I've seen a LOT of threads about this, but nothing seems quite like the issue I am having...this problem is intermittent, doesn't have a regular pattern, sometimes it starts up with no issue, and other times, it will:

Sputter, the idle will drop, and it will die. Doesn't matter if I turn the key to the accessory position for a while or not. It will always start, sometimes it just takes a couple of times of this doing over and over. It doesn't matter if I give it gas while it idles or not, sometimes it's fine, sometimes it just goes on and dies.

Have replaced dis cap, spark plugs and all spark plug wires. Fuel pump was done about three years back. Same issue if hot or cold out. Battery tested fine. It has no issues once it is running. Doesn't stall while driving or parking.

I've heard people say it could be a faulty crankshaft sensor/ Throttle sensor, but I've never tried to replace either. I don't think it's the neutral safety switch, is there a test I can try to see if that's the issue? I will run it through all the 'gears' before starting next time I drive it to see if that helps or not.

Also, it has not thrown any kind of code, other than the 'coolant temperature sensor is low' Which is why my check engine light is always on, that wouldn't be a reason for it to idle low enough to die, right? Hope someone can shed some light on this, going to work on it this weekend, just don't know where to start really.


EDIT EDIT! So I did some reading, and the coolant sensor at the front of the engine has been replaced, but no change. I read there is a second sensor somewhere, on the drivers side towards the firewall? I haven't been able to find it. Also, checked wiring, and seems to be fine, no corrosion as far as I can see. Would love to get my baby running right!

Thanks in advance!

 

Try this, push the pedal to the floor activating "clear flood" mode. If it starts easier, I think I know your problem:

If the coolant temp sensor is reading a low temp, you're remaining in open loop mode where the injectors are told to dump fuel into the engine until it reaches normal operating temp. All that fuel eventually floods the engine.
When codes pop up, especially in OBDII engines, get them fixed. They communicate with other parts and cause problems.

Edit* Clear Flood mode is not for you to continue to ignore the code and keep driving. It is just a test

 

Have you tried the poor man's prime before starting? Turn key on for a few seconds, back off, back on for a few seconds then try starting. "On" is described as key turned as far forward before engaging the starter. The dash lights should all be illuminated when you're in the "on" position. Accessory is when you turn the key backwards from the "off" position. You may have meant "on" instead of "acc" but it is important to be clear when you're diagnosing problems.

My XJ would do something similar to this if I simply tried starting it without going through the poor man's prime. It would start, sputter, then die and there was nothing you could do to save it. Turn the key again and it would start and run fine.

EDIT: When the fuel pump was replaced, did you replace the entire unit or just the pump?

 

I will try replacing the temp unit, I didn't think to try that first, good point. And I'll try the gas pedal thing tonight before I go to work. Sounds like the CSP sensor is a pain in the butt to install...

Also, poor man's prime doesn't do anything to help : ( And just the pump was replaced.

Thanks for the input, will keep you all updated!

 

Don't load your parts cannon just yet. Test it here

 

But we love the parts cannon!

Nice article, good information in there!

 

haha

 

Good article, will check on that this Sat! Also, the 'clear flood' pedal thing didn't work either. : ( It's a jeep thing!

Has anyone here actually replaced their CSP sensor? (Just in case it's not the therm sensor.)

 

CSP? Refresh me on this one.

 

I think you are looking at P0117, ECT sensor voltage too low.

Here's some possible causes for this:

P0117-ECT SENSOR VOLTAGE TOO LOW

When Monitored: With the ignition on and battery voltage greater than 10.4 volts.

Set Condition: The Engine Coolant Temperature (ECT) sensor circuit voltage at the PCM goes below 0.8 volt for more than 3 seconds.


POSSIBLE CAUSES

INTERMITTENT CONDITION

ECT SENSOR INTERNAL FAILURE

ECT SENSOR SIGNAL SHORTED TO GROUND

ECT SENSOR SIGNAL SHORTED TO SENSOR GROUND CIRCUIT

PCM


Here's some test ECT procedures:

ECT installed and connected, back probed using a safety pin.

Voltages may vary by coolant temperature.



.
Testing the ground circuit only:



.

 

CSP Crank Shaft Position Sensor. Sorry.

And wow, super helpful diagram! Will borrow the OHM tester from a friend and use this, 100%. Will let you guys know results on Sat evening.

 

CPS - Crankshaft Position Sensor

 

So I did some reading, and the coolant sensor at the front of the engine has been replaced, but no change. I read there is a second sensor somewhere, on the drivers side towards the firewall? I haven't been able to find it. Also, checked wiring, and seems to be fine, no corrosion as far as I can see. Would love to get my baby running right!

Also, buddy didn't have his OHM reader on him, so looks like I'll have to go and buy one this weekend, and do more testing, but grounds and wire itself all looked okay. I've heard this 'second' sensor is the one feeding info to my dash, and is a PITA to replace, but again, can't find anything else about it. The reason for the stutter is because it's reading wrong, and causing the engine to be in a 'cold start loop' or something to that extent. Thanks for everyone's input so far!

 

Don't worry about that temp sensor that's for the gauge. It doesn't do anything BUT tell the gauge to move. It doesn't send any information to the ECU, that's what the front 2 wire coolant sensor does. Don't trust sensors just because they're new. I've had multiple "new" sensors be faulty right out of the box. Can't hurt to test it. Not to mention ALL the leg work has been done to find you the information necessary to test it correctly. Do these guys a solid and don't let their hard work go to waste. Get out there and test it!

 

I will as soon as I get time, you guys are awesome. Also my temp needle on the dash flops all over the place, so I was curious about the sensor.