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P0305 Code (misfire code) Topic is solved

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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adbalt
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P0305 Code (misfire code)

Post by adbalt » Fri Jan 08, 2016 8:37 am

98 Volvo S70 GLT. Code reader throws a P0305 code. Car drives fine but gets a little rough when you slow to a stop. Any ideas on what causes this code? Recently replaced the MAF and that code cleared and it does run a little better. Thanks



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abscate
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Re: P0305 Code (misfire code)

Post by abscate » Fri Jan 08, 2016 9:14 am

Lift the plastic lid (tor bolts) and look in the spark plug holes for oil and water. Then pull plug and insspect. Get ready to test compression in #3 cylinder too.

When were plugs rotor cap and wires last replaced??

On edit..misread code, cylinder # 5 potential problem


Empty Nester
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adbalt
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Re: P0305 Code (misfire code)

Post by adbalt » Fri Jan 08, 2016 9:26 am

I got the car with 250,000+ miles on it and it was neglected. I've been using it to learn on as I have never been mechanically inclined. I recntly changed the PCV, and the MAF but still runs a bit rough at slow/stop. I have no idea when the plugs and wires were changed bu they do not look stock. Probably a stupid question but how do you test compression? Thanks



Herb Goltz
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Re: P0305 Code (misfire code)

Post by Herb Goltz » Fri Jan 08, 2016 9:30 am

P0305 is a misfire on cylinder 5 (closest to the transmission). Plug, wire and distributor cap are all suspects-- if they are ruled out, then a compression test is in order.

Good luck!



adbalt
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Re: P0305 Code (misfire code)

Post by adbalt » Fri Jan 08, 2016 9:33 am

Cool Thanks for your help



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erikv11
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Re: P0305 Code (misfire code)

Post by erikv11 » Fri Jan 08, 2016 10:11 am

You check compression with a gauge, you can "rent" one for free at Autozone etc.

http://www.popularmechanics.com/cars/ho ... -14912158/

Some key points:
- engine must be warm
- throttle should be wide open, floor the pedal while you crank it
- I also pull the fuel pump fuse and unplug the coil wire
- crank it until the gauge stops climbing, usually like 5-8 cycles of the engine


'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 140k
'98 S70 NA, 210k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 280k
'06 S60 R, 160k
gone: '96 NA 850 210k, '98 NA V70 182k

obayha
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Re: P0305 Code (misfire code)

Post by obayha » Fri Jan 08, 2016 10:27 am

I pulled cap and wires from my '98 before in got scrapped. They are not very old and are yours for the shipping, if you want to try and get out cheap on a fix. Mine was a '98 V70 T5, so I think they would work on yours.
Do a compression check. I usually pull all plugs and turn off fuel pump.
Two people work best on some things.
Shane


1998 V70 T5 331,000 :( Her last day was on 3 cylinders.
New to me 1999 V70 NA 163,000 Now at 217,000
2006 V70 2.5T in driveway (WIFE'S)
1982 Toyota FJ40 Land Cruiser

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FLXC90
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Re: P0305 Code (misfire code)

Post by FLXC90 » Fri Jan 08, 2016 1:50 pm

Welcome to MVS-you'll find all the information you need here. Since this is a practice car, and not your daily driver, take the time and fix things right. Shane's offer sounds like a great way to get started-cheap. Read the threads on Stage zero-ing your car. I bought my 98 S70 (225k miles) for $300 two years ago, put about $600 in it in parts, including initial fluid changes, and that's been it. It still needs some things, but it starts every day on the first try, and is drop-dead reliable.

As mentioned, your 0305 code says your #5 cylinder is misfiring. pull the plug and check it, also pull the distributor cap and check the contacts, you might be able to clean them and get by until you replace them.

When you pull the distributor cap, look for oil leaking behind the rotor, common for the seal to come loose, cheap easy fix, but leads to next task, check PCV. Look at threads or RSPI's youtube videos on glove test and PCV cleaning and repair.


Current Volvos:
1998 V70 T5, 112k sat 5 years, still in mechanical coma (finally at the top of the pile )
2004 XC90 T6 AWD: 186k, 60 on transaxle ( traded in )
1998 POS70 N/A: DD/training aid, 236k but really about 240k, I think...ABS module( passed on to son who sold it)

adbalt
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Re: P0305 Code (misfire code)

Post by adbalt » Sat Jan 09, 2016 5:07 pm

Thanks Oba and FLX. I just checked the plugs and pulled the wires while it was running and 2 of the wires did not arc so I take it that means wires are bad for starters. Also one of the plug wells had a lot of oil in it. I'm sure that cannot be good. What would that be a sign of? and how difficult a fix? Starting to think it may be a bit more than I can do.

Thanks



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Re: P0305 Code (misfire code)

Post by erikv11 » Sat Jan 09, 2016 7:18 pm

The oil in the plug hole(s) could be minor, the most common cause of that is a leaky PCV hose, the one that connects under the plastic plug wire cover. Is there a fair bit of oil up there, on the cam cover? Also, a leaky oil can cap lead to the same thing.


'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 140k
'98 S70 NA, 210k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 280k
'06 S60 R, 160k
gone: '96 NA 850 210k, '98 NA V70 182k

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