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Discussion Starter #1
Heres what I got.. 86 5.0.. stock.
Well.. I spent the day putting in a set of rebuild EV1 DRI injectors.. and while I was at it I replaced all the vacuum lines and removed the remaining inoperative smog parts (truck has no cats, isnt a daily driver, and we dont have smog checks).. And then cleaned a 1/4 inch of crud out of the throttle body and upper intake manifold.. I left the TAB and TAD sensors plummed in with the vacuum, I just caped them off on the side that actuates the smog pump valve and diverter valve.
So, once I got it all put back together, gave it a few hours to let the gaskets set up a little bit. I started it up, it Idled and ran smooth for about 5 minutes.. When, as I was trying to locate an exhaust leak that I'd never heard before, I was ever so slightly moving the throttle cable to make the ticking louder, and all hell broke loose.. RPM's revved up, then came crashing down, and now it wont hardly idle. The crappy temp gauge on the dash was just starting to show movement, so I fugure it was close to 120*.

My thoughts on possible causes..
1. Plugs got fouled with crud that got broke loose.
2. After I ran out of B-12 spray cleaner... I may or may not have grabbed a can of Break Clean in my haste.. And I may have used it to clean some of the crud out of the throttle body.. I am wondering if that could have ruined my IAC or TPS sensor..
3.. Vacuum leak.. even though I don't see how that would be possible, I triple checked all the vacuum lines and connections.

I haven't had a chance to check codes, my plan is to pull the plugs tomorrow after work, and try it again.. If I cant get the truck to operating temperature.. Will it still pull codes?
Any thoughts or ideas? :banghead
 

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if you sprayed a bunch of cleaner down the intake, it may have fouled a plug or two


pull the plugs and see how they look


and be careful running brake clean through an intake, some can produce extremely hazardous gasses like phosgene(mustard gas) and take your breath(and life) away
 

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Discussion Starter #3
yeah.. and to clarify.. the intake was OFF of the vehicle when I was spraying it.. I didnt spray anything down the intake when it was on the vehicle. But yes, I totally agree with you, and thanks for the concern and heads up.
I know you arent supposed to use brake cleaner on intakes.. I ran out of cleaner.. and had one little spot left to clean out, and a rag just wasnt getting it.. and I was to lazy to drive to the parts store again.. guess it serves me right..
 

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imdabes
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Second on the never use chlorinated brake cleaner. I'm a chemical weapons major and I'd never use chlorine anywhere it could possibly mix with any other chemical. Pretty much pools and that's it. Mustard or phosgene won't kill you unless you've got weird allergies but it'll hurt like hell.
 

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imdabes
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Phone won't let me edit for some reason but if you got chlorine into the engine its real easy for either of those to co.e out, phosgene is just cl, carbon and oxygen, and sulfur mustard is the same plus sulfur, which is in all gasoline o.o
 

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Discussion Starter #6
Yeah, I'm going to pull the IAC tonight and try and clean it. The intake manifold was clean and dry when I reinstalled it, So I'm pretty confident there wasnt any cleaner left in it. And in the odd case that there was, you'd think it would have had issues running the first 5 minutes and not after 5 minutes. IDK.. I'm guessing it screwed up a valve or something.. I'll post back tonight with what I find.
Thanks for the input.
 

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Actually, IAC doesn't really come into affect until after the engine has ran a bit and warmed up, when the fuel mix changes due to a number of factors, including piston friction, and air temp, so 5 minutes sounds about right. You might be better off just replacing it. If any brake cleaner got in there, it can corrode the seals that allow the IAC to even work.

Try unplugging your IAC and see if it will run at all. If it does run, it won't be running good, but that will tell you that it is the IAC. With the IAC unplugged, the idle air circuit enters a fault mode, allowing the engine to run at a less efficient idle setting. But if the IAC seals are damaged, then the IAC won't send the correct signals to the PCM which will cause the engine to run more lean/rich than it otherwise would, but wouldn't initiate a fault mode.

On the other hand, if the engine doesn't start, then its something else.
 

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Discussion Starter #8
Ok, it starts, I only restarted once it since it started, and it started fine, just wouldnt idle.. but this was about 2 min after it initially messed up. I have started it since I shut it off last night. I pulled the IAC off it doesnt look to bad, but I did notice that when I pulled it apart, the plunger wasnt sprung back to the normal location.. I pushed on it a few times and it finally seated all the way up. I'll probably just replace it. I guess I need to go back over the vacuum lines, or get a vacuum tester and see what its actually pulling.. the more I think about it.. the more I'm wondering if its a vacuum issue.. I replaced all the lines from the intake tree to the TAD and TAB.. other than that, I didnt mess with anything else.. so Who knows..

Does anyone know how to test the EGR valve to see if its working properly? I tried searching, but I guess my search skills are pretty bad.
 

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Discussion Starter #9
Also.. I see multiple IAC valves for the 86 Bronco.. The one on mine has no part number, or any number for that matter.. So I'm a little confused on which one I should be getting.. Any ideas or input?
 

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Discussion Starter #10
She's Fixed... I got to thinking about it.. and went back to double check my vacuum lines and setup.. turns out I had one that was Totally pinched shut, not sure how I missed that.. and the other, apparently in my haste... I hooked all the other vacuum lines up wrong.. OOPS.. so, now its all hooked up right, started it up.. Idled great.. let it get up to operating temp.. all is good. Now I just need to get the front axle back under it and take her for a drive!
Thanks all for the input, got the hamsters in my head movin.
 
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