Idle Question on V8 swap -
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > Idle Question on V8 swap

FREE, FREE, FREE EVENT!! Save big on Lockers now till ApriJKS Grand Cherokee WJ, Adjustable Front Trackbar 1"-6Teraflex JK HD Hinged Carrier & Adjustable Spare Tire

Unread 07-31-2002, 04:18 AM   #1
highway jeeper
Registered User
Join Date: Jan 2002
Location: Lisbon, CT
Posts: 34
Idle Question on V8 swap

I have an 87 YJ automatic, and I just completed a 305 install with dual exhaust. The truck has a model 1850 Holley carb and I am having idle problems now that the exhaust is on.

There is a huge loss in rpm when I shift from park to drive and the engine practically wants to die. My tach gage is off since it is setup for a 6 cyl, but I say I am at around 1100 rpm at idle in park, and when I shift into drive I bet I am only at 200 rpm.

The weird thing is that I drove it to the muffler shop with a temporary exhaust Friday night and I did not have this problem. It only came after the complete exhaust was on.

The float level on the Holley is fine. The air fuel screws are at the bottomed out position with a 1 1/2 revolution turn from bottom (I just positioned them there as a starting point). I double checked the hoses (all new) but do not see any leaks.

Anyone have any idea why it is changing rpm so much? It runs great on the road - love the new power.


highway jeeper is offline   Reply With Quote Quick reply to this message
Unread 07-31-2002, 01:26 PM   #2
JF Administrator, eh?
NaeKid's Avatar
1988 YJ Wrangler 
Join Date: Nov 2000
Location: Calgary, AB
Posts: 6,879
The only thing that I can think of (without standing beside your beastie) is that there is might be some backpressure in the exhaust system that is causing your grief .. take it back to the muffler shop and have them check it over.

Another thing is the size of the pipes used .. do you have a Y or H pipe happening, or are you running complete dual with no cross-over? I am using dual exhaust with no cross over, and have no lack of power (for now )
Hello, my name is Vance and I am a Jeepaholic.
Its better to be naked with your friends, than to be clothed with your enemies
Silver 2006 TJ Unlimited, zombie ready as the daily-driver

- - - - - - -TEOTWAWKI- - - - - - -
NaeKid is offline   Reply With Quote Quick reply to this message

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools

Suggested Threads

Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. is not in any way associated with Jeep or the Chrysler Corp.