98 SOHC Cold Start Idle problem | Page 3 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

98 SOHC Cold Start Idle problem

Dear Ronev,

See if the following synopsis of temperature dependent engine conditions pertain to your vehicle:

COLD START – ENGINE NOT OPERATED OVERNIGHT – 40 DEGREE AMBIENT:

Upon cranking engine starts right up and the idle jumps to about 2K. Then it starts idling back to about 500 rpm then it jumps down to about 300 rpm and almost dies and then it settles down to a rough idle. This process lasts approx 15-30 seconds.

COLD START – ENGINE NOT OPERATED OVERNIGHT – 30 DEGREE AMBIENT:

Upon cranking engine starts right up and the idle jumps to about 2K. Then it starts idling back to about 500 rpm then it jumps down to about 300 rpm and almost dies and then it returns to about 2K and the cycle then repeats. This process lasts approx 2 to 3 minutes before settling down to a rough idle.

COLD START – ENGINE NOT OPERATED OVERNIGHT – 20 DEGREE AMBIENT:

Upon cranking engine starts right up and the idle jumps to about 2K. Then it starts idling back to about 500 rpm then it jumps down to about 300 rpm and almost dies. At this ambient temperature the engine acts like it is running on 4 cylinders; it sounds like a Harley V-Twin and the truck shakes violently (approximately 4 to 6 inches of side to side movement measured at the roof). It returns to about 2K and the cycle then repeats. This process lasts approx 10 to 15 minutes before settling down to a rough idle.

WARM START – ENGINE OPERATED WITHIN LAST 2 TO 3 HOURS – ANY DEGREE AMBIENT.

ALSO - COLD START – ENGINE NOT OPERATED OVERNIGHT – ANY TEMPERATURE ABOVE APPROXIMATELY 40 DEGREE AMBIENT:

Occasional extended cranking to start. Rough idle.




If any of the above sounds familiar you can tend towards the lower intake o-rings leaking. As to your recent issue of an idling issue once engine has reached normal operating range; i would respectfully suggest repair of the original fault condition (o-rings change out) before pursuing and further troubleshooting in this area. Is it possible for the o-rings cause complete idle failure? Yes. Likely? No.



To ensure your sense of humor remains: I recently stumpled upon a rather interesting diagnosis by a Ford Dealership (read "group of male reproductive genitalia") upon an "x', with 56k onboard and similar symptoms to yours and the above. The above captioned "group" decided the customer may best be "serviced" with a mere $700 being invested with them, for a work scope that included intake manifolds removal (as with o-rings change out), allowing them access to the rear side of the intake valves, of which they were to clean. Apparently, according to their diagnosis, the rear side of the intake valves were "choked" with carbon build up. Said build-up was responsible for soaking-up such voluminous quanties of fuel/air mixture that engine supply deprivation was the route cause of all ills.


Anyway, change your o-rings and check out your IAC isn't sticking (soak the mechanical mechanism in carb cleaner (ensure the cylindrical shaped solenoid is not).
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





Thanks, codipegrum. I checked w/my local dealer, and they're going to change out the ONP OOM12 O-ring kit at Ford's expense.

Not sure that will solve my problem, however. Your scenarios above don't really apply to my situation as the cold cranking will not start the engine at all unless I press the accelerator pedal while cranking. Then will not idle at all.

Sometimes (like today noon, 47degrees) just barely moving the accelerator (5% travel) before cranking will make it start beautifully, and idle perfectly. But to not touch the pedal before cranking cold (as the manual suggests) , will cause it to NOT idle at all.

I'll probably have the dealer clean the IAC when they change out the O-ring kit.

Funny story re: the dealership! Thank God for the internet!

Thanks for the suggestions.

Ron
 






You are welcome ronev.

Certainly worth replacing your o-rings. Your fault condition does not appear to be releated to them, but free is free; rather, I suspect your fault condition (given the AIR politely supplied by the 5% throttle actuation cures idling issues) is related to a "mechanically" sticking AIC valve (voiding its control ability) or leaking gasket beneath same (negating control function of valve).

More remotely, electrical failure (wiring) or electronic failure (yes, the "black box") to control the AIC will cause equal symptoms. Very simple tests by your dealership will prove.

It is remotely possible, the air supply to the AIC valve is blocked, but I need to repeat "remotely".

Lastly, your dealership will more likely wish to replace the AIC valve if found to be the culprit subsequent to troubleshooting. So that you are aware, it retails as approximately $65 and is mounted to the engine with two (2) bolts. Should it be changed may you adjudge associated cost well-versed. :chug:
 






Thanks, again, codipegrum....where is the AIC? Can it be seen in the pics above?

Ron
 






Ron,

As you open the hood and are faced with a rather large black plastic cover (with SOHC 4.0L written even larger on top) you will notice same cover is affixed to the intake manifold with four (4) screws. Remove the screws (and notice the cruise control cable towards the rear of the cover held by a small plastic clip - easily remove cable from clip) and remove the cover. The AIC is beneath this cover. It has a singular electrical connector attached to one end which is cylindrical in shape. It is attached to the intake manifold the other with two (2) screws. Voila.

You can see the cover and the four (4) screws and the cruise control cable plastic clip on the first photo of the engine above.

Colin
 






Well, still haven't heard back from Ford, and my dealer absolutely flat out refused to fix my O-rings either for free or at a reduced cost...their estimated repair bill (includes diagnostic fee for problem that I already diagnosed)

$712.54

You can guess my reaction :mad:

Sooooo, Looks like I'm going to have to badger some of my extreme buddies to help me do this, especially since I have very few tools :(

MikeH, is there any other pertinent information you would suggest? Thanks again for the write up!
 






Spas, That price is Bull. I wouldn't pay more than 4-500 for the job. The parts are only $50 and a good technician can do it in 1 1/2 - 2 hours.

The only thing I didn't stress in my writeup enough is to look over my tool list. Don't skip anything on that list or you will be sorry. Especially the assorted torx heads are important to make the job quick.

Good Luck,
Mikeh
 






Spas -- I agree with Mike. If you can't find some people to help you out, go to an independant shop that has some good referrences. When I had my o-rings replaced before the program was announced it only cost me $130 to have them replaced. The shop charged me for the o-rings and about 2 1/2 hours of labor. If you are certain that your o-rings are leaking, definately consider and independant shop. You shouldn't have to pay them a diagnostics fee to tell you something you already know. Just tell them to replace the o-rings. Be sure and give teh shop the kit part # so that they can get it from Ford or go and buy it yourself. With 2 1/2 hours in labor and parts you shouldn't have to spend more than $200. Even Ford's letter allows the dealer less than 3 hours of labor when the dealer is charging it off to warranty.
 






Thanks guys-yeah, I thought it was bull too, that's why I didn't show up wednesday morning for my appoinment. And to think, this is the BETTER of the two dealerships in my county! :p

No more than $200, huh? I'll check around with a few repair shops, if the estimate is still too high, I guess Das Frem and Muskrat will be watching over my shoulder as I try to do this myself...which is okay, because I'd really like to be able to say I did my own engine work ;)
 






Well, I hit up a few dealers around my town...nobody will do it for less than $250 :( I figure that once I buy the parts kit and pay for tolls and gas to get up to my Uncle's shop on Long Island, I'll have spent roughly $150, plus I get to see my explorer buddies (who I haven't seen in months!), so it's worth it to me. I figure we'll all learn something pretty valuable.

Robert, you mentioned another gasket, under the IAC valve? Is that something I should replace as well? How about the upper intake gaskets?

Mike-in your parts list, you mention #2 as being a copper washer of higher quality from Ford? What exactly do I ask for when I walk into the parts shop?

Thanks guys!
 






The shop that did mine mentioned that my IAC gasket was leaking also so they went ahead and put a new one on. I think the upper intake gasket is included in the ket since Ford specifies that it needs to be replaced when the upper manifold is separated from the lower manifold. Mike could answer if it was in his kit or not.
 






Spas, Ask for a new washer for the new Cam Chain Tensioner that comes in the kit. When the give it to you take the Cam Chain Tensioner out of the kit and put the washer on the tensioner to make sure it is a perfect fit. It should fit snuggly on without overlapping the half-round area at all.

Your kit will contain upper and lower manifold gaskets.

Good Luck,
mikeh
 






Well, I went and got the kit on friday, now I just have to wait a few weeks until I have the time and help to put it in...

Since I already had the camshaft tensioner recall done, I think I'll skip that part of the fix-it, but thank you anyway, Mike! And thanks to Robert for the PDF-much appreciated :)
 






HOLEE MOLEE!

Well, earlier this week the temperatures here in Maryland sunk down to the single digits overnight, much to my dismay...especially when I had to borrow my mother's electric heating blanket just to get my truck started the next morning!

I couldn't take it anymore, so I put off a few bills and pestered my mechanic until he dropped the price to $170. Turns out I needed a PCV pipe too, since mine was ripped. I took a lot of pics to post in addition to MikeH's-thanks to everybody for the help. All I have to say now is:

THANK GOD MY EXPLORER'S BACK TO NORMAL AFTER 3 YEARS OF THIS COLD IDLE CRAP!! :D :D :D :D :D :D :D :D
 






This sounds exactlly like my problem. I bought the Explorer last summer and had no problems at all until this winter. I have had it in to a trusted mechanic several times and he is stumped. Monday morning I will have to break down and call the Ford dealer.
 






Where can I find the AIC Valve on a 98 Ford Explorer SOHC V6? I want to check it to see if its the one causing the idle problem??
 






Replacing the IAC on a SOHC engine is a 5 minute job.

Longest part is taking off the black plastic Ford SOHC cover on top of the engine ;)

About a foot from the firewall smack dap on top of the engine you will see a silver tube like thing 4 inchs or so with a two wire connector and two bolts into the throttle body.

disconnect wire, unbolt bolts, but new IAC on, bolt and reconnect wire. Put the black plastic cover back on. All done.

Chris
 






I called the Ford dealer where I bought the Explorer and described the symptoms and a summary of what I have learned on the forum........... Of course he couldn't agree with me. He still thinks idle air control valve, even though I have already replaced it. Guess I will have to take it in and pay to have it checked out (again). I would hate to do the work if it doesn't need done. Or am I just wasting my money. I will find out and post again.
 






Just replaced the manifold gaskets...truck starts up beautifully now...

Thanks MikeH for a great write up, came in handy...

BK
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





X'ers,

i too have had this same problem for most of my trucks life (i have owned it since day one). My question is this...will any permanent/major damage occur if the problem is not fixed? in my case, the "pinging" only occurs for 10-30 seconds while at idle. once i drive it for a couple of minutes it goes away...until i have to start it again. however, last winter i experienced, for the first time, the problem of the engine dieing (while at idle)after a cold night outside. any thought would be appreciated. while annoying, it is not something that really bothers me...but if it is bothering my X, then i feel i need to pull the trigger sooner than later.


cheers,
nate
 






Back
Top