Ford Bronco Hard start after sitting ? Also exhaust question - Page 3 - Ford Bronco Forum
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post #41 of 89 (permalink) Old 01-28-2017, 09:43 PM
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You won't hurt anything pulling the SPOUT, in fact the SPOUT is pulled when setting the base timing. The only thing that will happen when starting/running the truck with the SPOUT removed is you won't have any spark advance. The truck will run, but there will be a decrease in performance.

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post #42 of 89 (permalink) Old 01-28-2017, 09:48 PM Thread Starter
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Alright man thanks for the replay should I pull the spout when the truck is hot or cold does the even matter ? If the RPM's do not fluctuate when cranking with the spout out is that a good indication that it is the PCM
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post #43 of 89 (permalink) Old 01-28-2017, 10:26 PM
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Do you know what the SPOUT is? It's just a 2 pin gray plug connector that is located in the harness near the ICM/PCM and the connector you used for pulling the codes. (on the driver's side near the hood hinge)

Notice in the schematic above that there is a shield (it's like aluminum foil) around a portion of the wiring between the distributor and the PCM. If the shield has lost its ground, there is a possibility of electronic noise getting into PIP signal. The shield is keep externally generated noise from being sensed by the PCM. Electrical noise is generated by the plug wires/coil/possibly the alternator. Noise could possibly be interpreted by the PCM as valid PIP signals, and maybe that could be the cause of those erratic tachometer readings.

I can only try and teach you how it works when it is working correctly, there could be multiple possible points of failure, you'll have to find them.

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post #44 of 89 (permalink) Old 01-31-2017, 10:10 AM Thread Starter
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Thank you both for all the info. But I made a appointment for ford to check it out. I have no time to properly test it. I will post back with what they find.
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post #45 of 89 (permalink) Old 02-02-2017, 10:22 AM Thread Starter
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Just got back from the dealer. They did not find anything. They did say I have a vacuum leak near the intake and that I needed a tune up. I just did a tune up. Luckily they did not charge me for a diagnosis. I did pull the SPOUT connector and nothing really changed. Should I pull the computer when I have time and then post some pic's here?
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post #46 of 89 (permalink) Old 02-02-2017, 12:25 PM
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Think about what's happening when you try to start the truck. The engine is turning over at a slow speed (~250 RPM), the pistons are trying to pull in enough air and fuel to get a combustible mixture, the throttle is closed, so all the air needed for combustion is entering the engine through the IAC, and now you introduce an additional air source, THE VACUUM LEAK!
Fix the vacuum leak, with the engine idling, spray some carb cleaner and if the idle changes, you are close to where the leak is.

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post #47 of 89 (permalink) Old 02-02-2017, 03:15 PM Thread Starter
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Originally Posted by Mikey350 View Post
Think about what's happening when you try to start the truck. The engine is turning over at a slow speed (~250 RPM), the pistons are trying to pull in enough air and fuel to get a combustible mixture, the throttle is closed, so all the air needed for combustion is entering the engine through the IAC, and now you introduce an additional air source, THE VACUUM LEAK!
Fix the vacuum leak, with the engine idling, spray some carb cleaner and if the idle changes, you are close to where the leak is.
Yes, The tech said the leak was near the intake. So right now my question is should I just replace all the vac lines with silicon ones I remember seeing a thread on here on how to do that. Also would that explain why the tach is erratic when starting or is that a separate issue? From my understanding they are separate.
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post #48 of 89 (permalink) Old 02-02-2017, 03:50 PM
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Changing out the 22 year old vacuum lines is always a good idea, but try and find the leak before you change the lines, that way you won't be disappointed when you find out that the leak was caused by a intake manifold gasket, for example.
By any chance did the dealer tell you where the leak was specifically? The intake manifold is where the vacuum starts, so a generic statement that the vacuum leak was "near the intake" is always right!

When starting the truck, are you pressing on the accelerator? Ford made the EFI starting strategy completely "hands (feet) off". When the truck is taking a little longer to start, are you trying to "help" it?

Did you ever meter your TPS? (I reread the thread and didn't see that it had been tested, excuse me if you have). The TPS wears out, especially at the closed throttle end of the potentiometer (the first few degrees of throttle movement). The TPS is best tested with an analog meter. What you are looking for is a small movement of the TPS that goes "open". That "open" will confuse the PCM. There are a couple of good write ups on how to test the TPS, do a little searching.
The KOER "goose" test will test the TPS to see if it responds correctly to the throttle changes, what could be happening, is that the TPS is worn and intermittent at the throttle closed portion of the pot, and that may be causing the intermittent hard start. Sometimes just a fraction of a degree of throttle movement could be the difference between the TPS sensing correctly or not.

You also mentioned checking the PCM, have you done that yet?

If you are looking for some magic fix, it's not here, no dancing around the Bronco splashing chicken blood and pixie dust on it will effect the fix. You have a couple of intermittent problems, effective troubleshooting is what you need to be doing.

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post #49 of 89 (permalink) Old 02-02-2017, 04:18 PM Thread Starter
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Well the TPS is only a year old and it was installed by a shop they told that they set the voltage to a ford shop manual it and gave me a receipt for it (its a motorcraft). I also recently tested it and its perfect. Whenever it hard start's my foot is off the accelerator and I just keep cranking until it fires. If it does not fire within 5 seconds i'll stop and recrank it. When the tech gave me my ticket it said "Found possible vacuum leaks on intake side" that is word for word what he wrote down. As for the PCM no I have not checked it yet. I do not have my TORX set with me because I am at school. I could run to walmart and see if they have some there that I can just buy and open it up. What size TORX do I need.

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no dancing around the Bronco splashing chicken blood and pixie dust on it will effect the fix.
Crap so does that mean I should return the chicken's that I bought off amazon

But on a real note mikey thank you for all of the help so far.
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post #50 of 89 (permalink) Old 02-03-2017, 12:44 PM Thread Starter
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So I went to to the parking deck and pulled the spout and nothing really changed. The tach was still erratic. So can I eliminate the possibility of a bad ECM. Should I pull the Ignition control module and have it tested at a autozone. When I replaced the ignition module 5 years ago the PO drilled new holes to hold the module on which it does but it's really loose. I'm thinking the thing overheats because it's making poor contact against the heatsink.
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post #51 of 89 (permalink) Old 02-03-2017, 04:20 PM
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Get a new ICM, a BLACK one, if they try and give you a gray one, ask for an ICM for a '95 5.0 Mustang, then they'll come out with a BLACK one.
Get some heat sink compound, most computer stores (and WalMart) sell Arctic Silver, that's overpriced, but any generic heat sink compound will work.
Get the correct tool for the bolts on the ICM, it looks like this, should be available at any good auto parts shop:



Lisle Ford Ignition Module Wrench LIS64650: Advance Auto Parts

Clean the old crap off the heatsink, spread the heat sink compound evenly over the heatsink and the ICM, a trick is to spread it with the edge of a credit card, then bolt the ICM securely to the heatsink.

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post #52 of 89 (permalink) Old 02-03-2017, 05:44 PM Thread Starter
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Should I get it tested first or just replace it. I replaced it before but like I said. I didn't know the PO ****ed with the mounting hardware and If it's not fitted tightly to the back it would not be able to distribute heat correctly. There for a premature failure. I could show you a picture of what he did if you want. I just checked it and it did not seem loose.
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post #53 of 89 (permalink) Old 02-03-2017, 06:35 PM
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If you can, get a Motorcraft ICM. If the bolts are wrong or whatever, fix it so the ICM contacts the heatsink. It's not a complicated assembly. Put helicoils in the heatsink to get the screw size so it can retain the ICM tightly, worse case, small bolts and nuts could be used to fasten the ICM to the heatsink. Don't overthink it, get the darn thing tight to the heatsink.
It's not a structural part, no need to torque it to 150 ft/lbs.

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post #54 of 89 (permalink) Old 02-04-2017, 02:34 AM Thread Starter
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So I found a junkyard close to my campus and they have 92 - 95 f150s there so i'm going to head out there and get a unmolested ICM heatsink in the morning. Then i'll take it to my apartment and clean it with rubbing alcohol to make sure all the old thermal compound off the new to me heatsink. After that I'll just get the old one tested. Whenever I build or replace a CPU on a computer that I work on I always use arctic silver it does drop the temp by a couple of degrees celsius. Ill let you guys know what happens fingers cross this solves the problem.
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post #55 of 89 (permalink) Old 02-04-2017, 01:56 PM Thread Starter
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Just got back from running around. I got a new heatsink with screws off a 1994 f150 in the junkyard. Also I'm ordering a new motorcraft module the one that I put in there five years ago is the autoparts store brand (was a noob at the time). I just want to take everyone's advice and get a black motorcraft one since it's more reliable. Let's see if this fixes the issue.
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post #56 of 89 (permalink) Old 02-07-2017, 03:37 AM Thread Starter
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So I was wondering. Could I connect the air tube in right before the cat. Or should I just get a new cat because it's the wrong one.
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post #57 of 89 (permalink) Old 02-07-2017, 10:52 AM
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Yo G,
PCM Removal in 92 to 96 bossind @ Changing out the Bronco Computer ECU

My Vacuum Leak Diagnosis in post #11
You should obtain a vacuum gauge. Some mom & pop parts stores may loan you one with a security deposit.
In the diagnosis you will see a Vacuum Gauge Diagnosis by Ford. Call dealership and have Service Manager ask technician where he found the leak. Chances are that he just used the vacuum gauge check & found
"INTAKE LEAK: A low, steady reading can be caused by an intake manifold or throttle body gasket (TB gasket) (9E936) leak."

Also, IGNITION TIMING RETARDING: Retarded ignition timing will produce a steady but low reading.
..

I believe your 94 5.8 was built with two catalytic converters. I forget where you are located; it makes a difference for Emission tests especially in California and and New York State.

CARB Converters Last Updated 02-01-2017
In California (as of January 1, 2009) and New York (as of June 1, 2013) it is illegal to install a required CARB-compliant catalytic converter based solely on physical shape, size, configuration, or pipe diameter.
By law, required CARB-compliant converters must be installed specifically as listed in this catalog, they cannot be substituted nor can they be installed on vehicles that are not listed in this catalog.
If you do not reside in California or New York, and do not require a CARB-compliant converter please use our EPA Applications Catalog.
NEW YORK: Determine the RIGHT replacement converter.
For more information on New York state regulations click here.
1994 - Ford Bronco
Engine - 5.8 Liter V8
Vehicle Qualifier Notes Location Product Line Part QtyQuantity Required per Vehicle
Legal for use in the states of California and New York.; Modifications and/or additional parts required. Front Universal Click Part Number for Product Information Page 80612 1
Legal for use in the states of California and New York.; Modifications and/or additional parts required. Rear Universal Click Part Number for Product Information Page 80708
Notes show that Neither have air tube tubes.
From what I recall, your air tube should be in the Y.

See Walker Exhaust for info on non CA and non NY State @ WALKERŪ EXHAUST SYSTEMS :: E-Catalog Lookup

See my partially recovered Bronco web site ...Will need to clean up dead links & add many more new links some day. Thanks to Mr. Schwim!
THANKS to ALL WHO SERVE!
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post #58 of 89 (permalink) Old 02-07-2017, 11:57 AM Thread Starter
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Thanks man. Ya I am from chicago so from what I just read is that the cat that is currently on there is ok and that I could just add the air tube before the cats correct? So the O2 sensors get the proper readings.
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post #59 of 89 (permalink) Old 02-07-2017, 05:41 PM Thread Starter
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So since I originally had 2 cats. Could I just run high temp exhaust hose into the pipe after the cat. So that way the system is still getting air.
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post #60 of 89 (permalink) Old 02-08-2017, 10:43 AM Thread Starter
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Hey guys before I rip this computer out and take a peek I want to know what TORX bit's do I need to take off the cover. Im at school and need to buy new torx bits please help.
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