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Stalling/Fuel/Heat Problem

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I'm a very novice mechanic and I have limited funds...so here's the story. I have a 94 Bronco with the 5.8. I have just recently changed the plugs, wires, water pump, thermostat, fuel pump and filter and, cap and rotor. The problem I'm having just started after the water pump went bad (maybe just a coincidence).

 

When she gets up to operating temp, she starts to sputter and stall. I pulled over and it seemed fine. Tried to go on she backfired under the hood. I stopped and then she quit on me. Had it towed to the shop and it started fine. They checked it out and said that the water pump was faulty and was shooting water into the distributor. They changed the cap and rotor. Next day, same problem. I avoided the tow charge and just let it cool off and drove it back to the shop. They think its the fuel pump. They said the fuel pressure was 8 pounds less than it should be. The shop that fixed the fuel pump says two things, fuel pump works or it doesn't, and that it sounds like a thermal problem (electrical or sensors) since it runs fine until it gets hot.

 

I drove in town this morning for about 30 minutes and it seemed fine. But this has been happening at highway speeds, mostly on interstate.

 

I don't believe it's the TPS. I am at a loss. If it's the fuel pump, it's under warranty. I just don't have the skill or knowledge to troubleshoot this on my own. I know that simply changing parts is not troubleshooting.

 

I welcome any advice or suggestions.

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is your check engine light on? have you pulled codes?

 

how to pull codes

 

sensor info

 

 

 

I have not pulled codes. The mechanic says there were no codes.

 

When if first happened to me, the check engine light came on and stayed. It is not on now.

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First thing that popped into my head was putting in the t-stat in backwards? In which case the truck might be overheating?

 

There is a fuel pump relay....I don't really know but maybe the relay is only working sometimes and the other times ( when it gets hot ) it quits and then no gas?

 

Anybody else have any thoughts on the relay?

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i would try pulling codes first. it's pretty simple and gives you a direction to go. i would also try to run the truck to the point it quits, providing it's not overheating, then hook up a timing light to the coil to distributor cap wire and make sure she has spark. the ignition module can be heat sensitive, but i would think it would have completely failed by now. as for your fuel pressure issue, there is a pressure regulator on the fuel rail, drivers side. there is also a valve for attaching your own fuel pressure gauge. it could be an iac issue. i'm not trying to be a wise ass, you're going to have to get your hands dirty or your bronco can quickly get expensive. just take it one step at a time and check in here with questions, the combined knowledge of the guys here is better than most ford dealers.

Edited by bobstrat

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I would say that the temperature sensor is going. its not 100% faulty or it would have caused a code, If I am not mistaken the Temp sensor acts like the choke to the computer, depending on the temp the computer changes the amount of fuel that gets used. cold signal gets more fuel, hot signal gets less fuel.

 

hope it helps

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i would try pulling codes first. it's pretty simple and gives you a direction to go. i would also try to run the truck to the point it quits, providing it's not overheating, then hook up a timing light to the coil to distributor cap wire and make sure she has spark. the ignition module can be heat sensitive, but i would think it would have completely failed by now. as for your fuel pressure issue, there is a pressure regulator on the fuel rail, drivers side. there is also a valve for attaching your own fuel pressure gauge. it could be an iac issue. i'm not trying to be a wise ass, you're going to have to get your hands dirty or your bronco can quickly get expensive. just take it one step at a time and check in here with questions, the combined knowledge of the guys here is better than most ford dealers.

 

First, thanks for all the help. It is greatly appreciated. I went ahead and rolled the dice and pulld the fuel pump myself. The pump did not have the sock on it and the pump was clogged. It looked like the foil from a gas treatment container stuck in the pump. Put it all back and she runs great now. There was a slight hesitation with acceleration at first...but she runs now.

 

I ask questions of this group because you guys know more than most about Broncos. Thanks again. I'm moving on to airbag fault code 51 and where that is!!

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yo!

51 Air Bag Diagnostic Monitor Internal Thermal Fuse � Fuse Blown Due to Intermittent Short to ground

 

The thermal fuse is located inside the air bag module ,,,and it not serviceable,,,you have to replace the air bag module AFTER finding da short.

This is for a Taurus, but similar; my 96's EVTM/PCED disc is @ home so maybe this will help for now.

 

DTC 51 The diagnostic monitor contains an internal thermal fuse that is not serviceable. "...The thermal fuse is controlled by the diagnostic monitor. The diagnostic monitor will blow the thermal fuse whenever a short on the deployment circuits occurs. The thermal fuse does not blow because of excessive current flowing through it. DO NOT attempt to jumper out the thermal fuse with a circuit breaker or any other type of fuse. WARNING: DO NOT INSTALL A NEW DIAGNOSTIC MONITOR UNTIL THE SHORT HAS BEEN LOCATED AND CORRECTED.

The diagnostic monitor measures the voltages at the diagnostic monitor connector Pins. When certain air bag deployment wires are shorted to ground (heavy lines illustrated in the electrical schematic above), the system may become susceptible to unwanted deployment of the air bag(s). The diagnostic monitor senses a short to ground on any of these circuits and helps prevent unwanted air bag deployment by blowing the diagnostic monitor thermal fuse.

Blowing this fuse removes all power (battery and back-up power) from the air bag deployment circuits. While the short to ground exists, the monitor will flash diagnostic trouble code 13 or code 14, depending on where the short appears (see code 13 and 14 for more details).

 

If the short to ground is intermittent and temporarily corrects itself, the diagnostic monitor will flash code 51.

 

NOTE: If the short to ground returns, the higher priority codes 13 or 14 will be flashed instead of 51.

 

If the Air Bag indicator is flashing code 51 and a short to ground has not been serviced, this means that an intermittent short to ground exists in the air bag system. The diagnostic monitor should be replaced only after service of the intermittent short has been completed.

 

Some service tips for finding an intermittent short to ground are: 1. Consult OASIS (Restraint Systems service Code 104000) for up to date diagnostics and descriptions of wiring concern locations for the vehicle (VIN number) you are working on.

OASIS is updated daily using concern descriptions from engineering and Dealership Service sources. 2. Inspect wiring and harnesses in areas where they pass through or are located next to metal components (i.e. engine compartment bulkhead, body sheet metal, component mounting brackets, etc.)

 

Code 51 After Air Bag Deployment NOTE: Diagnostic monitors can withstand several air bag deployments and do not need to be replaced after every deployment. Only replace the diagnostic monitor if it is damaged. Occasionally, after an air bag deploys, the internal wiring of the air bag(s) may become shorted to the metal housings of the air bag(s). This internal air bag short is detected by the diagnostic monitor as a short to ground in the air bag deployment wiring. Since the diagnostic monitor is still operating immediately after most deployments, the monitor will detect the short and will flash code 13 and blow its internal thermal fuse. After the deployment, as the air bag(s) cool off, the internal shorted wiring may correct itself, therefore the short to ground will no longer exist and the diagnostic monitor will flash code 51. If a vehicle with a deployed air bag is flashing code 51, inspect the vehicle for crushed wiring, sensors, etc. and replace as required. If no damage is found, assume that the deployed air bag was the cause for the intermittent short and replace the diagnostic monitor when the new air bag(s) are installed. After a short to ground has been corrected, the diagnostic monitor will flash out Diagnostic Trouble Code 51. Diagnostic Trouble Code 51 indicates that the thermal fuse inside the diagnostic monitor is blown and the short to ground no longer exists. If a short to ground has not been located and serviced (short to ground corrected itself), consult OASIS for potential wiring shorts. If a short to ground has been correctly located and serviced then replace diagnostic monitor. DO NOT replace diagnostic monitor until the short to ground has been positively located and serviced. Replacing diagnostic monitor before servicing a short to ground will result in repeat service..."

Source: by Ford via miesk5

-------------

 

Troubleshooting, Wiring Diagram, Overview & Codes for 94-96 by STEVE83 http://www.supermotors.net/vehicles/registry/media/472207_1

airbagcircuit96.jpg

 

In the diagram see the Note: "This shorting bar in the gray diagnostic monitor harness connector, Remove the plastic wedge in the gray connector before checking circuit 824 or 817 for a short to ground." Now, I believe the ckts should be 624 or 617

for da Clock Spring/etc. ckt & Front Sensor ckts;

 

So, Sensor, Front Location & pics in a 96; on the left and right front radiator supports

Source: by ThetaTauMan (Rob, UTURNOB163) at SuperMotors.net http://www.supermotors.net/vehicles/registry/17516/66626

 

my lousy Comcast service stinks... half the time, I can't open a SM page... no viri or adware/malware or hardware problems.. suspecting neighbor whose relative stops by their home at least 3 to 5 times a month and spends time on da Pole...

 

best bet is to spend about $7 to $12.00 on the Ford EVTM/PCED... it has saved me much $$$ !!!! See Steve83 for one.. very reliable!

 

DISABLE PROCEDURE AND TIME (Always Check the Service Manual)

* Disconnect And Shield Positive And Negative Battery Cables... etc.....

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@-) mmlopy

 

We have ways of getting rid of spa,,ers too.

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