jagshark89

A friend of mine blew his headgasket and decided to get a new engine so I decided I would do him a favor and replace the engine for him. I have done 4 maxima engine swaps in the past time consuming but otherwise pretty straightforward.

This has been this headache of all of them. The actual swap went off without a hitch the engine came out fairly easy and the new one went in fairly easy. The engine started up on the second crank no problem.

So i proceeded to finish tightening everything up engine starting no problem at least 4 times along the way. I even had my friend drive the car around a little cul de sac across from my house just to make sure everything was ok.

Right after this we put the hood on and the rest of the air intake and bam car refused to start up.

It cranks the engine turns just no start. I've checked the basics I have fuel and no intake leaks however I have no spark on cylinders 2,4,5 and it is intermittent on cylinder one. I have checked both crank sensors and the cam sensor and replaced all with known good ones from my own car, no change.

Also per the fsm I checked for the proper voltages from the ecu and shorts to ground to the sensors everything is within spec except when I test the crank sensor near the flywheel using the screwdriver test I only get 3.x volts instead of five but car is still missing lots of spark.

The only other thing of concern is as we were trying to start the engine as all of this was happening the starter somehow worked is way loose and made a god awful noise. But we retightened it and no other noises, I also checked the flywheel to make sure none of the timing gear teeth were missing, chipped etc. Also performed a leak down test to try and determine if the engine jumped timing. All cylinders reading similar leakage in the green.

I am about ready to grow some hair so I can pull it out please help!

Amerikaner83

iTrader: (17)

Did you scuff the grounding point between the engine and tranny real good to ensure the connection?

what is his car, and what is the donor car?

jagshark89

I didnt sand down the mating surface. However my grounds appear to be good. His car is a 95 maxima the engine came from a 96 maxima my car is a 98 maxima that i used the sensors from to test.

Amerikaner83

iTrader: (17)

I think you're suupposed to sand down the mating surface iirc. That itself is a ground.

jagshark89

I remember seeing that before throughout the forum, but I think that when that is an issue the car does not crank at all and this engine started up several times before it just stopped starting out of the blue

asand1

iTrader: (1)

If im not mistaken, the negative battery cable connects to the transmission, and the engine is then grounded through the tranny. With a poor ground between the trans/engine, the starter will spin good, but there be too much of a voltage drop between the engine and trans. This will cause a poor signal to the injectors and sensors during cranking.

jagshark89

On this engine the negative on the battery is running directly to the engine not the transmission. Should I try running it to the transmission instead.

jagshark89

anyone else have any input on this bizarre problem

tiphawk

Connect a wire from the NEG terminal down to the starter's long mounting bolt. If it then starts then you need to mount the NEG wire onto the trans and then add in several new low gauge GND wires.

jagshark89

I will give this a try later today and see if it helps.

cashoit

yeah, i have a ground wire from the negative battery terminal to the tranny housing in addition to the engine grounds shown in the above pic

Bad grounds on these cars is like death

DennisMik

iTrader: (2)

If the timing chain is off one tooth, the car won't start and you will not have spark on some cylinders. Cylinder 2 and 4 seem to be very common from what I have read.

But the car would probably never have started in the first place, unless the chain is extremely loose and jumped position after you ran it.

jagshark89

added ground wires and now only missing cylinder 2 however still no start. I am suspecting spark plugs may be fouled I am going to put new ones in and try to start again