did the same thing with the harmonic balancer separating and destroying belts and the CPS. Once I replaced the CPS, it was fine, sorry I don't have anything else to add to fixing your problem.
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1995 Maxima SE (313,000+ miles 10/2012) 1997 Maxima (193,000 miles - bought from daughter when she traded for a Hyundai Elantra Coupe) 2002 Altima (daughter - totaled 12/2011 with 210,000 miles) 2012 Altima (daughter - replaced 2002 with 8 miles, now with almost 30,000 miles) |
#11
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Quote:
There are also threads which talk about some of the starters having different #s of teeth on them which would effect cranking speed. You could also run jumper cables from another car with it's engine running to see if that makes a difference with your starting. When I tried that, it didn't help my car's starting. I also removed my starter and cleaned all the connections, greased the gears and counted starter teeth (eleven) which some people suggested was preferred. I don't think the starter on my car is at fault because it cranks pretty fast but I just wanted to pass it along in case it could be your problem....Good luck with the 95. |
#12
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I know mine isn't a starter problem, engine spins at the same speed (or at least it sounds like it). It's so intermittent/random and currently cranks as it's supposed to about 99 percent of the time. It's that 1 percent....
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#13
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I know this is an old thread, but I am having similar problems with my 1995 Max. Sometimes it starts perfectly, sometimes with a few cranks, but lately it doesn't want to start at all. It gave me a Crank Sensor error p1335, so I replace it with an OEM sensor, but it didn't help. Also replaced the starter and the crank sensor on the transmission. The shop I took it to is also stumped and they've had it for about 1 month now. I am also getting a misfire cyl 1 code along with the CPS code. I swapped coils 1 & 3 but the code didn't follow the coil. I need to check for a fouled plug next cause I replaced all rear fuel injectors a couple of years ago.
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#14
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You may have to do some circuit checks. There have been a lot of problems in the past with the EGI harness on these vehicles, in the bend of the harness between the engine and where it goes through the firewall on the passenger side. The flexing over time can cause one or more of the wires to break (sometimes inside the insulation, which makes it harder to locate). There is a Nissan Technical Service Bulletin on the issue; it's bulletin #NTB98-008b.
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#15
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Thanks for the info. The shop finally got the car to start but they're not exactly sure how. All they did was tap on the crank sensor (pos) and it started. Then they replaced it with the original and had to tap it also to start the car. It sounded like a ground issue so I wire brushed the mating surfaces but it didnt change things. It still cranks a couple of times before starting so it seems like the original posts suggestion that the (pos) sensor is good but the (ref) sensor has issues. Plus im getting code P1335 (ref) cps. I should have mentioned that all of this may have coincided with a shredded p/s belt. I had taped up some exposed wires at the (ref) sensor connector and when the shop untaped it for inspection, one of the sensors wires broke off. I soldered on a new wire and they used it to repair the harness. Ill take a look at their repair tomorrow, but if it looks good then maybe the shredded belt damaged another section of that harness.
Last edited by Hotchymotchy; 09-10-2016 at 08:25 PM. |
Tags |
bad, crank, maxima, problem, ref, sensor, starting, w or |
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