issue with cold start
10-18-2015, 11:41 AM
#1
issue with cold start
pretty much every time I start my car when its been sitting for a while, it bogs hard, and vacuum goes to 0 and it almost stalls out, once it did, also smells like gas. after 10 seconds it runs fine. what u guys think? leaky injector flooding a cylinder? or something else
10-18-2015, 01:12 PM
#2
Senior Member
My car is stock but whenever it gets cold my cars idle goes wonky and usually stalls once. After that it starts fine.
Wonder if my bad secondary o2 sensor would be the issue.
Wonder if my bad secondary o2 sensor would be the issue.
10-19-2015, 05:47 AM
#8
I've never had to wait on my fuel pump when starting it. Tom are your valves clean? Do you run a forge bpv? Is the tune ok? Don't know why you should be at 0 vacuum unless possibly your trying to build boost at idle. Could your bpv valve be sticking? Or an issue with your vacuum tank. If you tap the throttle does it go back to -20 or does it stay at 0?
10-19-2015, 09:44 AM
#9
New Member
please give us some details about the car?
is it tuned?
if it is tuned do you have Cat warm up turned off?
Catless downpipe?
aftermarket intake?
Here's my experience.
I have a catless downpipe, stock intake (k&n drop in), tuned it myself and turned off the cat warm up.I also had bad idle (very rarely it would even stall) for the first 10-15 seconds but ONLY on cold days on cold starts.
my solution: it was in the tune, getting the cam phasers right helped a lot, but what really fixed it was to do a good MAF tune (recalibrate the maf sensor).
Remember on cold start up the car can't run closed loop because the O2 sensors are cold and take a while to heat up. Therefore it runs on the MAF, open loop and if your MAF tune isn't basically perfect then it'll struggle.
Alternatively i could turn the cat warm up back on.
Other solutions that seem to work on the forum is cleaning the intake valves. but if ur tuned, im betting it's the MAF that needs to be dialed in.
is it tuned?
if it is tuned do you have Cat warm up turned off?
Catless downpipe?
aftermarket intake?
Here's my experience.
I have a catless downpipe, stock intake (k&n drop in), tuned it myself and turned off the cat warm up.I also had bad idle (very rarely it would even stall) for the first 10-15 seconds but ONLY on cold days on cold starts.
my solution: it was in the tune, getting the cam phasers right helped a lot, but what really fixed it was to do a good MAF tune (recalibrate the maf sensor).
Remember on cold start up the car can't run closed loop because the O2 sensors are cold and take a while to heat up. Therefore it runs on the MAF, open loop and if your MAF tune isn't basically perfect then it'll struggle.
Alternatively i could turn the cat warm up back on.
Other solutions that seem to work on the forum is cleaning the intake valves. but if ur tuned, im betting it's the MAF that needs to be dialed in.
Moderator
10-19-2015, 12:50 PM
#11
Platinum Member
Platinum Member
Cold start issues with the LNF generally almost always revolve around cam phasing.
Have you ever monitored your cam phasing during cold starts Tom?
Have you ever monitored your cam phasing during cold starts Tom?
10-19-2015, 02:04 PM
#12
I'm fully bolted, tuned , no cat warm up, I have forge which I just greased, no vac tank and I just blasted the valves. It only does it when it's cold over night, had it in garage and did the purge thing and it was good this morning. It started doing this a few weeks ago out of the blue. I will have to log a cold start and see what's up
10-19-2015, 02:18 PM
#13
I had this happen but I cleaned my original maf with some cleaner and it hasn't done it since. I don't know if this is your issue though but thought I would say about it anyway on the off chance. Good luck
10-26-2015, 09:00 AM
#20
Senior Member
Join Date: 04-15-07
Location: Canada , Nova Scotia , Sack Town Baby !!
Posts: 1,628
Likes: 0
Received 2 Likes
on
2 Posts
My lnf would die every morning last year. I replaced my purge valve and vent valve in the tank. Its been good ever sense. Idk why they where causing it to stall. But they were... I was always getting a code for small evap leak nd then it would stall. Replaced both. Only cost like $60 and its been good ever sense.
10-26-2015, 09:50 AM
#21
My lnf would die every morning last year. I replaced my purge valve and vent valve in the tank. Its been good ever sense. Idk why they where causing it to stall. But they were... I was always getting a code for small evap leak nd then it would stall. Replaced both. Only cost like $60 and its been good ever sense.
10-26-2015, 07:43 PM
#22
Senior Member
Hmm. Not getting any evap codes. I've been filling my car it keeps tripping the pump like it's full but it's not even half way full.
Wonder if I could have the same issue.
Wonder if I could have the same issue.
10-27-2015, 06:13 PM
#25
Senior Member
Does the car misfire and drop rpm's with catalyst warmup? or idle like **** until it's warmed up with it off?
both are normal but you can change the cold cam tables so it idles smooth when you start it.
both are normal but you can change the cold cam tables so it idles smooth when you start it.