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Topic: doesnt idle cold, hard start, IAC adjustment? (Read 5290 times) previous topic - next topic

doesnt idle cold, hard start, IAC adjustment?

Reply #15 –
ok peeps, so i got it good and warmed up, a nice 10 mile drive, and followed the instructions above.  made a jumper wire, put it into "test mode"  and the plunger did not retract on the IAC.  wheres my next move?

doesnt idle cold, hard start, IAC adjustment?

Reply #16 –
Have you ever seen the ISC plunger move?

Hook up a test light or an buttstuffog  volt meter to see if you are going into test mode.
You should see the light blink or the meter needle sweep as it outputs codes.

If no codes; try jumpering the pigtail wire to ground instead to the six pin test connector.
Does it now output codes? If so, this indicates a blown signal return land pattern in the EEC computer

When you put the ignition switch in run (without starting) can you here the fuel pump start and then shut off after a couple of seconds? normal
Or does it run continuously? not normal

This sounds like a bunch of dumb stuff to do but it tests the condition of your EEC.

By the way; your car doesn't have an IAC (Idle Air Control). That is used on EFI and SEFI engines not on CFI.

doesnt idle cold, hard start, IAC adjustment?

Reply #17 –
Quote from: softtouch;458657
There is no "base idle adjustment" with the 3.8L CFI  Idle Speed Control motor (ISC) system.
Uhhh yeah, having never owned a 3.8(no I won't touch one) I forget these things...

doesnt idle cold, hard start, IAC adjustment?

Reply #18 –
ok, Softtouch, heres what i got to answer your questions.

I cannot say i have ever seen the plunger move in the idle air thingie since i installed it.  the one that was on the car when i got it made a very loud buzzing noise, i was told that that was a pretty sure sign it had failed, and so i took the chance and replaced the part.

I will follow your test procedures with a test light next time i am working on the car, i will let you know the results from both the test wire , and from grounding out the test wire.
The fuel pump does run for 3-4 seconds and shut off, which i have considered a proper priming, but i guess i may be incorrect on this particular model.

your diagrams have been extremely useful for me, please keep them coming.  I'm a professional mechanic, but i only deal in undercar (brakes, suspension, exhaust, alignment, etc) and have never had a lot of hands on experience or training in engine diagnostics.  however, i do understand the basics, and will gladly walk through whatever steps have been placed in front of me. so for that, i thank you.



Also, a new symptom today.  I was driving the car home (approx 10 miles, highway speeds, car was running in town for about 10 minutes prior to that) the car seemed like it was running out of fuel while going 55 mph.  i stomped on the gas and it motored out of it, but it happened a total of three times in the last two miles of highway driving home.  once it was back home, it sat and idled like nothing happened.

doesnt idle cold, hard start, IAC adjustment?

Reply #19 –
Quote from: TurboCoupe50;458663
Uhhh yeah, having never owned a 3.8(no I won't touch one) I forget these things...

Trust me, the 3.8 is far from my favorite engine.  my parents both had a lincoln contiental with them in it (92 and 93) and they both blew the head gaskets at the same time.  fun stuff, doing back to back head gasket jobs.

i keep thinking that if i dont get this thing to run right, i should grab one of my spare 351Windsors and shove it in.  I can tune a carb.

doesnt idle cold, hard start, IAC adjustment?

Reply #20 –
Quote from: bootleggers deluxe;458664
The fuel pump does run for 3-4 seconds and shut off, which i have considered a proper priming, but i guess i may be incorrect on this particular model.
This is correct operation. It indicates the EEC has some life and is not a boat anchor.

doesnt idle cold, hard start, IAC adjustment?

Reply #21 –
I had some issues with the CFI on my '83 with a 5.0.  Majority of the issues turned out to be the in tank pump faltering and when that was replaced it lived a few more years until the external pump started to die.  I gutted all of it and went with a carbed 5.0 and a T-5.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

doesnt idle cold, hard start, IAC adjustment?

Reply #22 –
click on my diy link and scroll down in there as well for specfic 87CFI info.

although your ISC motor isnt showing signs of a pulse,  i think you said you replaced it but........... there is another area that will cause poor running / idle.

in the rear driver side of the cfi there is a gold vac line fitting about 2'' long bent at a 45deg.

long story short,,, in all cases on all 3.8L CFI's in all instances where no one has been there yet,, get a CFI base plate gasket kit.

remove CFI & EGR base plate.
flip over the CFI and chip out all that crusty black buildup thats blocking off the path this vac line area needs to be open.


Also,,
someone mentioned testing fuel presure.....
-connect fuel pres test up to the test port driver top left of CFI.
-you need a long hose on your tester but.. duct tape the tester to your windshield. -drive care and pay attention to the fuel pres levels ""IN BETWEEN"" shifts of your transmissioin. 
-if during high rpm's during shifts the fuel pres gets anywhere close to 20psi,, replace the pump.

*note - your CFI has a manual regulator.  if its never been replaced then there will be a steel freeze plug on top.  drill that out to reveal an allen head adjustment screw.
see diy link below for how many turns CW or CCW = X amount of psi.

on my old cfi car  cured something that these cars were famous for right off the showroom floor.  The shops had many complaints about "hesitation" off the line.
customers complaining that they would push on the gas and for about a 1/2 second or so nothing happened and then the motor finally worked its way into working up the rpms.  this is cured by removal of the CFI,, removing the four PITA phillups screws, removing poping out the injectors.
start a sheet metal screw into the top of the injector then with pliars yank on the screw really hard.  you will extract the tiny screen filter out of the injector.
install injectors without the screens.  test the car on the road and "hesitation Gone!"

doesnt idle cold, hard start, IAC adjustment?

Reply #23 –
i didnt forget about any of this, ive just been busy tryingto get my F350 back on the road so i can devote proer time to get the Tbird running properly!

doesnt idle cold, hard start, IAC adjustment?

Reply #24 –
The ISC motor is controlled by the EEC (Electronic Engine Control). When the ignition is turned off (and during a 5-10 second delayed dropout of the EEC power relay) the ISC plunger should extend to a fast idle setting for the next start-up.

The ISC motor can be bench tested by applying battery voltage directly to the motor. The direction the plunger goes is changed by reversing the polarity of the battery voltage applied to the motor. If you still have the one you removed maybe you can play with it and see what it does.
There are four wires on the ISC. Two are for the motor and two are for the ITS (Idle Tracking Switch).
The connector drawing I added to the diagram is from the Shop Manual. You may want to double check it with your OHM meter to verify it.
The ITS is operated by pushing on the ISC plunger tip.

doesnt idle cold, hard start, IAC adjustment?

Reply #25 –
ok guys, i got the F350 out ofthe shop and got some time to pull the Tbird in this morning.  the findings are.... disheartening.



so i went to tear out the throttle body and see about clearing out the passage that jcassity spoke of.  heres the first issue i see....



I'm pretty sure these wires at the front of the throttle body arent supposed to be bare.

pulled the throttle body off, found this .



yes, thats very wet.

finally, checked that passage that goes from the driver's rear of the throttle body to the PCV Valve.  very clean and free of debris.  then i plucked up the EGR plate and found this.



That entire passage is full of gasoline.


Care to put some input in, peoples?

doesnt idle cold, hard start, IAC adjustment?

Reply #26 –
That's the fuel injector connector with the bare wires in your first pic.
The red wire is battery voltage with the key on.
If either of the tan wires has a bare spot touching ground, that will open the injector and let the gas flow.

But I don't think that explains how the gas is getting into the PCV channel.

The PCV valve has a hose on it that comes from the carbon canister that collects gas fumes from the tank. Pull that hose off and see if it has gas in it.
I think you can pull the plastic piece off the top of the PCV valve that allows extra hoses. Then put the CFI hose on the PCV valve to take the canister out of the picture.
Does the exhaust smoke like it  is running rich?

doesnt idle cold, hard start, IAC adjustment?

Reply #27 –
I finally fixed the idle on my Cat after reading this link, thanks to boomer for the pics and tips.
 

doesnt idle cold, hard start, IAC adjustment?

Reply #28 –
I have been having a lot of issues with this IAC, I currently  can get it to retract but not extend by putting a hot jumper from battery to the yellow/black wire and the white/blue wire, Before replacing the relay under the dash I could not get it to do ANYTHING.
I have checked fuses and replaced relays still nothing but Aggravation.