Engine dives when giving it gas - 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 11-09-2006, 10:33 AM   #1
Senior Member
True Car Nut
Thread Starter
 
Join Date: Feb 2006
Location: Melrose
Posts: 4,596
Thanks: 0
Thanked 0 Times in 0 Posts
BLACK94SSEi is on a distinguished road
Default Engine dives when giving it gas

Heres my problem:

From a stand still, if I hit the pedal for a fast takeoff, the engine dives a second or so then gets up to speed. This issue just started after my fuel tank, Fuel pump, and sending unit replacement and im not sure why.

Heres what I tried:

I know that Traction control can slow down the engine if slippage occurs, so I tried to replicate the problem with the traction control off and I cant seem to get it to dive again.

Has anyone else experienced this?

Today when I get out of work, im going to try taking the traction control off first, then try it and see what happens, then try again with traction control on.

Fuel Pressure was tested at Bills and was around EDIT: 39-40 or so lbs

All of the replacement parts mentioned above were aftermarket.
BLACK94SSEi is offline   Reply With Quote
Old 11-09-2006, 10:39 AM   #2
Senior Member
True Car Nut
 
Join Date: Jan 2006
Location: NEBF:06,07 | NYBF:06,07 | ONBF:06,07 | CNBF:06 & more............
Posts: 8,029
Thanks: 0
Thanked 0 Times in 0 Posts
bandit is on a distinguished road
Default

i would suggest checking your fuel pressure like i did.

Extend the hose, and run it inside the car, have someone hold it and make sure you get all "all" of the air out of the line.

Next go drive around, Full throttle and what not and idle at stop light and half throttle and stuff.

then see what its running at.
because when i first did mine sitting in the driveway it was WAY different from when i took it out driving.
bandit is offline   Reply With Quote
Old 11-09-2006, 10:43 AM   #3
Senior Member
True Car Nut
Thread Starter
 
Join Date: Feb 2006
Location: Melrose
Posts: 4,596
Thanks: 0
Thanked 0 Times in 0 Posts
BLACK94SSEi is on a distinguished road
Default

Quote:
Originally Posted by bandit
i would suggest checking your fuel pressure like i did.

Extend the hose, and run it inside the car, have someone hold it and make sure you get all "all" of the air out of the line.

Next go drive around, Full throttle and what not and idle at stop light and half throttle and stuff.

then see what its running at.
because when i first did mine sitting in the driveway it was WAY different from when i took it out driving.
I remember testing it at Bills and I thought it was 45 but it was lower than that I guess.

Someone hinted it to be a possible FPR.
BLACK94SSEi is offline   Reply With Quote
Old 11-09-2006, 10:54 AM   #4
BANNED
 
Join Date: Aug 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
banned3800 is on a distinguished road
Default

With no Vacume on the FPR you shoule see Pressure in the high 40'*... Low end should be 40-41psi... The pressure will vary a few...

What type of pump did you use?

and what was the pressure before you replaced the pump?

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
banned3800 is offline   Reply With Quote
Old 11-09-2006, 11:25 AM   #5
Senior Member
True Car Nut
Thread Starter
 
Join Date: Feb 2006
Location: Melrose
Posts: 4,596
Thanks: 0
Thanked 0 Times in 0 Posts
BLACK94SSEi is on a distinguished road
Default

Quote:
Originally Posted by jr's3800
With no Vacume on the FPR you shoule see Pressure in the high 40'*... Low end should be 40-41psi... The pressure will vary a few...

What type of pump did you use?

and what was the pressure before you replaced the pump?
I never tested pressure before replacment, and the pump is an aftermarket one which I do not know the name.
BLACK94SSEi is offline   Reply With Quote
Old 11-09-2006, 12:02 PM   #6
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

Carter
BillBoost37 is offline   Reply With Quote
Old 11-09-2006, 08:34 PM   #7
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2006
Posts: 141
Thanks: 0
Thanked 0 Times in 0 Posts
motorhead is on a distinguished road
Default

Do you run a K&N air filter? Or a very dirty/torn paper filter? If yes to either, then you may want to remove and look at the tiny little wires on the MAF sensor and make sure they are clean. Any large amounts of dirt or debris on these wires will make the engine lack performance. You can clean the wires with rubbing alcohol and a Q-tip, but be very gentle with the wires as they are fragile.
motorhead is offline   Reply With Quote
Old 11-09-2006, 11:45 PM   #8
Senior Member
True Car Nut
Thread Starter
 
Join Date: Feb 2006
Location: Melrose
Posts: 4,596
Thanks: 0
Thanked 0 Times in 0 Posts
BLACK94SSEi is on a distinguished road
Default

Quote:
Originally Posted by motorhead
Do you run a K&N air filter? Or a very dirty/torn paper filter? If yes to either, then you may want to remove and look at the tiny little wires on the MAF sensor and make sure they are clean. Any large amounts of dirt or debris on these wires will make the engine lack performance. You can clean the wires with rubbing alcohol and a Q-tip, but be very gentle with the wires as they are fragile.
I had the MAF screen out not too long ago and just put it in about 2 weeks ago and all was clear. I am running a K&N filter in stock airbox, but I tried something today after work.

When leaving the parking lot where I park, I took the Traction Control off and mashed it. No loss of power or diving at all and the power was there. Im now leading to believe that the Traction control is the culprit. Not that theres anything wrong with it, it was just merely doing its job I guess. No issues with traction off.
BLACK94SSEi is offline   Reply With Quote
Old 11-10-2006, 12:39 AM   #9
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2006
Posts: 141
Thanks: 0
Thanked 0 Times in 0 Posts
motorhead is on a distinguished road
Default

I didn't know you had the MAF screen out. That screen serves a purpose! Most people (including the folks on here from what I've read) have no idea what that screen is for! It is actually very important for the engine computer to function properly.

Most enthusiasts believe that removing the screen will increase engine air flow and result in more horsepower. The truth about that screen that MOST enthusiasts don't know is its actual FUNCTION.

That screen was put there by GM engineers for a reason. The screen converts turbulent air into a straight flow pattern so the MAF sensor can "read" the air volume entering the engine ACCURATLY.

Turbulent air (swirling around) can not be measured accurately by the MAF sensor...the MAF sensor was designed to measure air volume with a straight flow pattern. When you remove the screen, you take away that straight flow pattern and create a turbulent, or "wash" air flow pattern that the MAF can not measure accurately. This results in false intake air volume measurements that the computer receives. The computer believes what it sees so it adjusts fuel and ignition according to its input values.

The input values are incorrect, but the computer doesn’t know this because the MAF sensor says it IS correct….and the computer believes ANYTHING the MAF tells it!

The MAF is one of the MOST important inputs the computer looks at. Altering the MAF by removing the screen is one of the MOST detrimental mods you can do.
motorhead is offline   Reply With Quote
Old 11-10-2006, 01:05 AM   #10
Senior Member
Certified Car Nut
 
Join Date: Oct 2003
Posts: 19,756
Thanks: 0
Thanked 0 Times in 0 Posts
1993 SLE is on a distinguished road
Default

Quote:
Originally Posted by motorhead

The MAF is one of the MOST important inputs the computer looks at. Altering the MAF by removing the screen is one of the MOST detrimental mods you can do.
i disagree completely.....
1993 SLE is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Engine giving me HELL vegeta6588 1992-1999 8 04-04-2011 09:19 AM
giving full gas, car shudders, power lose seeeiholland 1992-1999 3 12-12-2006 11:58 AM
Bonnie's giving me a headache! SSEiGrl92 1992-1999 26 09-19-2005 12:14 PM
GXP Brakes...Germans giving me crap! obis88 Bonneville GXP/ Northstar Powered Cars 30 03-14-2005 12:38 AM
there giving the car away 2000 Silver SSEI General GM Chat 18 03-12-2005 10:59 PM


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 01:56 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.