What would cause a no spark situation
Moderator: volvite
What would cause a no spark situation
Hi everyone, I did a spark test and got none, I have good cranking and battery power. My truck died in the driveway on a cold morning, for about two weeks before that, it was hard starting on cold mornings, but then restarted and ran fine. I have replaced my crank sensor with no luck, I also unplugged the sensor after the air filter, any ideas? Thanks...........
I did the check for codes that I found online, and all I got was 5 flashes, after entering the diagnostic mode. I never got a check engine light either. I changed the sensor behind the passenger wheel, is there another one? and could that be the problem? Thanks for any ideas.smj999smj wrote:There are two camshaft positions sensors that have been known to be problematic, one on the back of each cylinder head. Have you had it checked for stored trouble codes?
As I already posted, there is a cam sensor on the back of each head, and one of them "could" be the problem. I really don't like suggesting parts replacement without doing the diagnostics to confirm the parts are bad, as it can get expensive. There are downloadable service manuals on the web for the R51. We had one here for 2005. Other years are available at other site's, like Nico's website or in the knowledge base at NissanHelp.com; you need the "EC" section. The service manual gives the diagnostic steps to help isolate the problem of a no start/no spark condition. Testing may require a scantool and/or a multi-meter, among other possible tools. The correct thing to do would be to follow the diagnostic steps to correctly identify the cause of the no spark condition.
First of all, thanks for the help. I misread camshaft sensor for crankshaft sensor, that I have already replaced. Do you know, why if any one of these sensors would not be working, why the computer, would not report the sensor as not working. It just seems to me, that the computer should know why it is not letting the vehicle start because it is getting no signal from an important sensor, even if the vehicle is not moving. I have been driving for 30 plus years, and have never had a sensor failure, without a service engine light, this is the really frustrating part of this. Also, does one camshaft sensor tend to fail more than the other? I would start with that one then, I also have the manual, it seems to imply the crank sensor.... Thanks again.....smj999smj wrote:As I already posted, there is a cam sensor on the back of each head, and one of them "could" be the problem. I really don't like suggesting parts replacement without doing the diagnostics to confirm the parts are bad, as it can get expensive. There are downloadable service manuals on the web for the R51. We had one here for 2005. Other years are available at other site's, like Nico's website or in the knowledge base at NissanHelp.com; you need the "EC" section. The service manual gives the diagnostic steps to help isolate the problem of a no start/no spark condition. Testing may require a scantool and/or a multi-meter, among other possible tools. The correct thing to do would be to follow the diagnostic steps to correctly identify the cause of the no spark condition.
You'll have to ask an engineer why a computer wouldn't pick up a bad sensor; I can only tell you what I've seen. As I said, I try not to recommend replacing parts unless they can be proven as defective. The cam and cranks sensors have a similar design and have had a history of failures since the early 2000's, even though Nissan had been using them since around 1995. All I can suggest is that they are made cheaply.
Back in the '80's I would occassionaly run into a Z31 300ZX or a U11 Maxima with a bad mass air sensor. There was no code stored (ECM self-diagostics were a bit crude back then compared to modern systems) and they would pass the component test per the service manual, but install a new mass air sensor and the problem would be fixed. It is frustrating and why good auto technicians don't often get the credit they deserve.
Back in the '80's I would occassionaly run into a Z31 300ZX or a U11 Maxima with a bad mass air sensor. There was no code stored (ECM self-diagostics were a bit crude back then compared to modern systems) and they would pass the component test per the service manual, but install a new mass air sensor and the problem would be fixed. It is frustrating and why good auto technicians don't often get the credit they deserve.
Any ideas on how to remove camshaft sensors, that are only shown in the manual with the engine removed?smj999smj wrote:You'll have to ask an engineer why a computer wouldn't pick up a bad sensor; I can only tell you what I've seen. As I said, I try not to recommend replacing parts unless they can be proven as defective. The cam and cranks sensors have a similar design and have had a history of failures since the early 2000's, even though Nissan had been using them since around 1995. All I can suggest is that they are made cheaply.
Back in the '80's I would occassionaly run into a Z31 300ZX or a U11 Maxima with a bad mass air sensor. There was no code stored (ECM self-diagostics were a bit crude back then compared to modern systems) and they would pass the component test per the service manual, but install a new mass air sensor and the problem would be fixed. It is frustrating and why good auto technicians don't often get the credit they deserve.
Thanks smj, I actually took my hood off as well, don't really want to do that again soon. One more question, what type of antifreeze should I be putting in this, the book just says genuine Nissan or equivalent. So must I use Nissan, or is an aftermarket acceptable, and if so, what type and can or should the two be mixed. If Nissan is better I will buy that, any ideas? And thanks again for the camshaft sensor info...............!smj999smj wrote:Take the upper engine cover off, climb over the engine and reach behind the engine, remove the 10mm head bolt from the sensor and pull it out of the cylinder head, pull the sensor up by the harness, replace the sensor and reverse to install. I would recommend you do it on a cold engine.
It depends on the year. Most of the R51's have the Nissan green anti-freeze. My personal preference is for the Nissan stuff, but any green or universal anti-freeze like Prestone will work just fine. Nissan started switching over to a long-life, blue anti-freeze beginning in 2010; I'm not sure what year or even if they switched over on the R51's, but if you have a later year with Nissan blue, I would stick with the Nissan blue, long-life coolant, even though it is compatible with Nissan green and universal coolants. Switching from or diluting Nissan blue will likely shorted the recommended service interval. From what I've heard, Nissan blue only comes as a pre-mix and is a bit expensive. Last time I purchased Nissan green, which comes as a concentrate, it was around $17/gal. Aftermarkets are usually running anywhere from $10-$17/gallon.
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