1998 V70 T5 Wagon low fuel pressure

redt5 · Post by **redt5** » 17 Sep 2015, 16:07

Hope you can help. I believe I have a low fuel pressure issue. In the mornings I have to turn the key and let the car crank over a few times. I then wait a few minutes, turn the key and it starts but need to feather the gas pedal for a minutes before it will idle on it's own. The condition is worse in colder weather ( 65 degrees or below ), need to repeat the steps above several times before it will idle. There is also a slight hesitation during acceleration. I have replaced the fuel filter, acceleration hesitation is less but problem still persist.

Post by **FLXC90** » 17 Sep 2015, 16:40

OK, let's start at the start. When was last tune-up done? Fuel Filter change? Air Filter change?

If you feather the throttle will the engine rev? It sounds more like air than fuel to me. Once the car is up to temp and idling, does it stall or stumble beyond the hesitation on initial throttle application?

Do you have any codes/check engine light?

Check condition and connections to your MAF (connector on air cleaner hose), Idle Air control Valve, also unplug your ECT engine coolant temp sensor at the front right of the motor on a first start of the day and see if things change. Don't leave it disconnected, only for the test.

redt5 · Post by **redt5** » 17 Sep 2015, 21:55

Fuel filter and air filter are 2 days old

Engine does rev when throttle is feathered

Once up to temp, no stall or stumble

no check engine light

Connections to MAF are clean and tight, MAF replaced 1 1/2 years ago

Will unplug the ECT tomorrow am at start up and let you know

Thanks for the tip

Post by **abscate** » 18 Sep 2015, 05:16

Get that IAC valve off for a cleaning. Doubtful it is a fuel delivery issue

redt5 · Post by **redt5** » 18 Sep 2015, 15:37

Thanks for the tip on the IAC. Will clean it and get back to you.

Thanks!

Post by **FLXC90** » 19 Sep 2015, 14:46

Okay, you say the air filter is/was 2 days old, check all the vacuum connections and lines on the airbox, make sure everything went back okay. Make sure the big air inlet hose is clamped securely, any air leaking in downstream of the MAF (closer to the engine) will cause these symptoms.

Post by **abscate** » 19 Sep 2015, 20:05

You can measure the fuel pressure at the valve on the fuel rail with a cheap pencil style tire gauge...throw away afterwards

redt5 · Post by **redt5** » 25 Sep 2015, 12:03

I checked the IAC, found a crack in one hose. I ordered both hose's online. Should have them next week. Did my best to duct tape for now. Idle improved a bit. I will let you know what happens after I clean the IAC and install the new hose's