98' LS1 wont run after 92mm tb installed

[SRTRhino]

My brother put a tbss manifold on his firebird a couple days ago and I've been trying to get it to start and run with no luck. He has stock LSA injectors and a 92mm cable driven throttle body. It is a stock cam for now. It will run with the stock injector data but dumps a ton of fuel and surges. When I put in the LSA to LS1 injector data I found here on the forum, it will barely run. It always stalls out with the LSA data and the IAC count skyrockets. I managed to get it run if I set the injector flow data in the middle of the LSA and LS1 data but it was still very rich. We have tried adjusting the set screw and adjusting it just makes the car die sooner. It "runs" best with blade fully closed. It is a stock tbss map sensor with an adapter harness, and it appears map info is the same as what is in the LS1 file. We have verified no vacuum leaks as well.

Appreciate any help I can get

[SiriusC1024]

I attached a tune for reference that has a 92mm ebay throttle body. Reference:
- Idle tabs
- Fuel > Oxygen Sensors

Why is closed loop enable coming on so soon?
Why is power enrich so borderline lean? Those values should be 10% higher, in the 1.2xx range. Without tuning the added VE of the TBSS intake you're going to blow the motor. Not to mention ethanol content now vs in 1998 affecting base stoichiometric value.

[SRTRhino]

Thanks for the tune to reference off of, Ill give the idle stuff a try and see if we can get it to run.

Power enrichment is the way it is because we have been targeting 12.7-12.8 AFR and I have been adjusting the VE table to meet that AFR goal. It is noticeably quicker on a leaner AFR than say 12.4ish.
The car hasn't ran long enough for me to tune the VE for the tbss, we are still trying to get it to start up. I know its going to be lean and need fuel added.
I know the base stoic doesn't match pump gas e10 nowadays, but the VE table already accounts for the fuel being E10 and needing that little bit extra fuel.

[SiriusC1024]

Don't forget to verify TPS and IAC range. If it's inaccurate perform a tps relearn.

https://thetuningschool.com/blogs/ne...elearn-process

[SRTRhino]

I don't think we have done that, Ill have him do that and then try the new tune. Thanks!

[Alvin]

The LSA injectors aren't a great choice for NA engines as the spray pattern is meant for LSA type superchargers. It can cause excessive wall wetting and hesitations. That is not likely your issue now.

Here are our throttle body setup instructions. I think it is a better method than that posted above.


https://www.pcmofnc.com/2021/03/05/i...throttle-body/



*********** But your issue looks to be a bad map sensor. Its reading 3x kPa in all the logs. A stock car won't pull that much vacuum. The number is unchanging too. Looks very suspect. It should read 100kPa when the key is on engine off. there about anyway. Idle would typically be 50-70 kPa for most engines. The number will change as you manipulate the gas pedal.

[bk2life]

looks to be a bad map sensor. .

x2 on this--is it even hooked up?

[Hondaeater]

SRTR
The Airflow Dynamic Airflow hi rpm disable is set 4000 rpm, stock for blended mode. To tune VE should be set high. You have the DTCs P0101-03 for no error. That is incorrect.
Using 2bar OS it looks like you want to tune the SD/VE fuel model. You must fail MAF, set P0101-103 Mil on 1st error and raise the hi rpm disable to 8000rpm. In Engine Diag tab set MAF frequency fail to 0 or 50rpm.
Are you running boost? Your MAP is still characterized as 1 Bar sensor. Fine for NA but boosted needs 2 bar sensor. And it is reading 34kPa all the time. Is it hooked up?

Try log using these channels, add your WB between the AFR commanded and the EQ ratio commanded. log these will help evaluate many things. You have too many channels open and some are not needed slowing data. DBC channels.Channels.xml

Begin log with... Key ON, wait a few seconds. Now cold start car. If you have hard time starting or keeping it running, use pedal until it idles on it's own. If it still won't idle after reaching operating temp (170*+), post the log. If it idles stable at op temp, drive around going thru the gears and stay steady on the pedal about every 500rpm increase, like this.... 2000rpm hold in any gear, do same at 2500 rpm same gear then as you drive hold for a few seconds at a given rpm. Not TPS% all over the place, keep it steady occasionally to get a simple snapshot/ baseline of fuel delivery. Be conservative in case it runs lean and stay below 3500rpm.
In the Scanner green button special functions, clear LTFT before drive log but AFTER warming up to op temp. Also in the transmission tab of Green button you can hold the trans gear so it does not shift gears during that steady TPS% 500rpm increase logging.
Post the log.
Stay tuned,
Hondaeater.

[SRTRhino]

@Alvin

He got the injectors free from our buddy with a V2 ctsv, I wouldve had him get some FIC's if these werent free.
I will also look at the link you posted, thanks!
I thought the map looked suspect when I went back and looked at old logs, his idle usually fluctuated 33-37kpa at idle. I will have him double check it.


@b2klife
I will have him double check, im not there looking at it in person.

@Hondaeater
I thought I had the MAF failed in the tune as we have completely removed the MAF from the vehicle. I did not know about the dynamic airflow setting to 8000rpm so I will set that higher than the stock 4000 setting. The map sensor is supposed to be a stock tbss map sensor.
No he is NA, currently just a custom intake making use of the ram air hood, 92mm tb, TBSS manifold, Longtubes, 4k stall, and 3.73's. He is looking into putting heads/cam this year.
Ill check the channel file you uploaded out, thanks!
Ill make sure he waits to start car after log has started, I always do that when I log vehicles but im not there with him in person.

[SiriusC1024]

I like your method better, Alvin. When I set mine up I adjusted the throttle body stop and ended up having to clearance the mounting holes in the TPS in order to clock it to correct base voltage. A hole in the throttle plate is easier, though at the time seemed like a hack because I've seen people do this to regular stock cars that weren't idling correctly instead of addressing the problem. Good points about idle variance with temperature.

[SRTRhino]

Turns out he had the map wired backwards, map works as it should now and car doesn't shut off randomly now with the LSA injectors.
Still battling high idle/surging but its getting closer. He started messing with set screw after log ended and said it got a lot better on the surging but he had a fuel line rupture. After thats fixed hopefully its a lot closer.

[SiriusC1024]

Your IAC is going all wonky. Might try the idle settings like in my 92mm tune to see if that helps. Also, are you sure about 50F for LTFT enable min?

[SRTRhino]

@Sirius
I set LTFT back to like 125ish. I copied over all the idle tables you had except the base running airflow and throttle cracker/follower, figured those were meant for the cam portion of the car but if im wrong I will copy them over. He should be getting to the car in a couple hours when he gets off work so ill keep you posted.

Thank you all for the help so far, I very much appreciate it. This is my first DBC aftermarket throttlebody so im trying to learn. Most of what I mess with is ETC.