loping idle

[emo666]

OK--went into tech library --printed out work sheet for TFI. everything looked good --BUT-- the spout reading from the harness--cranking is high at 10.6 volts --go to the coil and it does flicker. Did not go into the computer to pin 56 as I'm totally lost when I opened the kick panel. Is there a tech write up on how that is done?? Also when I check the negative coil side for flicker it's a bright quick flicker not faint. Am I still looking at the TFI ?? I just bought one but don't want to ruin it. I am going to replace the coil tomorrow. This thing ran great before I pulled and rebuilt the engine.
Also what fuel pressure should I have at idle. I'm getting 36lbs with vacuum pulled but with vac on it goes down as rpm's go up--is that the way it works??
What sensors regulate the idle?? the ICA idles it up when cold but after it warms it lopes bad enough to stall.
Been all thru these forums but can't locate the answers I need.

 

[RonD]

What year and engine do you have????

Average fuel pressure pre-'98 is 35psi, yes it will go down to 28psi when REVed

Crank position(CKP) sensor tells the computer the RPMs
IAC(idle air control) valve is used by the computer to set RPM when throttle is closed, IAC valve is a controlled vacuum leak.

Loping idle could be dirty/bad PCV valve
Could be dirty IAC valve
Could be vacuum leak
Could be MAP sensor if you year had one.
Could be leaking EGR Valve, if your year had one.

 

[Road Angels]

Dont know what year or model but if its got an EGR valve after the truck warms up pull the vacuum line to it and plug it, if the looping stops its in the egr system, maybe the control unit for it, really need to know what you got but this only takes a minute to do

 

[emo666]

OK--went into tech library --printed out work sheet for TFI. everything looked good --BUT-- the spout reading from the harness--cranking is high at 10.6 volts --go to the coil and it does flicker. Did not go into the computer to pin 56 as I'm totally lost when I opened the kick panel. Is there a tech write up on how that is done?? Also when I check the negative coil side for flicker it's a bright quick flicker not faint. Am I still looking at the TFI ?? I just bought one but don't want to ruin it. I am going to replace the coil tomorrow. This thing ran great before I pulled and rebuilt the engine.
Also what fuel pressure should I have at idle. I'm getting 36lbs with vacuum pulled but with vac on it goes down as rpm's go up--is that the way it works??
What sensors regulate the idle?? the ICA idles it up when cold but after it warms it lopes bad enough to stall.
Been all thru these forums but can't locate the answers I need.

It's a 1989 bronco 2.9-- no EGR---If I pull the spout it idles decent--not good but does not stall or lope. What is the temp sensor nearest the thermostat with wires from harness called??? I used Teflon tape on it and get 0 on my ohmmeter from manifold to brass collar. Is there another way to tell if is properly grounded??
The reason I'm changing the coil is while testing- (removing and replacing the plug)--and with the distributor feed wire removed it would jump spark from nozzle to body when key was turned off. That's with the TFI wires and spout plugged in.

 

[RonD]

Any device with a 1 wire connector needs it's threads to have a good ground.
The temp sender for the dash board gauge is one.
Oil Pressure sender/switch is another.

So it you want to use 'tape' leave the bottom few threads bare