ok guys, have an 05 g35 that will crank but not start…i scanned it an it popped up needing a camshaft position sensor so i put one on it, still the same result, crank but no start…cleared the code after instal and now we have no codes at all….where do i start, fuel pressure?

 

Did you use an OEM Nissan or Hitachi crank sensor? It's well known that aftermarket crank and cam sensors don't typically work.

Does the tach move while cranking?

Is the NATS security indicator SOLID RED while cranking?

 

the sensor is an SKP, when cranking the tach doesn’t move and the light your asking about doesn’t do anything while cranking

EDIT: it was the camshaft sensor i replaced not the crankshaft

 

Are you sure it's not throwing any codes? If you tach doesn't move when cranking then you're not getting crank signal.

What code did it throw?

I would put the original cam sensor back in and rescan for codes.

 

im going to rescan in just a moment, but let me add that when it cranks its out of cadence

 

p0430 was the code it threw, so we changed that sensor….i have rescanned and yet again shows no codes

 

would it be the crank sensor?…kinda throwing me since its not showing any codes

 

P0430 is the catalyst efficiency code, this can be caused by quite a few things but not normally your crank/cam sensors. Usually it's either bad spark plugs or exhaust leaks.

I would put the original sensor in, then crank the engine, your rpm should go up to like 200rpm while trying to start the engine. If the tach isn't moving then you probably aren't getting crank signal.

Regardless I would also pull and inspect the plugs. Pay attention to oil in the spark plug well tubes, look in there with a flashlight before you pull the plugs out.

Also make sure you don't mix up the coil pack harnesses, it's easy to do.

 

my mistake, p0430 was not the code it threw…my scanner decided to erase the code apparently so im not able to see it again….the code was for the camshaft sensor….i have checked all fuses, plugs, coils, you can hear the fuel pump turning on…..the only thing i keep thinking it could be would be the crankshaft sensor but its throwing absolutely no codes now….am i wrong?

 

It doesn't necessarily need to throw a code for it to be bad. if the tachometer doesn't move when cranking the engine (fully battery so it cranks nice and strong) then it's not getting signal from the crank sensor. Unfortunately it requires an oscilloscope to actually test it's function.

 

so i put a new crank sensor in it and still no start…i dont want it to seem like im just throwing parts at it “it was only $16”…i can hear the fuel pump when i turn the switch over but if you just keep switching the key from off to on you cant hear it unless you take the key out of the ignition then reinsert it…is this normal, i wouldnt think so but there again i have found out these g35s are one in there own lol….where should i look next..?

 

I had the wierdest crank no-start experience this week. My battery was getting really close to complete failure but I just procrastinated going to get a new one. Finally it fails to start the car so I put the charger on it. This will usually get it back to where it will start the car and be okay as long as I drive it every day. But it's now so bad that it cranks the car but super slow and it doesn't even sound right like there's absolutely no attempt to fire. So I install a new battery but it still cranks slow and sounds like absolutely no fire. I put the charger on the new battery just in case it wasn't well charged and after a few hours it still sounds more or less the same but I get the tiniest hint of it wanting to fire but nowhere close to starting. This is like after probably 5 or 10 long cranks of like 10s. This is a long time to crank the car with no fire. So I'm worried I'm going to drain the brand new battery to death or overheat the starter. So I put the charger back on and go inside and start researching crank no start threads. I know how some of those turn into nightmares on here and I was dreading having to start my own... But I was starting to think crank and cam sensors because i'm not getting any reading on the tach while cranking but no codes. I could hear the fuel pump but couldn't confirm pressure. But I find some nutty thread I think it was on G35Driver about getting out of "lock mode" by turning the ignition switch on and off a number of times. So go back outside and try that.... no luck but it still sounds like it just barely wants to fire so out of frustration I just put the accelerator pedal to the floor while cranking and it coughs and coughs and eventually starts and runs rough for a few seconds but then eventually smooths out and runs perfectly normal like nothing ever happened. I never thought you had to use the gas pedal while trying to start a car with a fuel injection computer. I don't know why I think this (maybe my dad told me years ago) but I thought you WEREN'T supposed to touch that pedal when trying to start a modern car. But anyway I made a long story out of a simple problem. I was so worried I had a serious problem because it was NOT going to start no matter how long I kept cranking it until I put my foot in it. I don't know why that would be but there was another thread on one of those sites where you pay a mechanic to help you debug something that came to the same conclusion that they just had to floor it to get it to start. If I didn't experience it personally, I wouldn't have believed it was true.

https://www.justanswer.com/nissan-in...t-thought.html

I'm not saying that this is going to help the OP but wanted to share my story of a crank no start (after battery replacement) that was resolved in the most ridiculously easy but not obvious (at least to me) way possible. I hope it might help somebody else like me in the future because I was already starting to debug like pulling codes and pulling parts to check spark and pricing sensors and all that stuff. It didn't make sense to me that something would break just because I let my battery die but after that many cranks and NOTHING, I didn't know what else to think. So try flooring in while you're long cranking it if it's making any fire noises at all. Free and easy to try.

 

Interesting! I wonder what the issue was 🤔

 

Normally, when you press the pedal to the floor you trigger a car to go into "clear flood" mode. It's supposed to use in troubleshooting cranking the engine without enabling the fuel injectors. But, it also opens the throttle all the way, so I am wondering if maybe you had an air restriction? Maybe you had a lot of left over fuel from all the attempted starts and caused the sputtering.

I would check the cable from the battery going down to the starter. If you have a multi-meter I would put one end on the beginning of the starter cable and the other where the + lead goes on the starter. You want to check for voltage drop which can be caused by corrosion. My car was getting hard to start and had long crank times, I did the test above and ended up finding about 7 inches of corrosion on the wire. Cleaned it all up and car stopped acting like that.

 

If it didn't crank strong then either the battery wasn't fully charged, the starter is beginning to fail, or the connection between battery, starter, ground needs cleaned up.

You might also have some accumulation of grime on the throttle body which is why opening the throttle plate allowed enough air through to start, on a weak crank it's struggling to pull air past the tiny air gap on a closed throttle. I'm betting with a properly working starting system it would have fired right up though.