Engine Misfires

[XCHauler]

My 01 XC has been displaying an engine code of PO300 which is “Multiple Engine Misfires” This weekend I replaced (3) of the ignition coils with the IPC upgraded coils and checked the other two coils by simply disconnecting the ignition wire harness at each coil and listening to engine to see if it affected the smoothness of the idle. The last two coils had the biggest impact of affecting the engine idle so i left those in place and replaced the other three. I also replaced the sparkplugs with a Volvo OEM set. The engine misfire light continues to come on even after these upgrades. The engine does run smoother, but still has an uneven ide and seems sluggish on acceleration.


I replaced all (5) ignition coils with Volvo OEM about 2 ½ years ago but I'm disappointed with their performance and premature failure rate.

I did inspect the ignition wiring harness on top of the engine and have replaced all of the plastic looming in poor condition.. I also had all of the fuel injectors professionally cleaned about 2 years ago as well.

I heard somewhere on the web that a bad fuel pressure regulator could also be the problem of multiple misfires and was wondering if anyone had similar problems.

Any help would be appreciated.

XCHAULER

[Astro14]

I would replace those last 2 coils before going after fuel pressure...

Do you have a good FI pressure gauge?

[XCHauler]

Unfortunately IPD has their Ignition coils on back order for another 30 days, so I will have to wait until they are in stock. Unfortunately I am not familiar with checking the fuel pressure on my XC, can you point me in a good direction on how to accomplish this procedure?

XCHAULER

[dpaton]

There are two ways - through the ODB2 port (live data on my scanner/reader) to see what the sensor reads and there is a schrader valve on the right end of the fuel rail for the mechanical - they should be close.

[XCHauler]

My engine seems to be starving when the rpms exceed 2700-3000 rpm’s this may be the result of some errant engine misfires (engine code PO300). However when I shift the transmission manually and rev the engine to redline it is smooth and strong with no vibration. When I am at freeway speeds (60-65 mph) and let off the throttle the rough engine seems to diminish. This problem has been occurring for about 3-4 months, Gas mileage has not changed but the drivability is problematic with the rough engine .
I am not sure if replacing the last two ignition coils will have any positive effect. All of the coils were replaced within the last 3 years from FCP and these two coils seem to provide the strongest spark.

I am going to replace the fuel and air filter and see if this has any effect.

Any other thoughts on this problem would be appreciated

XCHAULER

[billr99]

My engine seems to be starving when the rpms exceed 2700-3000 rpm’s this may be the result of some errant engine misfires (engine code PO300). However when I shift the transmission manually and rev the engine to redline it is smooth and strong with no vibration. When I am at freeway speeds (60-65 mph) and let off the throttle the rough engine seems to diminish. This problem has been occurring for about 3-4 months, Gas mileage has not changed but the drivability is problematic with the rough engine .
I am not sure if replacing the last two ignition coils will have any positive effect. All of the coils were replaced within the last 3 years from FCP and these two coils seem to provide the strongest spark.

I am going to replace the fuel and air filter and see if this has any effect.

Any other thoughts on this problem would be appreciated

XCHAULER

It sounds like you are running into an issue that a few of us have had and have never quite sorted. IMHO it's the engine parameters programmed in for fuel economy and when it gets warm they are a bit too lean. I've changed coils, plugs, various sensors, etc. and it is always there to some degree when the weather gets decently warm. BTW I never have a code set when this happens. But if you get it sorted, let us know how.

Cheers,

Bill

[JRL]

Fuel filter
ETM
Low battery
The list is endless but replace those 2 coils.

I disagree, coils are coils, they work or they don't.
'This engine does not require a higher output coil(s) to run preperly

[XCHauler]

Could this engine misfire (P0300) be the sign of a failing ETM? I cleaned the ETM four months ago and it was rather dirty.

I have done the following:

Replaced all (5) ignition coils
New spark plugs
Check the spark for all coils and all 5 cylinders seem good
Replaced the wire loom for coils and checked for any bad wiring
New air filter
Cleaned the MAF
New fuel filter
Check the fuel pressure and it seemed OK
Changed the oil with Amsoil 5wx40w
Cleaned the intake system with a Seafoam treatment
Replaced the PVC system
Replaced a leaking rear cam seal

The engine seems to run rather smoothly up to 3500rpm and then it is a little rough. the power of the engine seems OK however but there is a noticeable vibration

The last thing that I was going to do before bringing my XC into dealer is cleaning the ETM again.

Any other thoughts on this multiple misfire problem would be appreciated!

XCHAULER


I am going to check

[dpaton]

My 05 is particular as to which spark plugs it had in when using 87 gas. NGK copper and genuine Volvo (labelled) were good but Bosch platinum would act up. The plugs looked like they were running lean although the engine was not.

Have you tried a few tanks of premium gas? Have you tested the injectors?

[XCHauler]

New sparkplugs are OEM, and the fuel injectors were sent out 2 years ago and professionally rebuilt, they were actually were in pretty good shape. I have used approx 3 bottles of Amsoil and Chevron intake cleaning products as well. I also use premium fuel 91 octane

[guyeye]

Please correct me if I'm wrong, but don't those cleaning products adversely affect the spark plugs sometimes?

[dpaton]

Check the TCV lines for cracks, the top hoses are not too hard to track back and they are the main ones. If the valve is rattling you may want them to try another.

[XCHauler]

I have replaced the turbo control valve and hoses (IPD products)about a year ago and check these hoses when I replaced the oil trap and associated hoses.

Yesterday when I drove my XC at freeway speeds for about 1 hour it seemed to run better. I ran the engine at 4000rpm for about 7-8 minutes to help clearr any carbon deposits and this seemed to help a little.

any other thoughts?

XChauler

[XCHauler]

I replaced the IPD turbo control valve with a new one and sent the faulty unit back to IPD (I’m still waiting to see if they will stand by their product and give me a credit). I also a replaced all (4) turbo vacuum hoses with the blue silicone hoses from IPD. The interior of these existing hoses were covered in a tar-like substance and some were partially blocked.

The engine misfire engine code still returns each time I clear the code. My XC runs with more power and has no problem reaching the redline in the lowest three gears. The real problem is the number one problem that I have had with my XC since day one …….is the rough and inconsistent idle!

I am pretty sure the problem is the throttle body unit but I have not experienced any engine codes indicating this an as the underlying problem, nor have I experienced any “limp home symptoms”

I would appreciate any help to solve this problem!

XCHAULER

[XCHauler]

Well….. this problem has become a maintenance nightmare!

I took my XC in to an independent shop and he found two big vacuum leaks, One leak was at the collar of the air intake tube that goes to the turbo charger, the other leak was at the throttle body. I replaced the air intake tube along with the MAF sensor and the air tube coming from the intercooler and going to the throttle with Volvo OEM parts. The result was disappointing to say the least.

I have also replaced the upper engine mount and the support bushings that attached to the strut towers. I checked the front transmission mount and the front engine mount, and they seemed OK, I have replaced all the mounts on my XC with the exception of the rear engine mount.

The result of my worked has still left me with a engine misfire code (PO 0300) and the engine still vibrates roughly, the power seems better, but it should be based on all the parts that have been replaced on my XC.

The good is I installed the silicone sub frame bushings inserts from IPD and my XC is more responsive and rides more composed. I highly recommend this upgrade. I was glad to purchase new bolts as one of the existing bolts was in pretty rough shape.

I am at a loss at what could be causing my XC to run so poorly! The Indy mechanic said the work I performed on my own ,would have been the same approach that he would have pursued.

The only thing that comes to mind is a faulty ETM and perhaps a rear engine mount which is difficult to see. But I did get under the XC and looked and felt this mount for any cracks or issues and it seems OK. Does anyone know how to confirm if a rear engine mount is damaged?

Overall the front suspension has been completely reworked and it rides like new!

After 6 years of ownership of my 2001 XC, it is probably time to rid myself of these frustrations. I love my XC when is running well, but I have thrown way too much money at it recently with few positive results. This will definitely be the last time that I would considering buying a car with a turbocharged engine ……way too many problems with few rewards!

One last call for help!

[Astro14]

You've done what I would have done.

But, while you've cleaned the MAF, you have not replaced it, is that right?

Since you're still getting the misfire code, you still have a misfire...this isn't a mount thing...this is a fuel/air mixture thing...with vacuum leaks and other problems fixed, the only remaining suspect is the MAF...

[howardc64]

MAF is a possibility but cost over $100 to try. I had MAF failure once with no code. Engine would just randomly cut out for a few seconds and die coming to a stop. Only buy Bosch or Volvo MAF. I tried aftermarket cheap ones, 2 out 2 was bad.

Since you have an 01, ETM is always suspect. Failing ETM TPS (throttle position sensor) usually show up as engine hunting at various RPMs. The easiest way to diagnose failing ETM TPS is to run a ETM test using the Volvo diagnostic tool (dealer shouldn't charge you more than 1/2 hour labor to run it) It will measure both TPS outputs through the entire throttle plate rotation and compare the difference. Here is a write up on ETM removal that include an explanation on ETM test

https://www.box.com/shared/cjh7pkl0cs

[XCHauler]

Howardc64, I am thinking of trying the Sacer TPS sa-300 non-contacting digital angle sensor and was wondering if my XC will to be reprogrammed to operate properly.

I have noticed that my engine RPM's have been fluctuating at certain times (around 300-700 RPM's)

let me know your thoughts?

XCHAULER

[howardc64]

ETM test would provide a definitive diagnostic. If you just want to replace the TPS. No need to reprogram. Do read up online for the procedures. Trickiest part is to remove the green epoxy? to get to the solder points and the alloy contacts require a really good solder joint. I believe a previous poster had a weak solder joint and had problems.