Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1987 - 1996 F150 & Larger F-Series Trucks
Sign in using an external account
Register Forgot Password?

1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

spark knock, rough idle

LinkBack Thread Tools Search this Thread
Old 10-15-2013, 03:32 PM
timbramo timbramo is offline
New User
Join Date: Apr 2013
Posts: 12
timbramo is starting off with a positive reputation.
spark knock, rough idle

Hello all, I have a 94 f150 with the 4.9l and E40D auto trans. It has AC and is 2whl drive. My problem is this. I had severe spark knock about a year ago and decided to rebuild the engine (almost 200k). Heads were in great shape however there was slight scoring on cylinders so pistons were part of the rebuild. rebuild went well however, and needless to say, I still have severe spark knock at idle. timing hovers between 4 btdc and 0 degrees. The MAP sensor tested good using a vacuum pump and a digital tach on meter. it went from 320 rpm at 0 inches vac to around 190 at 22 inches. There is good vacuum at idle ..or I think there is, its 20 pounds but drops to almost 0 as it surges. i checked all components that use a vacuum sorce for leaks and even bypassed them and same condition still occurs. I am currently bypassing the "vacuum cannister" as it was leaky. i will make a new one tonight out of 3" pvc.
The EGR vacuum solenoid was bad, the coil never activated, so it was replaced. I am not even sure it is coming into play.
I ran the DLC test for EEC-IV codes and here are the codes i retrieved.
KOEO test 33 and 133. KOER test gives 532, 536, 538.
if I unplug a vacuum manifold port the engine will idle but timing still sits aroun 4 dbtdc and 0. and of course engine gets hot. i get spark knock bad so i cant run the engine very long.
fuel pressure is 50 static and around 42 with engine idling.
I will do more electrical tests later. there are a lot of checks for the EEC-IV that are manual, I guess I will go through them later.
Any advice as to what to check would be appreciated.
Thanks so much, Tim
Reply With Quote
Old 10-15-2013, 03:32 PM

Similar Threads
Thread Thread Starter Forum Replies Last Post
94 f150 spark knock, rough idle timbramo Ford Inline Six, 200, 250, 4.9L / 300 17 11-12-2013 07:39 PM
What is the fascination II? greystreak92 1978 - 1996 Big Bronco 4 02-19-2013 02:16 PM
High Idle problem on '90 F-150 302 C.I. FRANKIE_FORD 1987 - 1996 F150 & Larger F-Series Trucks 19 07-24-2010 09:25 AM
1988 F-150 no spark or voltage to fuel pump timbarr 1987 - 1996 F150 & Larger F-Series Trucks 3 08-04-2003 07:55 PM
No codes from EEC-IV nar9695 1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks 6 09-15-2000 11:56 PM

Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1987 - 1996 F150 & Larger F-Series Trucks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Participate In The Forums

Create new posts and participate in discussions. It's free!

Sign Up »

All times are GMT -5. The time now is 12:24 AM.

Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup