Ford F-350 Pick-up

1997 Ford F-350 Pick-up Electrical / Lighting Systems Malfunction When driving When cold

After driving about 25 miles or so, the odometer and speedometer kick out and the overdrive lite on shift lever starts flashing. The trans also goes into failsafe mode. It is worse in wet weather. It is a intermitant problem. Sometimes when you hit a bump it will come back on, but usally you have to stop and shut off the truck for a while. Help! Tim

Hello, Here are some thoughts that come to mind.

It works for awhile before it drops out. It's likely that the Vehicle Speed Sensor is the component that quits working and the result is the speedo/odometer stop working and the trans goes to fail safe (limp) mode.

A poor connection at the speed sensor or a bad ground connection for the related circuit could be things to look for. Heat builds up where connections are loose or dirty. Heat means resistance.

The system "fixing itself" by hitting a bump suggests the wiring connection may be loose. Shutting the truck off for awhile with a favorable result suggests that a connection is "cooling down" which of course would lower resistance and restore current flow.

Take a look at the Vehicle Speed Sensor electrical connector terminals for condition, tight fit, weather proof seal, etc. If all appears good try replacing the sensor itself.

Your thoughts?,

Roger

I have already replaced two sensors with same results. Trying to find out what all is on this circuit. I've ordered complete manual with complete wiring harness, maybee this will lead me somewhere. Nobody I've talked to has ever encountered this problem. Thanks, I'll stay in touch. Tim

Tim, Will you please send me your email address or a fax number? I have a schematic that might be useful to you.

Thanks,

Roger

High Roger, here is my email address. [redacted]
Thanks, Tim

This vehicle may use the PSOM (speedo/odometer module) and may have a bad connection or internal failure.

1994 Ford F-350 Pick-up Ignition System   

I have a 1994 Itasca 32' RV that is considered a F53 stripped chassis or rated as a f350. It runs very smooth once above 30mph. It pops and bucks very hard when accelerating from a dead stop. Just did my own major tune up. New o2 sensor, plugs, wires and cap. Symptom is still there ? No codes ever and once under way runs smooth no misses. It only has 32k miles. Can it be a TPS or MAF?

Hello
Is it doing it while in park or nuetual, or is it doing when transmission is engaged?

Hello
Sounds alot like a coil on plug assembly gone bad to me. With it not showing any codes, and with it running rough like you say.
Heavychevy

I forgot to mention that it's a Ford 7.5 (G) and yes it does it while in gear while trying to move forward. What is a "coil on plug assembly ?" Are you talking about the coil itself?

Ok good 7.5 gas. I would recomend checking all the vacuum lines. Sounds like a vacuum leak (even a small one can give you problems). You can check this by spraying carb cleaner near the suspected leak (not recommended though with it being flammable). This is what most people do. If there is a leak the cleaner will be sucked into the engine causing a small change in how its running. Not recommended though it is a flamable substance.
Heavychevy

.

..

No vacuum leaks could be detected by spraying carb cleaner. No change in idle or nothing. I replaced the TPS and it greatly reduced it but still does it? Where is the spout connector pin located on these F53 stripped chassis. I would like to verify timing.

its located beside the mass airflow sensor and infront of the brake booster and resovoir. its about a couple inches long and half that wide.

,,

/

The spout connector was no where near the brake booster or Map sensor. It was located behind the drivers headlight next to the ICM. Not an easy find !
When I first checked the timing it was right on as the manual stated 10 degrees BTDC. I moved it to 14 degrees BTDC and it solved my problem. Like night and day. Plenty of power and runs strong. No ping or detonation and starts easy. Problem solved..........for now! LOL! Thanks

Glad to hear you got it worked out.
Heavychevy

//

Just doing a follow up th check on the progress og you Pick Up.
Heavychevy

1993 Ford F-350 Pick-up Chassis / Suspension & Steering Vibration When driving No pattern

I have a 1993 F350 Superduty, standard transmission, 4 x 2, Gas truck with a 19' Jerr Dan flatbed I use for my business (towing) regardless if I am loaded or unloaded I am off and on experiencing some very rough, strong vibration that shakes the whole truck, it feels like the damn thing is going to shake apart, so much so it makes it difficult to steer and stop so far I have only had this happen doing 30 to 40 mph on back roads, not loaded doing 65 on the highway, nothing appears to be damaged, tires are new, brakes are all in good shape, steering components seems to be alright also, no obvious damage or trouble. What do you believe this could be?

It could be driveshaft related. I have run across several trucks with your described symptoms and have found the driveshaft out of balance.This is about all that comes to mind as long as the front suspension is all tight. Good luck and happy new year.

Walt Boyer
ASE Master Tech

I thought that I would receive a more detailed response to my question.

The answer was pretty general and broad.

How do I fix it, where do I start to look?

What am I looking for?

raise the rear end up until rear tires are off the ground. Support rear axle housing with jackstands. Start truck up and put into gear. Have an assistant raise mph of engine to your problem speed. Observe driveshaft for any vibration. You will also feel the vibration in the truck. This will be a good way to isolate it to the driveshaft. If it is the driveshaft, remove it and take it to your local driveshaft specialist (yellow pages)and they can rebalance it or suggest replacement.
To check your front end for play, raise the front of the truck off the ground. grab the front tire (left or right) and try to move it side to side by grabbing the tire at the
9 & 3 position observe any loose feeling. this checks the tie rod ends, idler arm, & pitman arm for looseness. Next grab the tire at the 12 & 6 positionand try to move the tire back and forth... this checks for bad ball joints. You will also be able to see if the wheel bearings are loose. Hope this is a bit more detailed. For more in depth explainations you can Email me at [redacted] upon accepting this

1989 Ford F-350 Pick-up Engine Lagging When driving Always

I replaced exhaust manifolds and removed all emissions devises . both intake and exhaust. Now truck falls flat on its face how can i overcome this without replacing emissions system?

Which engine do you have, efi?

Yes EFI

Your best bet is to check for stored trouble codes. You'll likely have several. Some will only effect fuel economy/emmissions/etc while others will be critical to performance. Use the following link to access a repair guide that has instructions under Emmissions and Driveability (or similar).

http://autozone.com/servlet/UiBroker?UseCase=RG001&UserAction=viewRepairGuideYMMEYear

Let me know which codes you find.

Did you eliminate sensors on the throttle body (modern equivalent of a carburetor)?

Did you plug the egr passageway in the intake, I assumed you removed the egr valve?

The egr valve is still installed I dont think any thing was removed from throttle body position sensor. The codes indicated . 31 Egr valve position or exhaust pressure transducer sensor voltage low.
No gas oxegen switching detected always indicating Lean.

Truck when driven smells of fuel like its running very rich ?

First of all check the fuel pressure regulator vacuum hose to see if it smells like raw gasoline.

Douglas : How do I Identify the Fuel Pressure Regulator Vacuume Hose?

The site I offered-

http://autozone.com/servlet/UiBroker?UseCase=RG001&UserAction=viewRepairGuideYMMEYear

will contain a repair guide that'll show a picture of the fuel pressure regulator under 'FUEL SYSTEMS'. Let me know if you have trouble accessing the link.

Ok I did get into the site and made some copies of fuel and emissions system. Thank you. I located fuel pressure regulator and checked it for raw fuel smell with and without engine running, with and without vacuume line hooked up could detect no raw fuel smell.

Diconnect the controls to the egr valve and test drive. Note is there is any change.

Did you eliminate any other emissions devices other than the oxygen sensors?

Try unplugging the coolant temperature sensor and see if there is an improvement.

I disconnectedegr and did not seem to make a differance.
As I said before all emmissions divices have been removed. Changed exhaust manifolds and the new ones do not have taped holes for MTA system. So the MTA emissions pump is just used as a idler pully no airlines hooked up. Also Evaperative emission control system removedunder the hood only.
The oxygen sensor just ahead of convert is still installed. The catalytic converter is still installed. The egr valve is still installed Crank case ventsystem is still installed. Thier does not seem to be any vacuum leaks as I check them by spray starting fluid near them as it was idling.

How is the idle? Did you plug any vacuum lines that go to the intake, ones you may have disconnected?

If the oxygen sensor is not switching and always indicating lean, you likely have an air leak or a dead sensor.

Are the plugs and wires okay?

It Idles ok . I was not the one who removedthe devices , I will check with schematic to see if air lines to intake manifold are pluged or capped. Plugs are new wires seem to be fine . It ran just fine prior to removing the devices. How do I determine a dead sensor?

You can test the sensor with a voltmeter, although without a good voltmeter it is tricky. The oxygen sensor produces a small amount of voltage, so a digital voltmeter is needed. The problem is a oxygen sensor switches so quickly the voltmeter will effectively average the voltage coming from the sensor. That said, it can still be used to see if the sensor is staying at low voltage.

Measure the voltage with the voltmeter set on a low voltage scale. The voltage should fluctuate from .1 or .2 volts to .8 or .9 volts. This should happen very quickly and average on the voltmeter at .4x - .5x volts. If it stays low you can enrich the fuel mixture by adding propane to a vacuum hose (you likely have one plugged off). This will surely richen the mixture and the voltage should rise. If it doesn't rise or never registers any voltage (dead sensor) the sensor is bad and at least contributing to your problem.

Be very careful with propane, if you are not comfortabe with this step don't do it- an exhaust leak or ignition spark from a plug wire can igntite the propane. Don't use much at once to avoid danger.

The site I offered before likely has simpler test procedures, but requires removing the sensor. You simply heat the sensor with a propane torch while monitoring voltage.

Douglas : sorry about the delay I was out of town. I did test the oxygen sensor with a digital meter Started with engine cold it read 15mv. After about 5 min. into warm up it read 56.4 mv. I did not do the propane test. while doing this test I had computer hooked up and after clearing memory it gave me the same saying oxygen sensor not switching . do you suppose one of the wire from sensor to computer could be faulty?. There were 3 wires black , white , and blk/white. or is the mv. values incorrect as to indicate a bad sensor? Or ???

1974 Ford F-350 Pick-up Engine  When idling Always

I have a '74 F-350,390 bored .40 over,Edelbrock Performer intake,1850 Holley 4bbl carb. Recent repairs/improvements include,chaged points to Pertronix elec. ign.,rebuilt carb. I continue to have trouble with extremely rough idle,acceleration and power are fine. While searching for vacum leaks,I discovered that if I disconnect PCV valve from carb. the idle smooths right out,but it sounds like a Hoover vacum cleaner. I replaced the PCV valve but it made zero difference. It still idles very rough unless I pull the vacum line loose from the carb. or the PCV valve. Can you help?

Hi;
Sounds like your power valve in the carb is leaking. Try turning your air mix screws all the way in. This should kill the engine. If it does not than most likely the power valve in the carb is leaking. On holley carbs all it takes is just one backfire and it will blow the power valve. Good Luck Les.