Help please
Jan 28, 2018 | 07:47 PM
#1
Thread Starter
Staging Lane
Joined: Jun 2017
Posts: 75
Likes: 6
From: East Texas
Help please
So I finally built my motor and have 5,000 miles on it. 6.0 bored .030 over, flat top pistons, Elgin cam .560/.560 lift 216/220 with LS trunion upgrade. Ls1 pushrods 7.4” and EBay lifters. Tuned and dynoed. However, for the last 2,000 miles or so it’s been making an ANNOYING “coughing” noise that is very pronounced on a cold start but gets quieter as it warms up but doesn’t go away. Idk what it is. I had a flow master replaced for a magnaflow thinking it was a bad baffle. All my rocker studs are tight...I’m going to try to post a video with this so y’all can hear.
Feb 23, 2018 | 01:35 PM
#4
Thread Starter
Staging Lane
Joined: Jun 2017
Posts: 75
Likes: 6
From: East Texas
I figured out what the awful “coughing” noise was. I have the off road Y-pipe going to a single muffle out the side in front of the driver tire. Right where it exits I have a chrome splitter. It looked nice but for some reason it wasn’t jiving with my set up. Best way I can describe it. Thanks and maybe be this can help somebody down the road
Mar 29, 2018 | 09:33 AM
#5
Thread Starter
Staging Lane
Joined: Jun 2017
Posts: 75
Likes: 6
From: East Texas
SO cutting THe muffler tip just made the noise quieter, for a little bit. It got progressively worse. I bought a temp gun and checked the temp at the primaries on my headers right next to the head. Cylinder #1 was 615 degrees fareinheight! The others were mostly under 500. I tore it all down and saw heavy build up of carbon on the Pistons. Also oil in the intake runners. Scrapped and cleaned it all off. Took the heads to a local machine shop to have them inspected and they checked out ok, minus some heat signatures on my exhaust valves, they were “rainbowing”. Put it all back together with brand new baskets of course. Installed a catch can. Cranked it back up and the horrible noise was gone but the temp of the primaries was still the same heat. This is way too hot and I don’t know why. I’m going to have it retuned In the immediate future. I did do a compression check and they all had 210psi except #2 which was 200. It has a Stumble upon cold start. Any ideas?
Mar 29, 2018 | 12:06 PM
#7
Thread Starter
Staging Lane
Joined: Jun 2017
Posts: 75
Likes: 6
From: East Texas
I had a couple guys, two with tuners, look at it. The long and short term fuel trims were said to look good. I had my injectors bench tested. They were good. I’ve got 60 psi at idle on my factory fuel pump with 187k miles on the truck. It’s been a headache to say the least with this motor swap 
. But I’m definitely getting my truck back to the tuner!
. But I’m definitely getting my truck back to the tuner!Trending Topics
Mar 29, 2018 | 09:50 PM
#9
Thread Starter
Staging Lane
Joined: Jun 2017
Posts: 75
Likes: 6
From: East Texas
I will definitely re-check the connection on the injector. The wires aren’t in the plastic guides that are a part of the pig tail, didn’t figure it mattered. It’s my daily driver and I’m under the hood looking it over everyday just about. Thanks for y’alls feed back guys!
Mar 30, 2018 | 07:38 AM
#10
Curious why you think that is too hot? Speaking from (unfortunately) too much experience on the subject, that is actually very cool. Assuming of course the temperature has reached steady state and the primary temperature matches the exhaust temp... At that temperature a catalytic converter would be almost entirely inactive, so rest assured as production engines utilize even higher EGT to pass emissions. I'd be looking at injection timing...