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fuel pressure regulator test

Started by w116john, 08 September 2014, 04:20 PM

daantjie

Just my 2c, but have you actually checked your AAV for function? I know you say it is new, but may be worthwhile to check if it closes completely at 85 C.
If it stays open even slightly at temp reaching 100 C, you will have rough warm idle.
Daniel
1977 450 SEL 6.9 - Astralsilber

w116john

daantjie

deep down that is my suspicion and i cannot get that valve out of my head,  but the idle is good after a minute, and i still have the low rpm at start up at 70 degrees when the aav should be/is closed.

i have replaced the aav 3 times thinking it was the culprit, i have a spare wur and i might put it in tomorrow if i have time just to see if there is any difference  i have my kids  21st and 18 birthday to shop cook and cater for on Friday so events may intervene

then its of to the mechanics

thanks
john

daantjie

Best to start simple and work your way to more complex and expensive fixes.
My AAV gave similar symptoms, hot start would be rough, and when I gave it some gas it would perk up.
Best way to test them (not sure if you have done so already) is to remove it, and submerge the brass bulb in boiling water from the kettle/ stove.
As this water is near to 100 C, the valve should easily move fully closed fairly quickly.
You can also monitor temperature of water with food type ( meat) thermometre.

If at temp of 85+  , your valve does not close, you have a problem.

I tapped my valve down, so it closes early. Now it is a bit of a compromise as cold idle a bit rough, as it is a bit sticky and now does not open fully.

I am too cheap to fork out $$$ for a new one, so this "happy medium" works for me.
If your AAV is working nicely, and problem still persists, agree that you may have control pressure issues, which of course may lead to expensive fix.

Good luck.
Daniel
1977 450 SEL 6.9 - Astralsilber

w116john


a minor update on my boggy warm start, yesterday i decided i would have a look at the cold start injector to see if it was leaking, when removed it was dry and when tested no evidence of any leak.

i changed the wur for a second hand one that i had picked up cheaply it is a 015 from a later 450 mine is a 010, the only difference was that it was quicker to get to the correct idle speed the old wur was sluggish and when warm would start at 500 rpm and could take 30 seconds + to get to 750-800 this one starts at 6-700 and goes to 750-800 within 10 seconds approx

on a cold start it is also quicker to get to max rpm and then rpm comes down and when engine temp is at 60+ it is at 800

i will see how it goes over the next few days and i might send the old wur of for a refurb.

the next time the car is in i might ask to check for leaky injectors

regards


w116john


i thought i might check for a vac leak, nothing obvious found. i decided to have a look at the aav even though it is new and tested it with a spare i had, both closed x 80 degrees but amazingly the new aav did not open when left in the hot water to cool down it was still closed below 40 , any way i put the other aav back on the car i am sure it will be an improvement

anyway onward and upward


daantjie

I'm sure you have probably checked this, but might be worthwhile to make sure the vacuum connections on the wur are hooked up correctly?
Top fat hose connects to the AAV contour hose, bottom hose connects to the hose connecting the AAV and idle control valve which also houses the cold start injector.
Doubt this is your issue but may as well rule out all the easy fixes.
Daniel
1977 450 SEL 6.9 - Astralsilber

w116john

hi daantjie

i was just looking at the aav this morning not openning at all till cold i mean below room temp that was a . my fat vac hose on the wur goes to the rubbber hose between the aav and csv housing, my thin house goes from the side of the wur ( if the wur was lying down ) to a rubber hose from the aav to the manifold,

i do think now that the aav was a big part of the problem, and i am not so sure about the condition of the one i have put in but we will see.

my mechanic said he could not find any vac leaks but symtoms would suggest otherwise or some kind of vac advance ???

we will see if this aav improves things it couldnt be worse

thanks
john

w116john


hi all

does anyone know what this vacuum line is for it is the one on the extreme right of the photo


i bypassed it so my central locking still works it was causing some hunting at warm idle which has gone now its disconnected the check valves are all ok.



thanks

john

daantjie

That line connects to the vacuum reservoir in the left front (US Spec driver side) fender.
Daniel
1977 450 SEL 6.9 - Astralsilber

w116john

don't laugh   i had my suspicions and as my splashguard is off i had a look and i dont have a vacuum resevoir in there.

i do have the cable going through though and it must have been removed at some stage i suppose its any easy fix???????

thanks again

john

daantjie

Have not had to do it myself, but I would guess as easy as picking one up from the wreckers (they are generic across the range for 116) and sticking the vacuum tube in, perhaps with some sealant so it fits nice and tight.  Looks like 3 balls stacked atop one another, black plastic.

Just be sure to get the one for the front and not the back, as there is a flat style reservoir as well that sits under the package tray.
Daniel
1977 450 SEL 6.9 - Astralsilber

w116john

cheers daantjie

another job for the list,

john

ptashek

John, I have the front reservoir from my 350 if you're looking for one.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

w116john

ptashek

thanks a million but my impatience has undone me, and i bought one yesterday i probably won't get it for a few weeks
the splashguard has been of the car since i bought it and that will be one of the jobs to be done when i get a price on some body work next week,  there is some rust on that corner.

good to hear from you looking forward to more images from your restoration

john

w116john

#29
hi all i changed the injectors and seals today and thought i would post a photo of the old ones as i was wondering would they normally be this grimy when taken out.

it didn't fix my problem though its still boggy after a warm start, any way not much more i can do i will let the mechanic look at it.

issues loading photo needless they were covered in gunge



john