2001 XC70 Rough to No Idle after Trans Change

heyanderson · Post by **heyanderson** » 30 Sep 2014, 18:53

First post so let me know what is wrong? I just removed and swapped another stock transmission in my 01 XC70 and when I started it up it spikes from 500-1000 RPM and then dies after a couple of attempts at an ugly idle. When out of the car I removed the ETM and cleaned out with throttle body cleaner as I had read in a couple of threads about smoothing out the idle. When I first started the car I got a couple of misfire codes like P0301, P0305 so I pulled the coils and felt dumb for not checking the plugs so I changed them all with NGK iridiums. Also relaced #1 coil boot with a spare as it was ripped. Also had oil in #2 but cleaned out before plug removal and have replaced oil fill gasket. Now still idles the same but no codes? I replaced gasket and swapped to another ETM spare although white #346 rather than the original yellow #347 but runs the same. I had swapped the cat with the one that I took the trans and EMT from as mine was throwing codes before the trans swap and I was hoping that it may be better but now I am looking at it as possible cause? I am getting good at swapping the EMT but dont think that is what it is? Any help may keep me sane, thanks Steve

Post by **abscate** » 01 Oct 2014, 07:16

The lore here is Volvo plugs only for turbo models, and I think Iridiums are definitely known to give running problems. Ymmv. Did you replace the coils on the indicated cylinders? Misfire cylinder codes can be slow to show up, so don't take the no-code condition to be definitive for solution on coils/plugs yet.

draser · Post by **draser** » 01 Oct 2014, 12:31

Just to throw a wrench in the mix.. been running NGK Iridiums on mine for the last 20k miles.. smooth operator. But my question is.. what changed before and after tranny swap? Was it running okay before? It sounds like it's cascading into multiple issues..

heyanderson · Post by **heyanderson** » 01 Oct 2014, 18:07

Thanks guys, but yes it was running fine175k but strong engine. Trans was good if you drove it like you stole it but if you got into traffic and drove nice it would miss shift around 1400RPM and clank so out it came. Dropped the engine to not fight the install. Had Denso 1020 iridium's in the car when I changed so put the NGK equivalent in. Replaced coil on #1 and boot on #2 but the rest stayed. Figured codes were the plugs as there was nothing prior to swap. Changed the cat hoping that it was better than mine which was throwing P0422 before the swap. But I can not get any codes that say that the swapped cat could cause erratic idle? Not to further complicate this but I did take the opportunity while the engine was out of the car to do the timing belt, water pump, and roller. Yes I have the marks on the cams and crank in sync. Checked it so many times I am going blind.

draser · Post by **draser** » 02 Oct 2014, 13:26

All air and vac lines clamped and tight?

Post by **precopster** » 02 Oct 2014, 15:36

Since you were asking it would be nice to see some paragraphs splitting up your points.

If I were faultfinding this I'd put the original ETM back on and check and recheck vacuum lines.

Check all coil pack boots for white powder marks on end of the internal tube. It is VERY EASY to mix up the coil packs and get what you're getting.

I have NGK copper single electrode V grooves in my 2002 XC70 and runs fine.

heyanderson · Post by **heyanderson** » 03 Oct 2014, 20:28

Thanks for the advice on the paragraphs, will do next time.

I may get back to replacing the EMT again with the original but I can assure you that I have checked the vacum lines again and again.

Coil pack boots sounds good but what do you mean about mixing them up? I thought that they were all the same and it did not matter if i was to take one from #1 and swap it with #3 even heard of doing it to verify a misfire code? Or are you talking about the loom plugged into the wrong coil? I can double check tomorrow but the length of wires and bends dictate pretty well which coil should go where although I did redo the loom in the engine as Volvo seems to either use poor loom or not disipate the engine compartment heat very well.

Checking the ends of the boot where the plug connects or inside where the spring is conected to the actual coil?

Thanks again for the help as I am still baffled.

Post by **precopster** » 03 Oct 2014, 22:19

I meant swapping the coil positions because the wiring to coil packs can reach the wrong cylinder.

Post by **abscate** » 04 Oct 2014, 03:53

Make sure you get the coils bolted down firmly because the screw is the ground connection for the. Coils.

The contact area should be clean and dry from oil residue

draser · Post by **draser** » 04 Oct 2014, 12:15

Just caught that... If you reworked the wire harness for coils please 2 and 3-ple chech wiring again - against a wiring diagram. I am an EE myself and I can't recall how many times I was covinced I wired some project correctly only to discover lately that I swapped 2 wires...