Fluctuating Idle - Ford Truck Enthusiasts Forums



1999 - 2003 7.3L Power Stroke Diesel  
Sponsored by:
Sponsored by:

Fluctuating Idle

Reply
 
 
 
Thread Tools Search this Thread
  #1  
Old 10-25-2006, 09:56 AM
Dan R Dan R is offline
New User
Thread Starter
 
Join Date: Oct 2006
Posts: 10
Dan R is starting off with a positive reputation.
Fluctuating Idle

Hello,

I just bought a 99 250 7.3 PSD. It's great and I would never buy another gas powered truck. The only problem (?) I have is a weird idle when it is cool, the RPM's jump and drop for the first 30-40 seconds, but it is fine once it gets warmed up. This is my first diesel vehicle, but I don't think they are supposed to do this. Anyone else have this problem or know how to solve it?


Thanks,

Dan
Reply With Quote
  #2  
Old 10-25-2006, 02:12 PM
Medic 66's Avatar
Medic 66 Medic 66 is offline
Posting Guru
 
Join Date: Mar 2005
Posts: 1,458
Medic 66 is gaining momentum as a positive member of FTE.
What is the outside temp? This may be normal.....
Reply With Quote
  #3  
Old 10-25-2006, 03:14 PM
MTDewX's Avatar
MTDewX MTDewX is offline
Posting Guru
 
Join Date: Sep 2006
Location: Montana
Posts: 1,032
MTDewX is gaining momentum as a positive member of FTE.MTDewX is gaining momentum as a positive member of FTE.
on chilly mornings, my (exhaust) sounds like a mini me jet engine due to some thing that closes to help the engine warm up faster. its normal from what I have read. I don't know the name cause I am new also, but boy do I read on this site. and learning everyday
Reply With Quote
  #4  
Old 10-25-2006, 04:00 PM
Dan R Dan R is offline
New User
Thread Starter
 
Join Date: Oct 2006
Posts: 10
Dan R is starting off with a positive reputation.
I should have explained it better, its not just holding steady at 2k or so RPM, it jumps 1000-2000-1000-2000 (very quickly, every second or so, sounds like someone is pumping the "gas" pedal). I know most vehicles initially run at a higher RPM when its cooler to help warm up, but this fluctuates, and sometimes it will stall.
Reply With Quote
  #5  
Old 10-25-2006, 06:19 PM
Uzumati's Avatar
Uzumati Uzumati is offline
Post Fiend
 
Join Date: Jun 2006
Location: Central, Al
Posts: 5,362
Uzumati has a good reputation on FTE.Uzumati has a good reputation on FTE.Uzumati has a good reputation on FTE.
Whats the Oil Level, Oil Type, Last Oil Change

High pressure oil drives the injectors low, old, thin oil can cause the "romp-romp" idle
Reply With Quote
  #6  
Old 10-25-2006, 07:09 PM
DP-Tuner's Avatar
DP-Tuner DP-Tuner is offline
PREMIUM SPONSOR
 
Join Date: Mar 2005
Location: Hoschton,GA
Posts: 1,822
DP-Tuner is a splendid one to beholdDP-Tuner is a splendid one to beholdDP-Tuner is a splendid one to beholdDP-Tuner is a splendid one to beholdDP-Tuner is a splendid one to beholdDP-Tuner is a splendid one to beholdDP-Tuner is a splendid one to behold
Quote:
Originally Posted by Dan R
Hello,

I just bought a 99 250 7.3 PSD. It's great and I would never buy another gas powered truck. The only problem (?) I have is a weird idle when it is cool, the RPM's jump and drop for the first 30-40 seconds, but it is fine once it gets warmed up. This is my first diesel vehicle, but I don't think they are supposed to do this. Anyone else have this problem or know how to solve it?


Thanks,

Dan
If you can borrow a scan tool to see what is going on at that rpm. It almost sounds like an ICP issue. It is like it is trying to compensate the ICP(injection control pressure). Could be that it has a programmer on it and was not returned to stock or a chip possibly. Look on the J3 port on the PCM. Behind the emergency break there is a black plastic housing encasing the PCM. Let us know what you find.

Diane
__________________
Jody & Diane Tipton- DP-Tuner®
FTE Legacy Sponsors since 2006
Custom tuning for 7.3l, 6.0l, 6.4l and 6.7l
Get Tuned! 828-221-0076 ext. 802
Become our Facebook Fan
Reply With Quote
  #7  
Old 10-26-2006, 08:11 AM
EWALR1 EWALR1 is offline
New User
 
Join Date: Oct 2006
Posts: 7
EWALR1 is starting off with a positive reputation.
i am also having the same problem with the eratic idle. i have changed the high pressure pump, ipr,icp,idm,pcm,wiring harness,valve cover gasket, injector harness,cps, and all 8 injectors. still no luck with the idle. changed the oil several times and still no differance. its not too big of a problem but id still like to know what it is. the only difference is min only does it for about 10-15 seconds. im pulling my hair out trying to figure it out. if anyone has some ideas it might help both of us out, but im gonna keep trying to solve it.
Reply With Quote
  #8  
Old 10-26-2006, 09:42 AM
lesarjohn lesarjohn is offline
New User
 
Join Date: Oct 2004
Posts: 13
lesarjohn is starting off with a positive reputation.
Mine too. At startup, after not running overnight, and not everytime. Touch the gas pedal a bit and it goes away and idels right?
It used to on anything less that 40 degree(f) mornings it would idle pretty high for a few minutes. Not anymore.

Does this give anyone any better tips. Going on a long haul next week and would like to sleep better?

My scan tool was ordered last week and has not arrived yet?
Does anyone have one locally that I could check it out with
Guelph, Ont, Canada
Reply With Quote
  #9  
Old 10-27-2006, 07:00 AM
Dan R Dan R is offline
New User
Thread Starter
 
Join Date: Oct 2006
Posts: 10
Dan R is starting off with a positive reputation.
It sounds like we have the same problem, yes when I touch the pedal it does go away. No one has fixed this before?
Reply With Quote
  #10  
Old 10-27-2006, 11:46 PM
Tenn01PSD350's Avatar
Tenn01PSD350 Tenn01PSD350 is offline
Post Fiend
 
Join Date: Feb 2006
Location: Middle Tennessee
Posts: 11,898
Tenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud of
Gonna bump this for you guys because I don't feel like you're getting what you need. Initial search looks like it may be the accelerator pedal specifically the idle validation switch which is in the pedal assemby. Especially since it goes away if you press the pedal. It's all fly by wire gents. An entire assembly. Yeah, gotta love it.
*Condition , * Possible Source, *Action
<table border="1" cellpadding="3" cellspacing="0" rules="groups" width="90%"><tbody><tr valign="top"><td>
  • Irregular Engine Idle Speed (Diesel)
</td> <td>
  • Incorrect engine idle speed adjustment or idle validation switch.
</td> <td>
  • REPLACE the accelerator pedal and sensor assembly.
</td></tr></tbody></table>

Last edited by Tenn01PSD350; 10-27-2006 at 11:48 PM.
Reply With Quote
  #11  
Old 10-28-2006, 06:16 AM
lesarjohn lesarjohn is offline
New User
 
Join Date: Oct 2004
Posts: 13
lesarjohn is starting off with a positive reputation.
Thanks I will investigate that more!
Reply With Quote
  #12  
Old 10-28-2006, 09:48 AM
Kwikkordead's Avatar
Kwikkordead Kwikkordead is offline
Post Fiend
 
Join Date: Jun 2004
Location: North Seattle, WA.
Posts: 22,271
Kwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputationKwikkordead has a superb reputation
Quote:
Originally Posted by Tenn01PSD350
Gonna bump this for you guys because I don't feel like you're getting what you need. Initial search looks like it may be the accelerator pedal specifically the idle validation switch which is in the pedal assemby. Especially since it goes away if you press the pedal. It's all fly by wire gents. An entire assembly. Yeah, gotta love it.
*Condition , * Possible Source, *Action
<TABLE cellSpacing=0 cellPadding=3 rules=groups width="90%" border=1><TBODY><TR vAlign=top><TD>
  • Irregular Engine Idle Speed (Diesel)
</TD><TD>
  • Incorrect engine idle speed adjustment or idle validation switch.
</TD><TD>
  • REPLACE the accelerator pedal and sensor assembly.
</TD></TR></TBODY></TABLE>
You're the first one that I have heard from that actually has an answer for the morning romp romp idle.
I'll bet that Ford sells a lot of pedal assemblies this week!

.

Another thing that might help is to install a high pressure crossover line. That smooths and quiets the idle.
However, don't install the HX line to try and cure the romps, but rather install it after you get the problem solved.
Reply With Quote
  #13  
Old 10-28-2006, 11:57 AM
Tenn01PSD350's Avatar
Tenn01PSD350 Tenn01PSD350 is offline
Post Fiend
 
Join Date: Feb 2006
Location: Middle Tennessee
Posts: 11,898
Tenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud of
Quote:
Originally Posted by EWALR1
the only difference is min only does it for about 10-15 seconds. im pulling my hair out trying to figure it out. if anyone has some ideas it might help both of us out, but im gonna keep trying to solve it.
I would not worry about this if it only does it for 10-15 seconds. I would only really look at the pedal assembly if an idle problem persists after 1-2 minutes. On cold starts, there are a lot of parameters that need to get up to speed, so time must be allowed for that before blaming the pedal assembly. I would suspect the pedal if it idles poorly even after warm. Don't want a bunch of pedal assemblies being bought when not needed.
Reply With Quote
  #14  
Old 10-28-2006, 12:17 PM
Uzumati's Avatar
Uzumati Uzumati is offline
Post Fiend
 
Join Date: Jun 2006
Location: Central, Al
Posts: 5,362
Uzumati has a good reputation on FTE.Uzumati has a good reputation on FTE.Uzumati has a good reputation on FTE.
The IVS is a Prime Suspect for the Romp Romp but there are several other Idle Quality possibilities.

Poor idling
Vacuum leaks.
Refer to the appropriate section in Group 303 for the procedure. REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.

Malfunctioning or damaged ignition system.
Refer to the appropriate section in Group 303 for the procedure. REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.

Malfunctioning or damaged fuel system.
Refer to the appropriate section in Group 303 for the procedure. REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.

Damaged valve tappet or lash adjuster.
INSTALL a new valve tappet or lash adjuster.

Damaged valve tappet guide or lash adjuster.
INSTALL a new valve tappet guide or valve tappet.

Incorrect valve-to-valve seat contact.
REPAIR or INSTALL a new valve or valve seat.

Damaged head gasket.
INSTALL a new head gasket.

AND This

10b. Low Idle Stability (ICP Pressure)
Purpose:
To determine if idle stability or low power is caused by a stuck or dirty IPR or faulty ICP signal.

Recommended Procedure:
Install NGS Tester. Turn A/C off. Access ICP PID on NGS Tester and monitor ICP pressure. Operate the engine at low idle. If engine does not stabilize, disconnect the ICP sensor. If low idle speed stabilizes with the ICP sensor disconnected, the problem is most likely in the ICP sensor circuit. GO to Pinpoint Test DC . If rpm does not stabilize, change the IPR and retest. This test should be performed with engine at normal operating temperature.

Possible Causes:
Debris stuck in the IPR
Inoperative ICP sensor or circuit failure

AND This

10a. Injection Control Pressure Tests (Oil Aeration — Poor Idle Quality)
Purpose:
To determine if the engine lube oil is aerated and causing poor idle quality.

Recommended Procedure:
Install NGS Tester. Turn A/C off. Access ICP PID on NGS Tester and monitor ICP pressure. Operate the engine at 3400 rpm for 3 minutes. This test should be performed with engine at normal operating temperature.

Possible Causes:
Extended oil drain intervals — the anti-foam additives in the oil may be depleted either from severe use or extended intervals.
Air may be present due to recent engine repair on injection control pressure system. It may be necessary to run the vehicle aggressively for 24-32 kilometers (15-20 miles) to remove air.
Wrong type or grade of oil.
Reply With Quote
  #15  
Old 10-28-2006, 01:43 PM
Tenn01PSD350's Avatar
Tenn01PSD350 Tenn01PSD350 is offline
Post Fiend
 
Join Date: Feb 2006
Location: Middle Tennessee
Posts: 11,898
Tenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud ofTenn01PSD350 has much to be proud of
Thank you Alan. I did not want to go digging for those because everytime I get into that DVD, I find more and more interesting things and get stuck there.

Also, I would hate for somebody to misdiagnose the pedal and not cure the problem.
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
won't start without pressing pedal to floor danpiscotty 1987 - 1996 F150 & Larger F-Series Trucks 7 06-03-2016 11:00 AM
Bully Dog GT Problem dan150 Computer Chips & Tuners 1 05-23-2013 07:32 PM
92 f150 4.9L o2 sensor problems? Dan92 1987 - 1996 F150 & Larger F-Series Trucks 6 03-15-2012 02:42 PM
what does a shift lever bushing look like? girlwithatruck 1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks 56 10-11-2009 12:31 AM
Are Aerostar's infamous for sudden distributor cap failure? Baggins Aerostar 10 02-21-2008 01:58 PM


Go Back   Ford Truck Enthusiasts Forums >

Tags
1994, 2001, 2005, 73, adjustment, f150, fluctuating, ford, fuel, idle, irregular, line, parameter, powerstroke, procedure, ranger, replace, scab, xlt

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


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