Cleaned Throttle Body but still have sartup idle issues | Ford Explorer Forums - Serious Explorations

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Cleaned Throttle Body but still have sartup idle issues

explorermaninok

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Year, Model & Trim Level
2000 XLT V6 245 SOHC
Hello all. I am new to the site and I hope someone can help. I own a 2000 Explorer XLT V6 245 SOHC 4dr with 88,800 miles on it. I recently purchased this vehicle and love it so far but... When I start the car it turns over and idles up fine but when it idles down it stalls out shutting down the engine. I have to press the peddle and give it some gas and the rpms even out creating a nice smooth idle. The car drives fine at stop lights and at other times (not stalling). I took it to my local shop and they checked it for codes but found none, so they cleaned my throttle body plate and replaced the fuel filter and added some fuel additive. I started it up outside the shop $200 later and it stalled out twice. I did mention that to them but they said to let the injector cleaner they put in work its way through for a day or two.I have read that there are problems with IAC valves or MAF. Well two days later I still have the same issues. It does not seem to weather related. Not sure which thread this would be under but I hope someone can help before I buy a $150 Motorcraft IAC valve from Ford and replace it myself (running low on money...). The car has been maintained well and the previous records do not state an IAC replacement or any other engine control piece replaced. Seems like a lot of the IAC problems the cars stall out all the time. Mine only happens upon startup. I tested the IAC connector and got no reading. The IAC connector itself gave a good reding at 9 volts. When I tested the IAC conector against the IAC housing I got no reading. Thanks in advance!!
 



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The usual parts stores like auto zone, checker, advance auto sell idle air control valves for about 50.00 bucks, i have been running one for over a year with no problems, might want to try them before the dealership if you decide to replace the valve
 






have a shop check the fuel pressure regulator more than likely that's your problem.
a bad iac would make the car idle like crap, but if it shuts down right after starting it its likely the fuel pressure regulator.
 






So this (fuel pressure regulator) might be a cause even though I have no check engine light at all? So far no lights come on. If it was the IAC would it always idle rough or stall during use at all times (not just starting up)? This would be the third time to take it to the same shop, so I want to have my questions and list of things to check ready. I did not mention that it stalls out after start up about 90% of the time. Of course when I take it in it starts right up for them! It's not until I leave with it does it stall out on startup making me look kinda foolish. You guys rock on this site! Anymore suggestions?? I could probobly handle the IAC replacement, but the fuel pressure regulator sounds more in depth than I could do myself. Is it expensive for a shop to check? I know it's a lot of questions but the low cash flow puts a damper on just doing whatever the shop says you know.:D
 






I just read that Ford makes you buy the whole fuel pump assembly. Is this ture or can you just buy the regulator? Where?
 












Check the engine coolant temp sensor, make sure it's within spec at various engine temps. Are the intake gaskets prone to leaking on your 2000 SOHC engine? If so, that would def. be the next item to check as it's common and points to cold start up issues.
 






When my IAC went bad, I didnt not get a code. Same for the MAF.
 






I am not sure if it is prone to leaks, I have only owned it three weeks now. This problem became constant after about 4 days of ownership. I disconnected the IAC and started it up and it idled at about 100rpm, but did not die on me. I turned the truck off and reconnected it and the problem was the same but the check engine light came on. I took it to autozone and it was a code p1504 (open or shorted circuit, failed IAC valve). I took back to the same shop and now I am waiting to see if they can fix it (considering i told them I thought it was the IAC to begin with last time). i will post back later today. Thanks to all who posted on this! If it isn't the IAC I will follow uo with the other suggestions.
 






you need to clear codes after running with iac disconected. disconect your battery for about 10 minutes, reconect and runit for a 20 minutes to reset all your peramaters then see if you have any codes.
 






I would also go through Dale's list. (2000StreetRod) that's a good list to run through...
 






Before you do any of those things, you need to have the lower intake manifold gaskets changed (unless they've been done already). It's an oh-so-common problem with these motors that gets quite popular this time of year (i.e. when it's cooler outside).
 






Well the IAC has been changed out for a new one by the shop (just got it back tonight). The engine starts at about 1800 rpms and then goes down to about 100 for a split second and then up to about a constant 700 rpms when idling. The difference with the new IAC is that te truck does not stall out now. Is the split second throttle down to 100 rpms normal? I'll have to look into the new suggestions. I am glad the truck isn't dying but the startup still does not fel right with the rpms dunking that low (even for a split second)...
When I am in drive at a red light the rpms are at 500 always (in nuetral at about 750) is this ok??
 






I seem to hear a hissing or compressed air sound when I use the accelerator. I think its just the fan belts need to have some wd40 treatment to them, but may be a vaccum leak. Is that a similar sound to a vaccum leak?? Does relate to the gasket just mentioned above? It's like -10 windshield factor here right and I have no garage so looking for leaks is hard to do right now. The shop said to drive it for a while and see if the problem was fixed with the new IAC. The truck isn't dying yes, but does anybody think I am just being too picky? All I have ever owned is small cars, this is my first suv.
 






get a can of ether, spray a little at suspected vacum leeks. if theres a leak your engine well speed up as the ether is sucked in
 






IAC valve is "saving" the idle

Your basic engine idle is so low that the IAC valve has to "save" the engine from dying. When the engine coldstarts the PCM significantly enriches the A/F ratio. As I recall when the ECT reaches about 130 degrees the PCM rapidly decreases the richness considerably with a corresponding drop in idle speed. That's probably when you're seeing the drop to 100 rpm. The response of the IAC valve is too slow to keep the engine speed at a steady value. Performing the idle adjustment procedure will prevent the drastic drop but first you should make sure that you don't have a TPS or fuel pressure issue.
 






Well the IAC has been changed out for a new one by the shop (just got it back tonight). The engine starts at about 1800 rpms and then goes down to about 100 for a split second and then up to about a constant 700 rpms when idling. The difference with the new IAC is that te truck does not stall out now. Is the split second throttle down to 100 rpms normal? I'll have to look into the new suggestions. I am glad the truck isn't dying but the startup still does not fel right with the rpms dunking that low (even for a split second)...
When I am in drive at a red light the rpms are at 500 always (in nuetral at about 750) is this ok??

Hello? Hello? Is this thing on??

Lower intake manifold gaskets. Classic symptoms of a vacuum leak (low idle, stalling, surging when cold) and on that engine in cold climates, unless they have been changed recently, those gaskets are the prime suspect. $30 in gaskets and a couple hours on a weekend and all will be well again.

Performing the idle adjustment procedure will prevent the drastic drop but first you should make sure that you don't have a TPS or fuel pressure issue.

The engine idle speed is established by the PCM, not by adjusting the idle screw. Tinkering with the stop screw on the throttle body is a band-aid. It doesn't fix the underlying problem (which is, in all likelihood, a vacuum leak).
 






Definitely have a listen to gijoecam's advice. He doesn't give advice too often but when he does, you can be certain he is speaking from experience that comes with years of hand's-on.
 






I have almost the same problem with my 98 XLT 170,000m, IAC replaced, plugs & wires. I had a shop do a smoke test for leaks and computer analysis, checked fuel pump, filter and checked the idle adjustment. It still hesitates or stalls do to a rough 'low surge' idle.
Everything else runs fine when out on the road even in bumper-to-bumper traffic. However after start-up, hot or cold it can stall without warning!
The reason why I say 'almost the same' is that unlike explorermaninok is that mine did not start doing this until I shipped it to Panama, Central America. As the temp. here has been between 85 & 90 degrees, I don't think it is the gaskets that are prevalent in cold weather!
I'm going to start a new thread on this because although my symptoms are close, my situation and results aren't adding up. There are other factors involved that may be affecting this, like altitude, but so far I'm thinking it may be the MAF sensor. ??
Or maybe I’ve hit the ‘changed too much’ and found a faulty part in the batch?

Phil from Canada now my Ex is in Panama
 



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Well I replaced IAC valve and the car seems to run well enough for now. It has not dies in the last few weeks but a few times dips below 500rpms on startup. Thanks to all who helped out and sorry for the delayed update. Later this year I will look for either a vaccum leak or the TPS. But for now the IAC seemed to do the trick for the most part.
 






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