Restore of my 1986 Bronco XLT

[Gary Lewis]

Yes, the IAC should be able to get the RPM above 1K.  But we don't know what the ECU wants the idle RPM to be immediately after startup, which is somewhat based on ACT and ECT.  Big Blue goes to something like 1400 for a few seconds after starting when everything is "cold".

So something's not right, for either starting or idling "cold".

And yes, this year probably had a coolant-heated throttle body initially.  But it may not now, although I doubt that would make much difference in startup or cold idling.

[ArdWrknTrk]

Gary Lewis wrote

Yes, the IAC should be able to get the RPM above 1K.  But we don't know what the ECU wants the idle RPM to be immediately after startup, which is somewhat based on ACT and ECT.......

This year probably had a coolant-heated throttle body initially.  But it may not now, although I doubt that would make much difference in startup or cold idling.

I didn't mean to suggest that the heated throttle body would make any difference with a cold start.
Like I said, im not as familiar with these early systems as I should be, and just wanted to be sure I knew what I was talking about.

Surely the ECU should command enough 'idle speed' that the engine runs.  
Regardless the lookup table, it doesn't want the engine to stumble and die.

[Gary Lewis]

I'm not familiar with them either.  I know they don't have the full capabilities of what the EEC-V systems have, but I don't know how much less they have.

I think where we are is that with the given inputs we are either outside the "startup" lookup table or the answers in the lookup table aren't adequate to get this engine to run.  But by opening the throttle just a touch the answers get it to start.  However, even then the answers aren't adequate to get it to run at a reasonable RPM until it warms up.

It may be time to read up on the EEC-IV.  I found this which might help: EEC IV Inner Workings.  I'm reading

[ReneH]

I have the TPS as suspect every time...

I set the TPS between 0.9 and 1.0 volts when the throttles are closed (laying at the stop screw). Currently I have about 4.5 volts at full throttle. Maybe I have understand something wrong about setting the TPS...

[Gary Lewis]

Yes, I suspect the TPS as well.  But I don't know that much about adjustable ones, so will tag Bill, who does.

[ArdWrknTrk]

Thanks for that, Gary

[ReneH]

I also haven't an adjustable TPS...I only have widen the holes of the sensor to be able to rotate it slightly and adjust das basic value.

[85lebaront2]

Ok, Rene' I believe you said you are using a later computer, so it should not be as sensitive to closed throttle voltage. The newer computers measure the TPS voltage on startup and use that as the closed throttle value. The 4.5V max you are reading gives two questions (1) how far open is the throttle at startup (2) is the throttle opening fully (plates should be parallel to the bore at wide open throttle).

The chart I have for TPS values shows 4.538V at full throttle as normal. 5.0V is only reached in "overtravel" or when the full throttle stop is bent, or damaged.


Base idle rpm is set with the IAC closed and I can't remember if it defaults to closed when unplugged. I believe it does as it needs to be at minimum air flow in order to set base idle.

If your TPS values match the chart (+/- 3%) then everything is correct. If you can't get a good base idle rpm without a lot of throttle opening, see if the new throttle body has bypass holes in the throttle plates, these allow more air flow without having to open the throttle. If there are holes, they will probably be in US measurements, fractional inches. Find the nearest size metric drill you have and go up one increment (.01 or .1 depending on what is available to you) IMPORTANT, remove the throttle body while drilling and blow it off afterwards.

[ReneH]

Hi Bill, Yes I use the 1989 EEC-IV for the 351W. Thanks, this chart is very helpful!

I think, I have to adjust my TPS along with this chart. The plates of my new body have holes, but they're plugged with rivets.



But I'll try to set the idle alone the original Ford procedure, first and look about what values I'll get back from the TPS.

[ReneH]

So, I have done Ford's procedure this evening. The TPS voltage is about 0.89 to 0.92 when the throttle hits the stop screw now. It's about 4.42 to 4.55 on full throttle when key on and engine off.

I'll see, how it behave tomorrow. We should get about 0 degrees Celsius.

What is about the canister that filters the gasoline haze? If I clamp the vacuum hose that is connected to it, the engine is about to starve...is this canister a possible part, that can cause a vacuum failure?

[Gary Lewis]

That is the charcoal canister that absorbs (adsorbs?) the gas vapor when parked and gives it back when the engine is running.  It is a known "leak" and the ECU compensates for it.

Anyway, I hope all of your work pays off.  

[ReneH]

Ok. I understand.

The cold-start behavior is still very poor. I would say, my jeep, that using a carburetor starts better when it's cold outside.

I will change the ACT sensor this weekend.

I also mentioned, that I've made a mistake in Ford's idle procedure, so I'll do it again on the weekend.

[ReneH]

It seems, that I have a leak somewhere in the front upper area...if I touch the top of my steering shaft, where the ignition switch is located, after it rains a bit stronger, there are water drops on the shaft...

I've noticed before, that my carpet is a bit wet after rain, but I thought this was from my shoes...

Does anyone know for common points on which water can intrude?

[ArdWrknTrk]

That sounds very much like the caulking/sealant inside the cowl has cracked or come loose.

Usually if the windshield is leaking it follows the lip off to the side of the windshield and ends up by the kick panel.

Id think the best way to tell is tape a piece of plastic to the back of the cowl, under the wiper arms, and then use a hose or bucket of water to see if it's the cowl well leaking.

If you do remove this, Gary would suggest gluing a piece of screen to the underside of the slots to keep leaves and other debris out.

[ReneH]

Ok, thanks. I will check this tomorrow.

The screen is a good idea. I have some in stock, made of stainless steel, that will fit.

This sheet is loose:

[FuzzFace2]

ReneH wrote

Ok, thanks. I will check this tomorrow.

The screen is a good idea. I have some in stock, made of stainless steel, that will fit.

This sheet is loose:

That is just a cover to finish the body and has nothing to do with any leaks inside.
You will need to pull it off to get down into the cowl area to clean it out and re-seal.
BTW that cowl drains down behind the fenders where there is a "duck bill" that should let the water out.
What happens is the duck bill also traps dirt & leaves and it fills up and rust the area where the door jamb and rockers meet up.

To clean out that area and duck bill pull off the kick panels. If you dont have AC you can reach in the opening to clean it out. If you have AC remove the 4 screws holding the plate in place and I bet you will find it full of dirt. Once clean I would flush the cowl with water forcing water down both sides to flush it out.

Once the cowl is clean and dry you you then reseal the cowl area. The factory used seam sealer but it can be a pain to get to the outer areas where the water drains down to the duck bills.
Some have used that spray sealer they have on TV to make a boat out of screen, forget the name now
They get a nozzle and straw from say WD40 and put in on the spray sealer this way you can pin point the sealer right where you need it.
Let it sit up a day or 2 and do it again to make sure it is sealed.
Once the 2nd coat sets up you can test with water in the cowl area and see if you have any leaks.

At this time when testing with water you may want to start up on the windshield to see if it is leaking as a final test.
Dave ----

[ReneH]

I'm a bit late with my answer...but thanks, I'll try this next weekend...

[ReneH]

I haven't changed the ACT, but I've unplugged it...and the car starts also at low temperature! I'll try the same with another ATC, that I'll lay on the block, to see, if it also works, before o I install it.

When the engine is cold, I hear a mechanical rattling, near the sound my lifter makes when it stucks...when the engine is warm, this sound vanishes.
As I'm not sure, if my dipstick shows the correct value, I'll check if the engine needs some more oil...

Or is it normal, that you can hear the lifters, when the oil is cold?

[Gary Lewis]

Seems like the ACT may be the problem.

As for the lifter noise, Big Blue has one that taps when it is cold but goes away when warmed up. It is just a bit loose but isn’t causing a problem, so I’m not going to worry about it.

[ReneH]

Hi Gary,

I hope so. But it's very probably.

About the lifters: Ok, that calms me down a lot.