Stuttering ICP, stuttering performance
#16
Ok, I've pretty well confirmed with DP that the tune is not defueling, which the absence of codes support. So, what else could it be?
Fuel pressure - Could the fuel bowl be slowly draining by fuel pressure that is too low to support the demand of a long uphill run? I'd think I'd have some other symptoms if that were the case, and I don't. Rich asked if I was seeing smoke when the "stuttering" is occurring, and I don't think so. Can't say for sure, though.
Low oil pressure - Might my stock injectors be demanding, and T500 supplying, more oil than the LPOP can support, so the reservoir is running dry on long hills?
IPR - I suppose the IPR could be faulty, but wouldn't I see a code if that were the case?
I don't expect you guys to solve this, but I could use some help with troubleshooting. Buying a fuel pump, LPOP and IPR seems like the wrong approach...
Mark
Fuel pressure - Could the fuel bowl be slowly draining by fuel pressure that is too low to support the demand of a long uphill run? I'd think I'd have some other symptoms if that were the case, and I don't. Rich asked if I was seeing smoke when the "stuttering" is occurring, and I don't think so. Can't say for sure, though.
Low oil pressure - Might my stock injectors be demanding, and T500 supplying, more oil than the LPOP can support, so the reservoir is running dry on long hills?
IPR - I suppose the IPR could be faulty, but wouldn't I see a code if that were the case?
I don't expect you guys to solve this, but I could use some help with troubleshooting. Buying a fuel pump, LPOP and IPR seems like the wrong approach...
Mark
#18
#19
I'll do that. I'm hoping to tow again in a couple of weeks. I wondered about the temp thing, as I was having high oil temps on long grades last year. I think the new radiator fixed that, as I never saw EOT over 228* on even the toughest climbs on my last tow. The issue at hand remained.
Mark
Mark
#20
Another thread resurrection. I towed again last week, though on a road with shorter, slower climbs than I70. I fouled up Torque logging, but was watching things: Oil temp <220*, FIPW in the low 3ms range, boost <20psi.
On a several minute climb (Crow Hill out of Bailey, for you CO guys), I got slight stuttering as I approached the top, and could see the ICP "bouncing" at the time.
Whatever is going on, it's strongly related to how long I'm on it - it takes many seconds to a minute or more to occur - and not to short bursts like entrance ramps. I can get on it really hard all the way up to 65-70mph with no stuttering, at all, when entering the highway, and boost will be 23-26psi when doing so. That should eliminate "tune defueling" completely, correct?
Could it be...
Fuel pressure - I've not measured this, but could pressure fall to the point that the bowl is slowly draining? Would I see other symptoms of low fuel pressure? (e.g. hard starts, etc?)
Low oil pressure/volume - Could the LPOP not be what it once was, and the HPOP reservoir is draining on these long climbs? I'd think that would cause ICP to fall a good bit further than the 1800-1900psi that I'm seeing (from 2400-2900 that I see on climbs)
Flaky IPR - Doing something odd when high pressures are maintained for more than a few seconds?
What else? I'm not in a position to throw unlimited time or money at this thing, but I'm so happy with the way it's working otherwise that I'd like to get this issue resolved.
Mark
On a several minute climb (Crow Hill out of Bailey, for you CO guys), I got slight stuttering as I approached the top, and could see the ICP "bouncing" at the time.
Whatever is going on, it's strongly related to how long I'm on it - it takes many seconds to a minute or more to occur - and not to short bursts like entrance ramps. I can get on it really hard all the way up to 65-70mph with no stuttering, at all, when entering the highway, and boost will be 23-26psi when doing so. That should eliminate "tune defueling" completely, correct?
Could it be...
Fuel pressure - I've not measured this, but could pressure fall to the point that the bowl is slowly draining? Would I see other symptoms of low fuel pressure? (e.g. hard starts, etc?)
Low oil pressure/volume - Could the LPOP not be what it once was, and the HPOP reservoir is draining on these long climbs? I'd think that would cause ICP to fall a good bit further than the 1800-1900psi that I'm seeing (from 2400-2900 that I see on climbs)
Flaky IPR - Doing something odd when high pressures are maintained for more than a few seconds?
What else? I'm not in a position to throw unlimited time or money at this thing, but I'm so happy with the way it's working otherwise that I'd like to get this issue resolved.
Mark
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