View Full Version : Engine Running But Problems - KOEO Codes (Long)

04-30-2005, 11:58 PM
Well I got the SC back together and it is being a little difficult. It has no power at all from a stop and it will fall on it's face at partial throttle going 45-50mph. Once it gets going it will go like crazy. It has a bad lag from a stop before it starts to scream though. Also it will go like crazy if I put my foot to the floor when it is sputtering at part throttle. One good thing I can smoke the tires if I nail it going 40mph in drive, so I now the power is there. Also at idle it will surge from 1300rpm to 900rpm. I have checked for vacuum leaks and have found none. My vacuum a idle is around 10 and in drive it is about 5(see big cam below) Here are the codes that I am getting.

KOEO (With chip in)
511 Prom failure (Because chip is in?)
558 EGR vacuum regulator circuit failure KOEO
181 Fuel system at rich adaptive limit at part throttle system lean bank 1
189 Fuel system at rich adaptive limit at part throttle system lean bank 2

KOEO (Without chip in)
335 Exhaust pressure transducer sensor voltage out of range during KOEO
558 EGR vacuum regulator circuit failure KOEO
332 EGR flow insufficient

The chip is compensating for my deleted EGR so that is why I am getting these codes with it out.

I try to perform a KOER test but it keeps saying vehicle not responding. What could this mean? I have tried a new computer but am getting the same thing. The scanner works fine on a different car running.

The car runs about the same with the chip in or with it out.

My mods with the chip where:
(Made 300+ RWHP)

Ported stock exhaust manifolds
2 To 1 To 2 Exhaust With 3" Center
Magnaflow Resonator
Dynomax Mufflers
Deleted egr valve
Deleted Cats
Underdrive Pullies
10% SC Overdrive Pulley
42lb Injectors
Mac Intake
C&L 70mm
BBK 70mm Throttle Body
255 LPH HP Fuel Pump
Double Intercooler With Fan
Magnum Powers Inlet Plenum
Magnum Powers Ported Blower
3/4" Raised Top
1.73 Roller Rockers
Ross Racing Pistons
Balanced Engine
Crane Cam Regrind
Ported Heads With Bigger Valves

Things that I have added to the car now:

Kooks Long Tube Headers
5% Jackshft Pulley
Randy Baker Enlarged Intake Manifold
Randy Baker Enlarged Intake Plenum
Bigger cam then previous

I realize that I could use a new tune for the added items but it seems like there is more to it then just a tune, especially with the vehicle not responding on the KOER test. Hopefully someone has an idea what could be the problem. Thanks!


05-02-2005, 07:38 AM
Any ideas?

David Neibert
05-02-2005, 08:55 AM

I'm guessing that most of the issues your having are related to the new cam. I've got the Steg 240/240 .539/.539 cam in mine and it ran like crap until spending a few hours on the dyno tuning it. Mine has to have alot of fuel on the bottom end or it boggs.

I'm only getting 7 inches of vac at idle (1100 rpms) and can barely keep it running at anything lower. How big is the cam you put in ?

BTW, That MAF looks a little small for your mods...I would suggest a C&L 76mm with the correct sample tube.


05-02-2005, 01:15 PM
What type of scanner are you using???? The car is what year. Certain cars 89-90 did not allow data-log from a scanner. The scanner might have the wrong connector???

Also, the EGR codes you are getting due to the EGR delete. Had the same problem on mine with the EGR off. The Lean codes worry me. It means you're not getting enough fuel. This is dangerous. Running lean can cause engine failure due to lean mixtures. I suggest that with the new cam, that you re-tune the car, and see if you can get the mixture correct.

Also, the 511 code is because of the tuner or chip. The EGR codes are for the EGR transducer (shows EGR flow meaning that the EGR is opening) and Transducer failure means that it's showing no flow because it is not plugged in. I suggest again, getting it tuned or at least getting someone to richen the mixure a bit.

Also, where are the O2 sensors now with the long-tube headers??? I have heard of problems with people not having the O2's "upstream" enough for the engine to properly calibrate the mixture.

Either way, Keep us posted.


05-02-2005, 01:44 PM

The cam is probably my biggest problem like you said. The specs are .598 intake lift, .619 exhaust lift, 224 intake duration, and a 236 exhaust duration. LSA is 114. (It's a monster)

About the MAF. I have a 90mm lightning MAF, Magnum powers 3.5" intake, and an 80mm TB ready to go on. I'm waiting to get it running good and then have it tuned for the lightning MAF before I put it on.


I'm not sure what brand the code scanner is. I can find out tonight. It works fine for scanning the KOEO codes but not the KOER codes. I tried the scanner on my dads 93 and it works on his for the KOER and KOEO.

The headers are the kooks long tube headers. I will search to see if I can dig anything up on other people having problems with the O2 location.

Thanks for letting me know that the 511 code is because the chip was in. I was worried that the computer was bad.

For right now the car is just sitting. I don't want to hurt the engine driving it with a lean condition.

Thanks again David and Don! My next step is to get this thing tuned and running safe A/F. I will be sure to update you guys.


David Neibert
05-02-2005, 02:14 PM
The cam is probably my biggest problem like you said. The specs are .598 intake lift, .619 exhaust lift, 224 intake duration, and a 236 exhaust duration. LSA is 114. (It's a monster)


That cam is very close to my old one. I loved it, but it kept tearing up the valvetrain. Mine was 226/239 .625/.625 and had much better bottom end torque and a little more top end power than what I've got now.

Get it tuned and that car is gonna rip. I also suggest raising the rev limiter to 6500 or your gonna be hitting it all the time when the tires break loose.