No Start Weirdness

[P93suafilo]

Alright RBV and 4.0 Wizards I got some weirdness I could use your help with.

I have a 94 Explorer Sport w/ a 4.0 in it.

The other day I had a no start issue, this hasn't happen since I have owned it (2 months). I had crank, I had spark, and from what I could tell my fuel pump was running. It would just crank and no start for two days, then on the third day it started as if nothing was wrong. When it didn't start the weather was cold 20° and then warmed up to 30° and then got cold again 15°, temps are in Fahrenheit. There is also a slight odor of fuel when starting and stopping the explorer.

Any thoughts on what would have caused this?

 

[Josh B]

what was the temp when it started ?

 

[P93suafilo]

The temp when it started was 15-20°

 

[rusty ol ranger]

Coolant sensor?

Pull codes.

 

[RonD]

Could be your Choke Mode is not activating if all the no starts were with Cold engine

ECT(engine coolant temp) sensor tells the computer the temp of the coolant, I know, DUH, but its important because the computer must set Choke Mode to start the cold engine, Choke is a VERY Rich air/fuel mix and high idle

A cold engine needs a minimum 30% gasoline vapor in a cylinder to start up, the colder the engine and gasoline the less vapor it will have.

The ECT sensor tells the computer just how cold the engine and gasoline are, so how much choke to apply
Its a cheap sensor so I would replace it on speculation

4.0l will also have a one wire ECT sender in 1994, that's for the temp gauge on the dash only, this one works on 12volts, the ECT sensor runs on 5volts from computer so NOT interchangeable


To confirm you have spark, I would spray Quick Start(ether) into the intake when there is a no start, the ether has a higher vapor content when cold, which is why its used in cold weather, if engine starts and stays running then vapor content is/was the issue.

If engine starts and dies then there may be an electrical issue with the injectors when cold

Older engines have lower compression, compression is HEAT, so lower compression means less heat to vaporize cold gasoline enough for spark plug to ignite it, even in a Rich mix

 

[P93suafilo]

I will grab one today when I run by the parts store. It always just blows my mind how much technology is involved and how it all works together. Thanks for the input

 

[P93suafilo]

Although it starts and runs great I decided to pull codes last night and here is what I got-

• 214 - (M) Error in Cylinder ID (CID) circuit or signal - Ignition Systems
• 335 - (O) EGR feedback signal is/was out of range - EVR or PFE
• 528 - (M) System shows voltage at pin 10 (is A/C on ?) or pin 30 (PNP, CPP switch) - PNP

From what I understand the 214 is usually caused from a Crank Shaft Positioning Sensor faulting. The 335 is caused from a failure in the DPFE Sensor. And the 528 well I dont really know because I dont have A/C connected. Any input or correction is welcomed.

Would the faulty temp sensor throw a code?

 

[RonD]

ECT sensor would throw a code if it was not changing temp over time...............but computer is off between key off and on, so has no sense of time unless its on
So if ECT sensor is showing warmer engine, like you just turned it off for 30min, but its really been off for over 6 hours then it wouldn't Choke the engine enough for cold start, it thinks its just a warm restart, and no code

I would also replace CKP(crank position) sensor, code 214, and/or check its wires and make sure tone ring on crank is "mud" free, not an expensive sensor

The CKP sensor is the only way the computer "knows" to start spark and fuel injectors
Computer has no connection to starter motor activation, it just starts to receive pulses from the CKP and then starts spark and fuel
Since it is a wired electronic device it is possible for it to become temp sensitive, usually connections but can be sensor as well

335 can't cause no start, my 1994 Ranger 4.0L doesn't have an EGR valve, does the Explorer have one?

Not sure what 528 would mean without factory AC ??

 

[P93suafilo]

I have had a CKP sensor go bad in my old 2000 ranger and its really not a bad price/change so I will just be on the safe side and change that out.

The ECT I was looking at them on RockAuto and they Range in price from $2-$25. Any recommendation on price I should look at?

335 was the only code that wasn't a stored code. I didn't think it did because the OHV didn't look like my 97 OHV but after doing some research it appears that some models were made "low emission" so that they could be sold in california. Being that I am in the west I am wondering if that is what I got. All my research was done after I closed up the garage for the night so I will have to get into it tomorrow night. I think for that one I will change up the hoses and spray it out with some cleaner and see if the code comes back.

So I do have A/C but the PO doesnt have it plugged in for some reason. I think this code is throwing because when the defroster is turned on the compressor will start and because I have mine unplugged it is saying there is a fault.