Choking Engine

janwolff79 · Post by **janwolff79** » 30 Apr 2010, 06:34

When i start my volvo 850 2.5 20v n reg the engine sounds like its struggling (choking) and all of sudden ther is a burst of power. but after that initial choke the car drives fine. it only happens after i start the engine (cold or warm)
Is there anyone that could help me please.

Post by **jblackburn** » 30 Apr 2010, 07:23

Do you burn a lot of oil/does it smoke out the tailpipe when this happens?

There are other possibilities, a purge valve for the EVAP system or a bad coolant temperature sensor.

janwolff79 · Post by **janwolff79** » 30 Apr 2010, 11:32

No it dosent burn oil and no smoke. If i hold the revs at about 25000 rpm while driveing it chudders and hesitates then all the Thanks for relplying.

janwolff79 · Post by **janwolff79** » 30 Apr 2010, 11:35

I will finish off now lol.
All the power kicks in its like ive floored it.Its then fine until i start the car again.

Post by **phils94850** » 30 Apr 2010, 11:42

jan... how long has it been since the car has had a basic tune up ? do you have a check engine light on ? if so, we need to know the codes. how many miles on the car ?

janwolff79 · Post by **janwolff79** » 30 Apr 2010, 11:55

Hi ive owned the car for 1 year .The garage serviced it . I have also serviced it Oil,Oil filter,Sparkplugs,Airfilter. about 1 month ago. Refine basic tune up please . The car has been doing this for 2months now thats why i did the service. its got 103000 miles. There is a exlamation mark light on but i think thas low brake fluid.

Post by **jblackburn** » 30 Apr 2010, 12:11

Try this:

https://www.matthewsvolvosite.com/forums ... &mode=view

Disconnect that hose in the picture highlighted in red, and drive around for a little bit and see if the same thing happens.

Ignore the other blue arrow about the vacuum lines, I stole the picture from something else I did.

Do not leave it disconnected for longer than that - you might get an error code as it is, but you can easily reset it.

That's an EVAP canister hose, if the purge valve isn't working correctly, it will flood the engine with fumes at a start.

Post by **phils94850** » 30 Apr 2010, 12:23

if what jablackburn says doesnt fix it, you can try unplugging your MAF sensor and see if it runs better. If it does, then you can buy some MAF cleaner and try cleaning it or you may have to replace it.

Post by **jblackburn** » 01 May 2010, 09:35

I saw your email, but every time I try to hit send, Outlook crashes. So you'll either get that about 12 times, or not at all. I <3 my computer.

Hi thanks for helping. the car does respond better after startup with the pipe removed.What could the solution be? What is causing the problem? is ita home fix?
Thanks again
Jan

Wow, lucky guess! Your problem, then, is a bad purge valve. As I mentioned before, it's flooding the intake with fumes from the charcoal EVAP canister at a start and causing the car to bog down.

http://www.fcpgroton.com/product-exec/p ... urge+Valve

This is the part for a US car. You're in England, so if you want to send me your VIN number, I can double-check that it's the right part for yours too.

It's located here on my car, yours might be different, but you can follow that system of black hoses back to the valve.

Post by **jmmxc** » 01 May 2010, 16:16

Hi to you all.
I am curious about this fix. My engine would start and idle fine (rpm is about 980~1000). Now, for the last few days, when the car idles after a stop, the engine would slightly pulse and would loose its power. I can feel when the engine is about to quit. And when it does it gives a quick shudder and go off. After that it would start again...good idle, and the next day I would get a rough start with some smoke and the engine would be OK.
Could it be a problem similar as achoking engine? Can this fix be used to diagnose the situation?
Your comments would be appreciated.
Thanks,
jmmxc
Volve 850 GlT, 1996
≈140K, (broken speedo)
spark plugs and wires and cap changed 12/09