Author Topic: Shifting messed up after engine wash  (Read 167 times)

OLDGOLD

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Shifting messed up after engine wash
« on: 23 September 2018, 09:27 AM »
Hello friends,

I have a strange issue and I'm curious as to whether any of you have had similar experiences after power washing your engines. For some reason after I have power-washed my engine and transmission with a medium-power spray washer, my shifting points have increased significantly. My RPM's will climb to over 4,500 and to almost 5,000 and will eventually shift hard into next gear, but feels like its losing momentum between gears. I can get it to shift sooner if I let off the accelerator pedal, but the engine feels sluggish compared to how peppy it was before I washed it. I just drove her on the highway and have also noticed that I can't really go past 85 even with my toes to the floor pushing the pedal all the way down. She was never a rocket ship like a 6.9, but getting to 100 on the highway was never an issue before where I live in Texas where the roads are mostly straight and flat.

I've had this issue once before and had my technician adjust the modulator on the transmission which helped make the shifting more firm, but I'm getting sick of the engine noise at 5k RPM every time I accelerate. Yesterday, I poured about a gallon of brake cleaner all over the top of my engine and then power washed the sides and back of the engine including the top of the transmission. Now, she slower than she was and she shifts like crap. Any help or insight would be appreciated.

Thanks,
John

P.S. All fluids and filters, including the fuel filters, are new. I have newly rebuilt injectors with Monark nozzles and just changed the oil last week with Chevron Delo 400SD 15W30. The vehicle is very mechanically sound, besides a window regulator or two not working among other small issues. There something I have done while power washing that I can't put my finger on. Thanks again.
« Last Edit: 23 September 2018, 09:46 AM by OLDGOLD »

Alec300SD

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Re: Shifting messed up after engine wash
« Reply #1 on: 23 September 2018, 10:06 AM »
Sounds like you have lost the boost signal to the ALDA.


Hard boost line, or rubber connectors of boost sense (ALDA) line at switchover valve on bulkkead may be leaking.

Wire from boost sensor (on intake manifold) may be frayed, if grounded to body before switchover valve you will loose bost.
« Last Edit: 23 September 2018, 10:16 AM by Alec300SD »
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (FOR SALE $1,000 - must be gone by 11-20-2017)

OLDGOLD

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Re: Shifting messed up after engine wash
« Reply #2 on: 23 September 2018, 11:01 AM »
Would I be better off just deleting the ALDA? or should I remove the switchover valve?

 I have recently cleaned the banjo bolt on the back of the intake if that matters.

OLDGOLD

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Re: Shifting messed up after engine wash
« Reply #3 on: 23 September 2018, 11:30 AM »
One more thing....

I'm not sure if this is related, but after I shut my engine off, I can hear the VCV (vacuum control valve) on top buzzing until I lock my doors, then it immediately stops.

The central locking vacuum system is in working order by the way, as is the climate control vacuum.

OLDGOLD

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Re: Shifting messed up after engine wash
« Reply #4 on: 23 September 2018, 05:13 PM »
Thank you Alec!

She's back to life again. I decided to just bypass the switchover valve on the firewall. As you can see from the photo I just reused a piece of rubber hose and two clamps to make it work. Thanks again!

Alec300SD

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Re: Shifting messed up after engine wash
« Reply #5 on: 23 September 2018, 06:13 PM »
Glad I could help.

BTW what model year is your W116 300SD?
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (FOR SALE $1,000 - must be gone by 11-20-2017)

OLDGOLD

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Re: Shifting messed up after engine wash
« Reply #6 on: 23 September 2018, 06:26 PM »
1980.

Alec300SD

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Re: Shifting messed up after engine wash
« Reply #7 on: 23 September 2018, 08:38 PM »
Just remembered, ;D
You sent me a PM with the model and year back on 12-20-2017.
Tach amplifier still okay?
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (FOR SALE $1,000 - must be gone by 11-20-2017)

OLDGOLD

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Re: Shifting messed up after engine wash
« Reply #8 on: 24 September 2018, 05:43 AM »
Yes I did! I was wondering if you’d remember. Yes, I had to also buy a sending unit as well to get it working, but the tach amp still works. Thank you!