I'll try to be brief but have a lot of info I'm trying to sort thru with this issue: The truck won't start when overnight temps get below about 45 F. I can hear it "winding up" as if it's about to catch in the first couple seconds of cranking, and then it makes a stumbling kind of noise and all i hear is the starter spinning it. Sometimes cycling the GPs
a few extra minutes will work, but normally it has to be plugged in to start in cool weather. Fires up great then.
I have done the following work since first noticing the problem, some in an attempt to fix it, others for their own reasons:
- New ICP
sensor (Motorcraft) -- was legitimately bad, with oil in it.
- New CPS
sensor (Motorcraft/International "purple oring") -- not sure it was actually bad, but tried anyway.
- Mitsubishi Denso high-speed starter
- The PO put in a GT38 turbo, which appears to be making 11-14 psi
boost according to AutoEnginuity MAP
sensor reading (no boost gauge installed).
- Compression is 330-350psi cold, 340-350psi "warm"
- New OEM-type GP relay
- New (reman) injectors (LL in #8) along with new UVCH and fresh Beru/Motorcraft GPs
- Buzz test is fine.
- Cylinder contribution test is a pass.
- PERDELS after new injectors are: 2.3, 1.7, 1.1, 0.2, 0.0, 0.0, 0.0, 2.7
Fuel economy had been dropping off and I was losing power under heavy load, prompting me to finally replace the original injectors with remans from Full Force a few weeks ago. MPG
has recovered, and I had hoped this cold-start problem would be solved too, but now that temps are dropping again it's back same as before.
I do still have a tiny bit of power loss, causing the truck to shudder when towing long interstate hills; i have to back out of the throttle and just go slower to stop that. I've also noticed a small puff of black smoke any time i put my foot in it, which it didn't used to do. I did the Swamps Diesel "road test" for injection pressure a while back, and remember it being okay, but have lost where i wrote down the actual numbers (I plan to repeat it next chance i get). Does this sound like a bad HPOP
? What else should I be looking at?
I really appreciate any ideas or feedback. Thanks!