99 F450 7.3PS stalling when raining issue???

Ok.. here's an issue I've been experiencing on and off, and now am finally motivated to track down the cause.

Back story and info:

truck is a 99 f450 with the 7.3 powerstroke diesel. ( there is an early 99 and a late 99.. some different lights show up on the dash..e tc. mine is the late 99 AFAIK ).

Started life as a cab/chassis

Had a chip installed ( the kind that physically plug into the card edge on the computer ).

Few months ago truck died.. would stall now and then.. I replaced the CPS, then like a day later died dead. had it towed to the diesel shop, nada on the obd port, like computer was dead. they popped out the chip and it came back to life immediatly. I put a flashpaq on it to make up for chip.

All was fine for a bit, then I noticed it stalling again.. and finally figured out the commonality. RAIN. If I drive the truck in the rain or right after the rain when there are puddles or road water.. she will stall like the key turns off. you can start right back up. Actually.. to clarify.. if you are at idle, or say, under 800 rpm, it will stall. if you are over that rpm, you get a huge miss. if towing a big load, that huge miss is plenty enough to feel as a shudder going down the road, and you know it tried to stall.

It's not water int he tank. I have an extra filter and transfer tank.. no water period and I treat it. no water in the cup..e tc.. etc.

I know it has to be electrical and water.

Truck runs like a charm dry. Starts as fast or faster than my wifes new 2014 E350 gasser. ( engine is not tired, it's crisp and powerfull, responsive.. no smoke except when you expect a diesel to smoke on accel etc. )

This truck is not a dialy driver anymore. it mainly stays parked unless I need to move something 10K or heavier. like haul a big peice of equipment on the flatbed, or move a few tons of hay. it's good for heavy loads. i have all the toys for it.. pyrometer, extra gauges, better tranny and power steering cooler, intake upgrade filter system transfer-tech fuel gauge to measure main and aux tank, 4.88 rear, custom upgraded rear, 19.5" rubber, add on air bag rear suspension, has had full syn fluids all around from mile 1. When dry, she screams...

Well, florida has been getting rain daily for months and the truck is virtually useless as she sets. I have not ruled out the CPS, as I changed the first one ( which was really the second one, as the one she came with was replaced with a international one when there was the issue with the grey vs black ones and coroded terminals ).. this new one i put in was a napa one.. and I put it in thinking it might be it, then found out it was the computer/chip.. so I have not ruled out the cps i JUST put in might now be the rain issue.. but have never heard of it.

Any ideas?

I didn't remove the old chip, the guy at the diesel shop had it out by the time I made it there. truck was towed and I got a ride, and the had it fixed when i got there. tow cost more than the 'repair'.

My research says that computer is metal cased with parting halves and is somewhere under the left fender?

could that be getting wet?

any p'stroke 7.3 owners have similar experiences with what seems like a water/electrical issue?

I'm doing everything with my 99 350 , also a 7.3 pstroke.. but she's been used hard and put away wet n tired her whole life, and won't pull 14000# of hay like the 450 will. she also has a 4.1 rear. etc. She gets the job done, but tranny is getting tired... but.. she drives ok inthe rain... ( when the old wiper controll decides to play nice ).


any ideas?

The computer is not under the fender. The ECM (computer) is where you are plugging in the chip. On my old 96' it is under the the master cylinder, but the connections are in the cab, which again is where you are plugging in the chip. Yours maybe there too.

The first thing I would do is scan for codes. That might point you in the right direction. Did the "shop" that you took it to scan it. Because really, it doesn't sound like much of a shop to me.

I'd take it to a reputable diesel shop and have them scan it with the chip removed. The ford dealer can do it but that is a crap shoot too. I know more about the 7.3 than the techs at the ford dealer here, and I'm certainly no expert.

I would check the CPS wiring harness for a frayed wire with an exposed conductor. Also check the IPR wiring harness. There are two wires there and my old ford's wires got hot and melted together. It's a common problem and ford even sells that harness but I just separated the wires and taped them up, good as new. Also check the under valve cover harnesses. There are 4, two on each side. Also there is the IDM, Injector Driver Module. Check those wires too. Just check them all. It sounds like a wire or harness getting wet and grounding to me.

If the shop you towed it to only solution is to remove the chip, then I'd find another shop. What's a flashpaq? I've never heard of that before. Do you mean that you had the ECM reflashed? That's almost always a bad idea in my experience.

And if rain is the catalyst, you might try running the engine on a very nice day and with a water hose start wetting the harnesses one at a time. And I'd wait a while between each one so that I was certain of which one causes the problem when it happens, if it happens. It may not. I've never done this, and don't know anyone who has, but lots of folks clean their engines and hose them done as part of that process. Don't use high pressure water.

Had similar problem with my 99 F250 7.3PS. Turned out to be the injector system fuel pressure sensor located in the front of the left head. Although not at all weather related may be something to check. Nothing more aggravating than an intermittent electrical problem. Good luck with it..

I newest greatest updated cam sensor should be grey in color...
I would look hard at the connector also...
That's about as far as I go I don't work on engines are performance issues on a diesel...

If you want to play get some Stabalint 22 clean and treat the connectors.



http://www.dewitzdiagnosticsolutions.com/review/stabilant-22a-snake-oil/

yup.. aggravating.... drives fine dry.. 10 minutes after rain starts.. chugjerk drive, idle stall.. etc..

No offense.. but I must say, some of your message parts concern me.

First, you claim to be quite knowledgeable about the 7.3's

then your wonderment about removing the chip.

I already mentioned the ecm was dead while the chip was installed. no OBD port even, and the add on fuel gauge that needs the ECM wouldn't even boot up. they removed the chip, and it allowed everything to work.. Doesn't take much rocket science to figure out the chip was holding the bus low and nothing was comming on.

As for the flashpaq.

I didn't say i had the ecm re-flashed. I said I added a flashpaq to make up for the chip that was removed.

Flashpaq is a tuner made by superchips..

Googling flashpaq, it's the very first hit.

Unfortunately I havn't made it back to the diesel shop.. last time I was using the truck, it was raining, and I had a large gooseneck full of equipment on, and the shop is the next city up, and has a waiting list as they are the local power stroke specialist. Our local ford dealers even send customers there. My truck with trailer would not have made it thru their parking lot.

I will however get it unloaded and get the truck up there, just posting to see if anyone had similar experience that had already found a smoking gun.

thanks

Is the new CPS genuine ford or parts store brand? Seems I recall some had issues with non-oem CPS.

Did you try running the wipers when its not raining- Some 7.3 owners said it wasn't actually the rain, but some erratic signal from the wipers causing the issue

Yeah, I've heard so many issues about the cps models and connectors.

I have an international cps in it right up to this, then thought that might be the issue and put a napa CPS in it.

In retrospect.. the international cps was probably fine, and the chip was the issue.. now that the chip is fixed.. the cheap CPS is prolly the issue..

cps I had in it was an international, so it was a good one. I promptly changed it out to a NAPA one ( prolly a mistake ), when I was trying to figure out the stalling issue. ( which turned out to be the chip )

(quoted from post at 20:02:42 08/20/15) cps I had in it was an international, so it was a good one. I promptly changed it out to a NAPA one ( prolly a mistake ), when I was trying to figure out the stalling issue. ( which turned out to be the chip )

Click to expand...

Something I read tho may not be related to your issue is it will not set a CPS code unless it cranks for at least 15 sec and does not start..

Most folks would not hang on that long and I don't blame them...
I have replace a few no code stalling issues on them and it was the Cam sensor (no code) I got lucky

I looked at one for a bud the data stream and system test were covered well and EZ to my supersize (with a good scanner)... Once I determined the issue I recommended he take it to a young man that can work while standing on his head :twisted:

yup, this one starts in a couple spins. engine sounds good.. but I'm not ruling out that sensor... maybee bad contacts..

Can you remove the flashpaq, flash the truck back to stock, to see if the issue remains?

I know you said the original tuner was an issue, but any chance this one could be causing the issue too?


I've never messed with the superchips stuff, but when having electrical issues with duramaxes usually one of the firs things to reflash the tuning

Original tune was via a chip that apparently died. new tuning is as you say, just an ecm program update.

I can sure flash it back to factory next time it rains just to check.. just don't see how it could be an issue if it runs all day dry, and stalls wet, just on programming.

Hi Mine does exactly the same It's an early 99 250 superduty. The odd timer it will trip the check engine light, and it will go out without re starting the truck. i changed the cam sensor. and it's got rid of the total stall issue problem. mine is supposed to be chipped to. I get the shudder issue now when it rains or real damp and thats it.
I just live with it at the moment. But I have been told where the injector loom goes into the head at the rocker cover the wires can break down there and it's hard to see, or the plugs can mess around on that loom to as well as any other plug on the motor. I kinda wonder if the rocker cover wires damaged on both our trucks and it causes the problem in the damp..
Regards Robert

(quoted from post at 19:01:58 08/20/15) No offense.. but I must say, some of your message parts concern me.

First, you claim to be quite knowledgeable about the 7.3's

then your wonderment about removing the chip.

I already mentioned the ecm was dead while the chip was installed. no OBD port even, and the add on fuel gauge that needs the ECM wouldn't even boot up. they removed the chip, and it allowed everything to work.. Doesn't take much rocket science to figure out the chip was holding the bus low and nothing was comming on.

As for the flashpaq.

I didn't say i had the ecm re-flashed. I said I added a flashpaq to make up for the chip that was removed.

Flashpaq is a tuner made by superchips..

Googling flashpaq, it's the very first hit.

Unfortunately I havn't made it back to the diesel shop.. last time I was using the truck, it was raining, and I had a large gooseneck full of equipment on, and the shop is the next city up, and has a waiting list as they are the local power stroke specialist. Our local ford dealers even send customers there. My truck with trailer would not have made it thru their parking lot.

I will however get it unloaded and get the truck up there, just posting to see if anyone had similar experience that had already found a smoking gun.

thanks

Click to expand...

Where did I say, "I'm quite knowledgeable." I never did. I said, "The ford dealer can do it but that is a crap shoot too. I know more about the 7.3 than the techs at the ford dealer here, and I'm certainly no expert."

No offense, but your reading comprehension skills concern me. You say I said one thing, but I said something completely different. To paraphrase what I said, take it to a diesel shop. Tthe dealership here doesn't know much, and I'm no expert.

No need for you to be concerned. Ignore what I said, and I'll do the same for you.