So ive been fitting witht the girls 01 v70 non turbo. it keeps getting a cyl 5 missfire code. ive tried replacing and swapping coils, new plugs, swapped injectors, compression was 170 across all cylinders, headgasket check was good. i no its got a bad j hose on the canister which is throwing a code and it also has a p0420 so i no it needs a manifold cat. I smoked tested the intake and found no intake leaks other then the j hose. need some sugestions for wat to try next. it has oe volvo plugs. i was thinking try a maf. i also threw in a coolant temp sensor as well.

checked the freeze data andthe code has been thrown only at idle when coolant temp is below 150 and less then 1000 rpm. map hg showed 13.9 which to me seems like a leak now is that j hose under vacuum? need suggestions

thanks
ed

 

Check for a lose ground strap. Replace the coolant temp sensor. Check ALL air induction hoses for leaks.

Let us know what hapens.
Greg

 

I smoke tested the intake system and has no intake leaks. I replaced the MAF and nothing changed. I only found 1 engine ground strap and it looks a little corroded gonna change that tomorrow. Is their more then one. I also said I changed the coolant temp sensor and that fixed the hard starting it was having. Gonna replace the split j hose this weekend as well. Can a p0455 gross leak no flow evap code cause a missfire. I believe im getting that from that split j hose.

 

ECU (unlikely)? Have you had anyone else run diagnostics? Have you performed a leak-down test? How does the car idle? What about when driving? Are you getting a code and no symptoms of a misfire? Or is there in fact, a misfire you can actually feel? Is it constant or intermittent? Have you checked wiring, connectors, and grounding straps? As you probably already know, extended misfiring runs unburned fuel thru the catalytic convertor and can ruin it.

 

No Leak Down Test since compression was ok. Car idles and Drives perfect. It just a missfire every now and then when its started then evens out. I changed the leaking j hose on the canister and the ground strap since it looked old and I cleared the light. So we will see what happens.

 

I changed the j hose and no change. Still only does it at idle but mo more p0455, checked he connectors for #5 coil and injector and both clean and no seperated wires. what are the symptoms of a bad purge valve? could it be a map or o2 sensor. can a clogged cat cause a miss on only 1 cylinder since i no the cat is bad. the car has a intake with a dry flow airfilter could that be causing the miss ill have to try puttig stock air box back in.

 

A bad MAF can cause misfire. But I am confused as to cyl #5 being the only one. What condition are the plugs in? How old? What gap? If unsure, replace them.

 

plugs are new ngk iridiums. the old ones had some white deposits on them. maybe its running lean.

 

I would swap the injectors from #2 & #5. When you do, make sure the injector seals are in good shape. A non direct part like MAF, fuel pump, seat belt latch, etc. will not disturb 1 cylinder.

 

I would do a leakdown test, its more telling than a compression test