BBK TB Installed - Will not idle w/o IAC

[BuffaloXplorer]

Well, i installed the BBK last week but i cannot get it to idle without the IAC as described in the distructions. It's adjusted and idling at 775 when warm, but when disco'ing the IAC, it stalls out immediately. I wouldn't think that it;s a problem, but what could cause this. Messing with the stop screw any further isn't an option, b/c it idles fine when the IAC is hooked up -

Ideas?

 

[dreamr]

Mine idles around 850 and is barely running if I take the IAC off. you have to feather the throttle to keep it going. My advice would be to get the idle where you want it and call it good. This could potentially be telling you that you have a vacuum leak elsewhere as well, so rule this out first.

The most common error I saw with TB installs back in my mustang days was either forgetting to connect the vacuum hose underneath, or not tightening the lower bolts well enough as thwey were near impossible to get to on a Stang 5 liter, and slightly difficult on an Explorer.

 

[BuffaloXplorer]

The bolts are torqued enough, and they were no problem to get to.

I wouldn't doubt that i've got a leak somewhere - Getting less than 10 mpg takes more than just one problem!

At this point, i seriously need to have factory diagnostics done on the X, b/c i've tried all of the "at home" remedies to no avail. I can't seem to figure out why i suck down so much gas - my driving style hasn't changed (albeit never light-footed) and i've watched it go from 13mpg in '01 to <10 today (almost 8 last week).

I'd sell my soul for 13!

 

[shaman]

The bolts are torqued enough, and they were no problem to get to.

I wouldn't doubt that i've got a leak somewhere - Getting less than 10 mpg takes more than just one problem!

At this point, i seriously need to have factory diagnostics done on the X, b/c i've tried all of the "at home" remedies to no avail. I can't seem to figure out why i suck down so much gas - my driving style hasn't changed (albeit never light-footed) and i've watched it go from 13mpg in '01 to <10 today (almost 8 last week).

I'd sell my soul for 13!

What all maintenence have you done?

If your gas supplier recently switched to higher alcohol in their gasoline you might look at your fuel filter, even if they didn't, if you haven't it would be a good place to start.

 

[BuffaloXplorer]

I generally get 10-11, my last 2 fill-ups i got 9 & 8 respectively. Given the "winter-blend" fuel, i'm probably around 10 still, but no matter what i do (see below) i can't get more.

I've done all 3 O2 sensors, plugs & wires (twice since 11/01), fuel filter (x2), new fuel pump, dpfe x2, egr & evr, tested FP regulator (OK) & injectors (fpr holds pressure), replaced t-stat, routine oil changes; Mods include BBK & KKM, Flowmaster D-50 2.25" catback; I'm sure there's more but suggestions are welcomed!

I may be carrying more weight, as i have the conversion fiberglass roof, tv, vcr, ground effects package, but i can't believe it weighs THAT much more than a stocker.

 

[have2goski]

how do you calculate your mileage?

 

[BuffaloXplorer]

Fill Tank - Reset Trip - Drive - Fill Tank - Divide driven mileage by gallons filled and there you go - Generally, i'll wait for 3 fillups to get a subjective mpg, some weeks i'm mostly highway, others primarily stop-n-go city driving - but all in all it sucks the same!

 

[Rhett]

re: your idle

I don't want you to spend $$ on a tech to tell you nothings wrong with your truck. Only when you exhaust all avenues should you go to a tech. Your truck idling at 775 when warm is a little bit on the high side. You should be idling at 650-700 when warm. Is your TPS operating in spec?
And why is further adjustment of the throttle set screw, "not an option"?

Re: your mileage

My thoughts on your mpg/truck combo:
You do carry more weight; and you also carry more frontal surface area. Together with winter gas and the OHV engine, it doesn't surprise me that you are getting 10 mpg in town (I hope that's in town mileage). Even with all the mods I've done, my truck occasionally drops to 12-12.5 mpg in town driving in the winter. And that's a 2-door (Sport) model, which is about 200 lbs lighter than a 1st gen 4-door; and about 350 lbs lighter than a 2nd gen 4-door as you have. (and your conversion pkg? I'm probably 400+ lbs lighter, and you have the same engine...) You being in Buffalo, NY, means you'll have quite a lot more cold than I do here in the southern tip of Missouri. So I don't think it's too unusual to see your truck in the 10's range. 8-9? Yes, I agree with you, that's a little low. But then again, I don't know exactly how much extra weight and surface area you've got with your Conversion package. Might be enough to put you down there at 9 mpg in the winter.

 

[BuffaloXplorer]

Unfortunately, it's not JUST winter, but estimating a 2mpg loss due to the winter blend, that'd put me right in the 11mpg range. I remember a time where i got 13 (and 15 highway! - ONCE) - geez, those were the days!

Regarding the idle issue, i guess with the IAC connected i could adjust the set screw to lower the idle another 100rpms - but i figured there was a purpose in getting the X to idle at 500 with IAC disco'ed, and that by bypassing this process, i thought i may be doing more harm (not really harm, but you know...) by ramdomly adjusting things. Again, i haven't had the time to clean the IAC (i will tonight, though), so that may be at fault.

HEY, do you think i could pull another .5mpg with a lower idle (i know, i'm reaching).

 

[wpurple]

Those mileage figures seem rather low considering I am getting 14mpg on my 5L supercharged mounty on winter gas and the cold here in CT.(although I do plug my truck in at work......)

 

[jimbo74]

my dad has a stock ranger, and if you disconnect the iac, it dies or almost cant idle at liek 300 rpm or so it sounds...

 

[IAmTodd]

As far as mileage goes, You also have to consider that cold air is more dense. More dense air requires more fuel to burn properly. So you're 2mpg difference may actually be more. I would get 13mpg with my Sport with the OHV in the winter, 12 or less with the ski rack on, 16-17 in normal weather, and 20 on the highway.

 

[Heavymentill]

When I reset my idle I had the same problem with it dying. I just adjusted the stop screw till I got it to 700 rpms. Have had no problems. You probably already know what to do but heres a link on what to do. Idle re-learn