Idle issues at startup

[SirAltitude]

I've got an 1994 bronco, 5.0L, EFI,

I've been having some issues w/ the idle at start-up.

It tends to idle high, and drop quickly, and stall. Starts right back up, idles high, and stalls out again. Usually, after a couple minutes of start and stop, it will maintain regular idle rpm's and run fine.

I can usually feed her fuel prior to stalling out and that will keep'er running. But it's cold outside, and I dont like to sit there feeding her for ten minutes to keep it running.

So... Any ideas?

I have recently replaced the tank sending unit and filter (that ******* dropping tank, etc etc...).

This issue was prior to those replacements, and has not changed since. Seems to be more of an issue in the cold seasons than warmer climates.

Would a temperature censor do this? Perhaps a thermostat control module or some such? Some one told me something of the like, but, I dont listen to just any body when it comes to spending money and "fixing" things.

I dont think it's a vacuum issue on one of the lines. I could be wrong....

I appreciate any input and perhaps a resolve to this issue.

Chris "SirAltitude" K.

 

[bigtrux]

First I would check for codes have you checked the fuel presssure it could be a bad fuel pressure reg or most likely the pump itself but that"s just my 2 cents if it stays running while your feeding it fuel, Have you been able to get it started or did it ever act up when you were drving it specially when you took your foot off the pedal. My pump went out a few months ago thats why i ask i never had a problem while driving but it's an indication mine was simliar to yours but once it got started it was fine... good luck

 

[SirAltitude]

No codes, nothing pops up, no idiot lights. I've got a buddy that has a reader and nothing appears.

Fuel lines are good, pressure is where it needs to be. Pump is fine. Like i said, this was an issue prior to me replacing the fuel pump six months ago. And then, the pump just died on me, no occurances prior to the pump stall. It just quit. So I replaced that, and the fuel filter.

It runs fine, once i get it warmed up and going it does fine, just the initial startup.

 

[SirAltitude]

Just to clarify.

It's idles high on startup. Once the choke kicks out and normal idle speeds induce, it wants to stall.

I say it idles high, but, a V8 sounds loud and running fast at 1800rpm, so, it may not actually be idling high.

May just seem and sound that way to me.

Once it runs a minute or so, the choke does it's thing and supposed to idle down to slow rpm's, that's when it dies.

I start it back up, it idles "high" then kicks back down and stalls. This will happen a hand full of times before it levels out and runs fine.

I can keep my foot on the pedal, to regulate rpm's and keep it running, gently let off the pedal, and it will continue to run.

Operating rpm's are in normal range for normal operations. Nothing out of the ordinary when runnin' the streets' or mountains.

But everytime i start it from dormat, it idles up, choke kicks out once it warms up, idles' down, and stalls.

 

[bobstrat]

my first guess might be your IAC.

 

[SirAltitude]

Okie dokie.

I removed the electrical connection to the IAC. Started the motor, and it didnt rise above 4-600 rpm's. I actually had to feed 'er fuel to keep 'er runnin'. It's cold, very cold outside and feel that's why it wouldnt run.

I then replaced the connection and it jumped to 1800-2k upon restarting the motor. I let it run for a moment, gave it some fuel to 25-3k rpm's, the choke kicked off, and it dropped to 4-600 rpm and died.

What does that tell us... bad IAC? dirty IAC? or something else?

FYI: It's also getting the correct voltage from the computer..

 

[shift1313]

you keep using the word choke, there isnt one (i wouldnt think) the IAC is an idle air control. it has a sensor on the end of it and a "motor" that allows more/less air through a passage in the TB. you could have a sticky or slow reacting iac. the sensor on the end of it could think its in one position when its really not. if the eec thinks the engine or air is at one temp and its not this could be causing your issue as well. Its not uncommon for the TB gasket to get sucked in as well. It may look fine from the outside but between the two butterflys it could be either blocking the air passage or something else. I think the gasket is $5 and its worth pulling the TB to check. Also your egr works at idle. pull the vac line off the egr and plug it then start the truck(with the iac plugged in) and see if you get the same thing. the eec could be telling the egr to open up and its causing your idle to drop.

so first id, pull vac line from egr/plug it, start the truck.

buy new tb gasket, pull and replace make sure its fine

next replace iac($50 or so)

 

[SirAltitude]

ty ty for the quick response.

As much as I hate to, I'm going back outside to check the egr/vacuum line and do as you suggested.

Did I mention it's really cold here in Greeneville Tennessee??

But, I need my truck more than I need my fingers, ears and nose... /emoticons/[email protected] 2x" width="20" height="20" />

And I know it's not a choke, but it's doing pretty much the same thing as far as action goes, and it's easier to describe to some people than others that way...

Did I mention I'm in tennessee???

 

[shift1313]

im not too far away from you here in southern va it was 18 this morning and that was cold. 35 yesterday and i rode my motorcycle to work

I know the egr was "sticky" on my truck and was always giving me issues, ive had it unhooked and the line capped for about 3 years now /emoticons/[email protected] 2x" width="20" height="20" />

 

[SirAltitude]

I think the egr is doing what it's supposed to do. And the IAC.. so...

Maybe a temperature sensor somewhere? I'm not really sure to be honest. Air temperature sensor, or something? Coolant temperature sensor?

I tell ya, I really miss the old days when cars and trucks were easy to work on..

All these sensors, modules and modulating sensor sensors are worthless... One messes up, it's just a chain reaction and troubleshooting all of'em, cause, they all control each other.

I think i'm gonna buy a moped and snow tires.

 

[bobstrat]

so did it run any different with the iac plugged in and the egr plugged off?

 

[SirAltitude]

Yea, it ran funny.

When I took the EGR off and plugged it, it idled high, around 2k and better. I would give it some fuel and it would "choke", kind of a stutter when I give it a "shot" of fuel.

So I replaced everything where it should be...

I did however find a hose that connects to the intake that was dry rot, heated and crusty. I replaced that section along w/ the connecting section. I didnt see it on the first several inspections. Kinda hidden under the EGR location.

Not sure if it really did any difference because the motor was allready warm and had been driven for a little while by the time I got to O'Reillys.

Once she's started and running, she's fine. Just this crap when I start'er up /emoticons/[email protected] 2x" width="20" height="20" />

 

[SirAltitude]

Well, it's only been sitting there an hour. I rekcon it's not cold enough for it do " do it's thing"

I'll let it sit there a little while yet and go out.

I turned it over just a smidge, she started right up, and idled @ 400 like she should.

So, either the hose was what I needed, or, she's not cold enough to do her thing.

I'm thinking the latter.

But, I got my fingers crossed that the hose was all it needed.

My g/f says we've been home longer'n hour. Says we got home shortly after four. I dunno, I got my fingers crossed...

I appreciate ya'll help non the less. Nice to know people out here who care /emoticons/[email protected] 2x" width="20" height="20" />

But, I'm also sure, if I was discussing my g/f toyota, I'd been banned along time ago!

GO FORD!!!

 

[bobstrat]

hope it works out for you. here's a pretty good reference site that gives a pretty good overview of what all the sensors do.

ford fuel injection

 

[stangyog]

Hi all, I'm new to this forum. That's funny , I have the same exact problem when I started my Bronco yesterday afternoon to go to work. Please post what you find out is the problem. It is cold out here in central PA as well, I am thinking it is the AIC as well. Good luck...

Brad

 

[Yardape]

Well, it's only been sitting there an hour. I rekcon it's not cold enough for it do " do it's thing"
I'll let it sit there a little while yet and go out.

I turned it over just a smidge, she started right up, and idled @ 400 like she should.

So, either the hose was what I needed, or, she's not cold enough to do her thing.

I'm thinking the latter.

But, I got my fingers crossed that the hose was all it needed.

My g/f says we've been home longer'n hour. Says we got home shortly after four. I dunno, I got my fingers crossed...

I appreciate ya'll help non the less. Nice to know people out here who care /emoticons/[email protected] 2x" width="20" height="20" />

But, I'm also sure, if I was discussing my g/f toyota, I'd been banned along time ago!

GO FORD!!!

Firstly, no you wouldnt get banned for discussing toyota problems, or any other for that matter. We are all here to help each other the best we can. But being its a BRONCO site you will get the best Bronco advise we can give you. I dont own toyota so I really wouldnt have alot of toyota advise for ya, I wouls reccommend you try and get it on a toyota site, but we could use logic and try and help you that way. And for your problem, how are you so certain you do not have a vaccum leak/issue? Can you elaborate on what you have done to come to this conclusion? Sure sounds like a vaccum problem to me, Couple others that come to mind are the IAC (which has been mentioned) or the TPS. That Throttle body gasket idea was not too bad, if air was getting past that gasket it would cause irradic idle. You kinda confused me a bit, you said it is only at startup? or is it everytime it is idling? If its only at idle another thing that comes to mind is, my bronco had a throttle body preheater, I assume thats what it was anyway. I am unsure if yours has one but if it does might be worth a mention to check that out too. I hear you on the cold, its in the -30's here and it sux royally haha. Anyway goodluck, hope we can help.

Oh ya, I didnt know it got cold in Tennesse....

 

[SirAltitude]

This issue only happens at startup.

Idle up to 1800, warms up for a minute or two depending on the chill factor, drops to 4-600 rpm and stalls.

It will try to correct itself prior it actually dieing, and idle up, then back down, but it ultimatly dies.

Once she's running for a few minutes, she's fine. I gotta start it usually three or four times before she'll idle on her own at normal range.

As far as the vacuume lines, there's only a couple fittings and lines that I have'nt actualy replaced at this point. I'm running out of vacuum lines and patience!!

Local parts fella talking about a "thermostatic" or coolant temperature sensor. And another sensor located on the manifold driver side. I cant remember what he mentioned now.

Thanks for the link for the sensor overview. I think that will help me alot. Not only for this, but for future references aswell.

http://www.fordfuelinjection.com/

 

[bigtrux]

So how did you find the problem how's it been acting just would like to know for future recerance cuz you never know? And for your sake that all it was was a cheap repair.... I never have that kinda luck with mine it's always expensive .....

 

[SirAltitude]

haha, it aint fixed yet!! it's still doing it's "start-up" routine.

And, it "just" started, there was'nt anything that revealed this issue other than,

one cold morning it started doing it as far as I can recall.

So I dunno what to tell ya....