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Stalling when put into gear then starts hard

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Old 05-16-2014
strikerty's Avatar
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From: Branchport
Stalling when put into gear then starts hard

I have a 98 ranger with the 4 cylinder that I just bought for 650 and put about 500 into to have a nice little truck that gets decent gas mileage. I replaced the brake lines front pads rotors and calipers, the rear diff cover, the egr tube and the radiator. This morning it starting acting up in that when I put it into gear it stalled and wouldn't start for a bit. Now it has no check engine light on, and seems to run OK when idling and driving, but when you put it into gear and it stalls it don't want to start back up. Its getting fuel because when it finally does start you can see that its loaded up with fuel cause its blowing it out the exhaust. I was thinking neutral safety switch but normally that dont allow it to turn over when its acting up from my understanding. The truck turns over fine it just acts like its not firing/ getting fuel. Any ideas would be greatly appreciated and if you have any other questions about it let me know

Thanks
 
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Old 05-16-2014
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The '98 would have the 2.5l engine and the ICM(ignition control module) would be part of the PCM(computer) and not a separate unit like earlier 4 cyl models.

The PCM on your vehicle is in the upper firewall passenger side, the connector is the only part visible, one problem they had with this location was water getting into the connector, in later years they add a cover for the connector.
Because it is free.....I would disconnect the battery's Ground cable, then remove this connector and check it for moisture or signs of corrosion, clean it up if it looks bad.
Reconnect battery.

If you can get your hands on an old timing light you can check for spark on the exhaust side coil when this happens, only the exhaust side coil fires when cranking.
Both coils work once engine is running.

Because of this you may want to swap the coils around, if the exhaust side coil is starting to fail then that could cause poor restarts.
Ford Coil Packs can be tested at many auto parts stores, or you can test them yourself with an OHM Meter


There is a "flooded engine routine" on all Fuel Injected engines, this allows the driver to clear a flooded engine.
You can try this after it stalls.
Turn key OFF
Turn key ON
Press gas pedal to the floor and hold it there
Crank engine over, it should NOT start, the fuel injectors are shut off.
After a few seconds of cranking release the gas pedal and injectors will start working again.

If this works for getting it restarted then you could have an over rich fuel mix when engine is cold, or the IAC(idle air control) valve is not working causing the stalling and hard restart.
The IAC valve opens all the way to let more air in when starting the engine, if this isn't happening then you have an over rich mix
 
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Old 05-16-2014
strikerty's Avatar
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From: Branchport
IF it was the IAC wouldnt it throw a check engine light? I just had it inspected last night and it had no codes. I do have a USB OBD2 connector I could pull codes but the light isnt on so im not sure there would be any.
 
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Old 05-16-2014
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IAC valve is a control not a sensor, but can cause a code if it is not changing RPMs as computer expects.

Codes are about the computer's preset parameters of ranges that are for the most part reliable if taken with a grain of salt.
A code doesn't mean a sensor or control is bad, and no code doesn't mean a sensor or control is good.
i.e. you can have perfect engine operation and have the CEL come on, or you can have engine problems and no CEL will come on........

The computer has two modes of operation, Open Loop and Closed Loop.
Open Loop doesn't use any "feedback" from sensors, computer runs preset spark and fuel/air mixtures from tables it has in memory.
This mode is enabled when computer first starts up, and it will stay in this mode for a minute or two if engine was already warmed up or it will stay in Open Loop until engine coolant temp is above about 150degF, about 5 minutes.
This is also "Choke mode" if engine is cold, computer will set high idle, 1,000rpms, advanced spark, and a rich fuel mix.
As engine warms idle will slowly drop down until preset warm idle RPM is reached, 650-750rpm depending on transmission.

Once engine is warmed up computer will switch to Closed Loop, it will now use O2 sensors to adjust fuel/air mix in real time and use the CPS(cam position sensor) to adjust spark and injector timing, so it is using feed back from the sensors instead of tables in memory.

The ECT(engine coolant temp) sensor is what the computer uses to "see" engine temp, this is a TWO-wire sensor only used by the computer.
The dashboard temp gauge uses a one-wire SENDER to show you the engine temp.

If you have an OBD II reader then I would check the engine temp, cold and then warm.
If ECT sensor is reporting the wrong temp to computer then you would get hard starts.
i.e. if ECT says engine is at 190degF all the time then when engine is cold it wouldn't have a high idle and would have too lean of a mix for a cold engine, computer wouldn't think anything is wrong because all its parameters are based on engine temp of 190degF, but engine would lack power, stall and be hard to restart.

Same for IAC valve, if it is dirty then computer might set a code if it wasn't moving but if it was just sticking now and then it wouldn't, engine would stall when put in gear because IAC valve/idle is to low, and then not restart easily because IAC valve is stuck and not opening all the way.
Computer can't monitor IAC valve, it is a step motor, computer sends it a voltage "pulse" to set motor/valve to a specific point, computer does monitor RPM but if engine has stalled it would have no way to tell if "full open voltage pulse" it sends for cranking actually opened the IAC valve.


And you should never change sensors or controls without testing them first, a $25 Volt/OHM Meter will save you hundreds of dollars if you mistakenly replace perfectly good sensors or controls.
 

Last edited by RonD; 05-16-2014 at 02:58 PM.
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