DI rough at start and running rich

Lake_Bueller

Lake_Bueller

Well-known member
Aug 11, 2004
2,105
59
56
Beloit, WI
When I first start the truck for the day, it runs like shit (stutters and stalls). I know it's running rich because I can smell the unspent fuel in the exhaust.

I did a pressure check at the rail both with the engine off and while running. Seems to be around 38 lb all around. Tons of codes but that didn't surprise me. This is mainly a winter truck/trail rig. I haven't been too kind to it over the years.

I'm thinking it's the fuel pressure regulator. Is there any way to test the part? I don't want to throw good money at the wrong problem.
 
E

ezzzzzzz

Well-known member
Apr 22, 2010
604
7
SE Va
Unplug the MAF and see if it runs good at idle. If so, it's the MAF. As pointed out above the codes would be great to help diagnose the problem. I doubt it's the FPR.
 
WaltNYC

WaltNYC

Well-known member
Mar 3, 2010
710
138
NYC
Spend $30 to get a real time OBD reader (dongle + app). Could be an Intake Air Temp sensor going bad wherein the ECU thinks it is way colder than it is and over-fuels.
 
Lake_Bueller

Lake_Bueller

Well-known member
Aug 11, 2004
2,105
59
56
Beloit, WI
Thanks to ezzzzzzz for the idea of the MAF. Running much better.

I'm not sure why but there was a ton of dust/dirt all the way to the intake. Everything appeared to be connected properly. However I've noticed over the years that I suck in more dirt and dust with the snorkel.

I also sprayed some cleaner in the intake area. It was "gunked" with shit also.
 
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