Hey Everyone,

Have a question - I am starting to see a stumble on acceleration, but it is strange. Truck idles fine, when cold runs good too. As it warms up - 15 to 20 min in traffic, it starts to pick up a stumble from about 1800 rpm to 2500 rpm. In stop and go traffic, as I am coming up to speed it seems to hesitate or stumble. If I stand on it, it will smooth out as the revs go up before the tranny shifts. It truly feels like it is not hitting on all cylinders. When this happens, there is lower power, but still enough to get it moving, and no abnormal smoke or anything. Just changed oil and filter, air filter, fuel filter, fuel drain valve o-rings (leaking from the cold), and CPS (to one of the blue ones from Pure Diesel Power, because I read they make the engine run smoother, and it was time) about 750 miles ago. All fluid levels are OK. Problem has only been about the last day or so, but I want to nip it in the bud before it leaves me walking. About a week ago I filled up at a truck stop out of town, and the other day I filled up at an Exxon, also away from home (from my normal fuel stop). I don't think it was bad fuel, but both of these places had Ultra Low Sulfur Diesel (15 PPM) not the normal Low Sulfur Diesel (500 PPM) that I normally get. I know this is going to be the wave of the future, but could it be causing my problems? Or could it be the CPS is bum? I am going to check the fuel filter in the morning, because it is the cheapest and easiest fix. Any thoughts would be appreciated.

2000 F-450 7.3PSD, 171,000 miles
auto trans, replaced at 150,000 miles
11' enclosed work body on the back
about # 14,250 with a full tank

 

Have you checked the wiring harnesses under the valve covers?
https://www.ford-trucks.com/forums/2...or-wiring.html

 

No, I have not checked the wiring yet. I guess it could be, just makes me wonder why only at certain engine speeds. I will try the fuel filter first, followed shortly by popping the valve covers off. I have never had them off before - how much of a job is it? Can I re-use the gaskets?

Thanks

Spinge

 

The gasket is reusable, its not to bad just alot of stuff to remove to get at them.

 

Thanks


By the way, and I am not sure if this is related or not, as I decelerate, like coming to the top of a hill and letting off the pedal, occasionally, the check engine light blinks, but this is only occasionally.

I see you have the AutoEnginuity - is this a worthwile tool? I also have an 03' Escape, and I am thinking it would work on both. Might this help to find the problem (if it is not under the valve cover)?

Thanks

Rich

 

It could even help if it is under the covers. With the Ford Enhanced Package it will diag ANY ford since 1996. The light could be related an injector short or open can set a code.

 

Thanks,

Looks like I know what web site I am going to next.....

Rich

 

OK, here is an update...

Checked the fuel filter - OK. Problem has been intermittent. Then I noticed the other day, that the trans was a little warmer then normal. NOT HOT. It is cold here in MD this time of year, so the tranny barley makes 120 or 140 (led gaige fron Chelsea PTO a friend had...) anyway, noticed that the tranny was at about 160, like I said not hot, but warmer then normal given the temp outside. When tthis happens, the truck stumbles. Now I am thinking that it might be something in the tranny, but no codes (I got the Auto Enginuity Enhanced Ford Kit). Anybody have any idea what to check/look at that might give this symptom. Also, does anybody know where to get the information that I can compare to the Auto Enginuity to tell if the numbers I am seeing are right or wring?

Thanks

Rich

 

wring=wrong - sorry

 

Dennis at ITP Diesel sells AE and has a pretty good FAQ on the product page, He also has a forum dedicated to AE.

As far as monitoring the tranny you can look at TCC (torque converter commanded - should be 1020 when unlocked) and TCA ( torque converter actuall - should be 0 when locked) also there is input and output shaft RPM and gear ratio learned.

 

I would say Wrong or Bad oil, Especially if you are noticing it after you just changed the oil. That’s the cheapest try on your fixes anyway!!

 

I didn't even think of the oil. I know it was the correct grade, or at least the bottles were marked correctly, however I have a question. Why would it take 750 miles for the problem to occur, and then be intermittent? I actually thought the same thing about the CPS that I put in as well.

I also have a question about the Torque converter slip desired and Torque converter slip actual numbers. If I am seeing a "desired" of 1020 RPM, then the converter is not locked, correct? In that case, the "actual" has a wide range. If, however, the "desired" is 0, then the converter is being commanded to lock, and the "actual" should also be very low, correct? That being said, where do I look when the "desired" is 0, and the "actual" is in the 400 rpm range? I also monitored all of the shift solenoid output faults, the coast clutch output fault, and the torque converter clutch fault, none of them ever set the bit high.

The other reason I am thinking Tranny is the temperature, like I said before. On my recent run, about 45 minutes, the tranny made it up to about 170 degrees. I know that is not overheating, but it is 40 degrees outside, and it normally runs MUCH cooler this time of year.

Thanks for the help

Rich

 

As for taking 750 miles, the oil left in the crankcase and the little amount of anti-foam properties that all oils possess would have enough to get 750 miles.
As far as the tranny goes I know when I was having my problems like you described It finally threw a T/C code. I don’t know for sure but I think it was because the Wrong oil I had was causing a very brief shutdown (Low HPOP Pressure) to the computer. I don’t know that. That is my guess because when I changed the oil all the problems went away.

 

Check your oil level. If you overfilled the crankcase, the crankshaft could "beat" the oil, and cause aeraetion, and then it could be ran through the engine, and when it reached the injectors, (intermittantly) it could cause them to not work properly. When you check the dipstick, see if there are lots of oil bubbles on the dipstick, engine warm.

 

Didn't even think about the oil level being too high - I will certainly check it, probably just change it. What kind of oil you guys using. I have been using 15w40 for the life of the truck, but I leave it plugged in during the colder months, too.


Still leaning a little towards the tranny. Hit about 180 yesterday in traffic, which is WAY warmer then normal for the weather outside. Also, which is worse:"desired" rpm of 1020 and "actual" of 1199 or "desired" of 0 and "actual" of around 400?

Strokin_it7.3 - where in Carroll County do you live? I am in Hampstead.

Rich