hey everyone!
I have my 1987 Tbird, 3.8 auto. i bought it from a guy who only put a mile or two of city driving on it a day, and didnt do any maintenance on it, save for maybe an oil change in the last 5 years. I got it home, changed the oil, plugs, wires, cap, rotor, air filter, fuel filter, and PCV valve. i also changed the IAC, because it was making a very loud buzzing noise.
So, heres my issue.
when i go to start the car cold ( like sitting overnight or sitting all day while at work) it takes several times to get it started, usually with me aiding it with the throttle. once i get it running, i need to give it some throttle to keep it running for a few minutes until i finally get it warmed up enough to drive it. once driving, it drives fine, cruises down the highway, and other than the occasional stall out, it drives fine. but not great.
so, does anyone have any suggestions on where to look next? i noticed the the adjustable screw on the IAC bracket was recently cranked a whole bunch, so im sure the last owner screwed with it. is there a procedure to set it properly?
any other suggestions? id love to get this thing running and driving reliably.
If your IAC is electrical (ICS) you will need a 5.5mm 7/32 drill bit.warm the car up switch off and put into test mode. ignition on do not start place the drill bit in the gap and adjust using the adjustment screw till the drill bit just fits without pushing in the contact sensor ignition off take out of test mode and fire up.i would also recommend pulling codes.
how do i put it into "test mode?"
i did pull codes, none available, and i also tested fuel pressure.
When you pulled codes that is what I meant by test mode you can switch the ignition off once the ICS has retracted.i would run a compression test and check for play in your timing chain if you have no joy.
Any codes?
This. Codes tell you whats wrong.
No codes were stored, but i also saw no way to get into "test" mode. however, using the info you suggested, i was able to adjust the IAC to a somewhat closer vicinity to the correct position. Car now seems to fire up easier, it idles cold, and seems to run smooth through the powerband.
i will see what cold start up is like tomorrow morning before work.
I use a papet clip to get "test mode".
No codes mean the computer has no power.
sounds like i need to check fuses, i know in newer cars, there is a fuse that powers the OBD port. however, since using a scanner on these involves an external power source, i would think that it wouldnt be the same issue.
The car still has a cold start issue, its a bit grumpy and takes a few tries in the morning, but after it is warmed up for a good 2-3 minutes, it seems fine. idle has improved, drivability has improved. im thinking there is a bit more adjustment needed, but it is still a very good improvement.
is it bad that i sit there, look at it and ponder "cant i just tear it all off, put on a regular intake and a motorcraft 2 barrel?" It would solve so many issues for me, it seems.
Ive never owned a carbed car, and they scare the hell out of me to be honest.
The code reader just beeps unless you have a fancy expensive one. Everything you can do with a code reader you can do with a paperclip and a test light or volt meter.
Id ditch the code reader personally.
Google eec-iv codes. This will tell you how to pull codes without the code reader also check out diy stuff on this site.
Maybe this will help:
There is no power in a OBD-I test port, scanner has to be self powered or have a battery connection... Some computers just won't communicate with the scanner, had that problem with my '93 lightning and the pocket sized scanner I used on my Bird... Using a OTC it was fine... You can call me lazy but chance I'd ever go back to counting blinks are zero & none...
With a idle issue you need to be sure the base idle is up to spec... That's the idle speed without the ISC assisting...
Softtouch, that was extremely helpful, thank you. I will be doing that tomorrow morning.
Tubrocoupe50, i would like to think my Blue point scan tool that is capable of doing both OBD1 and OBD2 would be capable enough to accomplish such things, however, i shouldnt always put my faith on whatever comes off that big white truck with red letters.
You mentioned bumping the base idle up, where is the adjusting screw for that? i looked and got stumped. I think the idle seems a bit low, i would love to bump it up a bit.
Ive been driving the car about 150 miles over the weekend, it has been a bit easier to start ( 2-3 attempts, instead of 15-20) but i still need to assist with a foot pump to get it going, and i need to hold a high idle manually with the gas pedal for a few minutes to get it properly warmed up before taking off. other than that, it seems to run flawlessly, it cruses nicely. I'd just like to get the hard start and idle issues sorted out.
There is no "base idle adjustment" with the 3.8L CFI Idle Speed Control motor (ISC) system.
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?
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.
Uhhh yeah, having never owned a 3.8(no I won't touch one) I forget these things...
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.
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.
This is correct operation. It indicates the EEC has some life and is not a boat anchor.
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.
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!"
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!
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.
ok guys, i got the F350 out ofthe shop and got some time to pull the Tbird in this morning. the findings are.... disheartening.
(http://i.imgur.com/GG1AL1Tl.jpg)
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....
(http://i.imgur.com/cmazuXLl.jpg)
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 .
(http://i.imgur.com/02D7NI4l.jpg)
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.
(http://i.imgur.com/qPtPYUIl.jpg)
That entire passage is full of gasoline.
Care to put some input in, peoples?
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?
I finally fixed the idle on my Cat after reading this link, thanks to boomer for the pics and tips.
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.