You guys seem pretty sharp. Maybe somebody can help before the sanity completely goes....
We put a 98 motor in our 96 after the original motor threw a rod(thats a story for another time). I stripped the new motor down to a long block and put all the sensors and most of the pieces on from the old. Worked very carefully and things went well except that I can't get it running. The plugs are wet, it's getting fuel and there is an occasional pop out the exhaust but that's it, I believe the timing is way out.
The three sensors that control ignition have all been checked (Haynes method), resistances/voltages are right on, the harness has been checked, the grounds have all been checked. The ECM keeps giving the code 0407. I cleared the ECM and turned over the engine with all the plugs out to get a really good spin (the tach read 1500 rpm) and it still coded 0407.
What am I missing. Is there something about the 98 engine that is different, I gotta believe this is something simple that I'm just too close to see. The new engine was an auto and the car is 5 speed but I transplanted the flywheel and timing ring from the old with no problem, everything fit up fine.

Any sugestions would be appreciated. I'm out of ideas and gettin discouraged.

Thanks,
Jon

 

Maybe the crank sensor is bad. Are the grounds good?

 

when you pulled the motor down and put it back to gther you didnt line up the cams with top dead center the mating marks on the spockets, fuel on the plug clearly indicate the the injectors are loading the cylinders up with fuel , timing not being proper .

 

The new engine came with the timing chain intact, I didn't touch it. I also checked tdc #1 with the marks on the crank pulley, ok. The grounds are all good. The crank sensor is new (the old one tested ok too), the resistance on the cam sensor reads good. the flywheel sensor passed the 5v screwdriver test. All the sensors seemed to be positioned to pulse as the tabs come around. I have wrung out the harness all the way back to the ecm connector, good. But it keeps putting out 0407
To add to the mystery, it wouldnt start two weeks ago when I first tried to get it going and I started troubleshooting, just poking around and checking everything. Then it did start just once-fired right up idled fine, I don't know why. I had to shut it down after just a few seconds as the cv shafts were out and the tranny was only 1/2 full of lube. I figured great its ok and finished putting everything back together. Now nothing......
What am I missing?
Jon

 

Is it getting spark? It obviously did when you started it up that one time, but what about now?

The 98 engine is the same as the 96. Is it a CA spec engine or ECU?

 

My engine did this ,and believe it or not bad grounds the big harness that goes across the engine wasnt properly grounded

 

Thanks for the replies guys,
The grounds all test as ok for continuity with my multimeter going from the black leads on the sensors to ground (block/chasis)and I cleaned all the ground contacts that I could find. That was two together on the manifold right on the very top of the engine, the battery cable to chasis and engine block, and one small ground on the top of the tranny housing. Did I miss any?
The car is not a CA car.
Jon

 

Test the Crank/cam sensors at the ECU while cranking.

 

Did more testing tonight, what does this mean.
Just read the output of cam and crank(REF) sensors while cranking engine with my analog multimeter. Meter was set to lowest dc voltage range 2.5v.
cam sensor pulsed as engine turned each pulse read approx .05 v
crank (REF) sensor caused almost undetectable flutter of needle as engine turned. It was a more rapid flutter than from cam. You had to really look hard to see needle move.
I'm guessin dc voltage is what I should be looking for. What kind of voltages are normal? It doesnt seem like the ECM can function with that weak a signal.
These readings were taken directly from the sensors, disconnected from the harness and spliced right into my meter.
The crank sensor is new.
Anyone got any ideas?

Jon

 

Tried a few more things today: Printed most of the EC section of the factory manual last night, read it all thru and went at it again this morning. Did the entire diagnostic for 0407 code, signal to the ECM when read on the ac scale of my analog meter is about .2v(the book says 2.3 but it's an inexpensive meter and probably isn't registering the full pulse). I went right to the REF with a pigtail and still got the same reading Grounds are all good right up to pin #25 of the ECM, no shorts white to ground. Cannot find any wiring problems. cleared and retested, still got 0407.
So I pulled the crankshaft pulley off the old engine and installed it on the new engine thinking the REF sensor might not be seeing the tabs on the pulley close enuf. No change. Sat in the moaning chair for a while and had a cup of coffee.
The book says that the starter can cause problems if spin is erratic. It seems to be ok and I tested a few days ago by removing all the plugs and spinning with no compression. It still coded 0407. I may take the starter to a rebuild shop tomorrow and have it tested. I'm out of ideas. This thing has become my white whale, Il'l get it running no matter how long, it's a good thing I don't do this for a living.....

Jon

 

Test the signal at the ECU. I still think the ECU is not getting a signal from the sensor which is why it keeps throwing the 0407.

 

I tested the REF sensor both ways, once with a pigtail directly to my meter and once at the ECM at terminals 25 and 44/48. The readings were the same, about .2v ac. It's a mystery......

 

It's looking like you might have to throw in the towel and have it towed to the stealer.

 

Check the voltage going to the sensor. If it is low for some reason, then the sensor output will be low as well.

I'm not sure what the voltage to the sensor should be. I'm guessing 5V because I know that is what other sensors are supplied with, but it might be 12V.

If the voltage to the sensor is low, trace back through the harness until you get a good voltage supply to locate where the problem might be.

 

The REF is a two wire sensor. Are you sayin that there should be voltage to the sensor. I was just looking for output from the sensor, the book says 2.3 v (ac?). I get a reading with my analog meter but it is more like .2 v ac. The readings are the same if I disconnect and read right from the sensor. I do not read any voltage across 44/48 and 25 unless the engine is cranking.
Took the starter to Yankee Elec. today. They tested and said it is fine so we can cross that one off the list.
Does the dealer have test equipment that will look at everything, including all the inputs and outpuits, and not just pull the codes out of my ECM. I don't want to pay someone to do everything that I have already done. I talked with Auto Zone today and they would rent me their tester but all that would do is pull out the codes and explain what they were. I already have all that info.....

Jon

Jon

 

The dealer has a CONSULT, which is a proprietary nissan interface that gives much more information than the OBD-II port does.

All the voltages are DC. All sensors have a voltage supplied to them with the exception of the cam and crank sensors. What you should do is read the voltage being supplied to a sensor.

For example, the MAF is a little wire that changes resistance with temperature. The more air that goes across the MAF wire, the cooler the wire will be and its resistance will change. As the MAF changes resistance, the output voltage increases or decreases because there's either a greater or lessor voltage drop. If the voltage arriving at the MAF is 1 volt below what it should be, the output voltage will also be a volt lower and cause problems.

The crank sensor works by induction. There's a coil in the sensor, when the magnetized teeth of the flywheel pass near the coil in the sensor, a voltage is produced and sent to the ECU. The cam sensor works in the same way.

How was the condition of the flywheel? Did you reuse the old one? If the flywheel teeth were shot, the crank sensor wouldn't pulse.

I think if you took it to the dealer, they would be able to tell you within an hour what the problem was. Typical dealer labor is $75/hr. I think it would be worth it to pay that instead of spending hours upon hours figuring out what is wrong.

 

I believe this is correct. Disregard what I said earlier.

 

Thanks Blackbird, The flywheel has a toothed plate attached to it that pulses the sensor. Both were removed from the old and installed on the new. Visual inspection was fine and I can see in the hole with the POS sensor removed that the teeth line up. I could find no markings on the flywheel or plate to line anything up and a mechanic said indexing location did not matter so the mating of the flywheel to crank flange and toothed plate to flywheel are random. I believe this sensor just determines engine speed (the tachometer registers when cranking!). I think your suggestion to take it to the dealer (tow!) is my only remaining option. I think the 0407 code is masking other problems and I'm pretty much at the end of my abilities. The ego takes a hit, the wallet takes a hit and life goes on.......

 

Some more thoughts: My ignition problem is not electronic, I've checked everything eight ways from sunday. So tonight I'm poking around looking for something mechanical causing flutter when cranking and confusing the ECU looking for the timing pulse. The starter has already been checked by the local rebuild shop. I did a compression test. All cylinders read 176-195 except #2 which logged 82 psi. Could this unevenness in pressure be causing enuf starter flutter to cause my problem?
Are these engines prone to valve problems at only 78,000 mi? Jeez, this was supposed to be a solid engine.
Any thoughts.
Jon

 

You can run the engine on 2 or 3 cylinders. Even if one cylinder's compression is bad, it should still start up. It has to be an electronic problem if it is getting fuel. Are you positive it's getting spark? Try connecting a spark plug tester on the #1 cylinder and see if it sparks when it's BTDC.

Starter "flutter" would not cause it to not start. These cars push start very easily which is a lot less smoother than the starter starting the engine.

 

I connected my timing light to each cylinder and cranked. The results varied, no spark on 3,4,5,6. Very erratic spark on 1 and on 2 it seemed to be lighting up fairly regular, almost too much. I was alone so couldn't watch the timing marks on the pulley but doubt that would have helped as everything was so crazy. It ain't sparking right.
Earlier I borrowed another ECU and tried that, no difference. I can see a flutter in the tach when cranking, the needle swings up and down maybe 300 rpm. With no plugs it cranks about 1500 rpm.
What else can cause that 0407 code, Is there some type of ghost problem that will throw out that code, like the glove box is open.........
Jon

 

Are you using the coils that came with the new engine? Try using the coils from your old engine and see what happens. As a last resort, you could try using the old EGI harness.

 

Read this and verify that the EGI harness is properly seated in the ECU socket.

http://maxima.theowensfamily.com/tsb/NTB94-065.pdf

 

Thanks for the thoughts Blackbird, the plug is into the socket properly. I double checked yesterday.
I'm gonna get help and tow this thing down the street with my truck and see if it will jump start just to rule out the starter thing and irregular cranking.
I'm also trying to locate an osciloscope to see what the signal from the crank and cam sensors actually looks like. The factory manual graphs the signals as they should appear.

 

A scope on fleabay will prolly cost the same as an hour or two's worth of diag time at the $tealer, that is unless you can find one to borrow.

 

IT WAS THE FRIGGIN STARTER.....We towed it behind my truck this morning and it jumped started in a flash. Seems to be running ok now but I have to change the starter and check out everywhere for leaks, tension the belts, etc.
What a nightmare, the starter was checked by the local automotive elec shop way back to eliminate it as a source of the problem but they must have missed something. I have wasted a lot of time plus $125.00 that I sprang for a used ecu but sure learned a lot.
Thanks to everyone for all the help.
Jon

 

some times it always ends up something that was in your face the whole time.

 

Good to hear that you fixed the problem. Ebay your ECU so you can recover some of that $125.

Now that it's running, did you check the compression in the suspect cylinder again?

 

Not Quite, spent 168.00 for a new starter and 49.00 for a new battery and still no start. The ecu still isn't seeing a good signal when cranking. Yesterday we weren't even to the end of the driveway jump starting and we had it running.
The flywheel is off the old engine and has good teeth, I checked way back when we put everything together. What else could it be.........
I'm gonna push the friggin thing into the cape cod canal..........

 

update????

 

You probably already checked this. Is the ecu seeing battery voltage on pin 20 (start signal) while cranking?
The fsm calls this a low possibility item for causing a no-start condition.

 

So I took an extra battery and powered the starter directly from this external 12v source, including the solenoid. I left the car battery in place to power everything but the starter. Turned the ignition on and powered up the starter with my rig. It did start after some cranking but the external battery wasn't fully charged and I could not restart. So I'm charging it up and will try again later tonight. I need to get it running and let the ecu settle in and then see how reliably it will start.
I am trying to prove that the starter is able to start the engine and then I will look for some reason for the starting circuit to prevent or limit voltage to the ecu.

Jon

 

So I'm wondering what it is about the cranking process that prevents the ecu from seeing a good timing siganl. So I disconected all the starter leads and powered the starter and the starter solenoid from a separate, spare battery. Didn't disturb anything else electrically. I charged both batteries overnight to make sure they were fully charged. Turned the key to on and cranked the starter from the new battery. It still fires out of timing but after a while I can get the engine to start this way. Once running it settles down and runs smooth, idles good, power and acceleration are good. But even restarts after the engine has warmed up are difficult. It burps and farts and finally catches.
Any ideas?

Jon

 

anything new?

 

Nothing much new to report. A mechanic friend printed me another schematic from a service that he subscribes to and I am checking with the schematic I am using which I printed from the factory manual on this site, looking for any discrepancies that could give some clues. This mechanic doubts that my problem is mechanical and suggested that I keep looking for an electrical problem. I am going to double check everything this weekend. Good thing this car is not our daily driver.....
Jon

 

maxman12,

I have probably the same starting problem as you, the difference is that my car finaly starts after few cranks... fortunately because this is my only car. The voltage readings are different that yours. Have a look on this thread:

http://www.forums.maxima.org/showthr...=1#post4497515


Anything new on your side???

 

Wow, 0407- sounds like we got similar problems. One of the problems when reading continuity with a multimeter is that you can read 0 resistance but the wire is still bad and will not pass voltage other than milivolts that the meter sends out. I'm thinking that my wiring is bad despite the thorough checking I have done. I am going to rewire the sensor to the ecu, bypassing the bends the harness makes at the firewall. There is a tech bulletin that warns of failure at these bends and people have told me of problems there.
Other than that I am out of ideas. A mechanic who I respect highly told me that it is highly unlikely that the starter is causing my problems (after I bought a new one!!) and to look for the elec/electronic problems.
I sure am a lot smarter that I used to be.....
Jon

 

I believe the ECU harness bend TSB is for 00-01 maximas only.

 

Did you directly rewire the CPS to the ECU? Any improuvment?
Tomorow I'll took the car again to the Nissan dealer. I'll keep you informed.

 

maxman,
could you link the tech bulletin that you are talking about, please.