hesitation before 3000 rpm, awesome after

Simple88GT · Oct 12, 2009

when ever I take off from a stop, and just ease on the throttle the car just hesitates to go, it pops backfires and just plain wont go. It almost feels as if it is loading up on fuel. However once it hits 3000 rpm it picks up as if nothing were wrong. Also if I floor it from a stop it takes off like I would expect it to.

I pulled the codes and I get 33 41 and 91

I cannot find out what is causing the lean conditions I have checked the voltages on the O2s the were within the specified ranges, and searched for vac leaks using the brake cleaner method and didnt find any leaks.

the 33 is because the guy i bought the car from disconnected EVERYTHING that is smog related, so I am slowly getting the egr stuff back on.

Any help would be greatly appreciated

Thanks

Josh

liljoe07 · Oct 12, 2009

Where is the timing at?

But first you need to get 41 and 91 squared away. What voltages did you check, and where did you take the voltages from?

Simple88GT · Oct 12, 2009

timing ist set at 14* and I checked the voltages at the computer i averaged .44 and .43

Could having the EGR blocked off at the head and intake cause a lean condition, when the Holley intake was put on we used the spacer to block the egr valve that was included with the gasket kit, since he didnt have the egr hooked up he felt it wasnt necessary.

Thanks

Josh

liljoe07 · Oct 12, 2009

Blocked EGR wont cause a Lean condition.
What codes were these? KOER or KOEO?

Sounds like a vacuum leak to me.

Simple88GT · Oct 12, 2009

I am figuring it is a vac leak somewhere, or the intake plenum gasket needs to be replaced cause he reused that also and it was just the paper one not the metal core one that I will be buying to replace it

it was koer

koeo is all the smog stuff

liljoe07 · Oct 12, 2009

If the lower has been removed and put back on, make sure you retorque the lower intake bolts again. They loosen back up after an initial warm up.

Simple88GT · Oct 12, 2009

do you mean the lower to the hrads or the lower to upper

liljoe07 · Oct 12, 2009

Lower to the Heads.

Simple88GT · Oct 13, 2009

i'll give them the torque wrench this weekend and see if it helps, thanks for the info

Josh

bentley429isBAC · Oct 13, 2009

Unplug the 02 sensors see if it is still doing it then. This has happened to me twice and once to a buddy each time we went through everything and it turned out to be the 02 sensors. After 3k rpm the computer doesnt read them anymore.

Simple88GT · Oct 14, 2009

when I bought the car it didnt have O2's in it, and it ran perfect no hiccups or anything, I guess I should have just let it be, but I couldnt stand the smell of gas all the time. I just put the O2's in back in may of last year. It has been doing it since I put them in. I don't see way though. I have also upgraded to Maf since I bought the car in hopes it would help with the hesitation and running rich.

Thanks for the input

Josh

BK_CAULEY · Oct 14, 2009

Simple88GT said:
I have also upgraded to Maf since I bought the car in hopes it would help with the hesitation and running rich.

Thanks for the input

Josh

what size injectors are you running? are they matched to the meter? and if its a c&l meter did you instal the sample tube or was it already in? do you know what color the sample tube is?

liljoe07 · Oct 14, 2009

Is the 02 ground hooked up at the back of the intake, heads, or block?

Simple88GT · Oct 15, 2009

running 19lb injectors with 70mm maf from a 94 and the ground is hooked up i have triple checked that, plus i wouldnt think the voltages would read correctly if it werent.

Simple88GT · Jun 15, 2010

I know its been a while since the last post just wanted to update.

I unplugged the O2's and the problem has gone away. Could it be because I have Longtubes? I just cannot wrap my head around why this thing will not run properly with the O2's hooked up.

Thanks

-Josh-

Strype · Jun 15, 2010

Simple88GT said:
I know its been a while since the last post just wanted to update.

I unplugged the O2's and the problem has gone away. Could it be because I have Longtubes? I just cannot wrap my head around why this thing will not run properly with the O2's hooked up.

Thanks

-Josh-

Wow that is weird.

C&L notes a different MAF for standard 5.0's (93 vs 94)

http://www.cnlperformance.com/calibration.html

Do the error codes go away with them unplugged?

Custom computer chip?

bentley429isBAC · Jun 15, 2010

The 02s are prob just junk or one is. They are overrated anyways

Simple88GT · Jun 15, 2010

No the codes are still present, and they are both brand new, and they both replaced new ones. Basically there were new ones in the car and the guy I bought the car from took them out because it was having this same problem, so when I bought the car I put 2 new O2's back in, and it started the hesitation problem again. With the O2's in it feels like it loses 100 horsepower under 3000 rpm, without the O2's it will run sub-8 seconds in the 1/8th I just don't understand.

Mustang5L5 · Jun 15, 2010

+1.

The o2s stop affecting fuel/timing at 3500 rpm, so that is a strong clue. The code 41 and 91 is another strong clue.

Unplug them and see if the car runs better.

hesitation before 3000 rpm, awesome after

Simple88GT

New Member

liljoe07

Simple88GT

New Member

liljoe07

Simple88GT

New Member

liljoe07

Simple88GT

New Member

liljoe07

Simple88GT

New Member

bentley429isBAC

Simple88GT

New Member

BK_CAULEY

it's built for speed not longevity, woman

liljoe07

Simple88GT

New Member

Simple88GT

New Member

Strype

Cuthbert catcher

bentley429isBAC

Simple88GT

New Member

Mustang5L5

That is…until I whipped out my Bissell

Similar threads

hesitation before 3000 rpm, awesome after

New Member

New Member

New Member

New Member

New Member

New Member

it's built for speed not longevity, woman

New Member

New Member

Cuthbert catcher

New Member

That is…until I whipped out my Bissell

Similar threads

Privacy & Transparency

Privacy & Transparency