1990 bronco rough idle

[birishman]

hello I'm new hereI'm hoping for some help.I have a 1990 Bronco 5.8 automatic overdrive 15,000 miles on motor and transmission.started running a little rough so I did your basic tune up plugs,wires,cap and rotor.Nothing changed it still ran a little rough. The bad running issue turned into running extreamly bad with in a couple days. And this is when my nightmare started!

First I want to say I'm far from an idiot when it comes to the automotive world. I've been building top end small blocks for 20+years. I'm the guy that the shop mechanics call when there stumped. I'm the guy that can and will fix anything the right way. So now its my time to ask.

So after running codes, checking and going over the entire fuel system, emissions, ect, the rough shaking idle was still there. Conclusion.. must have some hard to find intake leak. No biggy, in the process of removing intake I pulled the distributor ( like I have hundreds of times before) and out of nowhere I hear the clank of the oil pump shaft hitting the pan. " do I have to say anymore?" But not what I expected to be dealing with. The book says the motor has to be pulled to handle the situation, well I proved the book wrong, not fun.

Sure the **** don't want it to happen again. I went over every nut bolt, vacume line, every bolt to torque specks, its what I do build them perfect.

Get it back together, drop distributor in, and well it wasn't perfect, so I pulled it out to correct the issue and the pump shaft came with it, again! Yes again! There are no words to describe the anger of the unfortunate disaster. This is far from an easy fix. Now I want answers, long forgot about the idle and running issues. After many hours of going over everything, and taking it down to the block, heads off, putting it back together, the bad shaking idle had not changed a all. Same as before I found that my distributor is magnetized and holding pump shaft. Now the problem is its installed once again in the motor. And I'm not pulling it out for nothing. I got my hands on a degausser and unmagnetized while Installed, no choice. It must have been sending crazy Signals everywhere. I believe its caused from cheap rebuilt alternator, where the ac voltage changes to dc current. To much ac, maybe as little as .03 of a volt would do it.just an opinion.

Here is a list of everything I've replaced. And i checked and rechecked before installing,any part that was even questionable. and done one at a time, and clearing codes as I went.

Iat

Tps

Tfi

Air bypass

Idle by pass

Engine coolant temp switch

Water temp switch

Canister purge solenoid

Map

Egr

Evr

Ever solenoid

Igntion coil

Fuel filter

Tab

Tad

Fpr

8 new injectors

Fuel pressure is good at all times

Replace all vacume lines and tested.

I believe the hall pick up is fine, tested it.

I don't believe computer is bad, and its just shakes rattles and don't roll. Any ideas??

 

[miesk5]

yo birishman,

WELCOME!

With your experience and knowledge, all I can do now is ask a Q or two until later today.

Do any codes re-appear now?

If so, list them here by KOEO and KOEO.

As far as the vacuum; were the vac hoses and devices in the HVAC system under dash and at HVAC vac canister &  Outside Recirc Door Vac Motor (near pass side firewall corner/hood hinge) and devices also tested for leaks?

"distributor is magnetized";

ok, I see that you know this issue well and addressed it.

For posterity and others;

Misfiring, Rough Idle, Surge, & Ping-Knock Symptoms, due to a Magnetized Shutter Wheel, (Bronco & all Fords w/EEC IV & TFI); "...Inside the TFI distributor is a Hall-Effect sensor that provides an RPM and POSITION signal to the Ignition module and ECM for fuel and ignition control. Mounted to the distributor shaft is a "shutter-wheel" that passes through the Hall-Effect sensor. The slots or windows cut in the shutter-wheel are what makes the Hall-Effect sensor switch on/off to create the signal it sends out. The shutter-wheel is supposed to be a piece of "dead" steel but can become magnetized. A magnetized wheel can cause very erratic operation of the Hall-Effect and resulting erratic output signal. The Test: There are a couple of ways to check for this condition. One is to simply pull off the distributor cap and see if something steel will "stick" to the shutter-wheel. Make sure that whatever you are using to check the wheel with isn't magnetized itself. A more accurate method would be to watch the wave-form on the "SPOUT" wire with a Vantage or Lab-Scope. The SPOUT is the wire with the connector in it that you unplug to set ignition timing. Monitor the wave-pattern on the SPOUT with the timing-connector in. If there is anything erratic about the wave-form, unplug the timing connector and re-check the wave-form. If the pattern "cleans up" all of a sudden, chances are good that you have a magnetized shutter-wheel. The Fix: Most shutter-wheels can be removed from the distributor shaft with a couple of screws. Everybody seems to have their own way of de-magnetizing the wheels but good success has been had with bulk audio-tape erasers or by placing the wheel in an engine parts cleaning oven and baking it. That last one sounds weird but it works..." Scroll down
Source: by snapon.com via http://web.archive.org/web/20020806143543/http://www.snapon.com/newsletter/sonews_08_2002.asp

Have to see a Doc, will bbl.

 

[birishman]

I'll run codes a little later today when I get my time, but for now I'm curious as to the type of damage caused by a magnetized distributor. Its wasn't just the shutter wheel but the distributor shaft also. Enough to hold onto the oil pump shaft and pull it out and drop it in the pan. I have a feeling that many people have experienced this themselves, without never knowing the cause and never getting full performance from their motor. Personally the experience has made me a better builder, I will check every distributor that comes in and out. And test every alternator before I put my name on it.

 

[miesk5]

yo birishman,

I have read advice on Ford magnetized distr. shafts in the past and most ASE techs advised replacing the entire distributor.  Here is one comment.

"The code 211 is usual set due to either a worn distributor shaft or a bad stator in the distributor. If the engine runs better with SPOUT disconnected and runs poor again when it is reconnected, the problem is likely to be in the distributor. There are several items that could cause this. A defective pickup can transmit erratic inputs to the module and powertrain control module (PCM). A worn distributor shaft bushing or a magnetized shaft can also cause erratic signals. Monitor the PIP signal with a labscope. At the same time, monitor the duty cycle of the PIP signal. Back probe the PIP wire at the ignition control module (ICM). With the SPOUT disconnected, the pattern is a 12 volt square wave with an approximate 50% duty cycle and clean corners. One square wave has less duration than the others. This signal is used on port fuel injected vehicles only to identify TDC compression to the PCM. With the SPOUT connected, a notch will be out of one corner of each square wave. The duty cycle should be 47-53% and be relatively stable. Any variation out of this range indicates shaft wobble. An out of specification, but stable reading, indicates a magnetized shaft. In either of these cases, the distributor will need to be replaced as an assembly. If the duty cycle reading is stable, but the square wave is erratic, replace the pickup assembly. Always confirm that the duty cycle on any replacement distributor is within specifications. A replacement pick-up/stator assembly will not cure a shaft magnetism problem."

by Ron, ASE Certified Technician



I haven't heard of a magnetized distributor's magnetic fields affecting the distr. mounted ICM or a new distr.

Speaking of alternators

Bad Diode Pattern 1

This waveform was captured using the diode pattern test located in the engine tests menu. This particular alternator has a bad rectifier, causing an AC voltage to ride on top of the DC voltage signal.This AC voltage affected the pip and spout signals (Ford primary ignition signals) causing a no code driveability problem. The fix was to replace the alternator.

Bad Diode Pattern 2

This waveform was captured using the diode pattern test located in the engine tests menu. This particular alternator has a bad rectifier, causing an AC voltage to ride on top of the DC voltage signal. This AC voltage affected the pip and spout signals (Ford primary ignition signals) causing a no code driveability problem. The fix was to replace the alternator. This waveform was captured using the diode pattern test located in the engine tests menu. This alternator, like the previous alternator, has a bad rectifier. This is another example of how a bad rectifier can affect the diode pattern. The fix was to replace the alternator. This waveform was captured using the lab scope. This is a good example of how an alternator with a bad diode can affect other signals that the ECM looks at. In this case it is an IAC motor. When viewing waveforms that have a lot of hash always look at the alternator diode pattern as a possible cause..."

See more waveforms by omitec @

http://www.omitec.com/en/support/waveforms/