1998 V70 Hesitation and weak airflow

ukdido · Post by **ukdido** » 25 May 2014, 07:40

Hi everyone.My first post here, I need help. As above my car V70 170bhp non turbo has small value of engine load also weak airflow (as you see my data from obd).I did change Maf, Throtlle sensor,Fuel regulator, Lambda sensor ,all ignition kit and car still drive with lack of performance.My catalyst seems to be ok .I have no idea ,what causing my problem .Just find some of data - Calculated Engine Load(%) 90.98 max 10.58 min. Any idea guys?

Post by **precopster** » 25 May 2014, 08:20

Weak airflow suggests a leak (vacuum) or poor compression.

Start with a compression test.

ukdido · Post by **ukdido** » 25 May 2014, 08:30

Thanks for respond.My compresion was good ,about 207 psi each cylinder.I did block evap and pipe to brake buster but no change. Oring on injectors was replaced, manifold gasket and TB gasket.Checking everywhere for leak, find nothing.At idlle vacum is 20hg which is good.

Post by **precopster** » 25 May 2014, 15:37

Ok are you experiencing symptoms or are you just concerned with those diagnosric figures? Any codes?

ukdido · Post by **ukdido** » 26 May 2014, 01:31

No codes,never. Car does not accelerate properly ,lack of power,bit noisy .One garage told me slugish injectors for some reason.Car is not turbocharger,but I should feel 170bhp (I'm not towing caravan yet

) ?

Post by **jreed** » 26 May 2014, 05:06

Just checking a basic item here... the ignition kit that you mentioned in the first post: what brand of ignition wires, distributor cap & rotor and spark plugs did you install?

Post by **precopster** » 26 May 2014, 06:14

Another thing to try. Have you seen/checked the hot air flap in the air cleaner box? They often stick open and draw hot air from the alloy conduit or from the engine bay if the conduit is missing.

Hot air from the engine bay and exhaust manifold robs horses from these non turbo engines.

Does your OBD II tool show intake air temperature?

With spark plugs the 3 prong OEMs are best however NGK make a compatible plug with 3 prongs as well.

ukdido · Post by **ukdido** » 26 May 2014, 07:35

Air box was blocked and spark are genuine from Volvo garage.Biggest issue rpm go slowly up to 3k(take ages),I dont know why. From 3k seems to be better.Fuel pressure ok but I need to check voltage under relay.Obd scan showing low engine calculated load,but no leak nowhere.Could be auto transmision causing problem?
Just find topic about knock sensor https://www.matthewsvolvosite.com/forums ... =1&t=22612

ukdido · Post by **ukdido** » 26 May 2014, 10:11

Test done. Disconected plug from knock sensor,drove 20 miles no codes,nothing change .

Post by **precopster** » 26 May 2014, 15:47

There are 2 knock sensors on a '98

If low speed progress is bad then picks up at higher revs I'd revisit the injectors. Have you run any sort of cleaner through the fuel system?