Hey All,
I need your help, advice, troubleshooting skills- all of the above- for my 2001 Excursion 7.3 PSD 4x4 LTD. This past summer I experienced a problem that's hard to describe, so I'll do my best.One afternoon I went out to the truck, started it as normal, waiting the few seconds for the "Wait to Start" light to go out and turned the key to start. Everything that I'd been doing for the last (almost) two years. The truck started fine, put in drive and away I went for about 30 feet, then the engine lost about 90% of it's power. I stopped and put it in neutral where it tried to idle, down just above 500 rpm, normal idle is around 700 to 750. The engine shook and sounded like it would quit, but it never did quit, just sounded like it wanted to. The O/D light at the end of the gear selector was flashing, the ABS light came on, the battery pictogram was lit and the "Service Engine Soon" was lit also. It stayed that way for awhile. When I would rev the engine in neutral or park, it would rev, but it sounded like about 2 pistons were firing and the other 6 were either holding the rest back or mis-firing. When I put it back in Drive, no matter how much I pushed down on the accelerator, the truck would only crawl, first at around 5 mph, but if I stayed on flat terrain it would gain speed, up to about 15 mph. If I tried to go uphill, it would barely move. Then when the engine completely heated up, everything went back to normal. Within a few on- off cycles of the ignition key, the "Service Engine Soon" light went out which was the last of the warning lights to clear- actually- all the other error or warning lights went out as soon as the engine started to work properly. The whole event took less than 10 minutes.

After this initial event, the voltage gage began to fall slowly from it's normal position (about halfway between 8 and 18 volts). So I took the truck on a long ride to see if the alternator would charge. It did and when I got back home I was once again in the normal range on the voltage gage. But this didn't last long, first I needed a jumpstart then I needed to charge the batteries from an external charger. I decided to replace the alternator and proceeded to look for the largest one I could find. I also bought 2 new optima red top batteries, but I didn't want to install them until I had a new alternator installed and until I externally charged them. The people I ordered the alternator from said it had shipped, but it never came. They had to send a replacement. When it finally arrived, I found that it was too large to put in without moving the intercooler hose, a radiator hose, using longer bolts and replacing the plug in connector on the back (of the alternator). When I had the original alternator out of the truck and in my hands, I noticed a lot of rust and debris coming from inside the alternator, so I blew it out with compressed air and re-installed it until I found a solution on how to get this huge alternator into the truck. I had the optima batteries charged (they were still charged from the factory, but I put them on 2% charge to top them off) and standing by, so I installed them. After all this I started the engine and everything seemed great. Alternator charging, batteries holding charge, no warning lights- life is good! This lasted until two weeks ago, when after coming out of an Ikea store, the truck wouldn't start. Called the wife for a jump start, barely getting the truck home (on the New Jersey Turnpike- where I had- RULED With IMPUNITY- the passing lane, dispatching Suburbans and Hummers to the rest stop with their tailpipes between their legs- I was extremely embarrased limping home). I replaced the alternator this past Saturday and again all was right with the world- I thought. Last night the whole cycle started over again- but it lasted well beyond the point where the engine heated up to normal operating temp. And I noticed something I hadn't experienced before- since day one when I bought the truck, in the winter especially, the drivers window would go down at what I thought was the normal speed for 1/2 way- then it would go slowly for another 1/4 and then crawl for the last 1/4 or even stop before reaching all the way down. It has always worked this way- it hasn't bothered me, all vehicles have their little "issues" and I could handle this one's. But last night, while the engine was running rough and showing all the symptoms that I saw last summer, the driver's window was zipping up and down like I never- NEVER- saw before. Way past normal warm up time, I shut the engine off and restarted it, it started and sounded normal. Then I revved the engine and it went back to limp mode. I took it home and left it till tonight, I went out and started it up and it started normally and stayed that way. But I did see two things that caught my attention- about 15 seconds after I started the engine, the tach shot up to 1000-1100 rpm (up from the normal 700-750) and the headlights got noticeably brighter (I didn't think they were a problem before- and I didn't see any dimming later), but I did not hear any change in engine speed. And the drivers window is back to the "normal" way of operating- 1/2 way slow-1/4 way slower- 1/4 way slower or stop.

Did I get a bad alternator? Is the tach getting it's reading from the alternator? Am I breaking in this alternator? Am I experiencing an intermittent electrical problem? Fuel delivery problem? Anyone with any similar experience or advice- please post. Your words will be greatly appreciated. Thanks.

Sincerely,
heatmon

 

Heatmon, that's a lot to take in but my recommendation (as much as I hate to say it) is to take it to your local auto electric guy and have him check it out. Sounds like you've got several things happening at once. I would however pull the fuse that gives your power windows their supply and see if your problem quits as that is the thing that you say has been constant through your problem. Hope that helps and good luck. Carl

 

sixpack2639,

Sorry about the long windedness... I'll try what you suggest and see if anything happens. Thanks.

 

I'm just wondering if there may be any stored codes from these events? Something like all readings are low-voltage types which might direct you to the charging system?
Just thinking out loud & remembering the KISS theory.
AL.

 

Al,

Thanks for reminding me, simple is my middle name- I'm sure something will be stored. The "Service Engine Soon" light is still on. I just got back from driving my son's girlfriend home and the engine did the same thing as two nights ago (last night it was fine). While he was walking her to her door I shut down & restarted- guess what- everything went back to normal. It's raining again tonight as it was 2 nights ago, I wonder if there's a connection. I'll either have to wait until after the holidays to buy a code reader or go to an Autozone to have them read the codes. Thanks again- I'll keep everyone posted.