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I'm hoping you guys can help me figure out why my Excursion, that used to run pretty strong, is noticeably down on power. (I posted about this a year ago, though my thread title was incorrect, as it doesn't tow fine. This thread will have more data.)
Symptoms - Under normal driving conditions, it actually seems to run fine. The power feels normal at light throttle. When I get on it, though, it starts like it's going to get up and move, but just seems flat. I might not notice this in normal driving, but when I tow through the Rockies with a 7K load, I can drive up the passes with the pedal matted, and never worry about EGT's. That is definitely *not* normal, as I've had to drive by the EGT gauge for years. No discernable smoke under any condition. Fuel filter with 2300 miles on it is white. Fuel pressure is good - 67psi at idle, and I never saw it below 60psi today.
Config -
DP tunes, that haven't been changed in 8+ years
MST, with ATS ported housing and Clay's wheel for same
Wastegate effectively wired closed
T500 HPOP that's 10 years old, but only has 43000 miles on it
ICP changed 9 years and 40000 miles ago. Connector is wet, but it may dirty dialectic grease from install. (I know... but it seemed like a good idea at the time. See photo in thread linked above.)
Oil analysis done last summer was normal, *except for high aluminum* (7, when it'd always been between 1 and 4 in years past)
Data from today
I just installed a new ATOTO S8 (thanks for the great thread @Sous !) and replaced my ancient Western Diesel gauges with an ISSPRO set that includes a fuel pressure gauge this weekend. Fuel pressure, as mentioned above, was fine driving around today. I logged one WOT run on flat ground with no trailer and, in my first attempt at using the PID Charting tool (thanks @BWST !), here's the data from that.
What does my description of what I'm seeing, and measuring with my butt, and the data I've provided, tell you? What other data can I collect? What else on the truck can I examine?
Many thanks!! I'm head over the Rockies again later this month, and would love to have this thing running right.
Ebp gets pretty high during that wot. Do you have a cat on the truck? If so and it's plugged up that would cause high egt's and sluggish performance.
I saw that, and noticed EBP jumping around and running high while driving around, too. No cat, and a 4" exhaust and downpipe that has been on for many years.
Yesterday was my first time using Forscan, and Torque Pro never showed those high EBP readings. Still, perhaps a look at the EBP sensor and pipe is in order. I replaced it once, ten years and 40K ago.
It’s hard for me to read the charts on phone, but it looks like ICP is falling off at peak RPM? I think 2500psi should be adequate, but wonder if you were peaking at higher numbers in the past and this is the extra oomph you are missing?
Those drive-by-pyro toons suck really bad. I know because I had them (and lost (2) engines due to them). You’ll know what I mean when you get better tunes. But, if you love them - I’ll make you a great deal on an Infinity monitor!!
BWST did a fantastic job at creating the PID Charting Tool!
Your welcome for the ATOTO recommendation, but I was only compiling and relaying the information from the fellas before me. It is nice to have a central location where people can discuss ideas and experiences observed.
Your EBP does go quite high, but so does the MGP at that same point. We cannot compare MAP to EBP due to MAP not being logged based on the gray tables on the top right. We can assume that MAP is ~14 PSI above MGP though, which puts MAP a few points behind EBP and what we expect. Typically EBP will be higher than MAP due to turbo air flow dynamics and turbine drive pressure.
I noticed EOT starts at ~150° and tops at around 180° at the end. Can you take a data log when the Ex is at full operating temperature and log MAP as well?
At the second MFDES blip, the MGP is quite low at ~4 PSI where at the first MFDES blip MGP is ~22 PSI.
I am not seeing the ICP drop off like SSJ is, but I could be wrong. To me, the ICP seems to track the ROM and MFDES quite well.
It looks like you stabbed the throttle to WOT on the first blip, then gave it a more gradual increase of throttle for the second blip, is that right?
It’s hard for me to read the charts on phone, but it looks like ICP is falling off at peak RPM? I think 2500psi should be adequate, but wonder if you were peaking at higher numbers in the past and this is the extra oomph you are missing?
Those drive-by-pyro toons suck really bad. I know because I had them (and lost (2) engines due to them). You’ll know what I mean when you get better tunes. But, if you love them - I’ll make you a great deal on an Infinity monitor!!
What you are seeing in the short run is worse when towing, when I'm hard into the pedal for extended periods in 3rd gear. ICP pops up, but then falls down to 2200psi, or less. Why might that be?
I know you hate on some DP , and I get it, but they've worked well for me. Having a tow tune that keeps the coast clutches engaged in 1-3, then being able to flip to a tune that doesn't, is hugely helpful in CO. When I had a Hydra, I tried to get others to create tunes that did that, and they would not. For the moment, though, the tuning, better or worse, hasn't hanged in 8 years.
BWST did a fantastic job at creating the PID Charting Tool!
Your welcome for the ATOTO recommendation, but I was only compiling and relaying the information from the fellas before me. It is nice to have a central location where people can discuss ideas and experiences observed.
Your EBP does go quite high, but so does the MGP at that same point. We cannot compare MAP to EBP due to MAP not being logged based on the gray tables on the top right. We can assume that MAP is ~14 PSI above MGP though, which puts MAP a few points behind EBP and what we expect. Typically EBP will be higher than MAP due to turbo air flow dynamics and turbine drive pressure.
I noticed EOT starts at ~150° and tops at around 180° at the end. Can you take a data log when the Ex is at full operating temperature and log MAP as well?
At the second MFDES blip, the MGP is quite low at ~4 PSI where at the first MFDES blip MGP is ~22 PSI.
I am not seeing the ICP drop off like SSJ is, but I could be wrong. To me, the ICP seems to track the ROM and MFDES quite well.
It looks like you stabbed the throttle to WOT on the first blip, then gave it a more gradual increase of throttle for the second blip, is that right?
Yes, I'll take it out again when fully warmed up. It'd been warm, but I did this a few minutes after being in the gym for an hour, and it cooled some. The roads were wet and I had a limited amount of road, so I did the best I could with the pedal. Memory says I rolled quickly into it and left it there, but I could be wrong.
BTW, I don't think the EBP sensor or tube is the problem. I just cleaned the tube, and while I got some soot out, I could easily blow air through it before. The sensor could be bad, but I don't see an indication of that, and I don't have a good way to test it.
Mark, on a cold and sat overnight engine, turn the ignition to ON without going to start. Bring up MAP, EBP and BARO. Baro will default to volts, but if you change the value to PSI as seen in the link below it will reflect PSI.
With MAP, BARO and EBP on the display in a KOEO state, they should be within .5 of each other. If one is out of range, say off by 1, then that sensor is likely faulty. BARO is internal to the PCM, so your really looking at MAP and EBP as a fault point with BARO as a reference.
It almost seems like you have a boost or exhaust leak, but boost gets up to 22 PSI during the first blip. That is not 30 PSI by any means, but you were on a moderately warm engine, rain on roads and not a lot of space. Please be safe out there!
Your ICP can fluctuate quite a bit based on engine load and MFDES. I regularly see ICP go up toward 3000 and back down to 2200 or so on the same climb while using cruise control. Once the PCM sees the engine is producing the work required based on MFDES, ICP can drop a bit. This is not indicative of an issue, but it might point us/you in a direction to look further into.
Mark, on a cold and sat overnight engine, turn the ignition to ON without going to start. Bring up MAP, EBP and BARO. Baro will default to volts, but if you change the value to PSI as seen in the link below it will reflect PSI.
With MAP, BARO and EBP on the display in a KOEO state, they should be within .5 of each other. If one is out of range, say off by 1, then that sensor is likely faulty. BARO is internal to the PCM, so your really looking at MAP and EBP as a fault point with BARO as a reference.
[sigh] Thanks man. I've actually done that test before, but had forgotten it. One of the problems with owning something forever - I've had this truck 18 years next week - and of getting old in the process - hurtling toward 63 - is that you forget stuff. Even stuff you've done before.
I'll run the test in a bit. I'm going to replace the ICP sensor and pigtail now. I don't think it's the problem, but I bought it in Moab last year, and it isn't doing me any good sitting in a bag.
It almost seems like you have a boost or exhaust leak, but boost gets up to 22 PSI during the first blip. That is not 30 PSI by any means, but you were on a moderately warm engine, rain on roads and not a lot of space. Please be safe out there!
Yeah, I think the boost system is tight. Unfortunately, I know this truck well enough to know that it won't break new tires loose, even in the rain, at least at this altitude. The solution to that is 8 sticks and about $3000 away...
Your ICP can fluctuate quite a bit based on engine load and MFDES. I regularly see ICP go up toward 3000 and back down to 2200 or so on the same climb while using cruise control. Once the PCM sees the engine is producing the work required based on MFDES, ICP can drop a bit. This is not indicative of an issue, but it might point us/you in a direction to look further into.
Keep talking to us and we will get it sorted...
The real test of this is a long pull, and I need to get that done. Thanks for your, and everyone else's, help. The rest of life should work as well as this place.
Mark, on a cold and sat overnight engine, turn the ignition to ON without going to start. Bring up MAP, EBP and BARO. Baro will default to volts, but if you change the value to PSI as seen in the link below it will reflect PSI.
With MAP, BARO and EBP on the display in a KOEO state, they should be within .5 of each other. If one is out of range, say off by 1, then that sensor is likely faulty. BARO is internal to the PCM, so your really looking at MAP and EBP as a fault point with BARO as a reference.
It almost seems like you have a boost or exhaust leak, but boost gets up to 22 PSI during the first blip. That is not 30 PSI by any means, but you were on a moderately warm engine, rain on roads and not a lot of space. Please be safe out there!
Your ICP can fluctuate quite a bit based on engine load and MFDES. I regularly see ICP go up toward 3000 and back down to 2200 or so on the same climb while using cruise control. Once the PCM sees the engine is producing the work required based on MFDES, ICP can drop a bit. This is not indicative of an issue, but it might point us/you in a direction to look further into.
Keep talking to us and we will get it sorted...
Dropping to 2200psi during sustained WOT means you have an ICP issue and will absolutely destroy power and reduce black smoke.
Tired injectors and/or HPOP are common culprits.
on edit: I think I see peak ICP before peak RPM. This is indicative of failure to create/maintain desired ICP.
What you are seeing in the short run is worse when towing, when I'm hard into the pedal for extended periods in 3rd gear. ICP pops up, but then falls down to 2200psi, or less. Why might that be?
I know you hate on some DP , and I get it, but they've worked well for me. Having a tow tune that keeps the coast clutches engaged in 1-3, then being able to flip to a tune that doesn't, is hugely helpful in CO. When I had a Hydra, I tried to get others to create tunes that did that, and they would not. For the moment, though, the tuning, better or worse, hasn't hanged in 8 years.
Mark
I meant to quote this in the above post... Maybe someday I’ll learn to use the Internet?
3300psi is probably silly anyway. Most trucks won’t maintain that and it doesn’t improve power, etc.
Dropping to 2200psi during sustained WOT means you have an ICP issue and will absolutely destroy power and reduce black smoke.
Tired injectors and/or HPOP are common culprits.
on edit: I think I see peak ICP before peak RPM. This is indicative of failure to create/maintain desired ICP.
Yes, but a MFDES reading that lowers down from WOT during a climb while ICP lowers to reflect the demand of fuel (MFDES) is normal. A WOT run would be reflected with MFDES above 75mg (loaded) with a maximum reading of 90mg. While unloaded (as chart indicates) MFDES can be much lower as by design it takes less fuel to move less weight.
As stated earlier, I regularly see a MFDES of 90mg and ICP of 2800 - 3000 PSI. As the truck climbs the grade, the ICP will lower to 2200 PSI or so as MFDES lowers to 50mg or so based on the truck adjusting to the work being requested.
I am not contesting that low ICP at high MFDES/WOT will produce smoke, I am agreeing with you. I am simply stating that a WOT with low ICP scenario is not what I see in the chart based on the MFDES trace line.
You stated that it looks like the ICP is falling off at peak RPM, to me it looks like ICP is following RPM and what MFDES is calling for, but I too am looking at this on a phone.
Below I blew up the chart and circled in red the ICP (solid blue), RPM (dashed green) and circled in orange MFDES (solid yellow). They each appear to follow along as MFDES is adjusted based on Marks right foot.
OK, ICP sensor and pigtail are replaced, and I've confirmed that MAP, EBP and BARO all read 11.5psi at rest (I live at 6350ft, so the readings are a good bit less than sea level.
Originally Posted by SkySkiJason
Dropping to 2200psi during sustained WOT means you have an ICP issue and will absolutely destroy power and reduce black smoke.
Tired injectors and/or HPOP are common culprits.
on edit: I think I see peak ICP before peak RPM. This is indicative of failure to create/maintain desired ICP.
I was afraid we were headed here. So, let's play a little game of "Bet ScaldedDog's Money": Are T500's known to give up the ghost after only 40k, and *might* the higher aluminum levels be a telltale sign of that? I'm gathering from your last comment that "failure to create/maintain ICP" makes the problem more likely to be HPOP than injectors. Am I understanding your point correctly? I've been reading the "Current HPOP recommendation" thread with interest, but have come away from it thinking none of them are perfect. So, any thoughts on going with a T500 again, vs an Adrenaline or CNC?
Of course, it seems we need at least another test run, with a longer, more sustained pull, before jamming a round in the $Buckzooka$. Still, I'm interested in the group's opinion on whether quick waering (in my book) T500's are a thing.
OK, ICP sensor and pigtail are replaced, and I've confirmed that MAP, EBP and BARO all read 11.5psi at rest (I live at 6350ft, so the readings are a good bit less than sea level.
Of course, it seems we need at least another test run, with a longer, more sustained pull, before jamming a round in the $Buckzooka$. Still, I'm interested in the group's opinion on whether quick waering (in my book) T500's are a thing.
Mark
Lower PSI readings are to be expected at that elevation, but as long as they were within .5 of each other they are good. For example, my EBPS read 34 or something when I tested the 3 sensors KOEO.
Clearly the EBPS was bad or clogged, turned out to be both.
Before you go spending $500, let's make sure you have found the problem. More testing, data logging and diagnosis is called for. You may in fact need a new HPOP, but let's be sure.
You know we are not a Facebook group that jumps to conclusions and throws money at the engine.
If you can, do a WOT empty or towing run with a stock tune as well as the tune used in the 1st set of data. Would like to see a stock baseline, and if IPR% can be well-behaved at 42% or so with ICP at a good strong 2800psi or better, given you have a T500. If IPR% climbs much above 42% in stock, I'd start to suspect the IPR again, then injector leaks or HPOP.
Interested to see if the new ICP changed anything.
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, and I get it, but they've worked well for me. Having a tow tune that keeps the coast clutches engaged in 1-3, then being able to flip to a tune that doesn't, is hugely helpful in CO. When I had a Hydra, I tried to get others to create tunes that did that, and they would not. For the moment, though, the tuning, better or worse, hasn't hanged in 8 years.
