Help with hard starting.

[nitrodude]

I revently bought a 97 explorer with the 4.0l sohc, and since I got it at been hard to start.
Usually I crank or for 5-10 seconds, stop then crank again and it fires up.
Other times it might start writhin those 5-10 seconds but not right away.

It mostly does it first start of the day, but it also does it when warm/after driving for a while and stop somewhere.

Example-other day got in the truck in the morning and it took two tries to start, stopped and filled up with gas, took two tries to start again. Then drove to the DMV and when I went to restart started first try.
Then on the way home I stopped at autozone, got back in the truck and went to start it, and t stumbled and fired three times before finally actually starting up. (Usually just won't start, this time it Barely started and stalled right away)


Things I've done since I got the truck
Oil change
Seafoamed vacuum line
Seafoamed gas
Seafoamed crankcase
Oil change
Autolite double plat Spark plugs
Timing chain tensioner
Cleaned entrance of throttle body
Coolant flush
Fuel filter

Checked fuel pressure the other day. Turn key, 35psi. Turn off/back on foes to 40psi. Cycle key again and 40 was as high as it went.
Started and running got 30 psi. Which manual says psi should range from. 30-45
Didn't notice it leak down on the meter.
However when I got home, came inside an changed and went back outside to change the fuel filter, went to depressurize the system on the rail and no fuel came out (pressure leaked down)

Not sure where to go about from here, at a lose of what to do or check next.
Hate having to crank an crank for an engine to start.

Sorry for the long read just want it very clear of my problem.

Goodie searching hasn't lead me to any answers.

 

[Abbondanza]

could be the fuel pump starting to fail, also you might want to clean your Idle Air Control Valve

 

[nitrodude]

As I said, fuel pump was tested and put out pressure in spec.

I have cleaned the iac as well, forgot to mention that.

Any other suggestions??

Open to anything I have yet to try

 

[Abbondanza]

The only other two things I can think of would be the Crank Position Sensor and Cam Position sensor. I have heard they cause problems starting due to timing issues.

 

[nitrodude]

Anyway to test them

 

[Abbondanza]

Cam Sensor comes off and you can check the condition of the magnet under the cap, Not sure about the crank sensor.

 

[nitrodude]

Thanks ill check that out later today.

I put some Lucas injector cleaner in yesterday to see if it would help.
Started up first try today. Lets see if it keeps this up

 

[nitrodude]

Mags looks okay? Hard to tell though.

Any other suggestions?

 

[Abbondanza]

One stupid thing that got me when I first got my explorer, is the < 1/4 tank of gas and parked on a decline, the truck won't start because fuel in the tank can't reach the pump. Just had to put that out there.

If it's getting proper fuel pressure for sure, then if it was me I'd think spark or timing. Those two sensors are important in the timing, especially on startup, so you may consider replacing the crank first and see what happens. They cost around $9-$13 on rockauto, so it may be worth the shot. The camshaft pos sensor is a little more involved and costly...

 

[nitrodude]

Day I took it to the DMV I filled the tank, ($60 later)..
So that's not the issue.

Ill see what the crank sensor costs and see if the helps.

 

[nitrodude]

Still an ongoing problem.

Don't really want to just throw $ at the truck and how it solves the issue.


Most the time te first start is the hardest. Like today I went to start it it took two tries but started. Then shut it off immediately after starting and tried to restart and it started perfect. Shut it off and restarted 5 times without a problem.
Occasionally if I stop somewhere (gas station mostly) for a few minutes and come back out sometimes it'll start right up, other times t takes two tries or a long crank.
Most the time it's when it sits for >30 mins when I go to restart it takes a few tries again. But not always.

Just want it fixed!

 

[Turdle]

Ok.
Next time you start the truck, switch the key just to on, and back off 3 times-
Switch on, listen for fuel pump motor to stop, switch off. Repeat 2 times. On the 4th try turn the key to start, see if it starts right up.

Let us know if this helped, as it will help narrow down the issue.

 

[nitrodude]

Ok.
Next time you start the truck, switch the key just to on, and back off 3 times-
Switch on, listen for fuel pump motor to stop, switch off. Repeat 2 times. On the 4th try turn the key to start, see if it starts right up.

Let us know if this helped, as it will help narrow down the issue.

I will try that again tomorrow morning.

I did this test before and still had a hard start (had a gmc jimmy I had to start that way due to a failing pump)

Plus to double check this fuel pump I tested it with a gauge and pump was within manufacture specs.

 

[nitrodude]

Ok.
Next time you start the truck, switch the key just to on, and back off 3 times-
Switch on, listen for fuel pump motor to stop, switch off. Repeat 2 times. On the 4th try turn the key to start, see if it starts right up.

Let us know if this helped, as it will help narrow down the issue.

Tried this twice today. This morning I cycled three times, turned key and it started right away but also immediately died. Restated an was fine.

Later that day after it was cold again, tried cycling 3x again, still took its normal 5+ second startup.
So cycling doesnt seem to help.

 

[nitrodude]

Tried the three key cycle again the other day and same exact thing. Sputtered to life for half a second then died.
Starts right up on second crank.

Any other ideas?

 

[koda2000]

one of my '00 Mountaineers (V8 w/180k) would do this on the first start of the day. after that if would start every time. i could not hear the pump prime on the 1st start unless i turned the key on and off several times. as soon as i heard it prime it would start right up. pressure was good when the pump ran. replaced the pump, sock and filter. problem solved.

 

[drdoom]

In my Haynes manual it gives the test procedure for most of the sensors using a multimeter. On the SOHC, pull the CKP & CMP sensors, hook them to meter, and wave a piece of stell in frront of thhem. You will see the fluctuations on your meter.

 

[drdoom]

Have you done a leak-down test on your fuel system?

 

[nitrodude]

one of my '00 Mountaineers (V8 w/180k) would do this on the first start of the day. after that if would start every time. i could not hear the pump prime on the 1st start unless i turned the key on and off several times. as soon as i heard it prime it would start right up. pressure was good when the pump ran. replaced the pump, sock and filter. problem solved.

I can hear the pump run when I first then the key.
Also when I cycled the key 3 times I waited for the pump to kick off before cycling again.

Drdoom, I believe those parts are working since If they weren't it wouldn't run t all? Correct? Maybe its a weak magnet but i would think if that was the case it would still show fluctuation on the meter?

I didn't do a leak down test, only left the pressure meter on for a few mins an it didn't leak down in that time.
However, half an hour after I got home I went to depressurize the fuel system tp change te fuel filter and there was no pressure at the shrader.
So I believe it does leak down over a matter of time.