Fuel Filter Blockage Can Cause Shudder in TCLU but not WOT - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 11-02-2005, 09:13 PM   #1
Junior Member
Thread Starter
 
Join Date: Dec 2004
Location: Lexington, KY
Posts: 9
Thanks: 0
Thanked 0 Times in 0 Posts
LilOrphan88 is on a distinguished road
Default Fuel Filter Blockage Can Cause Shudder in TCLU but not WOT

Would be interested to hear from the mods or interested gearheads why it is often suggested that a dirty fuel filter may be responsible for the shudder from 45-53 mph (prox) but there may be no noticeable decline in WOT performance?

Is it because the engine is lugging along near a peak torque condition at 45-53 MPH with the torque converter locked, and consequently is using a high rate of fuel? Hard to believe that would be more fuel used in a standing start, WOT condition.

Electric fuel pump should have fairly constant flow rate available at the injector rail, regardless of throttle position.

Thoughts, guys?
LilOrphan88 is offline   Reply With Quote
Old 11-02-2005, 09:27 PM   #2
Senior Member
Certified GM nut
 
Join Date: Feb 2004
Location: MI
Posts: 2,246
Thanks: 0
Thanked 0 Times in 0 Posts
Logan is on a distinguished road
Default

I'm racking my brain and don't know why...but...

It must be related to why your engine misses under those conditions as well.
Logan is offline   Reply With Quote
Old 11-02-2005, 10:48 PM   #3
Senior Member
Posts like a Corvette
 
Ol' Timer's Avatar
 
Join Date: Oct 2002
Location: New Jersey - Most of Our Elected Officials Have Not Been Indicted
Posts: 1,483
Thanks: 0
Thanked 0 Times in 0 Posts
Ol' Timer is on a distinguished road
Default Re: Fuel Filter Blockage Can Cause Shudder in TCLU but not W

While a Stink'n Rot'n Dirty Fuel Filter could possibly cause drivabliilty issues, I doubt it would be the cause of the infamous shudder between 45 & 53 mph. The ignition wires would be the first thing I would suspect if they haven't been replaced in awhile.
Ol' Timer is offline   Reply With Quote
Old 11-03-2005, 12:05 AM   #4
Senior Member
Posts like a Camaro
 
Join Date: Feb 2005
Location: Gilroy, California
Posts: 922
Thanks: 0
Thanked 0 Times in 0 Posts
Bob Dillon is on a distinguished road
Default

"Is it because the engine is lugging along near a peak torque condition at 45-53 MPH with the torque converter locked, and consequently is using a high rate of fuel? Hard to believe that would be more fuel used in a standing start, WOT condition."

No, it'* not. Fuel demand is a function of RPM. the fuel pump in our cars is obviously designed to handle WOT conditions at full pressure (3 bar). The only thing different happening at low RPM is that more fuel is returning to the tank via the return line.

Ergo, any lesser demand than WOT is not going to cause problems. If problems are caused by a diry fuel filter, they'll occur at any RPM or throttle position.

As an old-timer myself, I've had to learn to rethink fuel supply vs. RPM as provided by our old mechanical pump, single-line fuel systems.

"It must be related to why your engine misses under those conditions as well."

Correlation is not necessarily causation.
Bob Dillon is offline   Reply With Quote
Old 11-03-2005, 09:28 AM   #5
Senior Member
Certified GM nut
 
Join Date: Feb 2004
Location: MI
Posts: 2,246
Thanks: 0
Thanked 0 Times in 0 Posts
Logan is on a distinguished road
Default

Quote:
Originally Posted by Bob Dillon

"It must be related to why your engine misses under those conditions as well."

Correlation is not necessarily causation.
No doubt, but something to think about none the less.
Logan is offline   Reply With Quote
Old 11-03-2005, 12:48 PM   #6
Junior Member
Posts like a Ricer Type-R
 
Join Date: Aug 2002
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
willwren is on a distinguished road
Default

I would never attribute those symptoms to be fuel delivery. It'* ignition related 90% of the time. The rest of the time it'* a trans problem. Rarely fueling.
willwren is offline   Reply With Quote
Old 11-03-2005, 03:24 PM   #7
Junior Member
Thread Starter
 
Join Date: Dec 2004
Location: Lexington, KY
Posts: 9
Thanks: 0
Thanked 0 Times in 0 Posts
LilOrphan88 is on a distinguished road
Default

I tend to agree, probably why I posed the question. Elsewhere in the forum, dirty filter is proposed to be a cause of shudder, but nowhere has that been necessarily discounted.

Until now.

I also agree that a dirty filter should show up as driveability across all rpm and driving conditions.

Everyone is an expert on a bulletin board, ya know!
LilOrphan88 is offline   Reply With Quote
Old 11-03-2005, 03:33 PM   #8
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

Although the typical signs of a clogged filter would be a lack of fuel delivery at higher rpms.
BillBoost37 is offline   Reply With Quote
Old 11-03-2005, 04:17 PM   #9
Junior Member
Posts like a Ricer Type-R
 
Join Date: Aug 2002
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
willwren is on a distinguished road
Default

Quote:
Originally Posted by LilOrphan88
I tend to agree, probably why I posed the question. Elsewhere in the forum, dirty filter is proposed to be a cause of shudder, but nowhere has that been necessarily discounted.

Until now.

I also agree that a dirty filter should show up as driveability across all rpm and driving conditions.

Everyone is an expert on a bulletin board, ya know!
We've been religiously preaching ignition for these symptoms for over 2 years on this forum. It'* typical for the 3800.
willwren is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Cruise doesn't work and AC compressor runs on ANY setting but off. 2 probs 1 cause?? jmoline Buick 2 10-29-2013 09:13 AM
Anyone know what could cause a blockage like this? lunchboxx 1992-1999 4 02-03-2008 02:53 PM
Tire Shudder...Not The Usual Stuff harrydunn 2000-2005 3 06-07-2007 06:20 PM
not good. NOT GOOD. (hit and run, not bad-BAD, but not good) repinS General GM Chat 13 11-26-2004 11:35 AM


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



All times are GMT -4. The time now is 08:24 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.