1985 3.8 engine Q's

Topic: 1985 3.8 engine Q's (Read 4086 times) previous topic - next topic

1985 3.8 engine Q's

Reply #15 – August 19, 2006, 03:27:26 AM

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.

1985 3.8 engine Q's

Reply #16 – August 19, 2006, 06:51:40 AM

Throttle postion sensor Might have something to do with the idle. I don't know for sure.

1985 3.8 engine Q's

Reply #17 – August 19, 2006, 04:02:32 PM

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.

1985 3.8 engine Q's

Reply #18 – August 19, 2006, 05:04:27 PM

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.

1985 3.8 engine Q's

Reply #19 – August 19, 2006, 05:57:47 PM

Quote from: softtouch

Is the plunger against the throttle linkage and does it ever move?

Yes, when you rev it up it hold the throttle open and slowly return it to idle, that doesnt seem right to me.

Quote from: softtouch

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.

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.

1985 3.8 engine Q's

Reply #20 – August 19, 2006, 09:49:56 PM

Quote from: tbirdscott

Yes, when you rev it up it hold the throttle open and slowly return it to idle, that doesnt seem right to me.

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.

Quote

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??

Measure between the plunger tip and the square pad on the throttle it presses against.
Warm/cold--Doesn't matter.
Running/off---Off

1985 3.8 engine Q's

Reply #21 – August 20, 2006, 02:32:42 PM

Does anyone know what the tps voltage should be?? All the manuals I have are for 80-82 fords.

Thanks
Scott

1985 3.8 engine Q's

Reply #22 – August 20, 2006, 05:14:23 PM

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.

1985 3.8 engine Q's

Reply #23 – August 20, 2006, 05:46:42 PM

~.6-.8v

1985 3.8 engine Q's

Reply #24 – August 20, 2006, 07:16:21 PM

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.

1985 3.8 engine Q's

Reply #25 – August 24, 2006, 10:44:33 PM

Quote from: tbirdscott

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)

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.

Quote from: tbirdscott

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.

Get some liquid tape from a hardware store electrical dept. Try touching up the bare wires with that.

1985 3.8 engine Q's

Reply #26 – August 28, 2006, 01:59:16 PM

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

1985 3.8 engine Q's

Reply #27 – August 28, 2006, 03:11:17 PM

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?

1985 3.8 engine Q's

Reply #28 – August 28, 2006, 04:31:38 PM

Same symptoms, havnt checked codes again yet, gotta get/make a test light caust trying to read it with a volt meter sucks.

1985 3.8 engine Q's

Reply #29 – September 28, 2006, 03:10:14 AM

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