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Discussion Starter #1
I did a search-no finedee.

My 1994 Bronco When The engine is cold-cool and I turn the key, she starts stops, starts stops, starts runs fine.
Each start lasts for about 2 seconds and acts-feels as if it's choking out when shutting down(fuel starved?), and it does it that quick.
Two mechanics and two tune ups later-no idea.At this point 3 years, it can be lived with but I would sure like to fix.
Any ideas will help.Thanks.
 

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Dang I heard this on Car Talk a couple months ago.

I think they said to put a blanket on it overnight so the engine stays warm.

Maybe you've got a leak in your fuel line that develops a small bubble or dry spot right at the end and a couple starts makes it stop doing it.
 

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A broke kid with a bronco
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Check fuel pressure at the rail on key on engine off and then when trying to start it.
 

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That sounds strange. My F250 was doing that and still is here and there. It is a diesel , but, I believe it is the ignition switch. Its a 96 and everything on the truck goes through the ignition switch under the column. My trucks yr and make has a history with this and since it is intermitent I know it is an electrical problem. We pulled it out one day and it had this crusty feeling in the movement when sliding the switch up and down. We exorcised its demons a little bit and put it back in there and didnt have any problems for several months. Then the demonic posession returned. Whenever it does this sometimes I just cycle the key a lot in a right savage kind of way and it heals itself. try that for some diagnostics next time it does it.
 

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that is a pretty vague description of how it is running.

how long does it run before it stops, do you have to restart it? When hot does this happen?
 

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Discussion Starter #6
Thanks for the replys.I edited the post above to explain better.

Each start lasts for about 2 seconds and acts-feels as if it's choking out.
Once started you could drive to China.When warmed up she seems to start fine.
 

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What are the rpms when it first starts

Have u tried starting with the accel pedel pushed some to get a running.
 

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Check fuel pressure and try cleaning the iac. May be in switch but I think that was a recall from ford. I will see if I can find it.
 

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yo,
Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
The engine temperature must be greater than 50° F for the Key On - Engine Off (KOEO) Self-Test & at or more than 180° F for the Key On - Engine Running (KOER) Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:
KOEO
&
KOER
=

Our friend here, thin blue line mentioned the switch; am thinking it is the ignition switch; so check it using;
Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in 80-91 & 92-96
Source: by Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/registry/media/831772

'92-96
B1, B2, B3, B4, B5 - Y
GND - Bk
Accy1 - Bk/LG
Accy2 - Gy/Y (connected externally to A3)
Accy3 - Gy/Y (connected externally to A2)
Accy4 - Gy/Y
Ign1 - R/LG
Ign2 - not used
Start - R/LB
Proof1 - Bk/LB (diesel)
Proof2 - T/LG.

There was safety recall for earlier year switches, but doubt that you have onew installed by a previous owner, but who knows what was done before you bought it?
Here it is
Recall, Ignition Switch FSA 95S28 for 88-91 Bronco & F Series & many others; On some of the affected vehicles, a short circuit could develop in the ignition switch that could lead to overheating, smoke, and possibly fire in the steering column area of the vehicle. The condition may occur while the vehicle is in use or unattended. To correct this potential condition, the ignition switch will be replaced with a revised design switch. The wiring in the upper steering column area will also be inspected for the installation of any aftermarket electrical accessories. If an improper installation is noted you are to advise the customer of the need to have the condition corrected. These correction costs are not part of this recall. Media Announcement Announcement of this recall may occur in the media sooner than normal. Please order initial parts requirements immediately and be prepared to answer questions from owners. Circulate a copy of this bulletin to all affected dealership personnel. Special Question and Answer Information: A question and answer guide will be provided as soon as possible to assist regions and dealers when responding to customer inquiries. In addition you will be provided further information to help implement this recall as efficiently as possible. Owner Letter SAFETY RECALL 95S28 Ignition Switch Replacement Owner letters will begin to be mailed approximately July 1, 1996. Customers who bring an affected vehicle in for repair before receiving an owner letter should receive repairs promptly at no charge. OASIS and Claims Submission. Because of the large number of vehicles affected, VIN numbers cannot be identified in OASIS until approximately May 15, 1996. Please hold all claims until VIN numbers are identified in OASIS. Claims submitted before OASIS is loaded will automatically be rejected. Questions? Claims Information 1-800-423-8851. Other Recall Questions 1-800-325-5621 Attachments: Attachment I, Administrative Information, Attachment II, Labor Allowances, Parts Ordering Information, Attachment III , Technical Information. Affected Vehicle Identification Numbers cannot be identified in OASIS until approximately May 15, 1996. Before that time, use the list of affected vehicles noted above. For affected 1993 model year vehicles, refer to the vehicle build date found on the radiator support. Correct all vehicles in stock before delivery. Federal law requires dealers to complete any outstanding safety recall service before a new vehicle is delivered to the buyer or lessee. Violation of this requirement by a dealer could result in a civil penalty of up to $1,000 per vehicle. Promptly Correct Affected vehicles identified above. Hold all claims until affected Vehicle Identification Numbers are identified in OASIS which will occur approximately May 15, 1996. Claims submitted before OASIS is loaded will be automatically rejected. Enter claims using DWE. See ACESII Manual, Sections 5 and 6. Warranty and Policy Manual, See Sections 5 and 6 of the ACESII Manual.Refunds, See Section 3-59 of the ACESII Manual.Parts Purge, Return all previous level service stock to your facing PDC. Refer to Attachment II, page 2 for the instructions. All of the ignition switches listed below are to be withdrawn from your inventory and immediately returned, freight prepaid using the least expensive transportation, to your facing PDC within 30 days: E4UZ-11572-A (SW 1916) E4TZ-11572-A (SW 1562A) E6FZ-11572-A (SW 1744B) E7TZ-11572-A (SW 2101) F0LY-11572-A (SW 2219) F2TZ-11572-A (SW 2300) Ignition Switch Replacement: 1. Connect Rotunda Memory Saver 014-R1064 or equivalent. 2. Disconnect battery negative cable. NOTE: Access to the ignition switch varies depending on the vehicle line. In all cases the switch is mounted on the steering column and certain items will need to be removed to gain access. Examine the components around the ignition switch to determine what may need to be removed or positioned out of the way. Refer to the appropriate service repair manual for removal and installation procedures. Once access is gained, proceed as follows. The new ignition switch is shipped in the LOCK position. Keep the ignition lock cylinder (ignition key) in the lock position during this procedure. 3. Disconnect electrical connector from the ignition switch. 4. Remove ignition switch retaining screws. 5. Disengage switch from the actuator pin and remove switch from vehicle. 6. Remove the positioning clip from the new ignition switch if so equipped, and install the switch onto the actuator pin. Align the switch mounting holes with the column lock housing threaded holes. 7. If supplied, install new retaining screws. If re-installing original screws, apply Ford Threadlock and Sealer E0AZ-19554-AA (CXC-70) or equivalent to the threads. Tighten to 6-8 N-m (53-70 in-lb). 8. Connect electrical connector to the ignition switch. Ensure that the connections are tight and fully seated. 9. Connect battery negative cable and remove Rotunda Memory Saver. 10. Check ignition switch for proper function, including START and ACC positions. 11. Check the wiring in the area of the upper steering column. If abrasion or exposure of bare wires is found, repair as necessary. If aftermarket accessory wiring is improperly connected, advise the vehicle owner. Advise also that repairs of such faults are at customer expense. 12. Install any components previously removed for access ensuring that no wires are pinched and the components are properly seated. Refer to appropriate service repair manual as required. READ MORE
Source: by Ford via Chilton

and another, but not for your year;
Ignition Switch - Non-Mating Condition between 14401 Harness Asssembly & Ignition Switch - Vehicles Built after 5/20/94 - Service Tip TSB 94-19-7 for 94 Bronco, F Series, Aerostar, Ranger, Explorer & many others; "...Some vehicles may need re-work of the 14401 wiring harness. While attaching the harness connector to the ignition switch, a non-mating condition may occur. This is due to a design revision (larger tower on switch) of the ignition switch, and not having the proper spacer to clear the switch tower. While re-working any 14401 harness (on affected vehicles built after 5/20/94), determine if the correct spacer (F4TB-14A468-CA) is attached to the ignition switch connector. The correct spacer will allow the "old" or "new" 14A464 connector to mate with the ignition switch assemblies F2DC-11572-AA or F4DC-11572-AA. Refer to the following service procedures. Locate connector assembly F4TB-14A464-AYA or F2TB-14A464-VA and inspect to determine if spacer F4TB-14A468-CA (Service Number F4PZ-14A468-A) is attached (Figure 1). THE SPACER IS GRAY AND THE PART NUMBER IS EMBOSSED ON THE FACE OF THE SPACER. If spacer F2TB-14A468-HA is being used, please discard by prying off. Snap on the "new" spacer F4TB-14A468-CA (Service Number F4PZ-14A468-A). PART NUMBER F4PZ-14A468-A, PART NAME Spacer Wire Connection (Pk/5), CLASS A..."

Source: by Ford
 

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Roller rockers are gay
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OP, try turning the key on and off 5 times the next cold start (that you know it will give you starting problems) this will fully prime the fuel system. IF it fires right up, and doesn't stall, you are bleeding off fuel pressure while it's sitting. this is usually indicative of a fuel pump that is letting fuel drain back into the tank. it might also be a faulty fuel pressure regulator<---this is easy to check, pull the vacuum line off after it's been running for a few minutes. if you smell gas, it's garbage.

the fpr is probably junk if it's original, but replacing it probably won't fix your issue. it is most likely fuel draining back into tank through the fuel pump. or it's a leaky injector, but i doubt that, you'd probably have running issues.

how is your fuel mileage?
 

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I agree with miesk5. Try pulling codes :)

It could be caused by a number of things already suggested, including IAC, lack of fuel pressure, and I'm thinking temperature related things.

Perhaps the PCM is getting info that the engine is warm when it is not. It initially relies on its sensors until it figures out it is still cold, but after a short time it is warm, and runs fine.

I'd like to add as a possibility the ECT.
You could try disconnecting it to see if that makes a difference.

Pulling codes though is the way to go, and you should pull codes before disconnecting the ECT, or you will get a code for it and not know if it is one that you just caused.
 

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Pull Codes = continuous memory and KOEO = key on engine off - KOER = key on engine running if necessary. www.fordfuelinjetion.com for How To.
Test FPR = fuel pressure regulator, there are no codes for this, it's a vaccum issue so you'll need a fuel pressure guage to test PSI......37 psi engine off cranking, 40 psi engine running with the vaccum line disconnected.
Cleaning the IAC = idle air control can't hurt.
Test the TPS = throttle position sensor for voltage setting.
Test the ignition module, TFI = thick film integrated, direct distributor mounted or remote mounted module but several times for passing grade otherwise replace with Motorcraft.

(search)

There is a Ford Racing Performance Parts "idle setting procedure" Instruction Sheet (Techline (800) FORD788) steps 1-9 on How To adjust idle by disconnecting the IAC and drilling out the mounting screw holes on a newer "plug & play" TPS so you can adjust it for voltage setting.
In the past the ideal setting was thought to be .93-.97 volts or just under 1 volt but recently posted information regarding this appears the setting should be between .55v-.75 volts.

Posted by FSB member Jermil01:

Wanted to update this thread based on some TPS adjustment information I got from one of my tuning sites. This goes against the conventional wisdom of setting the TPS closer to .95 range. Thoughts??

Regarding any ECU controlled function (and idling conditions in particular), before any strategy based adjustment can be made by a computer controlled system, it must first run somewhat normally in a default and OL mode.

To do this with a FORD you must first follow a few rules.

You must keep the TPS input above the deadband area and below the "tip in" area. On a FORD this equates to below approximately 0.9V and above 0.45. Anything above 0.90V the ECU thinks the throttle is starting to open. This brings into affect possible dashpot and fuel cut strategies which can turn one grey real fast. Below approx 0.40-0.45V the system suspects an incorrect input and substitutes a default figure.

So first off, the TPS should be set to around 0.55-0.75V.You can also disconnect the IAC then disconnect the battery for 15-20 minutes, reconect and the computer should default back to factory settings.

Good Luck ~ :thumbup
 

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Your homework assignment for tonight is to read and try to understand how to pull codes.

I read three different sources of information, before it actually made sense to me. So read both of the links presented above on how to pull codes.

Despite all the information posted about the TPS, and the ignition switch, it is very unlikely that either is the problem. I say this because neither is affected by a hot vs cold engine. Well maybe the TPS could be, but it would be more likely to fail HOT than cold, and your problem is when it is cold. Not only that... if the TPS never reports a voltage below 1.0 volts, it will set a code that you will pick up when you pull codes.
 

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Discussion Starter #15
I am still getting the hang of pulling the codes but here is KOEO codes.
334,556.

With KOER I got a 111.

The fuel pump was replaced 2 years 15,000miles ago same with the fuel filter.
The MAF was cleaned on the last tune up two weeks ago. There is a Superchip on her so I burn 93. Thanks.
 

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556 = fuel pump circuit failure
 

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Discussion Starter #17
Any advice on plan of attack given the codes and symptoms?

I read 556 could mean a stall had occured.
 

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yo,
DTC 556
Possible causes:
Inertia Fuel Shutoff (IFS) switch not reset or electrically open (if in primary circuit). Inertia Fuel Shutoff (IFS) switch not reset or electrically open (if in primary circuit). Check switch; pass side, inside kick panel;
reset the IFS switch by pushing the reset button on the top of the switch (refer to Owner Guide). Note in the closed position the Source: by Ford via miesk5 at FSB

Open or shorted circuit.
Damaged fuel pump relay. Pull FP Relay and ck for corrosion on terminals and in socket; some have found a bad wire there. Swap FP relay w/Horn Relay (or Trailer Marker Lamps Relay) in Power Distribution Box - Diagram in a 94 Bronco & F-Series

Source: by Ford via Steve83

Damaged Powertrain Control Module (PCM).
---

as I mentioned in another thread here; In place of the breakout box, go to the EEC pin instead; for instance - Measure resistance between Test Pin 22 at the breakout box and battery negative post.
.... Substitute EEC for "breakout box"

EEC IV Connector Pin Diagram
Source: by Fireguy50 (Ryan M)
EEC Connector Pin Outs, Bronco & Ford Truck & Van: 4.9, 460, 5.0, 5.8; miesk5 Note, see his Connector Pin Diagram Link above)
Source: by Ryan M (Fireguy50) at http://fordfuelinjection.com/truckpinouts.html

Disconnect fuel pump relay.
Key on, engine off.
Measure voltage between VPWR circuit at the fuel pump relay vehicle harness connector and chassis ground.
Is voltage greater than 10.5 volts?
Yes GO to J2.
No VERIFY integrity of IFS switch. If OK, SERVICE open in VPWR circuit between the EEC power relay and the fuel pump relay. RECONNECT fuel pump relay. RERUN Quick Test.

J2 CHECK FUEL PUMP RELAY
Key off.
Fuel pump relay disconnected.
DVOM on 200 ohm scale.
Check fuel pump relay coil resistance:
For "ISO" relays, measure resistance between Pins 85 and 86 at the fuel pump relay (pin numbers molded on relay).
For other types of relays, measure resistance between VPWR pin and fuel pump circuit pin at the fuel pump relay.
Resistance should be between 40 and 85 ohms.
DVOM on 10,000 ohm scale.
Check fuel pump relay for internal shorts.
For "ISO" relays, (these are the Bosch style used in 92-96) measure resistance between Pin 85 and both Pins 30 and 87 at the fuel pump relay. For other types of relays, measure resistance between the fuel pump circuit pin and both the power-to-pump and B(+) pins at the fuel pump relay.
Both resistances should be greater than 10,000 ohms.
Are all resistance checks OK?
Yes GO to J3.
No REPLACE fuel pump relay. RERUN Quick Test.

J3 CHECK FUEL PUMP CIRCUIT FOR SHORT TO POWER
Key off.
Fuel pump relay disconnected.
Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Key on, engine off.
Measure voltage between Test Pin 22 at the breakout box and battery negative post.
Is voltage less than 1.0 volt?
Yes GO to J4.
No SERVICE short circuit. REMOVE breakout box. RECONNECT all components. ATTEMPT to start vehicle. If vehicle fails to start, REPLACE PCM. RERUN Quick Test.

J4 CHECK FUEL PUMP CIRCUIT FOR SHORT TO GROUND
Key off.
Breakout box installed, PCM disconnected.
Fuel pump relay disconnected.
Measure resistance between Test Pin 22 and Test Pins 40 and 60 at the breakout box.
Is resistance greater than 10,000 ohms?
Yes GO to J5.
No SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.

J5 CHECK FUEL PUMP CIRCUIT CONTINUITY
Key off.
Breakout box installed, PCM disconnected.
Fuel pump relay disconnected.
Measure resistance between fuel pump circuit at the fuel pump relay vehicle harness connector and Test Pin 22 at the breakout box.
Is resistance less than 5.0 ohms?
Yes REPLACE PCM. RECONNECT fuel pump relay. RERUN Quick Test.
No SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.
 

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for what it is worth, since the pump was replaced, I would throw a relay in for the pump. they get worn out over time, unless you put a new relay in recently.
 

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Boy, you've gotten a lot of terriffic advice!

I just looked up code 334... DPFE or EVP circuit above the closed limit of 0.67 volts.

I'm asking those who are more knowledgeable than I. Could it be that the EGR is staying open when the engine is cold introducing a vacuum leak that the engine is having difficulty dealing with when cold?
 
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