The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-06-2010, 01:02 PM   #1
crm318
Alright Alright Alright
 
crm318's Avatar
 
Join Date: Mar 2004
Location: Midland, Texas
Posts: 1,672
Sporadic idle after washing and timing my engine.

Yesterday before work, I decided to give my engine bay a wash down with degreaser and water. I made sure not to get any down the carb and as little as possible on the distributor. I also set my initial timing from 14 to 16 degrees. When I headed of to work ( a delivery job), I noticed that the truck had a low idle and that the rpms/tach would bounce every 5 seconds or so. It sounded like an intake leak. I made sure that all of the vacuum and electrical lines were secure and I set my timing back to 14. I also sprayed carb cleaner all around the carb to find leaks. I delivered for four hours last night and the problem was always present (any water in the distributor should have burned off). What do yall think?
__________________
1972 Cheyenne
Chevrolet red and white
357ci, Vortec heads,
GM Performance high rise intake,
Comp 268H .454/.454 218/218 110 LSA
Quadrajet carb, Flowtech headers, 2.25 40 series
HEI, Curve kit, TH 350, 3.07 gears
275/60/15s on 15x8 rallies
crm318 is offline   Reply With Quote
Old 07-06-2010, 01:15 PM   #2
storm9c1
*** That's interesting ***
 
storm9c1's Avatar
 
Join Date: Oct 2008
Location: Pittsburgh, PA
Posts: 2,772
Re: Sporadic idle after washing and timing my engine.

Quote:
Originally Posted by crm318 View Post
Yesterday before work, I decided to give my engine bay a wash down with degreaser and water. I made sure not to get any down the carb and as little as possible on the distributor. I also set my initial timing from 14 to 16 degrees. When I headed of to work ( a delivery job), I noticed that the truck had a low idle and that the rpms/tach would bounce every 5 seconds or so. It sounded like an intake leak. I made sure that all of the vacuum and electrical lines were secure and I set my timing back to 14. I also sprayed carb cleaner all around the carb to find leaks. I delivered for four hours last night and the problem was always present (any water in the distributor should have burned off). What do yall think?
Could be a few things, but when I get a dancing tach, I usually start with checking the high voltage side of the ignition system. How old are the plug wires? Could there be any cracks in the insulation? Once that happens and water gets inside the wire, it takes a long time to dry out.

Also check the plug boots. If you got moisture in the boots, it could be arcing or causing an intermittent connection. Pull all of the boots and check, and possibly clean and apply some silicone grease. Same goes with the distributor... Under those boots, it may take a long time for all of the moisture to escape. I know they are supposed to stop water from getting in, but in my experience, it's much easier for it to get in than it is to get it back out. That's where the silicone grease helps. Also, a little moisture could have also caused some minor corrosion or irritated existing corrosion.
__________________
Tom
Chevy by day...
1969 Chevy C30 Rollback Tow Truck -- 383 stroker, 4L80E
2011 Chevy Caprice PPV 9C3 6.0L
1995 Chevy Caprice 9C1
1994 Chevy Caprice 9C1 #3
1995 Chevy Caprice Wagon #2
1995 Chevy Impala SS
Mopar by night...
1969 Dodge Charger
1972 Chrysler Newport 2dr Hardtop (27K miles)

Plus others...

Last edited by storm9c1; 07-06-2010 at 01:17 PM.
storm9c1 is offline   Reply With Quote
Old 07-07-2010, 06:58 PM   #3
crm318
Alright Alright Alright
 
crm318's Avatar
 
Join Date: Mar 2004
Location: Midland, Texas
Posts: 1,672
Re: Sporadic idle after washing and timing my engine.

Well, today I pulled the cap and rotor of and removed the coil. Everything was dry. I then saw that the base of the distributor was also dry. I applied dielectric grease to both ends of each wire. After I got everything back together and started it, the problem was still there. I am stumped.
__________________
1972 Cheyenne
Chevrolet red and white
357ci, Vortec heads,
GM Performance high rise intake,
Comp 268H .454/.454 218/218 110 LSA
Quadrajet carb, Flowtech headers, 2.25 40 series
HEI, Curve kit, TH 350, 3.07 gears
275/60/15s on 15x8 rallies
crm318 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:31 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com