Starting Issues with my '86

[DankTank]

So, I bought my 1986 Ranger XLT over half a year ago. in January, I had an engine from an '87 B2 installed by a reputable shop. Now I'm having 3 issues that are more than likely linked in some way.

First, the truck doesn't "kick off" in the traditional sense. More like it just "sustains" itself. It will kick off a little bit when it's cold, but nothing significant.

Second, the RPMs suddenly tank about a minute after starting, and unused gas blows out the tail pipe (The truck was straight piped by the previous owner, so no worries about failing cats). This is probably because there's no kick off to burn the excess gas.

Third, It's hard to start when warm. Like, really hard. Sometimes I have to give a big helping of throttle to get it going.

so far I have replaced the Ignition coil, and the Idle Air Control Valve. When I pulled the wire off the coil, the large pin came with it and I had to pull it out with some pliers. I've also tried seafoam and injector cleaner and that hasn't seemed to help either.

That's pretty much everything I can think of. At this point I might be replacing either the injectors or the distributor

 

[RonD]

Welcome to TRS

Not sure what "kick off" means

On the engine there will be two fuel lines
IN line from the fuel pumps will connect to the Fuel Rail that feeds the fuel injectors
Return line, the one you want, will run to the Fuel Pressure Regulator(FPR)
Follow the Return line to the FPR
On the FPR will also be a Vacuum Hose, remove this hose and check it for gasoline, there of course shouldn't be any in that hose

Not uncommon for older FPR to leak a bit and raw gasoline is sucked into the engine thru this vacuum hose

This would cause harder cold start but cold engines need Richer mix, i.e. a choke
Warm engine does NOT like Richer mix, floods out
Fuel injected engines do not have a "gas" pedal, they have an "air" pedal
With a carb when you pressed down on the gas pedal you actually squirted extra gasoline into the engine, so a "gas pedal"
With fuel injection when you push down on the same pedal you let more AIR into the engine no extra gas, just more air

So if FPR was leaking letting in more AIR would clear out the flooded warm engine and it would finally start

 

[DankTank]

Thanks for replying, I'll definitely check the FPR when I can.

By "kick off" I mean that momentary jump in rpm that burns off the extra fuel used to start the engine.

 

[RonD]

On fuel injected engines the "kick off" is actually extra Air

The IAC(idle air control) valve is opened all the way by the computer when key is turned on, so full air thru this valve.
When RPMs get above 400(engine is started) the computer will then start to close the IAC valve to set idle RPMs based on engine temperature.
So on startup, without touching the gas pedal, engine RPMs can go as high as 1,800 then they will drop down to idle

Cold engine will usually idle at about 1,100RPMs, fully warmed up engine at 650 for manual trans, 750 for automatic

ECT(engine coolant temp) sensor is what computer uses for this IAC Valve RPM setting
No relation, or connection, to dash board temp gauge and its Sender.

ECT sensor was added just for the fuel injection computer to use, it has 2 wires.
Senders have 1 wire, they use engine as the Ground so only need the 1 wire

ECT sensor also tells computer when to "choke" a cold engine
All cold engines need to be choked, fuel injection can't change that, but a choke plate won't work with fuel injection, no Jets to suck extra fuel from

So when computer "sees" a cold engine it runs Richer fuel mix and higher idle(IAC Valve), which is what the choke plate did on a carburetor

 

[DankTank]

Update on the issue...

I took it to a mechanic shop to get a professional to look at it. He says that there's no reason for the truck to do that. Although He DID say that my fuel pressure is on the bottom end of the acceptable limit.

I'm stumped. How can an engine be in such good condition, but do something so weird?

 

[RonD]

Low fuel pressure would be most noticeable at higher speeds, higher demand for fuel, it would feel like running out of gas which would be what was happening, so shouldn't effect idle or lower speed operation

The TFI module was a common issue with hard starting when warm symptom

Good read here on that: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

The engine spark does need to be timed manually every now and then, you need a timing light
12deg BTDC is popular choice

 

[DankTank]

Thx, Ron

Manual spark timing eh? Sounds very interesting...

The TFI is brand new, but considering the placement (On the distributor!? Really???) I wouldn't be surprised if it's on the fritz again.

 

[DankTank]

Some updates.

I had the truck looked at in a shop and they fixed some vacuum leaks. Solved nothing. Although now that there's more vacuum, there's more air being drawn in, and more air = more boom and more boom = more power and I think you can see where I'm going.

It's fast now...

or at least it's fast to a guy whose fastest car he's ever had is a NA V6 Acura sedan. No, it's not as fast as my Acura, but it's close enough for being nearly half the HP.

...or maybe it just feels fast. Point is, it runs better.

As to my ignition woes, I think RonD was right and the hard warm start is just something I'm gonna have to live with for now. Also, Ford did tweak the V6 from '86 to '87. I wonder if the sputtering is just the computer trying to figure out the 'new' engine when the idle is supposed to drop to normal...