Help with 1999 B5254t - cranks but won't start Topic is solved

Post by **erikv11** » 18 Sep 2016, 09:06

I would keep checking for vacuum leaks too. How about the intercooler path, are the hose clamps all nice and tight?

Post by **bmdubya1198** » 18 Sep 2016, 09:24

Yes, vacuum/boost leaks will cause fuel mixture problems.

Post by **pvfjr** » 19 Sep 2016, 11:12

I did some spraying with some ether, and didn't find anything. All the clamps are tight from what I can tell, but some aren't very easily accessible. I'm going to try to build a smoke tester tonight. I've got an EVAP code on our Silverado to troubleshoot anyway, so now I have two reasons to build one. I'll update with what I find.

Post by **pvfjr** » 19 Sep 2016, 23:45

As it turns out, I had both a vacuum leak and a misfire.

I used an improvised smoke tester and found a split in the underside of a hose. I fixed it, and the car ran better, but not good. It sounded like a half-way rhythmic miss this time, I listened to all the injectors with a stethescope, and they all sounded about the same. I hooked up a fuel pressure gauge just for kicks, and it held pretty steady at 55 psi. So I started messing with the coils. Unplugging coils 2 or 4 made the car run worse while it idled, but unplugging coil 3 did nothing. So I swapped coils 3 and 4, and the failure seemed to track with the coil. I also noticed the boot is cracked at the tip, so perhaps the spark is shorting to the head.

Does anyone know if the coils from a 2001 S40 would swap over to my 99 S70? If so, I could probably borrow one to see if it makes the car run better.

Post by **scot850** » 20 Sep 2016, 03:22

S40 coil from 2001 does not fit. Different shape and part numbers.

https://www.fcpeuro.com/Volvo-parts/S40 ... =20&page=1

https://www.fcpeuro.com/Volvo-parts/V70 ... 212&page=1

Neil.

Post by **bmdubya1198** » 20 Sep 2016, 07:03

It seems you've got a bad coil. Grab one at the junk yard if you want to test it again, they're only a couple bucks usually.

Post by **pvfjr** » 20 Sep 2016, 11:06

bmdubya1198 wrote:It seems you've got a bad coil. Grab one at the junk yard if you want to test it again, they're only a couple bucks usually.

Our local yards will only sell complete engines, and won't let you take any parts off them.

Very annoying.

I ordered one online, it should be here Thursday.

Post by **pvfjr** » 20 Sep 2016, 11:44

scot850 wrote:S40 coil from 2001 does not fit. Different shape and part numbers.

https://www.fcpeuro.com/Volvo-parts/S40 ... =20&page=1

https://www.fcpeuro.com/Volvo-parts/V70 ... 212&page=1

Neil.

Thanks, those are quite a bit different. I'll just have to wait till Thursday.

Post by **scot850** » 20 Sep 2016, 15:01

I wish you luck!

Neil.

Post by **pvfjr** » 23 Sep 2016, 09:49

So I replaced the bad coil, and the car started right up and ran smooth. I was reluctantly feeling hopeful for a few minutes, but my skepticism proved wise. It started warming up, and seemed to develop a barely detectable miss. Once fully warm, putting it in gear and letting it idle makes it run pretty rough, and it starts to shake a bit. Driving with a moderate to light load makes it smooth out just fine. Getting on the throttle makes it run pretty rough again, and will throw a P0301 misfire code (happened twice). So there seems to be a sweet spot with this thing.

The fuel trims started getting pretty high again. I got a new scanner, and it's saying the MAF is getting 7-8 g/s at idle. Is that a bit high? I'm starting to think I've got either a bad MAF or O2 that's providing a false lean condition to the computer, which overcompensates and bogs the engine down with extra fuel. What else can I do to verify this?