Ford 7.3L Power Stroke (1999-2003) :: Alternator Light Comes On While Accelerating And Goes Off During No Throttle While Cold
Jul 3, 2016
Background: '01 Excursion 7.3 4WD, 264,xxx miles, batteries less than three years old, new alternator [URL] .... , using an Edge Insight for digital readings.
Problem: I replaced the alternator about three weeks ago, first week all normal. Second week alt/battery idiot light comes on, then to add more frustration it is consistently inconsistent in its reading.
The volts (upon starting) jump around 11.6 - 12.1 when first starting. The light comes on while accelerating and goes off during no throttle while cold.
After warm-up the light will come on intermittently even though the reading is 13.0>, but never during off throttle.
It seems to do this more when cold but it does not completely stop when it's warm. Yes, I don't think that should be a factor but it is a reality .
I'm thinking it's a bad voltage regulator.
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The past few weeks the dashboard warning light for my alternator/battery will occasionally light up while driving down the road. Whenever it does, my plug in voltage meter shows a healthy 14.x reading. It usually goes out after a few seconds, but will stay lit up for as much as thirty seconds. So other than voltage being too high or too low, what else will cause the dash trouble light to illuminate?
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Alternator locked up in a parking lot. Replaced it and had to replace pigtail due to a loose wire in the harness. Now battery light comes on intermittently. New alternator is doing fine producing anywhere from 13.9v to. 14.4v. No output voltage correlation to battery light at all. The belt is still in great shape so I don't suspect slipping. Fortunately I caught the old one locking up almost immediately and had recently replaced the belt. Output voltage looks great. Are there any fuses for alternator?
Only thing I can think of that I did...when splicing in the pigtail that connects to the alternator, I briefly grounded whatever wire in the pigtail is hot. Was just a split second, but enough to see a spark and maybe enough to blow a fuse? I've seen people reference an "under hood" fuse box, but I don't seem to have one. My truck is a 2002 CC with just over 100k on the clock.
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Had a bad alternator, changed it, and now the battery lite stays on all the time..Changed the alternator again with a known good one, and the light is still on all the time..
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I have a '01 7.3 Excursion 2WD. 220,000 miles. It has a 4" exhaust, K&N filter and Edge Reprogrammer set on emission illegal. It gets the best fuel economy and moves out very well for 8000 lbs. Recently, I started to feel a surge while making light throttle acceleration. For example, round a corner at 35 and try to gently resume the 45 Speed limit. It begins to accelerate and then cuts out or surges, sometimes several times. If I lay into it, it responds fine. I have serviced the air filter, the fuel filter, use synthetic Amsoil. I did notice a slight improvement after the service. Less frequent cutting out or surging. I also was in an area where Bio diesel is readily available. I added almost a full tank of B10 Bio and it seemed to work. Changed the fuel filter just after.
It has been cold for NC. This morning it was +14 when I started the truck. It seemed to finally catch on maybe 2 cylinders with lots o' white/ blue smoke. It cleared out in a few minutes and seemed to be hitting on all 8, or at least 7. Once it warmed up, it's fine. But I had the codes p0672, p0674, p0676, p0678. My question is: Is there a common thread in the fact that it appears that I lost 4 glow plugs on the same bank?
One arm chair quarter back's response to the surging, is that the under valve cover injector wiring harness may be breaking down, especially since the truck has 220,000 and the valve covers have never been off. I have a fresh turbo with the good wheel sitting ready. I have just been too lazy to swap it out. Would a fresh set of injectors be a wise choice, when I swap over?
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I have a 2002 F250 4x4 Powerstroke with Automatic. I have been having off and on issues for months with the throttle going dead. This only happens when I start it, if it works when started it will continue working until a different start session.
I have replaced the pedal several times before learning how to check its output with a meter and am quite sure that is not my issue at this time. However, when the pedal is depressed the check engine light lites up and nothing happens.
I am thinking it must be the computer itself, but was told there is another sensor or module under the hood that could cause the issue also which is several hundred dollars to replace as would be the computer.
Is there a way to test the computer, and what is this other module/sensor if it exists that could be the issue? Unhooking and rehooking the battery to reset the computer is no longer working to buy me a few more weeks, is there a simple way to reset the computer to try?
I love this truck when the throttle works but I am getting tired of paying on a truck while having to borrow a vehicle to drive to work.
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The brief information:
1. Stuck/non moving in traffic on the freeway for roughly 1 1/2. During that time the AC was running, but once I noticed my "battery light" on the dash turn on, I turned everything off.
2. Since then while on my way home from work the voltage meter only showed barely 12 volts at full throttle.
3. I charged my battteries, and started it up today to go into work. While going to work the voltage meter showed 14 at its high point, but shortly there after it dropped back down to 12. At which time the battery light came back on.
New battery or alternator?
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I bought a 99 f-250 7.3 a month or so ago and am impressed with the level of knowledge and hospitality you all show. This is my first diesel so I am completely new to a lot of the issues that occur with one and many of the diagnostic tests needed to troubleshoot.
When I purchased the truck the guy said it was very cold natured and I would have to plug in the block heater if it got chilly out. I didn't realize just how bad that problem was and have since had to keep it plugged in even on very mild nights to get a quick start. I have been very careful to let it warm up for 15-20 mins before I start driving it.
Also, I have noticed at around 40-55 MPH and light pressure on the gas I get a shudder, it was worse before I added a friction modifier to the oil but it is still there constant in overdrive.
As I was driving two or three days ago in a light rain (the first since I bought the truck) I noticed the SES pop on and stay on. Being new to the diesel world I immediately pulled into Autozone and tried to get a code, but with no luck. The truck has been running a bit rougher since the light came on and I am noticing a marginal power loss.
So my questions are: Where can I get the codes pulled off? I have been looking at buying a scan tool but the AE is out of my price range and the other options seem to have mixed results. Also, do any of the problems seem to be related or could it just be a few different issues that need to be ferreted out? From what I've read it seems possible for the UVCH to be the issue here, is that correct?
Again, I am really new to diesels so I may have been having loss of power even before this and not known it due to my inexperience.
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I am having an overcharging issue with my 2000 F350 diesel. It first started when I had a garage check the batteries due to poor starting this winter. They found one reading 6V and I had them replace it. After that the battery light came on. So I had them check it out again and they replaced the other battery. I can't remember if it started before or after the second battery but it started overcharging 16-17 volts according to the dash. I replaced the alternator still overcharging. Since then I have run a 4ga ground from one battery to the alternator and a 4ga ground wire from the other battery to the cab. I also checked most of the stock ground wires which all seem fine. Lastly, I also bought a ford alternator pigtail because one of the wires had cracked insulation and some corrosion. Currently it overcharges unless the battery light comes on which once it does the voltmeter in dash reads normal.
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On my 7.3 super cab, I changed the fuel filter last Friday and now on cold start the service engine soon light comes on for a couple minutes (approximately) on a cold start. No other issues. Tried scanning with my scan gauge 2 and no codes. (of coarse I think that thing is a joke for scanning). Not sure if this means anything, but last week before I changed the filter I thought I smelled diesel fuel on a couple different occasions. If I actually did it may not even be related.
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This morning on my way to work I pulled up to a light and the check engine light came on. I went to go and had no throttle response at all. The truck just idled through the intersection. About 45 seconds later the light went out and truck ran fine all the way back to work. What to look for or what it could have been.
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i got a 99 F250 powerstroke with 148K on its clock, i have a couple issues that i cant find a definitive answer for, 1 just started recently, Its an automatic and when it shifts into third around 40 mph the rpms drop to 1200-1300 or so, its done it since i got it, but recently it wont accelerate like it should or used to do, i have to put it down and make it downshift to recover.
Now I have no CEL. and it is still running perfect just has very little power, I do have a 4 inch turbo back exhaust and have a TS 6 position chip with i usually run in +50hp mode, but it does this in all positions. Now issue 2 is when its 30 degrees sometimes it will not start. It'll turn over with now fire. but if i cycle the key again it'll fire right up like a champ? It has a 4 month old starter and batteries and a month old alternator and i have tried several CPS' and Contently check the connections.
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I just put a regulated return system, two external filters and two fuel pumps, and I am still have problems.
Under acceleration driving it drops to almost 20 psi and that only 1/4 throttle.
3/4 throttle drops to 10 psi and barely idel. Died twice a block away from my house of test drives.
Tank is done with mods, new cps, icp, and ipr.
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My 7.3 has no throttle response, the code reader says pass, and there are no codes, would it do this even thow it has a bad TPS?
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Comming back from hunting today my truck suddenly lost power and stepping on the accelearator had no effect at all. We were on the highway thru the mountains but on a fairly level stretch for a few miles. Managed to pull the truck and toy hauler over and the engine was running fine but stepping on the accelerator had no effect. The check engine light came on every time I stepped on the throttle and went out when I released it. It started fine but no throttle response. Switched around a bunch of relays and checked the fuses and still nothing.
Not liking my parking spot i tried to see if it would move down the road at an idle but it would not. Then I thought to try it in 4 wheel low and as the shoulders were soft it wouldn't move forward so tried reverse and went back a foot, forward again and moved a foot and a half. did this several times and all of a sudden the throttle responded, took it out of 4 wheel and it ran fine all the way home. What would have caused this? I was ready to call a tow truck which would have been several hundred dollar bills for where we were and with the trailer
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When I let off on the throttle the truck jerk forward a little. It does it some times when hitting the throttle too. I have changed u joints in the drive shaft. I noticed the carrier bearing has a little play (going to change it this weekend). But I wouldn't think that would cause this.
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I have a 99 F450 with the 7.3L in it. I brought it home the other day and parked it. Later I went to do something with it and I had no throttle response at all. I checked the wiring going in and coming out of the throttle position sensor. I have approx. 5 volts going in and the voltage sits at about .5 volts and rises as the accelerator is depressed on the outgoing wire. The other switch on the pedal is open and does close when the pedal is depressed, so it seems those are fine. I'm not sure what I'm supposed to have on the 3rd wire that goes to the TPS.
I have a Bully Dog tuner and it shows an exhaust back pressure sensor error and a couple of voltage errors to the accelerator pedal. I read somewhere that someone had an exhaust sensor short out and it starved the accelerator pedal from voltage or something like that but I do have good voltage at the pedal going in and out. I ordered a new sensor and tube.
If the exhaust pressure sensor was shorting out and I unhooked the wires could that make the pedal work if the sensor was the problem or would the accelerator pedal not work at all without that sensor being connected? (The old tube was somewhat plugged up and I saw it had a small rust hole in it)
If it's not the sensor, what else can I check? Where can I check under the hood to see if the wires from the TPS are getting power to where they need to? I assume they go to the computer and that tells the pump or whatever to give more fuel.
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Ok, still working out some issues: It may be normal, but I hear (not feel) a slight roar when I'm pressing throttle petal very lightly. Seems to do it as we'll when I'm backing off throttle but it stops when I let off pedal completely. Not there when I get into the pedal. Not the tires because it stops all together when I get off throttle and let it roll. Turbo maybe ? Rear end (wouldn't it do it even when rolling)? No vibrations at all....just a little roar.
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My issue can be while driving with cruise on, or accelerating, the truck just losses power, then recovers. At idle, the rpm can, but not always, fluctuate.
There is no "misfire" when it happens, but it just falls on its face. I have NO diagnostic tools, and my injectors are not stock, so I am unable to unplug my DP.
My thoughts are to unplug the ICP and give that a shot? Meanwhile, I will put in a order for a elm327
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My 2002 f250 starts but has no throttle, I did replace the throttle body, still no luck, i did find a wire on the shiffter that had a bad spot , fixxed it still no throttle, code reader says it passes with no codes, I disconnected both batteries and waited 15 to 20 min, reconnected them, started the truck and let it idle for 20 min so what do i need to do now. I just cant figure it out....
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I have a 1999 f-250 super duty 7.3 .... Recently my truck has started making a humming noise when push the throttle and I can feel a slight vibration, the noise and vibration go away when I let off the throttle, I have changed all five u joints, both wheel bearings in the front, the steady bearing, changed tranny and both diff oils, put new brakes and calipers all around and pulled apart the hubs but I can't seem to find what's causing it. What it could be or what I could check? It has an 8 inch lift and is sitting on 37's and some performance upgrades, could any of that cause this ?
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