Hi everyone, i've been dealing with an issue for the past month or so, havent been able to figure it out. I havea freshly built and installed buschur 2.4lr motor all done by Buschur Racing. I've been in the middle of the process of getting it e-tuned, only got my first pull in but was told it was good to drive on casually which it was doing for about a month.

One day it was below freezing and my car began struggling to start, it eventually started but after a short drive (front of work building to back of work building) it stopped starting completely. I swapped my injectors to BR8EIX gapped to .018(recommended by tuner) and the car struggled to start but eventually started, except the car was super jerky and ran super rich (10-11afr) and took EXTREMELY long for the coolant temp to heat up. We're talking sitting for 15-20 minutes and it only moved a centimeter or so. So after trying to figure out why it was running so rich i go to try to start it again and it doesnt start.

So eventually i get it to start but it's still running super rich and like crap but it still drives, so im able to get it home. When cruising, the afr's were pretty good(14.3-14.7) but it would sputter and jerk occasionally as the afr would dip to about 12 or so for a split second and it died twice on the way home. Eventually got it home, and over the course of the last month ive been trying to figure it out.

So far ive replaced the sparkplugs as mentioned above^, drained the gas and replaced it, bought a redtop battery, checked for spark and fuel(sparkplugs have fuel on them after trying to start) soo Car has spark and fuel, i have changed the oil and oil filter from bradpenn penngrade partial synthetic 20w-40 to mobile1 10w-30(thought maybe the oil was to thick for the temps here), bought a new map sensor and swapped it out(same issues), cleaned the cone filter from the engine, and did an exhaust leak test. The car cranks but doesnt start, and every so often it will sputter as if its going to start, but doesn't.

TLDR!!: Freshly built and installed Buschur 2.4lr done by Buschur Racing. Car died on a below freezing day, stopped starting. Already swapped battery to a redtop, drained and replaced fuel, replaced sparkplugs, changed oil, cleaned engine air filter, did exhaust leak test. Car cranks and has fuel and spark but doesnt start. Occasionally it sputters as if it's going to start but doesnt.

 

Well for an engine to run it needs 3 things: fuel, spark and compression. If you have verified fuel and spark, I would throw a compression tester on just to cover all the bases.
That said, considering you are still tuning, it could be tuning around cold enrichment.

Also are you speed density or MAF?

 

wasnt sure if my post posted or not. Thanks so much for replying! Much appreciated! But figured out the problem... it was kind of dumb tbh. Turns out the brand knew sparkplugs were either gapped too low at .017 or they fouled out cause the richness. But either way, got new BR8ES sparkplugs just to test my theory of it being the sparkplugs, gapped them to .024-.025 and put them in and she started right up! She's still running rich and rough, made a run to the gas station and she made it but wanted to stall out at almost every stop. Had to gas it a bit. Im on speed density. Car was running around 11 afr but she was running. Gonna slowly close the gap to see if it'll run any better. Tuner is telling me it should be .016-.018 but builder is telling me .018-.020 soo we'll see how it works out.

 

Well its good that its running better but it still sounds like you have a probable tune issue on your hands given how rich the car is running.
As for the gap, this is dependent on boost levels and fuel used but in my application (600awhp, 37psi of boost, E85) I run 1 step colder plugs gapped to .018.

 

ALL RIGHT. So dropped the gap to .021-.022 and seems to be a lot more reliable. No more rpm drops at stops and no breaking up on partial throttle pulls. Just still running rich. Question is... should i drop the gap even more?

 

tune or bad front 02 sensor

 

I always forget about that front O2. That's a good call.

 

So it was the O2?