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Help: on road trip and truck loses power

771 views 7 replies 4 participants last post by  bikerider58 
#1 ·
2000 ML320, 132k miles

Only about 2k miles with trans service, crank and cam position sensors, plugs and wire, alternator, water pump, fuel pump and filter. 100 miles on oil level sensor and oil.

SoCal to C-springs CO.

Everything is fine with outdoor temps hitting 112. After about 5 hours driving, Going up hill trying to maintain speed, give more gas and trans shifts down. RPM goes up as expected, but truck loses power.

Letting up on throttle has trans shifting back up with expected power. On level and down hill same thing occurs when trans goes to passing gear.

No lights, no vibration or other misfire symptom.


Could it be bad fuel at the last stop?

What should I check?
 
#5 ·
Yes, once it started it happened repeatedly.
No, not towing.
No, not smoking.
Started this morning and all was fine. About 2 hours later started acting up. Called local a local shop at a gas stop to get a trans fluid check. On the way there it started mis firing and CEL.

Lots of codes, trans not communicating errors, misfire #1
Yes, trans fluid level is good. Looks like the new alternator was cooking. At idle15v 60amp and my instrument cluster has a dancing speedo needle for a second or two at start and stop. Second Beck&Arney alternator in 3 months.

Rental car to get to Denver and will go back on Monday to check on the truck.
 
#7 ·
I do not know the codes. Nth scanner they were using seemed to list everything, so I am not sure if there was some spin on it or not.

From my understanding of the alternator, the output was too high. The first beck & arnley alternator died (13.2 v out at 3,000rpm) after less than a week. This one did better since it lasted about a month. I thought B&A was decent quality. It looks like I was wrong.

On Monday I will pick it up (Grand Junction) with the new alternator and try to get it to C-Springs.

If the instrument cluster or anything else is still acting up, it will go to a local shop so my son can get it when it is fixed.
 
#8 ·
The new alternator was installed today and a battery test proved that it was cooked by the high amps of the bad item.

Everything worked during the drive from Grand Junction to Colorado Springs. The only issue was on the steepest inclines where the truck acted like it was governed. Down shift to 3rd limited to 3500rpm but things speed up on the flats.

This may be a throttle body issue.

The instrument cluster is acting better, but the speedo still jitters.

It goes to a shop in C-Springs tomorrow for a Star compliant scan.
 
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