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Discussion Starter · #1 ·
I've been trying to figure out a low boost issue on my V70R, and I just can't figure out why it won't make much boost. In 1st gear it tries, but just falls on its face and goes into vacuum in the higher RPM. Then in 2nd-5th, it only boosts to around 8-10 PSI, where it should be WAY higher on its Hilton stage 1 tune. I have the Pierburg upgraded TCV (the Porsche part) and I've tried swapping the original one back to no avail.

I installed the iPd HD CBV last week, that didn't change anything. I checked the wastegate pressure, seems to be right where it should be (around 4 PSI). I've thoroughly checked over the engine for any vacuum leaks, and I can't find any. The intercooler hoses are soft and worn, but they are not leaking. My boost gauge sits right around 20 in-hg at idle, which is right where it should be from my experience.

I have a code for MIL signal too low (somehow the wire is grounded somewhere, but I tested the light in VIDA and all appears to be fine) but I want to figure out one thing at a time. I don't think this issue would be limiting boost.

So, is my TCV just taking a long time to adapt or is there actually a problem? Rob at Hilton didn't seem to have any advice for me on this issue, unfortunately, so I don't know what to do. I've tested and inspected just about everything, and I can't find anything wrong.
 

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Could be torque limits. Seriously.

Flash the stock time back and trouble shoot based off of that
 

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Discussion Starter · #3 ·
Could be torque limits. Seriously.

Flash the stock time back and trouble shoot based off of that
You know, I've been thinking that it's the tune, but I thought maybe I was missing something. I'll give that a try tomorrow and see what happens. If I'm making full boost with that 4k RPM limiter from the automatic tune, at least I'll know where the problem lies!
 

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In my experience you should get pretty good performance right away... There could be a number of reasons. If you have VIDA check if you have any fault codes for MAF or MAP for example. I would also do live logs, check that MAF, boost pressure, IAT, fuel pressure, throttle, knock, TCV duty cycle, fuel trims and so on look sensible. From the TCV duty cycle you should be able to see if the ecm is trying to make boost or not. If it goes to 100% you probably have some kind of boost control or mechanical problem. Otherwise some other condition/sensor reading is probably limiting the boost in the program.
 

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Discussion Starter · #5 ·
In my experience you should get pretty good performance right away... There could be a number of reasons. If you have VIDA check if you have any fault codes for MAF or MAP for example. I would also do live logs, check that MAF, boost pressure, IAT, fuel pressure, throttle, knock, TCV duty cycle, fuel trims and so on look sensible. From the TCV duty cycle you should be able to see if the ecm is trying to make boost or not. If it goes to 100% you probably have some kind of boost control or mechanical problem. Otherwise some other condition/sensor reading is probably limiting the boost in the program.
I'll give that a try today as well. I have a strong feeling it's an issue with the tune.
 

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Discussion Starter · #6 ·
I checked out the duty cycle on the TCV, only goes to 94.2ish%. Granted, this was just revving it in the driveway. I did a couple pulls where it went into "full" boost, and I only noticed 20-40%. I coulnd't just look at it the whole time of course, I don't want to take out a mailbox, but that's what I observed.
I flashed back the stock tune and it still doesn't want to boost. It seems better in first gear, but with the 4k RPM limiter it's really hard to tell if there is an improvement.
 

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Discussion Starter · #7 ·
I did some logging in VIDA today. It's been about 100 miles of driving since resetting the battery/TCV last, and the boost has not changed. I'm still not seeing over 10 PSI on my gauge, and I just can't figure this out. I can't figure out how to display actual values on the graphs on VIDA, but I'll go ahead and post screenshots of the graphs anyway. I only did a couple first and second gear pulls, and hopefully you'll be able to make that out. The boost is acting really strange in correlation to the RPMs. The TCV duty cycle is just all over the damn place.

After doing conversions, the boost numbers in hPa don't make any sense. According to this, the car is making like 14 PSI at idle and peaking at 24. WTF!?!? My gauge peaks around 10 PSI and backs off to around 8 after that I don't think the gauge is the problem since my previous gauge displayed the same thing. In 1st gear, depending on if I hit it hard or not, feels like it hits a wall and the ECU restricts any boost at all. If I ease up to probably 3,000-3,500 RPM, then hit the gas, it just goes into vacuum on acceleration. This issue definitely seems electronic related and not mechanical.





 

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The boost sensor is before the throttle and shows absolute pressure, so it shows ~atmospheric pressure at all times until you develop some boost over the atmospheric pressure. Max seems ~0.6 bar in 2nd without the throttle close off spike. No idea why you are not getting more boost, and it's not even trying in the first gear. Not sure what's stock for R. If you see vacuum on your gauge, it means ecu is closing the throttle... The boost pressure and TCV kind of seem sensible though, just not sure why it's not trying to develop more boost. Can the M56 swap cause issues?
 

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Discussion Starter · #9 ·
The boost sensor is before the throttle and shows absolute pressure, so it shows ~atmospheric pressure at all times until you develop some boost over the atmospheric pressure. Max seems ~0.6 bar in 2nd without the throttle close off spike. No idea why you are not getting more boost, and it's not even trying in the first gear. Not sure what's stock for R. If you see vacuum on your gauge, it means ecu is closing the throttle... The boost pressure and TCV kind of seem sensible though, just not sure why it's not trying to develop more boost. Can the M56 swap cause issues?
Ah, that's what I was putting together about the boost numbers after I thought about it. So 0.6 bar is about 8.7 PSI, which is exactly what I'm seeing on my gauge.

I'm not sure. I've emailed Hilton, but he hasn't responded, and it's really driving me nuts. The only thing I can think is that the clutch sensor is required for ME7 (it affects the throttle to assist in taking off and closes the throttle on shifts, I believe), but I can't install that until I get a new clutch master cylinder to attach it to. That still doesn't explain the lack of boost in 1st gear and low boost across the chart. Rob even said himself that he doesn't think the clutch sensor/switch issue would cause low boost.
 

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Discussion Starter · #11 ·
That's what I'm not understanding here. I have no idea why the ECU would limit boost.

I emailed Rob again, hopefully I'll hear back soon. I have no idea what else could be wrong except the tune.
 

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That's what I'm not understanding here. I have no idea why the ECU would limit boost.

I emailed Rob again, hopefully I'll hear back soon. I have no idea what else could be wrong except the tune.
Well. That could very well be what it is, then. ScottishBrick suggested it in the first post

Could be torque limits. Seriously.

Flash the stock time back and trouble shoot based off of that
I want your problem to be solved, and there's nothing wrong with trying to be helpful. In fact... People need to understand that I am learning more about this every day, I wrench on cars in a currently limited capacity but I have at least two thankful customers this month alone. I don't claim to know more than anyone; in fact, I know almost nothing of the Volvo turbo operation, except that they are sportier cars than anyone would have thought and I have the forever bug. By far my favorite car and I've owned .... about two dozen in my life? So, all I did was share my basic troubleshooting. Any good mechanic, the first thing they do is "Verify the complaint" or "recreate the problem" so they are not guessing at it. Then they go into diagnoses. You sound like you have a nice build, and you're in one of my favorite cities, Charlotte NC, I resided there at one point and all future signs point to around there.. I'll probably be a Volvo enthusiast down there too, I wear this with pride. Maybe I'll come and hi-five ya and talk shop and go to Maggiano's with you and such. It's all good!
 

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Discussion Starter · #13 ·
Well. That could very well be what it is, then. ScottishBrick suggested it in the first post



I want your problem to be solved, and there's nothing wrong with trying to be helpful. In fact... People need to understand that I am learning more about this every day, I wrench on cars in a currently limited capacity but I have at least two thankful customers this month alone. I don't claim to know more than anyone; in fact, I know almost nothing of the Volvo turbo operation, except that they are sportier cars than anyone would have thought and I have the forever bug. By far my favorite car and I've owned .... about two dozen in my life? So, all I did was share my basic troubleshooting. Any good mechanic, the first thing they do is "Verify the complaint" or "recreate the problem" so they are not guessing at it. Then they go into diagnoses. You sound like you have a nice build, and you're in one of my favorite cities, Charlotte NC, I resided there at one point and all future signs point to around there.. I'll probably be a Volvo enthusiast down there too, I wear this with pride. Maybe I'll come and hi-five ya and talk shop and go to Maggiano's with you and such. It's all good!
I'm going to flash the stock tune back tomorrow and see what I can come up with. Like I said before, it's hard to do much troubleshooting under 4,000 RPM being that the problem area is closer to red line, but if I pull up the logs again I should be able to see if the TCV is operating properly.

I appreciate the help, there's only so much others can do on a forum, especially when it's a very specific problem!

I've been in the Charlotte area for about 12 years now, it's a great place to live! The growth is absolutely insane though. Constant development everywhere.
 

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Discussion Starter · #14 · (Edited)
I flashed back the stock tune and did a 3rd gear WOT pull. I think this is probably the best way to get a decent view of what's going on. It seems the TCV duty cycle is still whacked... unless it's supposed to be like that?



Zoomed in a little bit...


Again, I apologize for the lack of numbers, but I can't figure out how to view a graph with any numbers. It shows the maximum and minimum on the grid, so that should help a little bit.

Just a side note, but I noticed the engine revs much more freely while rev matching for downshifting. I need it to be like that on my Hilton tune! My downshifts in this car are usually crap because it takes to long to spin up. I'm used to my brother's Miata that revs right up when I hit the gas.

Anyway, the boost seems to be peaking at approximately 8.2 PSI. I think I can rule out the tune. I'm going to attempt to make a boost leak tester today and see if I can find a leak in my intercooler piping.
 

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I flashed back the stock tune and did a 3rd gear WOT pull. I think this is probably the best way to get a decent view of what's going on. It seems the TCV duty cycle is still whacked... unless it's supposed to be like that?

Zoomed in a little bit...

Again, I apologize for the lack of numbers, but I can't figure out how to view a graph with any numbers. It shows the maximum and minimum on the grid, so that should help a little bit.

Just a side note, but I noticed the engine revs much more freely while rev matching for downshifting. I need it to be like that on my Hilton tune! My downshifts in this car are usually crap because it takes to long to spin up. I'm used to my brother's Miata that revs right up when I hit the gas.

Anyway, the boost seems to be peaking at approximately 8.2 PSI. I think I can rule out the tune. I'm going to attempt to make a boost leak tester today and see if I can find a leak in my intercooler piping.
Yes 3rd gear pulls give a bit better data. I think TCV is functioning just alright. It goes to 100% for quicker spool up and then regulates once "target" is reached. A boost leak could be a problem, since air mass is measured before turbo (ecu targets mass air flow). You are getting like 467 kg/h @ 4000 rpm @ 0.55 bar. I should check my old logs and make a rough comparison if you are loosing large amount of air somewhere. You are not hearing a loud whistle under WOT?

I have used screen recording with graph zoomed a bit in + auto ranged and checked values after the fact, but it's far from perfect. You can't get accurate values just from the graph, best you can do is look at min-max and eyeball or measure with a ruler, lol. Also 5 params max is a bit limiting, without the graph you can do 10... AFAIK, Vida actually logs the raw traffic between DICE and ecu in a txt log file. Someone needs to develop a converter to excel. Guys like Hilton have their advanced logging solution for sale, but being a cheap guy...
 

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Discussion Starter · #16 ·
I used by makeshift boost leak tester yesterday and discovered a leak in my intercooler. Nice little hole near the bottom. I swapped it out with a spare I had, tested that one and it's solid. Upon a test drive it made absolutely no difference in boost levels... I just don't get it.

I'm hearing a whistle, but it's hard to tell if it's just the turbo or there's a leak. Would that oil weep hole in the bottom of the intercooler be a problem? It seems a bit ridiculous, but a lot of air escapes through those.
Otherwise I can't find anywhere there could be a leak.
 

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The oil weep hole in the IC isn't a concern from a boost standpoint unless it is damaged.
 

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Discussion Starter · #18 ·
The oil weep hole in the IC isn't a concern from a boost standpoint unless it is damaged.
I didn’t think so. I’ve got no idea why the boost could be so low.
 

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have you checked the CBV?
 

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Discussion Starter · #20 ·
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