01 Dodge Dakota 4.7l v8, 150k

If the truck sits for more then 10 minutes, upon starting it, I have to crank on it for awhile. Maybe 5 or 6 secs. It will then usually start, however, if it doesn't, I stop for a few seconds, and start again, and it will fire up on the second go around. Upon it starting, the engine lets out a puff of black smoke, and you can smell gas. It runs rough for a second or two before it clears up. It almost seems like the engine is flooded. It does always start, and the truck seems to run great. I checked for codes, no codes. I'm thinking I should start with a fuel pressure test? See if the fuel bleeds off quick?

I looked at some live data from my simple scan tool I have, and everything looked "normal" (at least to me) except my LT FTRM 2 is showing -14%. So my thinking is maybe I have an injector that is stuck open? Maybe the fuel is bleeding off an injector, and that's why I have the long start and maybe that's why the rich condition exists?

Am I thinking through this correctly? Looking for some confirmation or redirection. Other then the fuel pressure test, where should I start from, knowing what I know.

Thanks for the help

 

When is the last time you replaced the spark plugs?

 

I don't have any history on the truck, other then I was told that it had a "tune up" in the last few months. Supposedly new plugs and coils were a part of that. I haven't pulled them to see if this is true though, or even what brand of plugs were thrown in.

 

Yeah, I'd pull at least one. When I got mine, the owner told me the plugs were good. When I pulled one, the tip was worn to nothing and the whole gap tool could pass through it.

 

I'd be looking at your injectors leaking down too. Yes, start with the fuel pressure and watch how long it takes to drop.

 

So i checked fuel pressure. KOEO pressures around 44/45, engine running it's 48/49. Service manual says it should be 49 +/- 5psi...so I think I am good there. I was able to isolate the injector side and fuel pump side of the system. Thing is, they both lost fuel pressure over time. The injector side lost about 25psi in 15 minutes(45psi to 20psi), the fuel pump side was similar in that it also lost pressure, but at a slower rate 15psi in 15 minutes. Thoughts?

The injector side shouldn't lose any pressure at all should it?
The fuel pump side should bleed down slowly overtime correct?

I haven't pulled plugs yet to look at them, but I will. Other than that, where do I go from here?

 

There is a check/bleed valve sitting on the fuel pump, I believe if that is faulty, it might cause the symptoms, but you said fuel pressure is good so, not sure....


Other than the plugs, IAC valve may need to be cleaned and check TPS with voltage test.

 

I did clean the throttle body, and when doing so, I pulled the IAC and cleaned it and the hole it goes into. I believe the IAC is working as it should, as the engine increases when in reverse, or when kicking the A/C on.
I could check the voltage on tps, but from what I see on my live data on the scan tool, it at least appears the tps is functioning normally.

 

Fuel pump should hold steady pressure when you turn engine off. If it is bleeding down that fast you might have a bad fuel pressure regulator. A good test is to turn the key to run but do not start the truck. Leave the key on and wait 10 or 15 seconds then start the truck. If it starts right up then you know the regulator is bad. The only fix is to replace the fuel pump. Regulator is an internal part of the pump assembly. When the regulator is bad and you wait to start it gives the pump time to re-prime the fuel lines since the bad regulator can not keep the lines pressurized while the truck is not running.

Jimmy

 

I have tried priming the system, by turning the truck to run leaving there for a couple seconds, until you hear the pump turn off, and then turn it on, and then turn it off, and then turn it back on, etc, etc. It doesn't help the truck start though.

I haven't tried turning it on, and leaving it on for 10 seconds or so. Correct me if I'm wrong, but the pump only runs for a couple seconds anyways when you first turn it on right? It then shuts off, until you start cranking on it?

I'll give it a try when I leave work here tonight.