cold start knock / detonation?
10-08-2017, 12:42 PM
#12
Crank it over with the fuel pump deenergized. First with plugs in it.. Usually you can tell if a cylinder has low compression by an inconsistent cranking cycle noise. Can’t explain over typing. But thats if you don’t have compression gauges. Then crank it over without plugs. If that noise comes back. It’s probably mechanical. . Sounds like detonation to me. A really bad detonation at that. But it’s hard to tell. Feel the motor and see if you can pin point it by vibration.
10-08-2017, 11:04 PM
#13
I'd check your rocker assembly ASAP.. I'm confused how it can go away when warm, but I've heard that noise with a lopey idle before and it was a roller bearing on the rocker assembly that had grenaded, didn't go away when warm though.
10-30-2017, 06:16 AM
#14
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Running the motor without accessory belt it idles much better @ start up. Less idle surging, no knocking.
Put the belt on it surges and knocks just like in the video. With stethescope the sound comes from the block/head.
Deleted A/C running 45" belt now, changed alternator. everything spins freely. I'm at a loss for how the drag from the accessories causes knock and surging idle for cold start.
Good thing its winter here so i can put this turd in storage!
Put the belt on it surges and knocks just like in the video. With stethescope the sound comes from the block/head.
Deleted A/C running 45" belt now, changed alternator. everything spins freely. I'm at a loss for how the drag from the accessories causes knock and surging idle for cold start.
Good thing its winter here so i can put this turd in storage!
01-08-2019, 08:32 AM
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member messaged me about this so I figured I would add a conclusion for anyone searching.
I figured it out... kinda. Nothing mechanical. I'm running e85 only. I think that as temps drop and the e85 fuel blend changes it was unhappy on cold start. I drained fuel added the most quality e85 I could find locally and it ran fine. Part of the problem with the tune is probably associated with me telling my tuner that the injectors were ID1000cc which I thought they were. I ran out of fuel long before power goals were met and it seems like the injectors much smaller than 1000, but had no markings to determine size. I'm kinda assuming this plays a role as I used a very competent tuner. picked up some new injectors for retune
I figured it out... kinda. Nothing mechanical. I'm running e85 only. I think that as temps drop and the e85 fuel blend changes it was unhappy on cold start. I drained fuel added the most quality e85 I could find locally and it ran fine. Part of the problem with the tune is probably associated with me telling my tuner that the injectors were ID1000cc which I thought they were. I ran out of fuel long before power goals were met and it seems like the injectors much smaller than 1000, but had no markings to determine size. I'm kinda assuming this plays a role as I used a very competent tuner. picked up some new injectors for retune
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