06 3.0 new motor, long block. Starts then stumbles, smooths after a few seconds. I had this same issue with the old motor. Where would you start looking ?

 

First thing in the morning, 70 degrees outside, starts right up and runs smooth. 20 mile drive to work and it no longer starts instantly, sometimes takes two or three attempts to run, or does the start and stumble thing. No codes.

 

Anyone ?

 

Could be check valve in fuel pump, you are losing fuel pressure when engine sits.

Try turning the key on and off 3 times before starting, that "primes" the fuel system 3 times to build up any lost pressure.
If that helps then check valve is most likely the problem

 

I've done the prime thing from reading here, pumping and flooring it too. lol I would think it's holding pressure if it starting right up first thing in the morning after it sits all night ?

 

Fuel injection doesn't have a "gas" pedal, it is an "air" pedal now, so pumping doesn't really do what it did before when using a carb, just FYI.

When it starts cold, without touching gas pedal, does idle go up to 1,500rpm then drop down to 1,000rpm or so within a few seconds?

And then as engine warms up does idle drop down over time to warmed up engine idle?

That's the ECT(engine coolant temp) sensor and IAC(idle air control) valve working like they should.

 

I know, just getting frustrated.

I put my Harbor Freight gauge on. After turning on three times it went up to 25 lbs. Started and running it's at 65 lbs. I'll go out and check to see if it holds after a bit.

I haven't paid attention to the rpms in the morning, will tomorrow though.


I had problems before I swapped motors with it sometimes wanting to idle up and stay when it's very hot outside. All this fuel stuff has 300k miles on it.

 

About thirty minutes sitting and it's down to 35 ? I hate to have to pull the bed !

I started it with it at 35 and it stumbled. It took a good five minutes to build back to 50 and stopped there.

 

sounds like a weak fuel pump

 

pulling the bed is a lot easier than the fuel tank

 

Yes, 60-70psi is what it should be running

No lower than 50psi after sitting

If fuel filter is new then yes, change the fuel pump

 

I've done this on my 2000, just changed the Bosch motor on that one. I hate they put this pump where they do, makes it a two person job and I'm alone. Watched a youtube video where he tilted the bed up at the front, I might be able to do that with some 2x4s.

On the cold start. This morning started right up, settled at 1200 rpm and warm idle was 750. Is that close ?

 

Curious, Is there nothing that should up the rpm at start up the rest of the day, not just first thing in the morning ? Why does it bump up to 1500, drop to 1200 and start fine in the morning after sitting all night and loosing pressure ?

Here's how it's running. 20 miles to work, sits for 30 minutes, starts at about 700 rpm and a few seconds after you here an audible click and it up's the rpm to 800. Same thing after getting gas, starts at 700, audible click, then up to 800. Idles at about 700 while driving.

 

Usually when you turn on the key the computer will open the IAC(idle air control) Valve all the way for starting.
So any time you start a fuel injected engine(without touching the gas pedal), you should get 1,500+ RPMs, and then a drop down to Coolant Temp idle RPM, so cold or warm engine RPMs should be high at startup and then drop.
Foot on the gas pedal can over ride this with warmed up engine.

The 50-100rpm kick up can be from AC system, if AC was on or if Defrost was on then computer will kick up idle a bit.
If an automatic the computer will also kick up idle if it thinks transmission is in gear.
There is a Range Selector on the side of the transmission, I would think you would get a NO Crank if it was faulty though.

 

I tapped on the IAC some earlier with my ratchet handle and it seemed to start right up every time on that trip. I had replaced this a few years back with a cheap Autozone valve, I'm tempted to grab one at Napa and see if it helps any.

 

Did the following test and my truck started, not instantly, but did start after turning over a bit. Does this mean I could be loosing pressure through an injector ? I'm just researching any and all possibilities here.

 

I think I got it to pass the leaking injector test.

 

Over time the throttle cable can stretch, this prevents you from ever getting Full Throttle, so would also effect above test.

Google: Ranger throttle cable mod
very easy fix for this, also gives you back more PEP to vehicle if cable was stretched

With a leaking injector engine would start very quickly because there was gas in the intake already, no injectors needed.
If engine fires, even on 1 cylinder the RPMs jump up and computer exits Clear Flooded engine and starts the injectors, regardless of your foot position on gas pedal.

 

Thanks ! I really stomped down on the pedal and the test went good. I'm just going through every possible situation before I mess with the pump. I'm also just checking things as I go along because the mileage on the fuel system is way up there.

I had read about the cable mod, but I don't have a lead foot lol, I see where that would cause a wot issue. I feather the pedal when accelerating because I hate the way these transmissions are programmed to downshift two gears and wrap up the rpm when one is plenty. (another post I made here)

 

3.0l Vulcan engine is a high RPM engine, earlier models make best torque at 3,500rpm, 2006 version is 3,950rpm, best horse power at 4,900rpm
This why the 2 gear kick down is used.

4cyl 2.3l is about 2,800rpm, 4.0l 2,500rpm

It is just made to run at higher RPMs

 

To me it feels like it has more pull for merging/passing before it kicks down again and winds up to 5k like that. It's just not comfortable to me, I guess I grampa this thing. If I want blazing horsepower I need a different truck...........like my first Ranger, a 72 390/c6/4:56 beast, lol.

 

Yes, "there is no replacement for displacement"

3.0l Vulcan was a smaller car engine, Taurus/Sable, that found its way into the Rangers.
Very reliable but not a power house in this application.

3.0l = 182 cu.in.
not even 1/2 of 390 cu.in. engine

 

lol ikr

 

Different era for sure.

 

I put a Napa iac valve on the other day, it would idle at 1500, then 2000, then 1000 and back to 2000. Could drive without touching the gas pedal. Today my brand new water pump sprung a leak.