Location: Houston
Posts: 706
My VIN: 16113
Club(s): (SCDC) (DCUK)
I do apologise about the spelling errors, I'm typing this on my "smart" phone.
In addition, the following:
"Unscrew the 2 brass screws nearest the throttle plate by 2 full tirns each."
Should be:
"Unscrew the 2 brass screws nearest the inlet manifold W pipe by 2 full turns each."
Next time I'll use a PC.
Sorry all.
NickT
RIP Rob van de Veer Top bloke
I say Sir, I must be mad, one loves fixing K-Jet !
Make sure there's plenty in the tank for the weekend chaps....
Location: IRELAND
Posts: 27
My VIN: 6100,0707
Just another angle on the lumpy idle.. Back in the mid to late 80's ( i know, before a lot of you guys were born ) Mercedes Benz's had the same problem with there cars using the same fuel system at the "D's" mainly there big v8's .. A cure they found was to up grade the steel injector with a brass one.. Lumpy idle cured .. Just a thought.
Location: Northern NJ
Posts: 8,570
My VIN: 10757 1st place Concourse 1998
I have experimented with increasing the air bypass similar to what you have described and noticed the idle was smoother. My take is that by reducing the amount of control of the idle motor, the motor was able to dampen itself. I agree, setting things up "by the book" will not give the smoothest idle if that is your goal. I did not do emissions testing but I suspect doing it by the book is the better way for emissions and that is why it is the method offered in the book. The "best" way IMHO is to go ahead and get the motor running the best you can "by the book" and if you then want a smoother idle adjust the air bypass to smooth it out. The only problem I see in your method is that on many cars the heads are broken off of 1 or more of the brass screws. BTW, you are confirming that a "properly set up" PRV "by the book" doesn't run smoothly. I agree, I also agree your method will make it run smoother.
David Teitelbaum
Location: Rochester, NY
Posts: 2,405
My VIN: 01049
An in-tune and properly running PRV will run just fine. Put down the books and start actually working with cars, Dave.
-Mike
My engine twists my frame.
1981 DeLorean, Carb LS4 swap completed
1999 Corvette, cam/headers/intake manifold, 400 rwhp
2005 Elise, stock
2016 Chevy Cruze
Location: Northern NJ
Posts: 8,570
My VIN: 10757 1st place Concourse 1998
Holy Cow! I just did the adjustments you suggested and my engine is now running better than it has the whole time I've owned it. Kudos sir!! Now, ill let it cool off and see what the adjustments do to my initial cold start up. But when warm holy cow it runs smooth and my engine vibration is 98% gone!
You the man!
Thank you for replying to the thread!!!
You can't buy happiness, but you can buy a DeLorean and that's sort of the same thing....
You're welcome. I just hope you noted my post 6 posts earlier about my amendment.
I'm glad it worked out for you.
NickT
RIP Rob van de Veer Top bloke
I say Sir, I must be mad, one loves fixing K-Jet !
Make sure there's plenty in the tank for the weekend chaps....
Location: Surrey, United Kingdom
Posts: 181
Just to add my 2pence worth, Nick very kindly setup my car using this method a number of years ago and it totally transformed it.
My car hunted a lot, as can be seen in this cold start video I took back in 2012, it was all over the place.
https://youtu.be/oXy4y5Cpa0s
Fast forward to 2013 and here is a video of a cold start after Nicks adjustments, the results speak for themselves.
https://youtu.be/Glh_TaTSP1A
Having seen Nick perform this on multiple other cars over the years, I can say that this method consistently gives repeatable results. Idle is smooth across all engine temps, cold/warm/hot, it always runs smooth. Heed his advice on this setup, ignore the "book".
My emissions results were better after Nicks adjustments - In the UK emissions are tested yearly as part of the annual vehicle (MOT) test.
Last edited by MikeWard; 09-07-2017 at 03:42 AM.