Recently replaced: Water pump, plugs, wires, cap, rotor, timing chain, fuel filter. Not sure wether it was done at a shop or a "handyman"
Exhaust rotted off after cat, battery cables corroded to hell, battery toast, 245K k/m, engine is a big ball of grease from leaking v/c.
When its started up cold it will idle at 1500 rpm but occasionally it will fall to about 500, catch itself, then keep idling at 1500 rpm, when you rev it up it will rev fine but when you let off the gas it will almost stall (like someones cut spark) then once again catch itself and keep idling fine. I'm not sure wether it does this every time its reved, only had a quick look at it.
Any ideas on what could be causing this? Its an auto if that matters.
Thanks
Scott
This a carb?
Looks like tbi, I figured someone here would know for sure, i'm clueless with these computerised fox's :p
*bump*
Any ideas??
REBUILD THE ENGINE AND STICK A CARB ON THERE FAST!! BEFORE IT EXPLODES!! :tg: Lol. Seriously though that's what you're looking at unless you're grooming this thing for a demolition derby. Actually probably the best and cheapest thing is to grab a junkyard 302, stick a carb on it and plop it in. Just my 2 cents.
Okay maybe I'll be a little more constructive. My 302 used to drop it's idle like that too, it would suddenly while parked just drop down til it was just about dead silent and then somehow jerk itself up again. That was before the rebuild. And my engine was and is carbed so fuel injection may have nothing to do with it. My car had low oil pressure and from the sound of it I'd bet yours does too, what did help the overall condition of mine at the time was to change the oil for 20W50. DO NOT put in straight 30W, I tried that first and the pressure would be good for like 10 minutes until it heated up and then dropped to nearly zero. This may or may not help at all, but for the cost of a jug of Castrol 20W50 it may be worth a shot.
3.8mustang.com
So, is it CFI or carb? I haven't a clue wrt Canadian cars.
If it is CFI, pull the codes and get back to us.
Engine swapping or rebuilding isnt an option, low oil pressure is very possible seeing the state and mileage of the engine, The engine is FUEL INJECTED, which version of injection I dunno.
The interior is near mint, the body is pretty good and the price is oh so right, would make a nice beater.
http://fordfuelinjection.com/?p=13
WHAT R UR CODEZ!? ;)
That site says 1986 and up?? ahh well i'll figure out tomorrow when I go get the thing.
It is also true for your '85. Your '85 CFI engine is the exact same as my '85 and '87 CFI T-bird 3.8L engines.
I'm getting 12, 23, 31... I think, was reading with my voltmeter.
So the TPS and EGR are out of whack but wtf does code 12 mean?
Also noticed the antifreze is a bit low which means hg's are probabally on there way out.
The low antifreeze could just be a slow leak in the heater core, I have the same problem right now. I only lose coolant when I leave the temp slider on hot (whether or not the unit is on). Before you go messing with head gaskets I'd see if you can find a stain in the carpet up under the dash.
Interior is really clean, i'd notice a leak in there. I'll have to do some more testing tomorrow, I tore the exhaust off my 80 tbird tonight to put on it since it has nothing and sounds like a tractor at the moment, I'll try to adjust the tps (if I can find the specs) and burn down the highway and see how she does, right now its down to fixing this or doing the clutch in the sprint which I am not looking foreward to, almost rather do the head gaskets actually.
I'll still check for leaks, havn't had it warmed right up yet. I got it from a woman down the street so i'll ask her tomorrow how much if any coolant it was using.
Throttle postion sensor Might have something to do with the idle. I don't know for sure.
KOER 12 is an Idle Speed Control (ISC) Motor problem.
If it is interfering with the throttle linkage during KOEO test it can cause the 23.
The ISC is a motor that can run in either direction depending on the polarity of the voltage applied to it. It has a plunger that pushes against the throttle linkage to control idle speed.
The ISC has an Idle Tracking Switch (ITS) built into it that makes when the throttle linkage is pressing against the plunger tip.
This lets the EEC know it is in control of the engine speed.
I am going to see if I can find a thread that JeremyB started that has a lot of detail you should read.
(http://users.rcn.com/jroyle/CFI%20ISC%20'84.gif)
Couldn't find the thread I was looking for. I'm lazy, trying to save typing.
Take the air cleaner off so you can see the ISC and throttle linkage.
Start the engine and watch the ISC. Is the plunger against the throttle linkage and does it ever move?
Turn off the engine. Install the self test jumper to run the KOEO test. Turn ignition to RUN (do not start). The ISC plunger should retract all the way in. There should be 7/32" between the plunger and the throttle linkage. Use a 7/32" drill bit for a feeler gauge.
Yes, when you rev it up it hold the throttle open and slowly return it to idle, that doesnt seem right to me.
It retracts all the way in and stays there till the jumper is removed, where should I be measuring this 7/32"? while warm/cold, running/off??
Thanks
Scott
And the head gasket is goin, I get a little puff out of the rad when I remove the cap, more than there should be so that'll be on the to-do list. I found the oil leak though, vc bolts were loose, like grab the head and wiggle it around loose.
If the ISC is holding the throttle too far,that doesn't seem right. How does the return spring tension feel when you rev it up? Is it real light? I had to add an extra return spring to my '84 3.8 so it would press hard enough on the IAC plunger to operate the ITS.
Measure between the plunger tip and the square pad on the throttle it presses against.
Warm/cold--Doesn't matter.
Running/off---Off
Does anyone know what the tps voltage should be?? All the manuals I have are for 80-82 fords.
Thanks
Scott
Anybody? just checked at three places (can tire, walmart, cheiftain) and nobody has a manual for this bloody thing!
As for the IAC I tried adjusting it with the key on engine off and cold but couldnt get it loose enough, I think its sticking out too far (or i'm doing it wrong :p) I did find two wires one coming off the distributor (yellow) and one on the front ds of the intake (red? goes on to a sensor of some type) that have 2-3" of insulation missing and the wires are all corroded so I guess i'll be hitting the wrecker to grab a distributor plug next week.
~.6-.8v
Thanks, I actually just put a new one in, the old one was reading 1.9@750rpm as the trottle went to WOT (engine off, ignition on) it got up ti 3.4 then dropped down to 1.3 for the last 1/4 of movement, it now doesnt die on you when you floor it but its still sucked down, gonna check the cats as soon as it cools down and delete then if theyre still there, hopefully that'll clear things up a bit.
Loosen the mounting screws and adjust it turning the long screw with the spring on it that runs under the ISC. (Your car doesn't have an IAC)
The KOEO test checks the TPS with the the ISC fully retracted and the throttle linkage against the throttle stop adjusting screw.
This is also when you should be checking the TPS voltage.
Get some liquid tape from a hardware store electrical dept. Try touching up the bare wires with that.
I got the ISC adjusted, no difference.
The wires are pretty crusty so i'll just replace them.
Whats the tps supposed to be set to on this thing? ive heard (and have it adjusted to) .9V but i've also heard it should be .5V, anyone have a manual that covers these engines??
I also removed the egr valve to check its not stuck, its brand new and moves fine but was pretty carboned up, probabally from running so rich, I sed out almost all of the carbon, no change.
Scott
The reason you can't find a setting for the TPS is because officially it is not adjustable. If the Throttle Stop Adjusting Screw is properly set (and it should be unless someone has messed with it) then the TSP should be properly set.
If you don't have a KOEO 23 then it is ok, and with it at .9v you shouldn't be getting one.
Unfortunatly some after market TPS's are not held to tight enough specs for this to always work. Then they have to be adjusted to get rid of the code 23.
When you say nothing has changed do you mean you still have the codes or the same symptoms or both?
Same symptoms, havnt checked codes again yet, gotta get/make a test light caust trying to read it with a volt meter sucks.
Well got the headgaskets replaced, removed the air pump hoses, the pipes and fittings were rusted to nothing. Anyway the brakes seem to work better so I must have found a vacuume leak, otherwise the car still runs like it did before.
Got the TPS down to .5v, still runs too rich but better, gonna try unplugging the O2's tomorrow and see if that helps it at all, if not i'm contemplating tossing on the big tires and hitting the bush :beatyoass:
Codes?
Also, it is std. procedure to replace the O2 sensors when you do the head gaskets as the antifreeze can corrupt them.
Yes, rerun codes.
Are you sure you got the TPS installed correctly? It should not be at .5V either. AFAIK it should be ~.9V like every other EEC4 system.
TPS should be about .94 - .98V when idleing, warmed up, and in park.
Just out of curiosity, was this '85 a Canadian bought car? As far as I always knew 3.8L were carbed in Canada untill 1987. My first car a 1986 T-Bird was carbed.
Also a broken FPR creating too much fuel pressure will cause a cfi to run rich only at idle. I don;t remember the correct pressure numbers.
How would I check for a broken regulator? I turned the tps down to .5 to try and get it running a bit leaner, still way rich as is.
The problem is mainly when you first get going or at low RPM's, you gotta be real easy on the petal but once its up past say 200rpm you can floor it and go.
Now that you mentioned it it does sound like it could be the fpr..
Got a fuel pressure gauge? Check the pressure.
Have you run codes again?
Adjusting down the TPS is not going to help. Set it to the correct voltage.
Not correct for this engine.
The KOEO tests check for the correct TPS voltage with the ISC motor fully retracted and the throttle linkage against the throttle stop adjusting screw.
The engine temp. has no affect on this. With the engine running the EEC is going to extend the ISC motor.
If the TPS voltage is out of specs it will give a code 23.
I can't believe they would design something that is mechanicaly operated to require a operating range of a couple of hundreths of a volt.
I took some TPS voltage readings on my 3.8L '84 T-Bird with various shims between the throttle stop screw and the linkage.
.75v code 23 .80v ok 1.02v ok 1.07v ok 1.14v ok 1.23v ok 1.33v code 23
Did you change your coolant sensor? That is what was killing my 83, I know they have different computers but it would cause the same problem.
I actually got some help on another forum and git it correctly adjusted. put it in test mode, unplug the ISC, take out of test mode and start it up, turn idle adjust screw till car just runs and set the tps there... just incase anyone else needs to do it.
nooo, the tep gauge works fine.. does it use a different sensor? also the wire for what I think is a temp sensor has all the insulation burnt of.... havnt gotten around to fixing those yet though..
Thanks for all the help guys, once I finnish my curent mission i'll get back on to the stang and try to get it sorted out.
Scott
Actually, that is the incorrect way to set the ISC. softtouch gave you the correct way in post #19.
Yes, the EEC uses the ACT (2 wires) and the cluster uses a 1-wire sensor.
Thats how you set the tps :raspberry And yes I followed softtouch's instructions to set the IAC there after.
So the wire for my temp gauge is the one thats fried, the wires for the other look fine, this car is deathly original though i'm sure it should be replaced.
Sorry:sorry: . My bad. That whole previous post of mine was wrong. I was thinking of my SEFI 5.0L where hundreths of a volt DO matter on the TPS. For anyone else reading this SEFI also should be checked key on engine off measuring the voltage between both outside wires in the three wire connector.
I guess ill chime in,,,,,,,,,,,
As always with the 3.8 cfi, and i say ALWAYS and FOREVER,,,,, the first thing that hampers engine perfromance is the EGR base plate and trottle body base carbon build up. When the gold vac elbow fitting on the rear driver side of the CFI can not get proper vac becasue of carbon, the egr is not able to actuate properly. When it can not move or is carbon'd up as well, the EVP sensor can not chime in to its common buddy the Map, then the engine can not determine proper idle speed and the tps voltage range becomes more and more out of range.
Rule of thumb,, with CFI's,, always remove the CFI (4 nuts) and the egr base plate and chip away at anything that does not belong then reinstall.
The TPS was at one time adjustable as the mounting holes were at one time sort of oblong shaped. I brought this up not and then but no one seems to remember. Anyway, to make it adjustable,, just use a 7/32 chainsaw file and make the holes oblong yourself. Then you can pretty much dial in the voltage you need.
As far as the injectors,, ill bet you experience a slight hesitation before the actual power kicks in. The fix,,,, remove the injector screens and either replace them ore just leave em out. I dont run screens in mine.
As for your idle control motor,,, sounds like you have a hard to find working unit,, if you decide to run without one,, you will quickly notice what its primary job is,,, it slowly allows the engine rpm's to decrease when you let off the gas instead of a sudden drop in trottle plate movement from open to close. Makes for a smoother feel when letting off the gas.
I guess from what you said,, it was fairly virgin under the hood and if so, i would have never hampered with the tps or the isc until i removed the CFI and got rid of the carbon. Call my bluff on the carbon thing but you will be amazed if you take a moment to look.
The shop manual proceedure for setting the throttle stop adjustment screw starts with a new screw.
With the throttle plates closed, turn the screw inward until there is a .005 inch gap between the screw tip and the throttle lever surface which it contacts.
Turn the screw inward an additional 1 & 1/2 turns.
Well when I replaced the TPS (it was shot) I had to remove the cfi and the egr got cleaned out, and the tps holes ovaled out (I remembered that one ;) ) the egr valve is fairly new. Just tested the fuel pressure and its right at 39 where its supposed to be, ignition off and running.
How do you remove them?
so it doesnt really matter then? it will just feel like a standard? I hate the idea of a computer controlling my throttle anyway...
In my experience thats never a good thing... and yeah, the egr had some pretty big chunks of in there.
Thanks
Scott
ttt
Remove the CFI assembly, then remove the (4-5?) screws on the bottom of the CFI assembly to release the top/bottom of the CFI piece. It is pretty straightforward/self-evident.
If you think you have clogged injector screens, I would send them off and have them cleaned professionally for $12-$25/injector.
If you remove the IAC motor, you won't be idling unless you keep your foot on the gas at all times. It is a necessary component.
This engine has an ECT...you checked that yet?
If you are lucky,,,, VERY LUCKY<<<< you might be able to split the CFI in half so you cant remove the **lower injector retainer***
I did not re-install my lower retainer and dont bother asking how i keep the injectors in there,,, its really red neck to say the least but served well for several years.
removing the injector screen is simple. First observe the brass looking ring in the top of the injector. the brass ring transitions into a tear drop looking screen. Just find you a pointed tip screw that will start into the top of the injector and bites into the brass. Give the screw a good yank with pliers and out pops the screen. Go buy a new screens if you wanna and set them in the hole, turn the injector upside down and tap them on the work bench till the sceen is seated.
as for the idle control motor,, you can get away with not having an operational unit, the car will run, it just wont do the automatic high idle on start up to warm nor will it buffer the feel like you compared to a standard drive engine. It might stagger perhaps,, i cant recall since i got a few good back up ones. I do like this one do hicky i found on an old cfi. It had no Idle control motor. It had a spring loaded plunger that extended when you were on the gas. When you let off the gas, the linkage pressed on the plunger and it slowly retracted and lowers the idle. I would recon that the advent of the electronic controlled idle thingy only gained one advantage as it would increase your engine rpm upon startup to a specified rpm and then back off the idle for warm up purposes. with the old fashion type i described, i guess that option was absent so thats why the very first CFI ever had a choke pull off assembly. I believe these type of CFI systems were on the 82 or perhaps 83 V8's only.
in order for you to run without the idle control motor hooked up,, just loosen the adjustment lock screw which will be visible looking down on the mounting bracket. There is a spring in your way if you use a socket but i smoosh it to the side. with that loose, you can now adjust the long looking Bolt which brings the idle control motor plunger head up to the linkage. Just tweek it till you like the idle rpm you hear.
Im not trying to disagree with jeremyb,, im only suggesting what worked for me once upon a time.
Im still curious though,, you never really made it clear that you actually removed the CFI and the EGR base plate and removed carbon build up. You said you had to remove the CFI in order to replace the TPS,,,,,That in itself is plain nonsense and i cant for the life of me understand why. Perhaps you did not have a 14'' phillups screw driver. With that you can come in at the tps almost straight on with the screwdriver resting on the pass valve cover.
Im gonna post you a link i did up pointed directly to the type of motor you have and some of the digging / things ive done. It might be helpfull since i feel pretty certain your also not happy with all the different vac lines and what they do. You will be pleased to know that they are not all that complicated and can go away.
This link is pointed directly at the 3.8 v6,,,,,,http://www.foxtbirdcougarforums.com/showthread.php?t=2984
As far as your fuel presure,,,,,,, you really need to check the fuel presure while driving,, its actually mentioned in the shop manual that you install the pres tester and tape the guage to the windshield while driving and observe the the presure while the tranny is in labor in between shifts.
So,,,,,, are you getting anywhere in troubleshooting,, are you getting it to run better?
The carbon build up had all been cleaned out. I had to remove the cfi because the bracket that holds the fuel lines is in the way of the screws. The bracket is welded to I think a coolant pipe that runs down the intake so It couldnt be removed.
Car still runs as py as the day I bought it, I'm doing the clutch in my sprint right now but i'll see if I can work the stang in there a bit.
For now i've got some reading to do.
Chuck the temp sensors are in place and the wires are good, cant find any info on testing them.
Thanks
Scott
! thats everything I've been lookinmg for all in one!
Thanks jcassity
Scott
yep it is virgin under the hood,,,,,,, Delete that coolant pipe and the bracket that holds the fuel lines.
install a longer heater core hose in place of the pipe. That will open up the intake and the valve cover to get at things.
here is one sensor
Coolant Temp sensor (2wire)
about 55k ohms when engine is cold and outside weather is about 65deg
about 1.5k to 2k ohms when engine is hot.