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Discussion Starter · #1 ·
Been feeling dips in power when accelerating hard, finally got a DiCE unit set up and started diagnosing this issue further. All DTCs that I saw in VIDA were old and unrelated to engine function so I just cleared them out. When looking at other parameters in "Vehicle Communication", things start to get interesting. Boost pressure rises and holds at 10 psi, so I don't think I have an issue with the TCV, however when looking at "Ignition retarding (knock)" I do see that the ECM is pulling out a few degrees of ignition timing at full boost, which seems wrong to me on 93 octane.

Also ran the "quick fuel pump test" which seemed to check out, though I couldn't verify the initial pressure value with a mechanical gauge because I don't have an adapter that connects to the small schrader on the fuel rail, anyone know where to get one or even the correct terminology to describe that size?

Plugs are new OE, coils are not, but that shouldn't matter. Planning on doing a boost leak test in the coming days to see if I find anything. I've also cleaned the MAF and TB in the last week with no change.

Also looked at intake air temps and they were 35C-40C with it being 29C ambient today here in Charlottesville VA.

Anyone have any suggestions for what could be causing this that I'm not thinking of? Doesn't seem hot enough for this to be an issue, but maybe I'm wrong? I know my 240 Turbo doesn't ping at this temperature and it has a terrible steel intercooler, so I would expect the V50 to be doing better in the same heat.
 

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2007 Volvo V50 T5 AWD M66
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Not sure about your car but I know my stock V50 intercooler sucks and easily hits 70C+ doing third gear pulls in the heat.
 

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Well, it could be a lot of things -
Age of coils? Highest possible resistance is full load at full boost, could be firing late i.e. old coil about ready to die.
Otherwise, knocking and a retard of timing typically indicates either an issue with fuel or an issue with the curve because of heat. If you are running the stock IC - it would make sense what Jirv0id said - can't really run full advance timing when air is as hot as 70*C.
I assume your coolant level is acceptable, and you have no issues in that realm.

Me personally, I'd dump a gallon or two of E85 or some of that Water remover (HEET, etc, anything alcohol based or octane booster) in there, do some side to sides to mix it in the fuel and see if it fixes your issue - you may have just gotten a low grade of gas.

Obviously start cheap and work your way up.
 

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Discussion Starter · #4 ·
Not sure about your car but I know my stock V50 intercooler sucks and easily hits 70C+ doing third gear pulls in the heat.
Huh, my IAT's weren't that high in the little testing I did today, at least reported through VIDA. Though the issue does only seem to happen after a few pulls, the first couple don't show this issue, so it could still be impacting me, just at a lower temperature.

Well, it could be a lot of things -
Age of coils? Highest possible resistance is full load at full boost, could be firing late i.e. old coil about ready to die.
Otherwise, knocking and a retard of timing typically indicates either an issue with fuel or an issue with the curve because of heat. If you are running the stock IC - it would make sense what Jirv0id said - can't really run full advance timing when air is as hot as 70*C.
I assume your coolant level is acceptable, and you have no issues in that realm.

Me personally, I'd dump a gallon or two of E85 or some of that Water remover (HEET, etc, anything alcohol based or octane booster) in there, do some side to sides to mix it in the fuel and see if it fixes your issue - you may have just gotten a low grade of gas.

Obviously start cheap and work your way up.
Coils are original AFAIK, so they could be suspect at 114K I suppose. I've had this issue since I got the car in May so I don't think I *just* got a low grade of gas, but it is possible that there's some water in the tank that shouldn't be. I'll grab a bottle of HEET and see if that helps at all.
 

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I would suspect coils but I would think it would throw a mis-fire code. Perhaps they are not that bad yet.

I recently had a problem with mine when cruising with RPMs between 2000 and 3000 the car would surge and stumble but it would idle fine and wide open was good. I could see the fluctuation in my vacuum/boost gauge like I was on/off the throttle (lightly). It turned out to be the throttle body. There is a position sensor that is a variable resistor. The wiper of the resistor wares away the resistive material where the throttle sits most the time and causes a dead spot. The computer tries to get to the throttle to the desired position but gets bad info. I replaced the TB with a used one from the bone yard and problem is gone.
 

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Are you on stock IC? Unless your pulls only last 1 sec, it's a bit hard to believe your intake temps would be only 11 C over ambient after a couple of pulls.
I think I got something like 40 C IAT right after single ~120-180 km/h 4th gear pull at ~20 C ambient ~18-20 psi boost with Do88 IC, 98 RON and I didn't detect any knock retard in Vida (though the timing advance is most likely different with my tune).
I'm not sure if knock retard is only applied after knock is detected via the knock sensors, or if the ecu may apply it when it thinks knock might occur because of high IATs.
 

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Discussion Starter · #8 ·
Are you on stock IC? Unless your pulls only last 1 sec, it's a bit hard to believe your intake temps would be only 11 C over ambient after a couple of pulls.
I think I got something like 40 C IAT right after single ~120-180 km/h 4th gear pull at ~20 C ambient ~18-20 psi boost with Do88 IC, 98 RON and I didn't detect any knock retard in Vida (though the timing advance is most likely different with my tune).
I'm not sure if knock retard is only applied after knock is detected via the knock sensors, or if the ecu may apply it when it thinks knock might occur because of high IATs.
I am on the stock IC, I got these numbers after a quick jaunt out of my driveway and down the street so the pull was really short, but enough that I could see the retard in VIDA.
I also had the same question about knock retard, I'm thinking based on description of the parameter in VIDA that it does so in reaction to knock: "Ignition retardation requested due to knock in the cylinders"
 

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Coils are original AFAIK, so they could be suspect at 114K I suppose. I've had this issue since I got the car in May so I don't think I *just* got a low grade of gas, but it is possible that there's some water in the tank that shouldn't be. I'll grab a bottle of HEET and see if that helps at all.
I would definitely vote coils for sure at that age...I haven't seen one make it to 125k, I'm sure there are, but I bought my car at 114k and had to replace all 5 as they were all misfiring.
 

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Discussion Starter · #10 · (Edited)
@avenger: noted. I'd expect to see misfire codes if that were the case but I'll keep the coils in mind as I progress through this.

Did a boost leak test today by pressurizing the turbo from the turbo intake, broke my tester and dropped a brass fitting into the turbo and spent 2 hours fishing it out :angryfire:

Otherwise did find some interesting things.

1) The vacuum lines that come off the intake manifold where that red clip is were pressurized with air coming out of the one that connects to the over-engine intake pipe. Does that y-piece on those lines not serve as a check valve? It doesn't seem intuitive to me that there would be a big hole in the intake manifold that's dumping pressurized air out into your unpressurized intake tract.

Disconnecting that line and plugging it I discovered:

2) I pressurized the PCV system apparently because I started getting noise out of the oil fill cap, which I then promptly removed before I started blowing seals out. This isn't my first rodeo so I understand that this could be caused by a number of things, but I did come across this post: https://forums.swedespeed.com/showthread.php?205600-Turbo-Check-Valve and I wonder if that valve is doing irregular things on my car. I don't understand why that valve exists, its placement seems to me like it would always be in vacuum since it's before the compressor wheel, but other people say it caused them boost issues.

Also while crawling around, it appears I blew up something coolant related between yesterday and today, as there's dried coolant all over on the driver's side of the motor and coolant is low. I suspect it's the upper radiator hose based on the reading I've done...this car just keeps treating me well
 

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84 plus degrees on a stock intercooler could easily cause a timing pull after repeatedly running it. I’m sure you have heard of heat soak??? Couple of options. Dont continue to run it hard in hot temps as this could lead to detonation if a sensor of switch would fail. Use an octane additive like Boostane during the hotter months. 1/2 a can with 93 will get you in the ballpark of 98. No more timing pull. Now you have timing advance.




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@avenger: noted. I'd expect to see misfire codes if that were the case but I'll keep the coils in mind as I progress through this.

1) The vacuum lines that come off the intake manifold where that red clip is were pressurized with air coming out of the one that connects to the over-engine intake pipe. Does that y-piece on those lines not serve as a check valve? It doesn't seem intuitive to me that there would be a big hole in the intake manifold that's dumping pressurized air out into your unpressurized intake tract.

Disconnecting that line and plugging it I discovered:

2) I pressurized the PCV system apparently because I started getting noise out of the oil fill cap, which I then promptly removed before I started blowing seals out. This isn't my first rodeo so I understand that this could be caused by a number of things, but I did come across this post: https://forums.swedespeed.com/showthread.php?205600-Turbo-Check-Valve and I wonder if that valve is doing irregular things on my car. I don't understand why that valve exists, its placement seems to me like it would always be in vacuum since it's before the compressor wheel, but other people say it caused them boost issues.

Also while crawling around, it appears I blew up something coolant related between yesterday and today, as there's dried coolant all over on the driver's side of the motor and coolant is low. I suspect it's the upper radiator hose based on the reading I've done...this car just keeps treating me well
1) There is supposed to be a check valve in that Y-piece. Mine was passing air both ways. I happened to be at a junk yard and found one that seems to be good. I can't swear that it made much difference though. It goes to the power brake booster.

Very likely it is your upper radiator hose leaking.
 

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Discussion Starter · #13 ·
1) There is supposed to be a check valve in that Y-piece. Mine was passing air both ways. I happened to be at a junk yard and found one that seems to be good. I can't swear that it made much difference though. It goes to the power brake booster.

Very likely it is your upper radiator hose leaking.
Hmm, though in that thread I linked, the test procedure for that check valve involves clamping off the line that goes to the intake pipe which leads me to believe that maybe there isn't a check valve on that part of the line, just on the part that goes to the booster.
 

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Sorry but i made 315.000 km with original ignition coils. Changed only 1 bcs of broken by heat connector female on it. Anyway after 13 years and this km preventive new 5 will do it.
I had similar problems when i fill bad petrol in country Serbia on some stations...never problems in Slovenia high octane 100 petrol. Never. Now im using only Shell high 98 octane as they dont have 100 V power super race one.

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Echo HongKong


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Discussion Starter · #16 ·
Had my buddy try blowing into his vacuum line on his C30, says he can't, so I guess my Y-piece is shot. Unfortunately looks like I'll have to buy the whole part 31201432 which will be $125-$150. Also just a found a hole in the muffler on my E30, all of my cars are terrible.
 

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daaaaang really? 315.000km? That's incredibly lucky.
 

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daaaaang really? 315.000km? That's incredibly lucky.
Yes 315.000 km original coils. For preventive service I will change them all soon as now new cables harness new sparks good isolation and even air ventilation...also injectors i will put new.

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Had my buddy try blowing into his vacuum line on his C30, says he can't, so I guess my Y-piece is shot. Unfortunately looks like I'll have to buy the whole part 31201432 which will be $125-$150. Also just a found a hole in the muffler on my E30, all of my cars are terrible.


Hey did you manage to resolve the ignition retard issue , my brother has been facing similar issues with his volvo s40 t5 , logging with vida shows boost hitting only around 4.7 psi and ignition retard due to knock going as high as 11 to 14 degrees , car as a result seems down on power , i noticed on some logs with vida the "ignition retard due to knock" comes at very low boost to around 2 to 3 degress of "ignition retard due to knock" , i can only assume the ecu is correcting for the ignition knock by reducing boost as the duty cycle of the tcv is very low and the fuel trims are rich which according to vida maybe the injection period being increased to cool the cylinder after detecting knock ,


from the logs there is always some degrees of "ignition retard due to knock" as soon as boost hits , and boost is never over 4.7 psi even under full throttle . he has changed spark plugs , coil packs, brand new tcv, brand new oxygen sensor, changed out the oil reset valve(vvt solenoid), checked all the vaccum lines and boost and induction hoses , changes out the check valve on the turbo as others suggested , changed out the throttle body and none of this has solved the issue


looking forward to hear if you have solved this issue as at this point the most probable and susceptible parts that might be affected have been replaced and checked and still the issue is not resolved car never boost above 4.7 psi and the car short terms fuel trims indicates a rich condition

thank you
 
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