Very high idle and gas smell

[Tazman]

Just did a rebuild on my TBI,hooked everything back up thought all was well.Went to check the TPS before starting cannot get a reading.When I do start it the idle is so high I have to shut it down.Any idea on why I cannot get a reading?

Thanks

[Engineer]

Start by checking to see if you have any vacuum leaks. The TBI engines that use a map sensor (that would be all of them) instead of a mass airflow sensor can be fooled into adjusting the lean condition of a vacuum leak by pouring in more fuel.

Also, make sure the 4 wire connector to the IAC motor (passenger side front of the throttle body) isn't unplugged.

[VileZambonie]

Make sure you put the correct base gasket on too.

[Irish_Alley]

The tbi uses those hard plastic lines can break or crack real easy. Even changing the pcv can crack or break a line

[454Man]

If you can't get any ohm reading from the tps at different throttle positions its bad.

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[Tazman]

Rebuilt my TBI yesterday ,got the idle fixed but now after driving there is a smell of gas.I checked both lines and all is well.Is there a chance extra gas is getting through after the engine is shut off?
Thanks,

[Boone83K10]

Probably either seeping.out while running and evaporating or is the vapor line unhooked some where

 

[454Man]

So what was the problem?

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[DuckAholic1]

Wish I had some words of wisdom on this subject, but I don't!
Although, I happen to be in the middle of my first TBI rebuild on my 87.
Sure am interested in how you solve your problem so as to learn from it. Good Luck to ya!!

[Tazman]

As for the high idle that was easy once I back tracked and found the TPS lever was on the wrong side of the idle tab.
Found the gas was leaking from the inlet line,just gave it some more tightening.I am always afraid of putting nuts to tight a strip them,just have to be careful.
Duck as for your first TBI rebuild it was my first also,went better than I thought.Believe me it has made a difference,my truck has not idled this smoothly in some time.This site has a lot of help,just look around or ask.You will not go wrong.
Thanks,

[bd]

...Found the gas was leaking from the inlet line, just gave it some more tightening....

Tazman, did you install new nylon gaskets on the steel line adapters and new Viton o-rings on the lines?

[Tazman]

There were no o rings on the lines when disassembled,so I did not replace any.

[bd]

The fuel line connection to the TBI is tube and o-ring.  There should be one Viton o-ring sealing against the shoulder of each fuel line, where each threads into the steel adapters at the back of the TBI body.  The o-rings are similar to the o-rings sealing the fuel filter.  There are two sizes; I believe the o-ring kit is Napa P/N - CRB 218416 for 1/4" & 3/8" lines.

There should also be thin nylon gaskets that seal the steel fuel line adapters into the TBI body.

If any of these seals are missing, you risk serious fuel leaks and fire!

[Tazman]

Do these o rings go over the nuts?If so how can they be two different sizes,are the lines not the same?

[bd]

The fuel supply line is ~3/8" and the return line to the tank is ~1/4" in diameter.  Each line has a raised concentric shoulder located about 3/8" from its end; the fuel line retaining nut seats behind the shoulder clamping the line into the adapter fittings; each o-ring is captive between the shoulder and its steel line adapter in the throttle body.  See the images, below:  The steel adapter fittings thread into the back of the TBI housing and seal using thin gaskets (pictured in the upper image) - the larger fitting is fuel inlet, the smaller fitting is fuel return.  The lower image is the fuel line and o-ring in cross-section; the 'red' o-ring rests against the shoulder of the tube.  Though not pictured, the line retaining nut would be to the left of (behind) the shoulder.