5.5 gen tune-up, now no start :(
 

Background: 125k miles, 6-spd transmission, completely stock (prior). Ran well (no SES light/codes) but a tad sluggish, IMO. My exhaust blew out, so I figured it was replacement/upgrade/tune-up time.

What I did: changed spark plugs (NGK IFR5AIX-11), installed OBX headers with new gaskets, new Walker OEM catback with new gaskets, new valve cover (the one by firewall) since it was old, new upper plenum gasket, extended both primary o2 sensors via crimp-connectors, brand new Bosch secondary o2 sensors (no o2 simulator).

Problem: cranks and doesn't start. Verified spark on one cylinder bank. Checked SES light for codes: getting 10 slow blinks, 3 fast blinks, 4 fast blinks, 10 fast blinks (and repeats from here). I assume this to be code P0340 - correct? Would this cause a no-start condition?

Additional information:
-I used crimp connectors to extend the o2 sensors because I was unable to solder the stainless steel wires. I did not keep track of the order of the two white wires. Does their order of connection to the plug matter?
-when I removed my rear-center coil, there was oil all over the outside of it. Didn't look like any oil got inside where it contacts the spark plug though. I cleaned the cylinder out the best I could and maintained order of coilpacks upon reassembly.
-All spark plugs were in terrible shape, believe they were original.
-Unknown age of all coilpacks. Like I said, car threw no codes before though, and I verified 2 of the coilpacks' resistance was within spec, so I reused all of them.



Any help is greatly appreciated as I continue trouble-shooting on my own.

If you are indeed getting a P0340, there is a problem with your CMP sensor (PHASE) and/or with the associated circuitry. If the sensor is OK then either your starter is bad/weak, or your battery is weak. BTW, get yourself an ODBC reader; it's a necessity for working on these cars, and you can get one quite inexpensively, for example here https://www.amazon.com/Vehicle-Reade...ds=obd+scanner .
Be aware: Our coils contain a transistor circuit, so measuring their resistance is a very poor method of evaluating their health! (But, your car ran before the repair, and it's unlikely that all of them just failed .... ).

Also, get yourself a copy of the FSM, from here: http://boredmder.com/FSMs/Nissan/Maxima/. Once you can read your ODBC codes, the EC section of the FSM tells you what to do.

Thanks for the response. I measured 12.31 volts at the battery terminals just now. My starter always seemed strong prior to the maintenance I performed. I may get an obd2 scanner but hope to resolve this in the meantime if possible. I'm running out of ideas for things to check though.

Quick update: tried starting this morning after cleaning some engine grounds. Now there isn't even enough juice to turn the engine and I'm getting fast clicks - tell-tale sign of bad battery/connection. That's consistent with the P0340 code I'm reading. Charging the battery now, will try a spare battery if/when possible. I'll be very relieved if that's all that was wrong!

Old battery got tested at only 200 CCA. Replaced it with a fresh one. Still just cranks and doesn't start. Will occasionally fire but not for long. Not sure wtf is going on

You may have more then one problem; say, a weak/bad CMP sensor, and with multiple starting attempts, you then ran down the battery. But, that's just a hypothesis.
There is no easy lunch. I suggest you re-read post #2 ..... .

Edit: Some other potential causes of your "crank-but-no-start" problem:
• NATS or bad key
• Bad/Poor Crank or Cam sensor
• Not enough fuel - Fuel Pump or clogged filter
• Too much fuel – busted diaphragm in fuel dampener or regulator
• No spark (easy to check for),
• Bad IACV or busted ENGCONT1 fuse.
And don't just keep cranking - you may ruin your cats.
Good luck!

I no longer have cats. Installed OBX headers (extended primary o2 sensors via crimps) and installed a resonated 2.5" test pipe.

The car now has brand new battery and brand new bank 1 (that's the one nearest the firewall, right?) camshaft sensor. Still cranks without starting. I also verified full voltage at the starter, so wiring there is fine.

As mentioned before, the car ran well and started up immediately prior to the work I performed. I didn't mess with fuel at all and it has a full tank of gas. I'll be borrowing an OBD2 scanner after work today, as well as checking every single fuse

Reseat he IM? I recall my SES doing a similar dance when I had put in phenolic spacers.

Thanks, I may try that here in a little bit. I'm skeptical that's the cuprit due to the forward-thinking decision by Nissan to use alignment studs on both ends of the upper plenum but I have no other ideas. The gasket appears to be aligned correctly.

Since my last post I've quintuple-checked for disconnected vacuum lines and electrical connectors. I've verified continuity on every single fuse and relavent relay (putting power through each relay via 9V battery while checking continuity). Getting it towed to a shop on Monday if I can't figure it out by then.

Can the integrity of the vacuum system (including plenum gasket) be checked with a vacuum pump like the Mityvac? I used one to troubleshoot a leak on the last fuel injected car I owned.

I'm going to say no on the plenum gasket, since most cylinders will have open intake/exhaust valves while the engine is off (due to the current crankshaft position it's in). Would need TDC of compression stroke to have closed valves. You could possibly apply a smoke test to the vacuum lines though.

I ended up getting it towed; didn't bother re-setting the upper intake plenum because the gasket only goes on 1 way and I could tell it was fitted correctly all around even with the plenum bolted down. I'll update with what the issue was, assuming the shop figured it out :/

Sounds like you missed a connection somewhere.