86 7.5L - Cold Start
Thread Starter
|
Tuned
Joined: Jun 2006
Posts: 363
Likes: 3
From: Graham WA
86 7.5L - Cold Start
I have a cold start issue that I don't have a solution for. It does not seem to be the choke setting as I have tried several choke positions. Runs fine after warm up. I'm wondering if maybe the EGR could be kicking in when it should not be (cold engine). If that were the case, then likely a thermal vacuum switch may have failed in the open position. Is there a way to test the switch?
Any other ideas? Thanks!
Any other ideas? Thanks!
Moderator
Joined: Jan 2001
Posts: 56,980
Likes: 2,735
From: Virginia
Rev the engine when cold, and pull the vacuum line off the egr. If it has vacuum, the switch is bad. You have to rev the engine, because the egr is on ported vacuum on the carb.
Does it seem to run rougher when it's damp outside, rainy, or a heavy dew? If it does seem worse, make sure your heat duct system going to the aircleaner is working correctly.
Does it seem to run rougher when it's damp outside, rainy, or a heavy dew? If it does seem worse, make sure your heat duct system going to the aircleaner is working correctly.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
Make sure the alternator isn't bad, it could be keeping power on the choke heater with the engine not running. Also make sure the choke closes, sometimes they stick. I know mine is an absolute PITA to start if I don't drive it regularly due to the fuel in the carburetor slowly evaporating.
Thread
Thread Starter
Forum
Replies
Last Post
loveless41908
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
1
Oct 12, 2011 11:00 PM
bigland
1973 - 1979 F-100 & Larger F-Series Trucks
3
Nov 27, 2009 05:55 AM
86rustbucket
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
5
Mar 13, 2008 06:41 PM
84-250
Fuel Injection, Carburetion & Fuel System
9
Mar 2, 2003 11:19 AM
