IndySporty

Hello,
I'm new here but I found this to be the only site where I might have any chance of getting this car running. I just purchased a 96 I30 (Same as Maxima right?) and the car had no-start condition upon purchase. I have replaced the CKPS, CPS, and CKREF sensors. All 3 test out good per the specs I've found on them. The car has fuel but no fire, ie. it gets injector pulse and fuel on the plugs. Here's where it gets wierd. It has spark on cylinders 1 and 4 only, no others with the exception of an occasional spark on 6. I've swapped all the other coils from cylinders 2, 3, 5 and 6 onto both 1 and 4 and when any of the coils is on one of these cylinders it has fire, which is telling me that all the coils are fine. Now seeing that, I checked the ground and power at all 6 coils and all of them are matching at dead ground to the black wire and full 12 volts to the red wire. So I went to the wiring pinout for the ECU. All 6 injectors are showing continuity to the appropriate pin at the ECU from the signal pin on the coil connector in the engine bay. So everything looks good there. Below is a list of all the things I've done to try and rectify the situation;

1.) Upgraded the battery cables to 2/0 (pos and neg) and grounded the negative cable to the body on clean metal with a clean bolt as well as to the transmission bolt nearest the CKPS sensor on clean metal there.
2.)Added a ground from the negative cable to the intake manifold near where the injector/coil harness grounds.
3.) Added a 2/0 ground from the body on clean metal with a clean bolt to the timing cover side of the engine with a clean bolt on clean metal.
4.) Cleaned the grounds on the intake manifold to shiny new metal as well as the metal they ground to, then reinstalled them.
5.) Acquired another ECU from a 96 I30 that was reman'd by Nissan and tried it.
6.) Tested continuity from all coil trigger wires to appropriate pins at ECU (all are good and in the right place)
7.) Tested continuity from the white wires on CPS, CKPS and CREF sensors to appropriate pins at the ECU (all were good and in the right place)
8.) Tested the ground and power wires at all 6 coil connectors (all were good and had power or ground where appropriate)
9.) Tested all the ground wires at the CPS, CKPS, and CREF sensors (all were good and had solid grounds) as well as tested the switched 12V at the CKPS (had a good 12V signal with KOEO)

Now with all of that said WTF am I missing? This damn car has something wrong with it and I can't figure it out, and I'm pretty damn good with wiring! Could the crank pulley not be triggering the CREF for 4 of the 6 cylinders? Could the flywheel not be triggering the CKPS all the time? I used the wiring pinout from another thread on this site for my wiring pinout of the ECU....its in the thread I linked at the end of this post. I've read the entire thread and tried everything they tried and still no luck. I also have the haynes manual and of course cross-referenced the wiring diagrams with yours and everything matched up. The only thing I have not done is replace the MAF because that has no bearing on the no-spark condition right? Oh yeah and I forgot to add, the car shows no trouble codes...also I didn't replace the starter because it turns the motor just fine. I guess I'm going to do a compression test on all 6 cylinders to see if the timing chain might be off? Will post back in a few with the results.

http://forums.maxima.org/4th-generat...ont-start.html

IndySporty

Oh God dangit. Compression test results: Cylinders 1, 3, 5 varied but between 120-125. Cylinders 2, 4, 6 varied but between 80-85. I'm assuming that since the timing covers have fairly new gasket maker on all the seams this means that someone did a timing job and f***ed it up? How can I check for certain that the timing is correct on the top end without removing the timing cover? That thing looks like a nightmare to get off....

Trini Boom

iTrader: (5)

Without removing the timing cover will be difficult but not impossible. You can take of both front and rear valve covers and rotate crank pulley per FSM to check cams for valve clearance. The cylinders should be on the specified intake/exhaust depending on crank rotation.

Much easier to take off the timing cover because the sprockets are all marked.

IndySporty

Yeah I ended up taking it off... I have to sit down with my manual tonight and pore through it. I don't know how to read the timing marks on this motor.... I'm a Hondaguy...I would kill for a timing belt here hehehe...But the timing being off on the front cam would inspire the condition I'm experiencing wouldn't it? If the timing signals from the cam sensor were conflicting with the ones from the CKPS and CREF it would cause intermittent spark on some cylinders and no spark on others concievably unless I'm totally wrong.

Trini Boom

iTrader: (5)

Its very easy to line up timing on the VQ. First, note that there should be three paint marks on the timing chain. The two that are the same should align with the arrows on the cam sprockets. The last paint mark should match up with the motch that's on the cranskaft. Once those three are ligned up, that's all there is to it. Rotate by hand a few times to ensure it turns over smoothly.

IndySporty

I'm gonna have to check the little timing chains too. The idiot I bought the car from lied about it as well as being a poor mechanic. I won't be able to mess with the car much until Friday since I work 12 hours a day at my regular job and I'm a single dad. Thanks for all the advice tho folks and I'll definitely update the thread if and when I get this thing running lol.