Engine attempts to start

[kibatheloanwolf]

Engine turns over with the starter and I have spark and fuel but It takes 7 tries to start it and when it does A huge black cloud escapes my exhaust and it runs Like It's missing but I know its not Any ideas? Besides a new truck..

[RT22]

If you have fuel and fire maybe compression is low or timing is off, may check timing see if the thing has jumped timing, that would cause hard starts and rough missing type running.

[kibatheloanwolf]

Timing is Good Hooked timing light too it and It's still in time I'll check compression later

[kibatheloanwolf]

Okay update : I notice it only acts up after its been driving for a while and has a hot engine Also I let it idle till it got about midway warm and You can hear the idle bog down slightly

[seang]

PCV?

[kibatheloanwolf]

wheres that?

[seang]

Somewhere on the underside of the intake manifold, off the block, by the oil filter I believe. The breather on the valve cover is the PCV system's intake. You should familiarize yourself with it. I have to access mine through the wheel well with the splashguard off, or from underneath the truck with the skidplate off. Its tucked away in there, and you might want to check around the 720 forum for more detail of its whereabouts on the z24 engine.

If the PCV isn't working, its gonna run like ish. My ka24 creates some strong pulses in the crankcase as evidenced by idling the engine with the oil filler cap off, (I think the z24 engine does this too, being it has the same bore and stroke). This is normal because pistons travel faster at TDC than at BDC. The flat plane crank in our engines makes it so two pistons are at TDC while the other two are at BDC, they do not balance each other out perfectly. It has to vent blow-by gasses as well, so you can see how important it is. I hope you get it all figured out.
Modified by seang at 6:55 PM 8/25/2009

[seang]

Whoa, I just thought of something else. You don't have too much oil in the engine, do you? I can see if there were, how some would blow through the PCV into the intake manifold, causing all the smoke you see when it actually starts up.

[Rev_D21]

Z24i? Leaking injectors? Black smoke is unburned fuel. It's flooding out somehow. Is your EGR performing properly?

[seang]

Z24i? Leaking injectors? Black smoke is unburned fuel. It's flooding out somehow. Is your EGR performing properly?

Good thinking Rev, I do remember now hearing about z24i injectors failing. I hear those injectors can be expen$ive, maybe Kiba should do this, zer...rsion

He should do an EGR check, too, since its one of the easiest things you can do.

[kibatheloanwolf]

Well If it's cool it starts up NO PROB but if I try to start it when its hot It starts the starts wanting to choke itself out and I have to put it to quarter throttle until I see a light puff of black smoke out the rear then it's fine it just idles a bit low

[seang]

Well If it's cool it starts up NO PROB but if I try to start it when its hot It starts the starts wanting to choke itself out and I have to put it to quarter throttle until I see a light puff of black smoke out the rear then it's fine it just idles a bit low

Oh... it might be the thermostatic heat riser coming off the exhaust manifold. This provides hot air to the intake tract to aid in warm up. There is a little flap that directs air that can freeze up and route hot air even after its warmed up, causing it to run like its out of tune. check that

[Q451990]

It definitely sounds like it's flooding. I tried remanufactured injectors in my old Q back in the late '90s and had an identical problem with "hot soak" starting issues. The car started great first thing in the morning, or after sitting for 5 or 6 hours. But let it sit for more than 15 minutes and it would smoke black and start hard. The reason it would "cure itself" overnight is that the fuel will eventually seep past the rings and into the oil crankcase - so change your oil if it turns out to be the problem!

I would get a fuel pressure gauge and T it behind the filter... clamp the return line, and then look to see if the pressure drops off rapidly. Or if you can pull the entire rail and pressurize it while it's still connected to the lines, you should be able to see the leak. Your issue sounds severe enough that it should be pretty obvious.

I'm not sure if the injectors on your engine are side feed like on the 1990's era Q45, Hardbody, Maxima, etc. but if so, you could have a bad lower o-ring rather than an actual leaking injector. In fact this is usually the case. A bad lower o-ring causes flooding... a bad upper causes a fuel leak under the hood.

Good luck!

Heath

[seang]

The reason it would "cure itself" overnight is that the fuel will eventually seep past the rings and into the oil crankcase - so change your oil if it turns out to be the problem!

I would get a fuel pressure gauge and T it behind the filter... clamp the return line, and then look to see if the pressure drops off rapidly. Or if you can pull the entire rail and pressurize it while it's still connected to the lines, you should be able to see the leak. Your issue sounds severe enough that it should be pretty obvious.

I'm not sure if the injectors on your engine are side feed like on the 1990's era Q45, Hardbody, Maxima, etc. but if so, you could have a bad lower o-ring rather than an actual leaking injector. In fact this is usually the case. A bad lower o-ring causes flooding... a bad upper causes a fuel leak under the hood.

Good points except that Kiba's engine is not MPFI. It a TBI unit with only two injectors, and if they are leaking, you could just take off the air filter and see it plain as day spraying on the throttle plate. No fuel rail either. If there are o-rings on the injectors, its just to hold them nice and snug because air has to move around them anyway.

*Note* TBI's run lower fuel pressures than MPFI systems.*

[kibatheloanwolf]

Hmm Took off my air filter and looked into the Throttle body while the truck was idling and I noticed small beads dancing above the damper that controls airflow... Possibly gas I'll check and let yall know

[kibatheloanwolf]

What about the sensor underneath the throttle body?

Seems like everything elc is original why not that part be original and failing?

[kibatheloanwolf]

Z24i? Leaking injectors? Black smoke is unburned fuel. It's flooding out somehow. Is your EGR performing properly?

Is that the hockey puck lookin thing on the driver side twords the middle?

[kibatheloanwolf]

Well Cranked it up after I ran it around 12 minutes before and it started to pitch a fit so I unplugged the sensor underneath the TB and It corrects it self and begins to idle right....

Does anyone find that odd?

[Q451990]

Good points except that Kiba's engine is not MPFI. It a TBI unit with only two injectors, and if they are leaking, you could just take off the air filter and see it plain as day spraying on the throttle plate.

Ahh... good to know. Scratch all of what I said... except for the bleed down and running rich part.

Heath

[mswit209]

check you plugs bro if it warms up then starts to bogg down thats an ignition problem. the black cloud is probably unburnt fuel from it flooding trying to start and when it does it all goes out the exhaust.

[kibatheloanwolf]

Plugs are brand along with the router and distributor cap and plug wires

Also do lil beads of gasoline dancing on top of the throttle plate mean anything?

[Rev_D21]

Little beads of fuel means the injectors are working.

[kibatheloanwolf]

Well I've learned to run it without the sensor under the Throttle body unhooked so it's fixed... For now