Odd, uneven idle problem at startup - Ford Powerstroke Diesel Forum
 
LinkBack Thread Tools Display Modes
post #1 of 6 Old 03-23-2013, 04:58 PM Thread Starter
Member
 
Join Date: Mar 2008
Location: North Central Texas
Posts: 55
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Odd, uneven idle problem at startup

I just bought another Powerstroke. It is a 1997, with 319,000 miles. This is the 16th, 7.3 I have owned, but, it has a problem I have not seen before.
At startup, hot or cold, the idle is uneven for about 20 or 30 seconds. It goes from regular idle RPM down to "almost dies" RPM, then bounces right back up to regular idle speed. Does this repeatedly for about 20 or 30 seconds, then it smooths right out. If I give it a little throttle at startup, it will run smooth during startup, until I let it go back to idle.
Again, this only happens on startup, not during driving or at stop lights etc.
Otherwise, truck runs great. I drove it 100 miles to bring it home, all at around 65 - 70MPH, with no problems.
I don't think this is related, but it needs a glow plug relay most likely. The wait to start light goes off after only about 5 seconds every time you start the truck. It should be on longer than that in cold wet weather.
What is causing this.
Thanks,
Jeff
mowingman is offline  
Sponsored Links
Advertisement
 
post #2 of 6 Old 03-23-2013, 08:25 PM
Compression Ignition Addict
 
Patrick Feeley's Avatar
 
Join Date: Oct 2011
Location: Tehachapi, CA
Posts: 2,228
Thanks: 0
Thanked 87 Times in 85 Posts
Mentioned: 0 Post(s)
Quoted: 5 Post(s)
Feedback Score: 0 reviews
If this an automatic, does it do it if you start it in neutral? Just a note on the Wait-to-Start light: The length of time it is on has nothing to do with when the plugs are actually on (watch your voltage gauge as that will basically tell you when the plugs are on). Cheers!

1997 F250 SC 4x4, E4OD, 4.10 LS, Basically Stock, Relocated Block Heater Plug, External Trans Filter, Tru-Cool Max, I/C Mounted but not Plumbed

SOLD - 1994 F350 CC DRW 2WD PSD, 5 Speed, 4.10 LS, SBC Con-O, Baldwin Filter, Tymar HPX Hose, DPPI DP, Bilsteins, $12 AIC, Coolant Filter, Explorer Overhead Console, A-Pillar w/ISSPRO Black Ice, EV Boost, and EV Pyro, Modified Pedestal, Gutted EBPV.
Patrick Feeley is offline  
post #3 of 6 Old 03-23-2013, 08:52 PM Thread Starter
Member
 
Join Date: Mar 2008
Location: North Central Texas
Posts: 55
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
It is an automatic. I will try cranking it up in neutral and see what happens. Will report back here.
Yes, I forgot all about that wait-to start light versus voltage draw, for checking how long the glow plugs are on. Thanks for reminding me about that.
Jeff

Quote:
Originally Posted by Patrick Feeley View Post
If this an automatic, does it do it if you start it in neutral? Just a note on the Wait-to-Start light: The length of time it is on has nothing to do with when the plugs are actually on (watch your voltage gauge as that will basically tell you when the plugs are on). Cheers!
mowingman is offline  
post #4 of 6 Old 03-24-2013, 10:28 AM Thread Starter
Member
 
Join Date: Mar 2008
Location: North Central Texas
Posts: 55
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Ok, today I started the truck in neutral. It idles fine when started in neutral.
So, what advice do you have for me??
Any help appreciated.
Jeff
mowingman is offline  
post #5 of 6 Old 03-24-2013, 06:08 PM
Compression Ignition Addict
 
Patrick Feeley's Avatar
 
Join Date: Oct 2011
Location: Tehachapi, CA
Posts: 2,228
Thanks: 0
Thanked 87 Times in 85 Posts
Mentioned: 0 Post(s)
Quoted: 5 Post(s)
Feedback Score: 0 reviews
Usually the fix (I've never had this problem myself ... just from my times on the forums) is replacement of the Transmission Range Sensor on the transmission. Cheers!

1997 F250 SC 4x4, E4OD, 4.10 LS, Basically Stock, Relocated Block Heater Plug, External Trans Filter, Tru-Cool Max, I/C Mounted but not Plumbed

SOLD - 1994 F350 CC DRW 2WD PSD, 5 Speed, 4.10 LS, SBC Con-O, Baldwin Filter, Tymar HPX Hose, DPPI DP, Bilsteins, $12 AIC, Coolant Filter, Explorer Overhead Console, A-Pillar w/ISSPRO Black Ice, EV Boost, and EV Pyro, Modified Pedestal, Gutted EBPV.
Patrick Feeley is offline  
post #6 of 6 Old 03-26-2013, 06:18 PM Thread Starter
Member
 
Join Date: Mar 2008
Location: North Central Texas
Posts: 55
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Patrick,
Thank you for that info. I am going to see about replacing that part next week. My son is going to fix it next week. He was a Ford mechanic at one time, but he never worked on any of the Powerstrokes at the big dealership he worked in. He said that this should be an easy fix.
Thanks again.
Jeff
mowingman is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Powerstroke Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









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
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome