got the valet switch put in today...less than an hour from start to finish...

pic of the parts:




fittings and air line from Parker...switch and wiring connectors from Advance Auto...air solenoid and exhaust muffler from Grainger...Teflon pipe sealant from Fastenal...

parts were picked up at random times over the last couple days...I could've bought more of it at a single stop, but figured I'd list where I got the stuff...


main problem I ran into was finding a way to replace the banjo bolt...I could've used the OEM tubing and just used an adapter from there (that's what wannadiesel did) but I wanted to get rid of some of that clutter...

come to find out, 1/16 NPT is very close to the M8x1.0 thread:




I removed the banjo bolt, and the NPT fitting from the intake...and replaced them with Parker Prestolok fittings:




the solenoid I used was a 3-way...which has an exhaust port that will allow the pressure in the AFC to vent off when I flip the switch off (off = valet mode)...I put some 90-degree swivel Prestolok fittings in the IN and OUT, and put an "exhaust muffler" in the EXHAUST port. The muffler was ~$1.60, and I figured it was a safety device that would actually function as a filter to keep anything debris from getting into the AFC housing and messing up the diaphragm:




bought a basic ON/OFF switch...and since the solenoid only uses .38A, I robbed power off the cigarette lighter:




BTW...are those the factory headlight and parking light switches? they just looked odd to me...


mounted the solenoid on the fender wall...just used a fancy zip tie I had laying around...could go to bolts or screws later:




got all the line run:




I used the 90-fitting just to keep from having a sharp bend in the air line.

If I ever need to ditch the whole setup, I can just spin the 90-degree fitting around and plug right into the manifold...


I haven't had it out on the road...but I did test the switch and could feel the airflow stop when the switch was in the OFF position...

PARTS LIST:

solenoid:
3-way 12V from Grainger (1/8NPT ports)
Grainger Item: 6JJ52
Ingersoll-Rand Model #: P251SS-012-D
Quantity: 1

exhaust muffler (used as filter):
Grainger Item: 1A325
Speedaire by Dayton Model#: 1A325
Quantity: 1

air line:
Parker air line (comes in multiple colors)
Parker part #: E-43-B-0100 (that may just be for the blue I bought)
Quantity: 3-6 feet (I bought 6', and have over 2' left)

fittings:
Parker 1/8NPT Prestolok 90-degree swivel elbow
Parker part #: W169PLNS-4-2
Quantity: 2

Parker 1/8NPT Prestolok straight coupler
Parker part #: W68PL-4-2
Quantity: 1

Parker 1/16NPT Prestolok straight coupler
Parker part #: W68PL-4-1
Quantity: 1

Parker 1/4 tube Prestolok 90-degree fixed elbow
Parker part #: 165PL-4
Quantity: 1


FYI...the first part of the Parker part number is the fitting. The second is the tube size in 1/16" (i.e. the 4 means 4/16, or 1/4" tube). The third is the NPT thread size in 1/16" (i.e. the 2 means 2/16, or 1/8...the 1 means 1/16)

you also need:
12V switch of your choice
wire
wire connectors
teflon pipe sealant (optional, but recommended)


NOTE: the 1/16 NPT is not the same as the banjo bolt you are replacing...but it fits nicely. I would not want to remove it and reuse the banjo bolt, but you can make a new AFC hose with what you just installed if you ever want to ditch the whole setup.

Greg

 

Well done, and nice write-up

 

gonna try to work on the full power adjustment tomorrow...

I do have a question...reading about preventing the runaway...

if it doesn't runaway at idle, or after bumping the throttle linkage while sitting in the driveway...is there a possibility it "runs away" on the road?

Greg

 

went ahead and pulled the full power screw last night...so I could swing by my local shop and get rid of that pesky welded on crap this morning...

it's not pretty, but I can spin the lock nut 5-6 full turns, so I think I'll have plenty of wiggle room...

I really want to work on bumping the timing first...might give it another shot this afternoon...


BTW...it was idling at ~600...so I moved the throttle bracket one tooth (or so I thought) and it now idles at 1000, and the idle screw is backed way back...is the safest option put it back to idling around 600, since the idle will raise when I turn the full power screw in? (or at least that's how I understand it)...


Greg

 

FINALLY





went home at lunch...decided to try to bump the timing...and was able to loosen the tricky third bolt on the first try...

seems what I thought earlier was something blocking my way was actually a VERY tight nut...

the hard part was figuring out where to place the pry bar without breaking/bending something...

hard to measure exactly, but it's ~1/8"...

also go the fuel screw back in...turned it 2-1/2 turns from what I "think" was stock...I counted threads to determine stock, so I guess it could be off by 1/2 turn...

however, I haven't cranked it, yet...didn't want to fool with removing the intake, etc...had to leave...but that'll be first on my list after I get home...the test drive with the timing bumped and full power screw turned!!

I would like a couple questions answered about the full power screw...one I asked earlier today:

1. if it doesn't "run away" on the first crank, or after blipping the throttle...can it run away going down the road?

2. can you adjust the screw while the motor is running like I do the idle screw?

3. if it does run away...do I back off in 1/4 turns? 1/2 turns? just wondering how wide that "fine line" is of runaway...

4. I want to set it to tow when in "valet" mode...so I want as much power as possible with acceptable EGT's...so I'm not sure how many more turns it could handle without running away, but keeping the EGT's at 1200F or below...


the last one wasn't really a question...but share your experiences as to how many turns you've gone past 2-3...

Thanks.
Greg

 

Very nice writeup, Greg! It's now in the sticky. I think I'm gonna clean up my plumbing a little, that looks really slick compared to my cobbled-up mess.

On to the questions:
1: Not usually.
2: Yes, but be very careful since you are working right above the shutoff solenoid which has 12 volts to it.
3: I'd go back 1/2 turn to prevent #1 from being a possibility. When you rev the engine you want it to drop right back to idle.
4: Beats me. You're just gonna have to try it out.

 

New here, and still trying to learn so excuse the stupid questions.


What exactly is the purpose for this "valet" switch?

And technically how does it function?

 

The purpose is to allow a truck that's turned up a lot to be run by an uncaring operator - like a valet - without fear of melting a piston. Or, in Greg's case, he wants to be able to floor it up hills while towing his Jeep without having to keep an eye on the pyrometer.

The valet switch controls a solenoid valve that blocks the boost to the AFC housing. This reduces the amount of fuel available by a significant amount, resulting in lower power and EGT's.

 

Dave got it...as he's the one that guided me in that direction...if you read the last 20-25 posts in this topic, you'll see the discussion...

I wanted a rig that I could play around town with...but I also tow ~6,000lbs once a month (Jeep on 16' trailer)...

It's been hard to get a nice combination of play/two setup with the pump, so Dave suggested the valet switch...

He has one in his, and is making ~250RWHP/~650RWTQ...

if you've ever messed with your pump...you may know what the fuel pin is...it's pushed down by boost in the AFC housing...

the solenoid is inline with the boost feed to the AFC housing from the intake manifold...

when it's "OFF"...you only get the fuel from the full power screw...so, I turn it up quite a bit, and hopefully will be able to tow through the mountains with the pedal to the floor and not worry about EGT's...(once I get it dialed in correctly)...

then, when I unhook the trailer...I can flip the switch and have my dually rocketship back...

mine towed fantastic (although I had no gauges) when I bought it in stock form about 6 months ago...but after some tweaking, the EGT's got a little high for my liking, so the valet switch was my best option...the truck will be more powerful than stock, but not quite what it is when the valet switch is "ON" (which actually opens the airflow to AFC)...

the OFF/ON is kinda backwards...OFF is really "IN" valet mode...I prefer to call it a tow/flog switch, where tow is OFF and flog is ON...


I've been keeping this single thread going the whole time...so I'll update it once I get everything running good...along with any other questions I may have...



Dave...BTW...if you want me to get some part numbers and add them so they'll be in the sticky, let me know. I hung onto all my receipts just for that purpose...


my conference call is over...time to go home and fire that puppy up!!

Thanks.
Greg

 

A part number list would be a nice addition.

 

I'll take care of it sometime this evening...at least for the Parker and Grainger stuff...and I'll be sure to add it to the post above, so your link is still accurate...

the switch, wiring, etc, can all be whatever you find off the shelf......I almost opted for one of those switches with the flip-up cover, like a missle launcher...

Greg

 

I knew that BigW username looked familiar.

I am here reading up to go buy a 1rst gen to tow my Jeep too.

 

beats the heck out of the '92 F-250 w/ 7.5L gasser I had for a couple months as my first tow rig...it got ~4-5 MPG through the hills...

the CTD got 13MPG going through the same hills on this trip:




delivered it from Charlotte to Louisville (~500 miles) after I sold it on Ebay...for $700 more than I bought it two months earlier...




Greg

 

got it fired back up...no runaway...

actually had to crank the idle screw up just a bit, and it's a REAL smooth 800RPM now...

runs strong with the switch OFF...and I never saw temps much over 1000F (no trailer)...

when you flip the switch ON...the black smoke pours out on a WOT run...

was too busy watching the boost and tach to notice what the EGT's did with the switch ON...

I'm going to hook the trailer back up sometime tomorrow and hit the interstate for a bit, just to see how it goes as far as power and EGT's...

Greg

 

general smoke vs. power question...

isn't the heavy black smoke wasted diesel?

if I back the full power screw out until the smoke just disappears, have I lost power? or is it using all it can get?

just wondering where the fine line of making the most power is...and if it's pushing too much fuel now, but actually using more than if I backed out the screw?

I don't mind the smoke so much in full power mode, but with the valet switch OFF (in tow mode) it still pours pretty heavy at heavy pedal and higher RPM's...

Thanks.
Greg