1997 2.3 hard to start
#1
#2
RF Veteran
iTrader: (1)
Reads like possible problem with the ECT(engine coolant temp) sensor.
This is a TWO WIRE sensor, used by the computer.
There is a ONE WIRE sender, used by the Dash board temp gauge
They look similar but are not the same.
A fuel injected engine can not use a Choke plate like a carb had for cold starts, there are no Jets to suck extra fuel from.
So all fuel injected engines use an ECT sensor, when you turn on the key the computer looks at the ECT sensor, and if it sees cold engine, it runs fuel injectors rich and raises the idle, just like a Choke plate did.
As ECT sensor warms up idle will drop and fuel will be leaned out.
Since you are getting "low engine temp" warning it could be the ECT sensor is no longer working or a wire is bad.
On the 2.3l the ECT sensor is on the drivers side of the block, towards the front, just under the intake, you can usually see it through drivers side front wheel well.
I assume the dash board temp gauge is showing normal warmed up engine temp after 5 to 8 minutes of driving, and heater is working OK, if not your thermostat may also need to be replaced.
If you get a new ECT sensor make sure it is the TWO WIRE sensor, auto part guys confuse the sensor and sender.
Also coolant WILL come out when changing sensor, so either drain it or be prepared.
If you want to test sensor then use a sewing needle and pierce one of the wires, use Volt meter set for DC volts.
Turn on key and ground black meter probe, touch Red meter probe to pin.
If it reads 4.7-5.3volts that is the "power wire", you want the other wire, remove pin and pierce the other wire.
If wire reads under 4volts that's the right wire
30degF should read about 4.0volts
50 degF 3.5volts
70 degF 3.0volts
100degF 2.0volts
160degF 1.0volts
200degF .5volts << correct operating temp of gasoline engine
This is a TWO WIRE sensor, used by the computer.
There is a ONE WIRE sender, used by the Dash board temp gauge
They look similar but are not the same.
A fuel injected engine can not use a Choke plate like a carb had for cold starts, there are no Jets to suck extra fuel from.
So all fuel injected engines use an ECT sensor, when you turn on the key the computer looks at the ECT sensor, and if it sees cold engine, it runs fuel injectors rich and raises the idle, just like a Choke plate did.
As ECT sensor warms up idle will drop and fuel will be leaned out.
Since you are getting "low engine temp" warning it could be the ECT sensor is no longer working or a wire is bad.
On the 2.3l the ECT sensor is on the drivers side of the block, towards the front, just under the intake, you can usually see it through drivers side front wheel well.
I assume the dash board temp gauge is showing normal warmed up engine temp after 5 to 8 minutes of driving, and heater is working OK, if not your thermostat may also need to be replaced.
If you get a new ECT sensor make sure it is the TWO WIRE sensor, auto part guys confuse the sensor and sender.
Also coolant WILL come out when changing sensor, so either drain it or be prepared.
If you want to test sensor then use a sewing needle and pierce one of the wires, use Volt meter set for DC volts.
Turn on key and ground black meter probe, touch Red meter probe to pin.
If it reads 4.7-5.3volts that is the "power wire", you want the other wire, remove pin and pierce the other wire.
If wire reads under 4volts that's the right wire
30degF should read about 4.0volts
50 degF 3.5volts
70 degF 3.0volts
100degF 2.0volts
160degF 1.0volts
200degF .5volts << correct operating temp of gasoline engine
Last edited by RonD; 12-17-2014 at 10:59 AM.
#3
Changed ECT no change in starting. Also changed temp sender, it was also bad. Tested for vacuum leak, ok. Only thing I see is a small skip,[rough idle for about 30 seconds, so small you have to pay very close attention to hear it. This is on cold engine in 30 degree weather. Truck runs great for a 4 cylinder after cranking. Any thoughts? THANKS FOR YOUR TIME.
#4
RF Veteran
iTrader: (1)
Your '97 needs 40psi of fuel pressure to start engine.
If you have a small leak in the system your fuel pressure could be 0psi after it sits for a few hours.
When you turn on the key the computer primes the fuel system, but only for 2 seconds.
So I would turn key on, count to 3 then turn key off.
Repeat this 3 times.
So Prime the fuel system 3 times, that will restore any lost pressure.
Now try to start engine.
If it starts right up then you do have a leak, if you don't smell gas then it could be in the tank(line from pump to cover), or fuel pressure regulator leaking fuel to return line.
Neither of these would effect MPG, just make for harder starting
If you have a small leak in the system your fuel pressure could be 0psi after it sits for a few hours.
When you turn on the key the computer primes the fuel system, but only for 2 seconds.
So I would turn key on, count to 3 then turn key off.
Repeat this 3 times.
So Prime the fuel system 3 times, that will restore any lost pressure.
Now try to start engine.
If it starts right up then you do have a leak, if you don't smell gas then it could be in the tank(line from pump to cover), or fuel pressure regulator leaking fuel to return line.
Neither of these would effect MPG, just make for harder starting
#5
Primed 3 times still took 30 sec. to crank in 40 deg. weather. Tested fuel pressure with Autozone test equipment and found 38.5 psi. after 3 primes and when cranked. Found 33 psi. at idle so pressure regulator is ok. Still at idle a very small skip for about 30 seconds. The engine sounds like first fire off of a rebuilt motor, with timing off about 10 degrees popping, backfiring, and shaking, but runs fine after cranked. Never saw any motor do this and then run great. Thanks for your help.
#6
RF Veteran
iTrader: (1)
Could be a delay in spark starting.
Crank position sensor(CKP) is what starts the ball rolling for the ignition module(ICM), it sends pulse that denotes #1 at TDC but also degrees of rotation of the crank.
Without this pulse ignition module doesn't know you are cranking over the engine, so no spark, or fuel injectors since they start with CKP pulse as well and then are fine tuned by Cam Position sensor(CPS)
ICM is in the computer on 1995 and up Rangers.
If you can get a timing light I would test Exhaust side coil for spark when first cranking.
If memory serves only the exhaust side coil works when cranking 2.3l/2.5l engine, intake side doesn't start up until RPMs are above 500.
This also brings up that the problem could be exhaust side coil starting to fail, delayed spark, you could swap them around.
Crank position sensor(CKP) is what starts the ball rolling for the ignition module(ICM), it sends pulse that denotes #1 at TDC but also degrees of rotation of the crank.
Without this pulse ignition module doesn't know you are cranking over the engine, so no spark, or fuel injectors since they start with CKP pulse as well and then are fine tuned by Cam Position sensor(CPS)
ICM is in the computer on 1995 and up Rangers.
If you can get a timing light I would test Exhaust side coil for spark when first cranking.
If memory serves only the exhaust side coil works when cranking 2.3l/2.5l engine, intake side doesn't start up until RPMs are above 500.
This also brings up that the problem could be exhaust side coil starting to fail, delayed spark, you could swap them around.
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