surging with cruise control

[DPKetchum]

Ok guys this discuss a hard one. With cruise on at times its ok. At times surges up and down BAD and at times surges moderate. Rarely if ever is it a smooth ride. In past have done a TSB for speedo drive gear and i replaced cruise servo. Obviously its been a problem on 1st generations due to the tsb's that were out on it. I love cruise buts its not worth a darn in these trucks. Any thoughts?

 

[RGT]

sorry I can't help, but thought I'd say that mine hardly varies at all

 

[DPKetchum]

You lucky dog you! Until i did tsb that describes the symptons it was REALLY bad. If you watch boost gauge and feel what its doing it would make a sailor seasick. Some days it kinda ok. Seems like maybe tps releated. On later models with lockup torque convertor they mention how it will tear up convertors etc.

 

[Paychk]

Trouble shooting tree shows; 1) lock-up torque converter roughness, 2) amplification of engine surge, 3) defective servo, 4) defective cable, 5) defective PCM







Not sure what else to suggest

 

[Mad Bomber]

Surging on cruzin

I can't help to much because I have a 24 value but I found that the surge that I was having was caused by I had a intercooler leak where I was loosing all my boost so the truck was trying to recharge the boost. Best of luck Eric

 

[DPKetchum]

Well for sure its not lock up torque converter. Its non lockup. Truck has no surge cruise off. Pcm is a thought. Wish there was a way to access D. C. Star. Bet there was a lot of tech calls on this issue back then. Truck has done it for ever. It was REAL bad until i did tsb on the plastic speedo drive gear thats in the rear of transfer case. Its like your constantly gooseing it on and off on and off. Boost gage goes like 2 to 8 psi,2 to 10 psi etc or at times even a little less. The reason i asked was reading about a conversion and he commented that his cruise did same thing and was asking about a adjustment point and there is none. Sometimes it is almost not a issue. Other days it can do it bad. No rhyme or reason.

 

[BushWakr - RIP]

Have you checked ALL your vacuum lines?



Have you noticed your speedo fluctuating or jumping up and down... with or without cruise on??



Have you double checked all the elect. connections on the trans.



Have you done a vacuum check on the vacuum pump itself?



Just a few idea's...



bob.

 

[DPKetchum]

Speedo at times does bounce all over. Worse towing. Not towing hardy ever. Hook trailer up and its not steady,worse at times. Vacumn lines i've checked several times,appear ok. Also seems worse in wet/humid weather.

 

[BushWakr - RIP]

Based on what you see as symptoms, I'd say your speed sensor is at fault.

If the speed sensor is erratic it keeps triggering the CC to increase/decrease based on the speedo fluctuations.



When the speed sensor goes bad, it usually thrashes up and down as if it has a mind of it's own. That is how mine acted anyway.

Before removing yours for replacement make sure that you take a real close look at it. On some there is a proper indexing, on others (mine) there was none. Look at the bottom outside edge of the speed sensor. If it has two sets of numbers on it, make sure it all goes back together the same way. The numbers are for a correct speedo reading based on rear end gear ratio's I believe.





Bob.

 

[DPKetchum]

The other day i adjusted idle and in process moved and tweek with harness from tps(may have nothing to do with it) and it rained and drizzled all day today. I SWEAR cruise has never been so correct and speedo NEVER moved. We will see tomorrow.

 

[DPKetchum]

Finally got correct speed sensor and as of tonight cruise and speedo rock solid. Lets see if it continues to stay this way. Thanks foe help.

 

[Paychk]

DPKetchum



What is the P/N for that thing and is it the 2 wire version? Also what did you pay for it?



Thanks!

 

[DPKetchum]

It was the same sensor as the old one. No changes. It was $55. 00 had to get bag out of trash. Part # is 56027014

 

[Paychk]

Your da heat!

 

[DPKetchum]

A special thank you to Bushwkr. Its been TWO days now and speedo and cruise still rock solid. Cruise is SMOOTH up and downhill. Speed sensor has been like it was for several YEARS.