2004 XC90 T6 , difficult to start at times

Bluesman · Post by **Bluesman** » 04 Sep 2012, 21:35

My 2004 XC90 which is the T6 model has 130k on it. When I got it , it was just sometimes difficult to start. It would crank and crank but not fully turn over. When it does start, maybe 3 or 4 times in a row with no problem and then back to difficult a message saying "reduced Engine Performance" would light up. It needed a MAF sensor which I replaced and my mechanic told me that the transmission had been replaced. (which is good on this one) He seemed to think that my starting troubles were due to the trans rebuild crew accidently bending the flywheel. He said he had seen it before and that a slight bend anywhere on the flywheel would not allow the timing sensor to detect the sensor ring on the flywheel. His solution was to bump the ignition until it would read and then it would start.
Since then I have discovered that if I feather the gas pedal when I start to turn the key then it starts right up every time. In addition the "reduced engine Performance" message does not come on. That makes me think more of a fuel issue or vacuum. What could this possibly be and how could I get it right so I don't have to pretend its an old chevy when starting it>
Anybody seen this problem?

Bluesman · Post by **Bluesman** » 23 Sep 2012, 20:44

Thanks for lack of responses. Maybe I should of asked something stupid like ; how do you put air in the tires on an XC90 to actually garner an attempt at a helpful or any response!!

Post by **precopster** » 24 Sep 2012, 04:14

With about as many manners as a bull in a china shop you probably won't garner any more than a fart in your direction.

Your lack of response was probably because you threw a curveball at our less experienced members with your particular vehicle and the more experienced guys who may not have been online and missed your post at the time (probably having a holiday, or away with their family somewhere instead of giving their own personal time to a forum where often gratitude is lacking, though in most cases this is not the norm)

Some of our members work on Volvos for a living and have a huge wealth of experience in oddball matters. It is up to you to find out who they are and perhaps send them a PM and if they are kind enough to chime in when you ask a question then you are fortunate.

As far as questions about pumping up tires that's probably not a bad idea. I've been looking for suggestions on how this can be done more accurately and any suggestions YOU may have would be very welcome!!

Rocky · Post by **Rocky** » 24 Sep 2012, 08:03

When you replaced the Maf, did you clean the iac?

Post by **jimmy57** » 24 Sep 2012, 08:13

The engine to transmission mating surfaces are dirty or you have a faulty starter. The distance between the starter and the rpm sensor is close. The magnetic field from the starter causes erratic signalling from the RPM sensor and the ECM can't sync the cam sensor and rpm sensor in order to operate coils and injectors. If the transmission had not been removed and replaced I'd do amperage testing on starter but with the trans repair it puts the blame more on the engine and trans faces being dirty. The suppression afforded by the bell housing is jut barely adequate. If the area that gives the shielding is not cleanly contacting the engine then the suppression is not adequate. Ground leads added and things like that do not do it.
Volvo reman'd transmissions started being painted from the contract remanufacturing company. The long crank/barely start problem cropped up. We tried everything and then tried a few more things as suggested by Volvo. What fixed the problem was trans removal and cleaning. By that time we had several cars with the problem and every one required that cleaning of paint. Then we had a car brought to us by a used car lot that had installed a used transission. It was not paint but just terribly dirty transmission to engine faces.
I bet when your engine does start it is usually when the key is released. That is what we found.
I had a manual transmission car with the problem and the car would start if you put it in 3rd gear and a couple of guys pushed it where it turned over a faint amount but would only occasionally start with starter. We loosened all but a three of the bolts and moved the trans back 1/2 inch and attacked the faces with brake cleaner spray and rifle cleaner brushes and it fixed it.
The problem is visible on an oscilloscope viewing of rpm sensor compared to a vehicle without the problem.
The faulty starter issue cropped up once after I had replaced a starter. The engine did not crank over briskly and would take long cranking at times. The battery was tested as good and then starter amp draw showed the starter drawing too much current. The starter was replaced again and it was fixed. That vehicle had never had trans and engine separated so there was no suspicion of the dirty surfaces problem.