91' Ranger hard to start

[lokjaw]

I go out every morning and start my truck as usual it doesnt have a strong start but it does start. If i drive to the gas station witch is about a mile away i shut off the truck befor i go inside. Come back out and attept to start the truck. it will turn over run for half a second then just stall. when i attept to restart her she will just turn over. it is getting to the point where i have to hold the key for over a minute to get it to start! I have changed all the plugs, wires and cap and rotor. No loose connections that i can see anywhere. She is a 91 ranger 3.0L with only 77,000 miles on her!!

 

[RonD]

There are a few things that can cause those symptoms.
To cut that list in half it would be nice to find out if the problem is fuel or spark.

If you get a spray can of Starting Fluid you can test if it is a fuel issue and by default a spark issue.
Next time there is a no start, spray the starting fluid into the intake, turn over engine, if it starts and dies then you have a fuel delivery issue, if it doesn't fire then you have a spark issue.

Couple of other questions:
After engine is warmed up does it start OK?

Does engine ever cut out while driving at higher speeds?

Does the engine have an EGR system?
Some 3.0ls did some didn't

Some auto parts stores will read the OBD I codes on the truck for free, have you had that done?
OBD I codes don't always cause the check engine light(CEL) to come on but they are stored in memory.

 

[lokjaw]

There are a few things that can cause those symptoms.
To cut that list in half it would be nice to find out if the problem is fuel or spark.

If you get a spray can of Starting Fluid you can test if it is a fuel issue and by default a spark issue.
Next time there is a no start, spray the starting fluid into the intake, turn over engine, if it starts and dies then you have a fuel delivery issue, if it doesn't fire then you have a spark issue.

Couple of other questions:
After engine is warmed up does it start OK?

Does engine ever cut out while driving at higher speeds?

Does the engine have an EGR system?
Some 3.0ls did some didn't

Some auto parts stores will read the OBD I codes on the truck for free, have you had that done?
OBD I codes don't always cause the check engine light(CEL) to come on but they are stored in memory.

Thanks for the FAST reply!! I will try the starting fluid next time it dies!!

After engine is semi warm is when i have the most problems with hard starting. If i go out and start it now (cold) it will start but sounds like it wants to die only runs on a few cylinders. When i drive down the road it runs fine no problems! It also sometimes blows a cloud of unburned gas after cranking it after the hard starting issue.

Never cuts out at higher speeds or cuts out at all while driving.

NO EGR system and NO A/C.

 

[RonD]

Because of the low miles I would put a can of Seafoam or similar gas treatment into the tank the next time you fill up or part of a can depending on the amount of fuel in the tank.

While low miles is good it also means lots of sitting time which is bad, fuel can get varnishy and make injectors sticky.
Name brand gas usually has cleaners in it but adding a little more once a year won't hurt.

There is a valve on the intake called an IAC(Idle Air Control) it is in essence a controlled vacuum leak that the computer runs, it sets the idle RPM by adjusting the "leak", more air = higher idle, less air = lower idle.
When cold does your engine idle above 1,000 as it should, or does it stay at around 700(normal warm idle)?

When first starting the IAC opens all the way then after engine starts it closes to set correct RPM for engine temp.
That's why newer engines start up and go to above 1,000 RPM then drop down to lower idle, if your engine doesn't do this check the IAC.

You can remove the IAC and then clean it and test it if you think this could be the problem.
With connector in place when you turn the key on the IAC should click and open you can usually see the shaft move.

Fuel injected engines do not have chokes like carberurated engines.
They have the IAC and an ECT(engine coolant temp) sensor, this is a different sensor than the dash board temp "sender" unit.
The ECT has 2 wires and is located near the dash boards 1 wire "sender", usually at the front of the intake near the t-stat.
The ECT tells the computer the engine temp and the computer then runs the IAC and injectors accordingly.
So if ECT tells computer engine is cold computer opens IAC for higher idle and opens injectors longer to run engine rich(like a choke did) until engine warms up and can run leaner for better mileage.

If ECT is going bad it might be telling computer the engine is warm all the time, so lean mixture all the time, this would cause engine to run poorly when cold.
The ECT is just a resistance sensor so can be tested with an OHM meter, you test it with engine cold and then test it again with engine warm, and see if there is a difference, there should be.

 

[lokjaw]

Because of the low miles I would put a can of Seafoam or similar gas treatment into the tank the next time you fill up or part of a can depending on the amount of fuel in the tank.

While low miles is good it also means lots of sitting time which is bad, fuel can get varnishy and make injectors sticky.
Name brand gas usually has cleaners in it but adding a little more once a year won't hurt.

There is a valve on the intake called an IAC(Idle Air Control) it is in essence a controlled vacuum leak that the computer runs, it sets the idle RPM by adjusting the "leak", more air = higher idle, less air = lower idle.
When cold does your engine idle above 1,000 as it should, or does it stay at around 700(normal warm idle)?

When first starting the IAC opens all the way then after engine starts it closes to set correct RPM for engine temp.
That's why newer engines start up and go to above 1,000 RPM then drop down to lower idle, if your engine doesn't do this check the IAC.

You can remove the IAC and then clean it and test it if you think this could be the problem.
With connector in place when you turn the key on the IAC should click and open you can usually see the shaft move.

Fuel injected engines do not have chokes like carberurated engines.
They have the IAC and an ECT(engine coolant temp) sensor, this is a different sensor than the dash board temp "sender" unit.
The ECT has 2 wires and is located near the dash boards 1 wire "sender", usually at the front of the intake near the t-stat.
The ECT tells the computer the engine temp and the computer then runs the IAC and injectors accordingly.
So if ECT tells computer engine is cold computer opens IAC for higher idle and opens injectors longer to run engine rich(like a choke did) until engine warms up and can run leaner for better mileage.

If ECT is going bad it might be telling computer the engine is warm all the time, so lean mixture all the time, this would cause engine to run poorly when cold.
The ECT is just a resistance sensor so can be tested with an OHM meter, you test it with engine cold and then test it again with engine warm, and see if there is a difference, there should be.

ok went through hell working on this thing the whole day!! You were correct it was the ECT!!!! its weird how that little thing that has to do with water temp can make a truck not run!!!! But thank you very much you have fixed it!! I did all the physical work!! THANK YOU THANK YOU THANK YOU

 

[RonD]

Good work