5.3LS10

Hi Everyone.

I have a friend with a 1987 Camaro and is having issues with idle and driving quality after an engine build about 8 years ago. He tried replacing just about everything on the car to rule out any sensors etc and still having the issues. After awhile he lost faith and gave up on the car. I talked him into spending some more time and trying to get this figured out so he can start driving the car again.

Rebuilt 355ci shortblock with aftermarket rods and pistons to factory CR spec
TPIS: Miniram intake / Fuel rails / Adjustable Fuel Pressure Regulator
Lingenfelter Cam Shaft: part number 74219 (219/219 .525/.525 112deg)
Edelbrock 350-60859 Street legal Performer 60cc
Magnaflow muffler/Magnaflow Cat (stock size 2.5 inch pipes)
160-degree thermostat (computer sees 180* CLT temps while driving)
Hypertech 200 degree secondary fan temp sensor
K & N air cleaners
Honed stock throttle body to 52mm and added TB Airfoil
Ford 24lb. Injectors (Blue Tops)
MSD Cap and Rotor and External Coil
Comp Cams Heat treated pushrods 5/16 - 7.300
CompCams Magnum Rocker Arms with roller tip
SLP Ceramic Coated Headers 1- 3/4" - 1-Cat w/A.I.R. - SLPonline.com part 30001C
B&M Holeshot 2400 Stall Torque Converter

Car is running the ARAP.bin.

Back to my original question. The car idles rough. It has a noticeable stumble and with the cam specs I would not think that it should be. It feels like my high CR 108LSA 355 idles smoother. I looked at the plugs and they do not look overly rich but unfortunately with the factory narrowband I can only see that it is richer than stoich. So first thing I suggested for him to do was to get a wideband sensor in the car. Only issue I see is that if I remove the narrowband and install the wideband the car should only room in open loop correct? Will there be any other issues with the ECU?

Thanks
Shane

92GTA

iTrader: (11)

I think most people run a WB with a NB simulator going into the stock ECU input then run the raw WB output to an unused pin and mapping that so it shows up on data logging and we just create a view for it based on the WB sensors manufacturer specs. I'm running a Zeitronix myself. For the sensor, I refuse to use that Bosch **** and exclusively run Denso sensors. Long as you get a good WB sensor with a linear progression, making the output graph for the data logging is cake in TunerPro.

Unfortunately I did this several years ago and haven't even really had a chance to do allot of tuning with the setup because of family, time, etc. I'm just now getting back into it but still won't be tuning again until next year.

Six_Shooter

iTrader: (2)

I prefer adding a second bung (most WBO2 kits come one one), since the simulated NB outputs never seem to be quite right.

There will definitely be some tuning need with all of the changes made to the engine. The ECM won't just trim itself to run perfect. The ECM can only trim the fuel delivery so much. So all of that sensor swapping was in vain, since it's not the snesors that need changed, but the tune itself.

Also check over the mechanicals, just to make sure everything is good and how it should be, nothing worse than trying to tune around a mechanical issue.

5.3LS10

I will definitely like to see how it idles with a bit more fuel at idle. It's odd that the vacuum level and rpm are constant but there is still a vibration. I would hate to suspect a bad balance job I forgot the narrowband output. I over thought that one a bit