S40 T4 | Power loss/hesitation under boost
Discussion
I picked up my old T4 this afternoon (spent the last 2 years cruising around in my BMW 5 series which I sold today) and drove the 183 miles home not touching the boost partly due to the traffic on the M1. As it had been driven by my dad for the past 2 years I thought I'd take it out tonight and let it breath a little as it hasn't been over 2,500 rpm in the past 2 years!
On the run I noticed immediately that there was a hesitation and a split second loss of power intermittently when on boost. This occurred through gears 2 & 3, didn't get to 4th gear, immediately the engine light came on flashing until I came off boost and has remained on since...
I thought turbo issue initially but am really at a loss as I've not experienced the issue before.
Anyone have any experience of this type of issue or any idea what it could be?
I'm going to take a look under the bonnet tomorrow when it's light to make sure all hoses are still attached and that the engine sounds smooth. I am concerned it's a turbo issue... but there is my excuse to upgrade to the 16T from the 850 T5!
On the run I noticed immediately that there was a hesitation and a split second loss of power intermittently when on boost. This occurred through gears 2 & 3, didn't get to 4th gear, immediately the engine light came on flashing until I came off boost and has remained on since...
I thought turbo issue initially but am really at a loss as I've not experienced the issue before.
Anyone have any experience of this type of issue or any idea what it could be?
I'm going to take a look under the bonnet tomorrow when it's light to make sure all hoses are still attached and that the engine sounds smooth. I am concerned it's a turbo issue... but there is my excuse to upgrade to the 16T from the 850 T5!
Do you know what boost pressure the car is running at WOT?
If its 1bar, then the first thing I'd look at would be the plugs (if necessary replace with genuine Volvo ones) and coils (make sure they have no cracks). The flashing engine management light sounds like its detected a misfire. The MAF could also be another culprit as they are known to fail.
Might be an idea to see if anyone local / close to you is equipped with the Volvo diagnostic kit so that they can check the car for fault codes - that may well pinpoint the cause of the problem. You'll find quite a few people both on the VOC and T5D5 forums who have the diagnostic kit and are willing to help.
If its 1bar, then the first thing I'd look at would be the plugs (if necessary replace with genuine Volvo ones) and coils (make sure they have no cracks). The flashing engine management light sounds like its detected a misfire. The MAF could also be another culprit as they are known to fail.
Might be an idea to see if anyone local / close to you is equipped with the Volvo diagnostic kit so that they can check the car for fault codes - that may well pinpoint the cause of the problem. You'll find quite a few people both on the VOC and T5D5 forums who have the diagnostic kit and are willing to help.
Thanks both,
ran diagnostics today and the MAF did indeed come up which we cleared. I've either got injectors that require a refurb or more likely a bost leak.
I'm running it and really letting the engine breath to see if the issue clears and resolves itself but will I'm going to get some silicon pipes and new pipe clamps all around.
ran diagnostics today and the MAF did indeed come up which we cleared. I've either got injectors that require a refurb or more likely a bost leak.
I'm running it and really letting the engine breath to see if the issue clears and resolves itself but will I'm going to get some silicon pipes and new pipe clamps all around.
Potatoes said:
I'm running it and really letting the engine breath to see if the issue clears and resolves itself but will I'm going to get some silicon pipes and new pipe clamps all around.
The standard Volvo rubber hoses are more than up to the job - I've run my T4 at 2bar boost on a Garrett GT30 and had no issues whatsoever. If you do decide to change the boost control solenoid hoses, 5mm fuel hose does the job nicely and doesn't break the bank.Be careful if the MAF is flagging codes because in open loop (at WOT) it solely dictates fueling and you may risk serious and permanent damage to the engine.
Thanks T4RRR,
my thinking is it's a boost leak - the sensor believes there is a differnet amount of air in the engine than there is, it's therefore not putting the right amount of fuel into the engine causing issues.
I'm booking it into the garage next week to run some tests on the hoses to sus out any leaks.
my thinking is it's a boost leak - the sensor believes there is a differnet amount of air in the engine than there is, it's therefore not putting the right amount of fuel into the engine causing issues.
I'm booking it into the garage next week to run some tests on the hoses to sus out any leaks.
Potatoes said:
my thinking is it's a boost leak - the sensor believes there is a differnet amount of air in the engine than there is, it's therefore not putting the right amount of fuel into the engine causing issues.
In my experience, boost leaks also tend to cause uneven idling. Which model year is the car? Try and get it read with the Volvo diagnostic kit - generic OBD2 code readers are fine but will not pick up manufacturer specific codes (especially some fuel trim ones). In addition, if it is indeed a boost leak, you may need to reset the fuel adaption(depending on model year).
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