This is crazy, I can’t understand it...intermittent no starts

[98_Q45]

I’ve brought this up before, but wanted to come back again with a better explanation.

Basically: having an issue with starting once engine is warmed up. First thing in morning, usually starts right away. I did an oil change and added bar’s leak valve seal Repair because of the blue/grey smoking exhaust during idle (I know stop leak is a no no, but this seems to be more of a seal conditioner, and I’ve used it a couple times in the past with good results). The first morning after adding it though this last time, engine took 2-3 seconds to turn over after crank. Normally, it cranks the instant I turn the key.

I’ve discovered 3 fail-proof methods that seem to “cure” the issue temporary. But I haven’t confirmed which one exactly is what helps as I tend to do them at the same time. This week I did all 3 separately: one is change the oil, the other is clean the throttle body/intake chamber with spray seafoam or CRC.

Changing the oil (5w30 synthetic + bars valve seal) didn’t seem to help. That was 5 days ago.

Cleaned throttle body yesterday, even went as far as removing IACV and really getting the nozzle into the intake chamber (didn’t do the run engine and flood chamber trick as shown on seafoam website).

Today, which seems to be the most effective: adding 6 ounces of seafoam/gum out oil treatment: the stuff that smells like kerosene...directly into the oil. Haven’t driven it enough to get a result yet.

This has been a recurring issue. I’ll get it to stop for a few weeks, then it’ll come back. This issue has seemingly already burnt out a couple of starter motors, and now that I have a Denso reman, I’m determined to not let it happen again.

So far I can’t seem to figure if it’s dirty intake valves, or something else. The oil treatment seems to be the best trick, and then it’ll start instantly for a couple of weeks or more.

I’m now wondering if it’s perhaps PCV valve. I’ve only changed it once, a couple years ago. Would this be a likely suspect?

[Ryantzer]

Your oil system has nothing to do with the extended cranking you're experiencing. I would start by testing the coolant temperature sensor and checking it's wiring.

[98_Q45]

Your oil system has nothing to do with the extended cranking you're experiencing. I would start by testing the coolant temperature sensor and checking it's wiring.

Update: problem solved! It WAS the PCV valve. I was wondering why a previous code scan was reading bank 2 system lean or something like that.

I took both of, the one under the air filter was still jiggly, and I spray cleaned it. The one on the battery side had no jiggle. I cleaned it too, but it would still only move a little bit. Went and got 1 new one as a test, and the jiggle was significantly noticeable. Installed it right away on a hot engine, and made a few stops. Cranked up right away each time.

I had already did both coolant temperature sensors to no avail. Fuel filter, spark plugs, etc. I think the oil change and adding seafoam helped by slightly clearing whatever debris was inside temporarily. Hence why it always seemed to work fine the first 1,000 or so miles after an oil change. Then the hard starting would come back especially after warmed and sitting awhile. But now it was getting to where it would be hard to start as soon as I shut off the engine.

Sorry for answering my own question lol. But if anyone hasn’t changed their PCV valves (there’s 2), do it. I had already changed mine 80,000 miles ago...but I just forgot to think of it because it’s simply not in the manual as a maintenance item. But it will drive you crazy trying to figure out.

I have a Nissan Maxima that had given me the same trouble for years too, I changed the PCV valve but can’t recall if it helped right away. But I’m going to change it again as well. Glad I didn’t have to go the leaky injector or fuel pressure regulator route (which I previously brought and returned as it didn’t make sense that it would start right away when cold or sometimes and not others).

[98_Q45]

Day 2: it was definitely the PCV valve. Has not took longer than half a second to crank since replacing the valve. I’m so RELIEVED but also equally angry lol. I was running around to 3 different mechanics including the dealer, trying to figure out what was going on. Everybody would just shrug their shoulders and talk about spark plugs and fuel cleaner.

So yeah, solved my issue for $3.