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Hi guys,

Got an l67 running E85. Ever since putting the ls1 throttle body on it, I'm having issues driving the car when its cold. I need to wait 5 minutes before being able to drive it.

So what happens is, I start it up. It idles fine. The moment I touch the throttle, the car almost stalls. Almost feels like its being flooded or the spark is blowing out. Eventually, when I can manage to drive it, the issue disappears as It warms up. Once fully warm, it has 0 issues at all. The wideband reads lean, but I'm not sure if that's sure if that's due to the stumble. Any ideas on where to look? I've tried playing around with Acceleration enrichment at lower coolant temps. Running The1 enhanced vs l67 tune. Tia

Did you adjust the Throttle Gain %age?

different injectors i assume ? can you post a log ?

definitely sounds like too much air vs fuel (lean out) when the throttle cracks as expected with larger TBs.

I don't think AE is going to help you there. I think it would be a fuel transient table of sorts but I don't know exactly as I have 0 experience with MAF bases ECUs so I don't know what terms and tables they use.

Immortality I haven't adjusted that, not sure what it does. Sounds helpful though

Holden202T : 1000cc injectors. Will get a log asap.

Vlad01: I think you might be onto something here.

I'm not sure why it happens only when it's cold. Others dont seem to have the same issues and they're running 102mm Tb. As its warming up, it gets more and more responsive. It is really embarrassing though trying to leave work at 1am, the boss is waiting for you to shut the gates and you can't get your car out. Even turning the wheel and putting load on power steering kills it.

it could just just need more cold enrichment as ethanol doesn't vaporize too well when its real cold and often needs more richer mixture when cold compared to petrol. Or it may even be the other way, too rich and downs the engine as I found in a similar situation on a E85 v6 race engine. Had a rich spot around idle that cause it to hunt badly and nearly die.

also the injectors need to be characterised in the tune, send them to The1 so he can test and generate the correct injector data. That will help a bit as voltage drift from hot to cold in the charging system will effect fuel delivery if the injector data is wrong and the ECU is compensating incorrectly based on wrong data. Also why 1000cc injectors? how much hp is the engine build for? 800hp?

I'd adjust the Throttle Gain %age up a bit. Stock is 59%, for a 69mm TB we generally use 64% so for a LS1 tb you probably want to try 70%. The1 can probably explain what it does a lot better than me.

There are 2 tables for AE, one for P/N (park and neutral) and one for drive. I'd adjust the Acceleration Enrichment - Sync Delta TPS Multiplier V's Coolant - P/N, increase the low engine temp areas and then test to see if the engine still stumbles when you stab the throttle when it's cold. Using the P/N table you can test it cold without needing to drive it. If that improves the stumble than try the Acceleration Enrichment - Sync Delta TPS Multiplier V's Coolant - Drive table

I think vlad01 has nailed it. If it cuts out when you turn the wheel I assume your not touching the accelerator at that stage. Huge injectors and E85 says big vaporising problems particularly at idle. I seem to agree you need to put a lot more fuel in during cold running.

Thanks for the reply guys! I'll try your suggestions and go from there.
Vlad01, running 2.4" pulley with overdriven balancer has me somewhere at 18,000 rpm on the m90 puts me at around 75% duty cycle at my commanded afr at 5500rpm. I have had data generated for the set of these injectors, including the battery offset, so I think that part is all good. I guess I'll try richen the coolant temp offsets and the throttle gain

Alright, played around with the settings, nothing seemed to make a difference. Can't get the damn thing to work when cold haha. I've forgotten to get a log. Will get one today with wideband output as well.