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914World.com _ 914World Garage _ 914 Decel Valve

Posted by: smooth_eddy Jul 10 2005, 01:26 PM

Last time I took my car into the shop I had them put on a decel valve. The car came w/o one. I was told the 914 decel valve is NLA. So a 911 valve was installed. Well the car no longer dies at stop signs, but idles really high for 30 seconds or so. Finally it will settle down to 900 RPM. Do I need to find a 914 decel valve to get a good idle?

Posted by: bd1308 Jul 10 2005, 02:50 PM

sounds like your car is working as it should....how high is "really high"

Posted by: SirAndy Jul 10 2005, 04:53 PM

QUOTE (smooth_eddy @ Jul 10 2005, 12:26 PM)
but idles really high for 30 seconds or so

i should not take that long for the DV to wind down the rpm. it should be smooth decel as soon as you lift off the throttle ...

stupid question: why did you opt to add one? i like the more responsive throttle without the DV much better anyways ...

Andy

Posted by: qa1142 Jul 10 2005, 06:26 PM

I pulled my decel valve on recomendation of Porsche Factory trained mechanic. First theing they did when selling new 914's before they even left the dealership.

Check for other problems if you car won't idle

Djet or L jet????

Posted by: bd1308 Jul 10 2005, 06:37 PM

well going upon his signature, it's a D-Jet.....

personally I'd check the timing and dwell and idle...

Posted by: smooth_eddy Jul 10 2005, 10:06 PM

QUOTE
sounds like your car is working as it should....how high is "really high"

At a stop light, the idle is 18-2200 RPM.

E

Posted by: skline Jul 10 2005, 10:09 PM

QUOTE (smooth_eddy @ Jul 10 2005, 09:06 PM)

QUOTE
sounds like your car is working as it should....how high is "really high"

At a stop light, the idle is 18-22k RPM.

E

How does it not blow up? I dont even know any cars that run that high.

Posted by: smooth_eddy Jul 10 2005, 10:09 PM

QUOTE
stupid question: why did you opt to add one?

The car idled fine w/o the decel valve. But when I came to a stop quickly the motor always died. I have an aluminum flywheel and was told my RPM's dropped too fast, so I needed the decel valve.

Posted by: smooth_eddy Jul 10 2005, 10:10 PM

QUOTE
How does it not blow up? I dont even know any cars that run that high.

Oops... fixed my post

Posted by: bd1308 Jul 10 2005, 10:14 PM

does it only happen when engine is cold, or all the time....

dude bump the idle up and toss the DV.....

Posted by: smooth_eddy Jul 10 2005, 10:17 PM

QUOTE
does it only happen when engine is cold, or all the time....

happens all the time.

Posted by: bd1308 Jul 10 2005, 10:18 PM

i'd just bump the idle up and toss the decel valve....

timing might be fuched up.

Posted by: smooth_eddy Jul 10 2005, 10:20 PM

Just checked my email. The PO (a club member) said the idle problem might be to a leaking injector.

Posted by: bd1308 Jul 10 2005, 10:20 PM

woah....thats cool and wierd.

Posted by: dmenche914 Jul 10 2005, 11:13 PM

my 914 did not have a decel valve on it, however your aluminum flywheel might make one needed,

Could be the decel valve is: a. broekn, and taking to long to slow the engine down. or b. the 911 valve you have is just to much of a slow decel for the 914. After all does it not work on a vacuum principle? I bet a 911 six draws at the rpms, and displacements they run, a tad bit more vaccum than a 914. thus the decel valve is made to let more air flow on the 911 (just a hunch, comments???)

One thing to try is a used 914 decel vale from someone, maybe that will help, and make it run right.

If even a stock decel valve is too much for you lightend flywheel, try restricing the rubber hose that goes tot he intake. that "might" have an effect, maybe a clothes pin clamping he hose will reduce the air bypasssing the throotle such the engine settles to idle faster.

anyway try that, the pinching off the line a bit trick it might just do it for you, it's cheap and easy to to find out.

good luck

Posted by: North Bay 914 Jul 10 2005, 11:42 PM

This car does not have an aluminum flywheel...it has a 13 pound Bontempi flywheel, an a 911S aluminum pres. plate and

matching lightweight 911S disc, almost a grand all that cost me....which I wish I had back right now, and would never

cause this problem, it never needed a decel valve for this, and this problem I would bet is vacuum leak related in some

way, more than likely a sticking aux. air valve, or loose hose. After this car left my possesion, someone told me

(Brad Roberts) that the only issue I had with the engine (after spending nearly $5000.00 on it anf the gearbox)

was more than likely an injector leaking after closing. That problem was a mild bucking unless the ECU was slightly

enrichened. The extra fuel released caused the engine to speed up mometarily. I agree with this theory, and never had the

oppurtunity to find out if that was indeed the problem.

Posted by: North Bay 914 Jul 10 2005, 11:51 PM

By the way, if any one needs one of these paperwieght 914 decel valves, let me know, I have 4 or 5 of them, doing what they do best... far way from a d-jet engine...FYI all for every one who thinks you need this on your car, it was NOT installed on the Euro/ROW cars. What they do best is provide an excellent source for another vacuum leak.

Posted by: North Bay 914 Jul 11 2005, 12:05 AM

For future reference on my old car...

Flat top 2056, 8.7 to 1 compression ratio
Ported heads
Web #73 Grind D-jet camshaft
911 swivel foot rockers
Perfomance double valve springs, height matched and pressure balanaced
New everything in the cylinder heads, minus exhaust valves, as I wanted to retain the sodium filed stem type
Align bored case
Crankshaft trued/turned
Rods reconditioned/ARP bolts
Matched injectors
Lighten flywheel 13 lbs
911S clutch assembly
Pertronix ignition

Built at EBS racing in Reno.

Posted by: Bleyseng Jul 11 2005, 06:38 AM

Smooth Eddy. I could look at your car this week and check it out. I even have a couple of 914 decel valves as I rip them out. What shop did you take it to??

Sounds like a couple of things are going on related to the FI and the Djet is tricky to tune the idle right.

I also run a 13lb flywheel so that is not a problem.

So thats where Martins car went, cool

Posted by: smooth_eddy Jul 11 2005, 08:43 AM

Thanks for the offer Geoff....I sent you a PM. Eddy

Posted by: Bleyseng Jul 12 2005, 08:32 PM

Ok, Smooth Eddy stopped by so I could take a look see at the problem.

Hmmm, this is one clean 'Mofo engine.
Ahh, why is this PVC hose going to the aircleaner?
Weird decel setup, so we should just plug it to stop any vac leaks.
Ahh ha! the AAR valve is leaking alittle bit so we plug that too!

check the timing..hmm thats ok. Now adjust the idle down to 950-1000 and set the mix. Seems better so Smooth goes off for a test drive. Says its ok!!

Needs to lube the AAR valve so it closes completely, order a new PCV valve and I gave him a old decel valve IF he wants to hook it up but it shouldn't need one as I never run them POS.

Ok Martin I took care of it as these other soo called Porsche Mechanics don't know how to set the idle on a 914 with Djet as its Rocket Science, right? hahahaha

Posted by: smooth_eddy Jul 12 2005, 09:29 PM

Geoff........

Amazing.......Whew, I just blink and the air cleaner is off and all my vac hoses are removed. Next thing I know is you find the problem(s), then pooof.....fixed. You would not believe how much time that car has been in the shop. Thanks for the help and I will work on the items you mentioned this weekend.

Also, this is the best my car has ran since I have owned it.

Thanks, Eddy

Posted by: Bleyseng Jul 12 2005, 10:55 PM

Wait until you put the sway bar on like I talked about!

hehe, we didn't even have time to crack open the beer. Took 20 minutes to BS and poke around seeing what the other "mechanixs" did wrong. Why can't these guys look at a hose diagram?? "shit this must go here, hmm maybe over here...nah, that can't be it maybe we should look in the transmission???"

I owe all my 914 tricks to the "914 God" blame him if it craps out tomorrow....

Posted by: bd1308 Jul 13 2005, 06:10 AM

you're my hero.

I want to be just liek you when I grow up.

Posted by: Bleyseng Jul 13 2005, 07:13 AM

You too can be a "hero" or a "914 GOD". Take the course offered here on this site and pass the "final exam" and you're there!

Brad and Dave Darling are the professors so don't skip any classes when scheduled.
Fees for the classes are on a sliding scale or rather a slipery slope.

Posted by: Bleyseng Jul 13 2005, 07:18 AM

this is for you Eddy. Print is out as it shows where all the hoses go on a 73-74 DJet engine. They aren't mix and match like some mechanics like to make you believe. Keep it in the car along with your owners manual.

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