old but good GLE

Okay all, I have searched the forum's high and low and none quite have the symptom that I am running into with mine. Just for starters, The starter motor has been replaced (about 3 months old), cam and rear crank sensors have been cleaned (I plan on checking front crank sensor today) Battery is about 10 months old, all the grounds are clean and good, alternator just recently replaced as well. No codes, no check engine light, absoulty no drivebilty or running issues after starting.

What my car does intermit. is will have long crank times before starting, it will turn over good and strong just requires more than normal cranking..once started all is fine. Another symptom...related or not, is that at times when cranking the engine it sounds as if suddenly the battery is dead and will crank really low for a second but then fire up. The battery never goes under 12.3v when cranking and alt is charging a strong 14.2 when running. Im kind of at a loss as if I am dealing with 2 different issues or just one. I thought possibly fuel psi reg or fuel pump, there is no fuel in the vac line and I dont have the special guage to check on these cars, I just have one that I can screw onto a fuel rail.

On a side note I tried to search you tube videos of this noise and I can hear it when people are trying to crank their cars for a different type of starting problem but I have never come accross a good solution. Some people may say ignition switch, but why would that cause a intermit long crank time, and would a crank sensor cause a wierd dip in cranking speed? Any help will be appericated, it only has 105k.

cashoit

Does the car hard start after sitting for long periods of time? Does it hard start if the engine warm? Is camshaft postion sensor good? Clean MAF and TB per how tos? LAst tune up?

HArd start can be attributed to a few things:

I think its the ECTS, Engine cooltan temp sensor. If its messed up, it will send a false reading to the ECU that the car is flooded.

Cost 25 bucks from autozone. Test it per FSM.

Also,

jus becuz u cleaned the rear crank sensor doesnt mean its working properly. Its magnetic and overtime can lose polarity. Test it per FSM.

Add a ground wire from the negative battery terminal to a bolt on the tranny housing.

old but good GLE

Yea t/b has been cleaned maf good also did seafoam on it. I changed the plugs on it about 5k ago. It will do it hot or cold no rhyme or reason. As for testing the ect will it just show a wacky reading with key on eng off on a scan tool?

cashoit

Naw man. U have to get a coffee cup or bowl and measure its voltage at different liquid temps. for 25 bucks i say jus replace it.

Also add the ground wire.

bobflood

I had this same problem. Eventually, shop found an "intermittent" signal problem with the rear crank sensor (at engine/transmission junction). Even thought it ohmed out OK, cleaning was no help and replacing it fixed the problem. Been almost 2 years with no further cranking issue.

irish52084

I'll second the extra ground and testing the sensors again. Ground can be a problem even if they seem to be correct. I had a few grounding issues on a 71 toyota land cruiser that we swapped a 2007 vortec into. The grounds were very important and we had to re-locate some of them.

old but good GLE

The grounds have been cleaned and in really good shape. It orginally was a southern car so it only has had a handful of chicago winters so everything is really clean underneath and in the engine. I tested the crank sensor at the crank pully and it ohmed out good, it was however coated in a nasty oil buildup of crude over the years. The car still does not start any different however. It seems to do it more when it is ice cold in the morning and seems to be ok once warmed up.

Bobflood, did your set any codes at all before you had to change the crank sensor? I know nissan is famous for their crank sensor issues. I just dont get why their are 2 of them on these cars? It is my understanding that the one by the crank is just used for starting and then the fuel timing is based off the one at the flywheel?

On a side note can the fuel psi regulator be checked with a vac pump to see if the diaphram is holding vacuum internally? If so does anyone know the spec?

bobflood

Unfortunately, the bad crank sensor did not set a code - that's why it was so tough to find. It ohmed out OK also - took a scope at my mechanic's to see the bad signal. The crankshaft one tells the ECU when the engine is at TDC; the flywheel one is used for ignition/fuel timing. No idea why they didn't arrange an indicator of TDC on the flywheel.

old but good GLE

Hmm... I was leaning more towards a crank sensor as well. I figure an ignition switch will cause other problems as well, and will certanly not cause a long crank. I am just between the fuel psi regulator and crank sensor. I am one that likes to test everything and anything and then buy one part to fix the problem as opposed to just "throwing parts at it" theory. Anyone know if there is a vacuum test to do on the fuel psi reg? How about the cheapest place to find a good crank sensor?