97 sohc 4.0 cranks but won't start - sometimes

[97controltrac564]

First thanks to all - I have read and searched this forum extensively and appreciate all I have learned thus far!
So here we go: Just bought a 97 explorer xlt and it ran perfectly. Began to have the issue of cranking but no start. Was getting spark, and plenty of cranking, but no start. This truck was purchased from an older gentleman who let it sit for porlonged periods. Figured it was the fuel filter. Changed it out and the old one was too clogged to blow through - truck ran flawlessly for about a week. It has always idled perfeclty, and no indication of fuel starvation under load once the truck is started - runs great. I have put several tanks of gas through the truck so I am not thinking bad fuel. The truck always starts right up when warm, this seems to be a cold start issue. Usually it won't start initially when cold, but will crank up 1/2 hour later after a few cranking seconds. Had my wife try the ignition switch to on for 5 sec. and repeat cycle three times and it started right up (but this was during the second try from cold where it has been starting anyway...)
So, after reading what I can find here on the forum, and again thanks to all for what I have learned, here is what I am thinking:
1. Fuel pump or fuel pressure regulator going (gone) bad.
2. Dirty or bad idle control valve
3. crank or cam position sensor

What do you actually educated and skilled folks think? What is the best troubleshooting strategy for a poor and marginally skilled person as myself?

Problem that was initially sparcely intermittant is now occurring every day. Additionally, the fuller the gas tank the less frequent the problem - or at least seems to be.

THANKS IN ADVANCE FOR THE HELP!!!!!!!!!!!

 

[Cobraguy]

Any of those three could cause an issue such as yours. But let's see if we can't drill down a bit and eliminate some things. First things first...get your hands on a fuel pressure gauge and hook it up. Watch and record your fuel pressures at all times during starting. Does cycling the key bring it up? Cranking? Let's see where the fuel pressure is before we go any further.

 

[ZBlackBeast]

Also, to eliminate the IAC as the culprit, does it start normal and then die right away? the IAC only effects idle so if it was bad it would start normally (like rev up to about 2k or whatever) and then just die out like you turned the key off!!

 

[97controltrac564]

Z and Cobra - THANK YOU!!
The truck idles great when started so looks like I can eliminate idle control valve...
I will get a hold of a pressure guage and measure during start up - I am assuming at the schrader valve on the fuel rail.
If start pressure profile is good then I am assuming that crank position sensor becomes likely suspect, eh? Curious that it would be intermittent, but I had a similar issue with my BMW E36 M3.
I will do a search and see if I can find pics of the CPS connector(s) so that I can recycle them to remove possible corrosion or intermittance in the connector. I assume that it is some kind of hall effect switch that can be readily tested...
Thanks for the generous help!
I will most certainly keep the brain trust "Posted"!

 

[saewoody]

This has been a popular topic in the last several days. If you take a look at some of these posts there is some good information. When the engine is cranking look to see if the "check engine light" is on and also check to see if the "theft" light is doing anything.

 

[97controltrac564]

Solved!!!

OK Sorry for taking so long to repost...
Well, my efforts to purchase a fuel pressure guage ended when the cheapest one I found was 75$ at Pep Boys, a new fuel pump was 95$. So I figured that since the fuel filter had been badly clogged for an undetermined time the fuel pump could indeed be the culprit. Took about three hours to put in (Thankfully there were minimal rusty bolt issues) Cranked right up and ran perfect - for about 2 days. Arrrgggg
So I looked at the CPS and pulled the clip on the connector and recycled the plug a few times. VOILA! Cranked right up and has been perfect for the last three weeks. I did notice though that the hall effect magnet was quite a distance from the toothed pulley - maybe 3/16 to 1/4 inch. Remembering from my engineering classes that magnetic force (like EMF energy) is a square function of distance, I thought that the sensor should be closer. Or at least the pulse train would be much stronger if it were. I realize that in my case the resistance of a poor connection attenuated the signal to where it was undetectable, and once that was fixed all was well. But I was thinking that replacement of the part for some folks may not be necessary if they could just move the sensor closer to the pulley. It did not seem like there was any adjustability, but the sensor bracket could be shimmed to locate the sensor closer.....just a thought
Anyway thanks to all for the help!

 

[Cobraguy]

Glad to see it's fixed! Weird the pump would fix it...then you had CPS problems. I suspect your pump was your problem, then the sensor issue reared it's head.

 

[saewoody]

I've actually been waiting to make this post to be more positive of the results, but this may be similar to what controltrac is talking about. I was going to replace my sensor, but it was not as easily accessible as I thought it looked like it was and I was short on time. As I looked at the sensor, I realized that it was very dirty and had a significant amount of grime on it, so I wiped it down and just sprayed some mass airflow cleaner on it (to be sure it was safe for the plastic). At this point, I have not had a problem for 4-5 weeks. It might sound crazy, but maybe the signal was simply weak.

 

[97controltrac564]

Hmmm, the sensor gets is signal from the teeth in the pulley crossing the magnetic field from the sensor. Cleaning the sensor shouldn't of helped. In my case the issue was the connector.

 

[outdoorman99]

thanks for the post! i am having the exact same problem. Now if only i can find out where the crank position sensor is...

 

[powerdmos]

97 Explorer SOHC Intermittent starting issue and no spark

Hi all,
The intermittent starting issue seems to be quit common!
I've had this problem for about a year now.
My wife complained about it and of course I didn't believe her!
It never happened when I drove the Explorer!
Sure enough I let a friend borrow the truck and he said it would,t start it just
kept turning over....
Finally it started the next day, problem has been getting worse and worse...
Car is stuck in my garage now for 2 days 12/28/08.
Fuel or Spark? Can't have combustion without both of these!
I got a spark tester and Fuel Pressure gage from Parts America,
$12.95 and $39.95..
Tried the cheaper one first, I'm not getting a spark.
My wife turned the key I checked for spark.
I have a Haynes book on this car and I can honestly say it's pretty good, this time....
I've hated these manuals in the past because they leave out things like
socket size, accurate diagrams, the fact that rear disc brakes are adjusted by rotating the piston back into the caliper, etc...been there huh...

BTW: Of course the car started when I started to trouble shoot it!

So I started to measure things just in case it dies again!

OK
4 things to check according to the almightly Hanyes manual..
(1) 12V on the pin 1 of the connector on the coil pack with the key on(The manual shows pin 4, Wrong!)
(2)There are 3 coils in the SOHC V6. 1 coil is shared between 2 cylinders. They spark when one is on the compression stoke and the other is on the Exhaust stroke. Place a LED tester light on Pin 2,3,or 4 and look for it to blink... when someone cranks over the engine (I used a Digital Multimeter and saw it try to measure, when I cranked the car. I don't have a LED test light)
(3) The CKPS,crankshaft positon sensor,remove connect. You have to push the spring in and gently tug on the connect, comes out real easy for a connector.Turn the key on and measure about 1.5V DC on 1 of the 2 pins on the connector. I used a local gound and measured 1.1V. I think this was good enough because my GND lead wouldn't reach the battery.
(4) Crank the engine and look for the LED tester to toggle on the other pin of the CKPS. I did't do this one because I was alone. But I think the connect must be plugged back in? The great Haynes book didn't elaborate on this,
Let me know if you get this one to work...

I also disconnected the wiring harness to the EEVC,computer and reseated it, Not sure if this did anything but the problwm is intermittent...

The car is running now and I'm going to extract the codes from the computer ,if their still there!, at Autozone...They do it for free...

Based on the previous post I hope it's dirt in the CKPS. Does anyone know for sure that they have fixed this problem...

Please let me know!
Thanks,
Andy

 

[countrygirl37]

1997 ford explorer won`t start sometimes

Ok,I`m a girl,and this stuff is WAY over my head,and yes,here comes another question for all you automobile gurus!
I love my Ford sporttrac,but it seems to have some kind of problem with starting.I have had the fuel pump replaced,fuel rail replaced,and still,this problem has not been resolved.So,I`m asking as a absolutely clueless woman(can`t afford this) to the Gentleman with a clue,what could be the problem? Oh,by the way,It seems to bog down when I am driving,like it wants to stall out.

 

[leoJr]

This has been a popular topic in the last several days. If you take a look at some of these posts there is some good information. When the engine is cranking look to see if the "check engine light" is on and also check to see if the "theft" light is doing anything.

Same crank but no start problem. Fuel pressure measured good with a gauge. No spark from a removed spark plug grounded to the block. Check Engine and Theft lights were on during cranking. I believe all lights were on during cranking. No tachometer movement during cranking. Removed the connector to the crankshaft position sensor, spray cleaned and then applied silicone to the connector and to the sensor and the engine started right on up.
I know this is an old thread but I believe it is good to provide feedback...even if a few years late. Thanks for all of the input here!!