Recently my 94 bronco has started acting very strange. At a full stop with it gear the tach starts fluctuating from 500 to around 1100 at the same time the voltage guage is fluctuating along with the idle, both going up and down up and down, all the while the lights are bright dim bright dim. I just forked over $360 to my mechanic and it is still happening Any ideas?
Idle Problems
Started by
Guest_bdcej_*
, Jan 22 2004 04:47 AM
17 replies to this topic
#4
Guest_Sturgell_*
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Posted 03 February 2004 - 06:12 PM
My 91 Mustang does this sometimes. It helps to get some Berrymans B12 Chemtool spray the idle air motor, take off the top throttle body hose just in front of the valve that allows air into the intake there will be a hole about 3/8ths to 7/16ths of an inch in diameter, have someone set in your truck and hold it at about 2000 to 2500 rpm with it running and that top hose off spray the hell out of that hole stick the little straw that comes with B12 up in that hole and spray it, do this for 30-45 seconds and then let it run for a minute until the solenoid on the outside of the hole gets warm again. Kill the truck and clean both the top and bottom throttle bodies. If this doesnt work you might have to get a new idle air motor thing. Also timing has something to do with this because I messed with the timing on my Mustang and it stopped fluctuating I dont know where it was timed at but oh well, can also be a vacuum leak spray B12 on the connections of vacuum lines and if you hear a change in teh way teh vehicle is running then check closer for a vacuum leak. Good luck with this, it can be very annoying when it is idling.
James Sturgell
James Sturgell
#6
Guest_JerkyB2K3_*
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Posted 23 February 2004 - 04:24 PM
Huh..imagine that..i just replaced my gas tank here this past week, and also the fuel filter today. My problem is the same thing. In Park or Neutral, the idle stays around 1000rpms, but as soon as you put it into reverse or any of the drive gears, it bounces around between 500-1100 rpms, and eventually stalls out. Now I don't have a full tank of gas, probably only about 8-10 gallons (the gas gauge doesn't work, tried fixing it when the pump was out, but to no avail) Anyways, i really need some help too, as this problem is just killing me. By the way, its a 1990 FS-B 302 rottenmatic eddie bauer with a big stereo. So, any answers guys? I'm pretty desperate. What about an O2 sensor, is that a possibility? Any help is greatly appreciated, and I'm glad i found this place at the time i did.
#7
Guest_JerkyB2K3_*
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Posted 24 February 2004 - 03:15 PM
Well, another day, another dollar, and still no luck. Replaced another fuel filter just for good measure, took off (what i would assume to be) the idle air motor (just the solenoid, not the actual part (valve?) on the intake, i was afraid of messing up the gasket) and cleaned that with some WD-40 (ran out of carb. cleaner) and it helped some, but it still does it, especially when in gear and driving, seems to be more notable going uphill. letrain, when you say cheap, do you mean 60$ cheap, or am i looking up the wrong part on autozone's website? I need any help i can get, just had an interview today, and they asked if i had reliable transportation, i had to think twice before lying and saying yes, lol. Anyways, like i've said before, any help is very appreciated. Oh yeah, i ran a blinky code thing and the CEL still flashes me a code 11 saying everything is checking out okay. So i'm at wits end with this thing, somebody stop me before i slap my license plate back on my firebird.
#8
Guest_JerkyB2K3_*
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Posted 25 February 2004 - 06:50 AM
Okay, well, here's my situation, again. I changed my gastank, but not my fuel filter. About 30 miles up the road, the bronco started surging. SO, i just gave 'er hell and limped it home, then put the new fuel filter on the next day. After doing so, i get this idling problem. Now, is it possible that the engine was just running so shitty that carbon built up inside the area where that IACV is at and is what is causing my problems? I am going to take that whole assembly off today and clean it up and check it out, but if that doesn't solve my problem, where do i look next? New IACV? Something else? If this isn't the fix, i'm def. switching back to the 'bird. Somebody help, lol.
#9
Guest_letrain_*
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Posted 25 February 2004 - 02:16 PM
I had a problem with starting my truck then walking away and i'd come back and it had died, then sometimes when i put in reverse it'd go low idle and die, it was my "carb" that needed to be cleaned, i have fuel injection so i do'nt know exactly what the mechanic was talking about but it worked and havn't had a problem since!
#10
Guest_JerkyB2K3_*
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Posted 25 February 2004 - 06:28 PM
Well, i took off the IACV and sure enough, it was covered in black carbon deposits. Carb cleaner fixed 'er right up though. So that solved the idle problem. Now it idles too fast, lol. In the vicinity of 1400 or so, but that i can live with, it doesn't bother me any. I'll just not mention it when i sell it :-P
#11
Guest_Raven_*
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Posted 25 February 2004 - 11:01 PM
kind of along the same lines my 94 when it is cold doesn't like to run very well tillit warms up as soon as it warms up it runs fine .. it almost sounds like some one stuck a potato up the exhust and is holding it there till it warms up ?? I al so notice a bunch of carbon blowing out when cold likeit is blocking the exhust and then once it is warmed up no carbon and everything runs great.. replaced the o2 senser and egr valve and egr sensor computer still gives a egr code .. just seeing where I should go from here.. was told possibly the computer but begining to think might be something else .. any ideas would be helpfull ..
#12
Guest_amcabbott_*
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Posted 26 February 2004 - 06:49 PM
its your idle air control valve IACV. 3 fords I have owned had a rolling idle problem. the iacv has a plastic worm gear that gets all carboned up and moves to slow so the computer keeps trying to change the fuel settings giving it that great rolling surging idle. it can be cleaned but usualy it will stick giving a high idle or no idle at all. replace it with a new one there not to much. mine was $35.00 from advance auto parts.any vacume leak can make it even worse.
#14
Guest_Guest_*
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Posted 11 April 2004 - 06:30 PM
had similar problems with 88 f150 and using both suggestions from other
replys was the fix. Cleaning the IACV and cleaning around the butterfly
valve in the throttle body solved most of the problems. Also the throttle
body sensor can cause surging when under light acceleration.
replys was the fix. Cleaning the IACV and cleaning around the butterfly
valve in the throttle body solved most of the problems. Also the throttle
body sensor can cause surging when under light acceleration.
#15
Sorny
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Posted 12 April 2004 - 11:30 AM
Well i know my 89 Bronco did that but only when it wasn't in gear, but I put a bottle of STP injector cleaner (just to see if it would work) and well it did. I don't have any problems with a up and down idleing anymore.
#16
Guest_Capt Buck_*
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Posted 23 April 2004 - 04:52 AM
I m now having a simular problem with rolling idle and engine idling rough. It ran well before I had the injectors serviced, new wires and new plugs installed. IAC was cleaned and EEC was depowered for adaptive relearn. Stiil idles badly and the exhaust has a tottaly different "tone' than before tuneup. Someone had mentioned to go to 8.5 mm plug wires and maybe a MSD TFi coil. The truck runs like a bear at highway speed,but has a stutter at low throttle settings (1500 rpm) under way(i.e.: Moving @ 35 mph with just a touch of throtle to keep rolling). Any ideas?
Thge Bronco is a '93 Eddie Bauer with 351 and E4OD tranny.
Thge Bronco is a '93 Eddie Bauer with 351 and E4OD tranny.
#18
Justshootme84
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Posted 23 April 2004 - 06:40 PM
In some cases, even cleaning the IAC is not as good as replacing it, but I would first check the fuel pressure. It seems like the fp relay switch and the filter give the most problems. I'm just not that current on the MPFI!!!
1984 Bronco XLT, 351W H.O., C-6 AT, Ford 9", SkyJ 6" lift, 35" tires on MT Classic rims, S&W Racecars 10-pt cage kit, custom "shaker" assembly.
1988 Bronco Custom, 302 EFI, C-6 AT, Ford 8.8". parting out
1986 Bronco Custom, 300I-6, NP435
1988 Bronco Custom, 302 EFI, C-6 AT, Ford 8.8". parting out
1986 Bronco Custom, 300I-6, NP435
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