v3fullSD Engine will not idle on its own. completely lost.

[Funfettie]

Hi there,
So my engine has always been very tough to start. crank it over 4-5 times before it will fire, and another 2-3 restart tries before it would idle on its own.

Over the winter, i switch to SD, and now the problem is worse. Its nearly impossible to start the engine, and when it does, it 'lopes' really hard for a few seconds, then revs up to a little higher than idle speed, sits there for a bit, and the it dies. something is causing the engine to just stop. it doesnt appear to lean out, or run too rich.. nothing drastically changes to cause it to die, it just slowly gives up.. ugh, very frustrating..

So im trying to get it running to check the base timing at 5*, but it wont idle long enough for me to do so. I think this could be why its so tough to start is because the timing could be off, but it was at 5* last year, and it was still hard to start.

Everything is mechanical sound, new LC1 wideband, new o2 sensor last year, just checked for exhaust and boost leaks.. new NGKbr7ES plugs gapped to .023, new taylor 8.5 wires. Any help would be very greatly appreciated!

***Datalogs attached***
Thank you!
Funfettie

Engine setup: 2.0 eagle crank, h beam rods, Ross pistons, BC 284 cams, BC springs, BC 1mm over valves, SMIM, 104mm throttle body, tail 50mm bov, SBR cooler core, tubular manifold, evo10 turbo, dual walbro255 pumps, AFPR, FIC 1550cc's.

 

[95DsManiac]

Sorry to hear about that. Have you tried to do a leak down test. Or check your compression across the board? Is this a project that your trying to finish or is this your daily driver and this started happening? Before this started to happen what was the last thing you did to the car? Besides the SD I mean. I had similar problems, but it was because I put a 1g cas on my 7 bolt and forgot to invert signal and change spark plug wires. And when I first went SD it wouldn't start because I didn't have the sensors dialed in correctly and didn't have link set up right for SD.

 

[Funfettie]

This is a project car that I plan to use as a daily driver. I had it running for a few months before winter last year, and I was working on tuning it. Last thing i did besides SD was a full build. The engine, drive train, intake, turbo, all new. CAS is inverted, and wired right. plug wires are in the right order. everything is setup for SD correctly I believe. I just dont understand why its so tough to start. I can do a compression test in a min here, but it will be on a cold engine.

EDIT: the full build was running last year when i was tuning on a gm maf. SD, plug, wires and a catch can setup are the only new parts over the winter.

Compression tests were 125-130 across the board on a cold engine, no oil dumped into the cylinders. Thats also on bc284 cams, so i guess that seems... decent?

 

[95DsManiac]

Just out of curiosity, what kind of fuel are you running and how long was the car sitting before last start up? Is sd all dialed in correctly?

 

[WES_393]

We are in the exact same boat! How much are setups have in common is a very strange coincidence...

Last Fall I was running 2g MAF and E85. When I switched to E85, I noticed cold starts being a little difficult, but learned to cope with it. Over the Winter I switched to SD for my Holset setup (and added some parts that I'll list) which resulted in the engine being nearly impossible to keep running. I've also replaced the Front O2 as it seemed a little lazy, but that had a minimal effect. I've gotten around the issue by setting the stock boost gauge to front O2 and watching it while it warms up. It appears to drop right when the engine is trying to die, but I'm not sure if that's part of the cause or just a result. However, A quick tap on the throttle shoots RPM's up to 1-1.5k. The RPM's lingers for 5-10 seconds, the O2 voltage drops, and the engine tries to die again.

Here's what our setups have in common:
- E85 fuel
- Omnipower 4-bar and GM IAT (my IAT is in the throttle body elbow)
- Non-Projected BR7's gapped at .020
- Freshly built 2.0 with maybe 6k miles
- GSR Ralliart base fuel and timing maps (although I tried stock maps too with the same results)