1997 Volvo V40, very rough idle at start up. No normal engine performance until warm

Hershey

Hello Everyone

I am in Melbourne and have a 1997 Volvo V40 Wagon

I have been trying to locate the Mass Airflow Sensor in my car.

On the web and YouTube, people point to a unit which is located just after the Air intake box. However, my air intake box and rubber hose does not house such a unit the unit. I have taken the Air intake rubber housing and the the Filter box unit off and the MAF is NOWHERE TO BE FOUND

At lease there is no filter which is described on Ebay as a 1997 V40 replacement (see pic)

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This ebay sensor is $544.95, which seems absurd.

Can anybody help with this mystery

Hershey from Melbourne

Ex850R

Pix of your engine bay?

Hershey

Ex850R
Pix of your engine bay?

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Hi Snoopy

Here is the pic of me engine bay...!!!!

Hershey

timbo

Why are you chasing the maf sensor? Your car may just run a map sensor up on the firewall.

Hershey

Hi Tim

Thanks man

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My Haynes manual is obviously not for Oz, so no joy there I didn't know about the map sensor Don't know where the map sensor on the back fire wall is Have attached a pic

timbo

Hershey
Hi Tim
Thanks man
https://cdn.ozvolvo.org/uploads/T21HGOT6KJQI/20230324-140934.jpg
My Haynes manual is obviously not for Oz, so no joy there I didn't know about the map sensor Don't know where the map sensor on the back fire wall is Have attached a pic

That plastic cover lifts off and there's a map sensor under there part number should be 31303211.

The map sensor is pretty robust though so if your chasing engine codes for fuel mixture it's more likely going to be a vacuum leak/PCV faulty/fuel pressure regulator/fuel pump.

Hershey

timbo
https://ozvolvo.org/discussion/comment/216758#Comment_216758
That plastic cover lifts off and there's a map sensor under there part number should be 31303211.
The map sensor is pretty robust though so if your chasing engine codes for fuel mixture it's more likely going to be a vacuum leak/PCV faulty/fuel pressure regulator/fuel pump.

Sorry for being a newbie

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,but is this pic attached where that cover lifts off on the back firewall. Is that the one ya talking about ?

nh2868

Just to add to Tim's comments: Fuel injected engines fall into 2 broad categories, MAF sensor and "Speed-Density"...or sometimes both. MAF equipped engines measure the amount of air flowing through the sensor, usually by measuring the current required to maintain a heated wire at a constant temperature. They usually have a inlet air temperature sensor built in the same unit. Speed-density engines estimate the mass of air flowing in by measuring the inlet air temperature, engine speed and engine vacuum (MAP = manifold air pressure). Speed-density is virtually an electrified version of what the carburettor used to do.

What problem are you chasing ?

Hershey

Hi Staggers

When my engine starts it is sluggish, like it has no fuel or air, and it is hard to accelerate, BUT ONLY IN THE FIRST TEN MINUTES from start up. However, after about ten to fifteen minutes, the engine runs as if it is finally tuned, and accelerations is as smooth and responsive as it should be.

nh2868

Yes it's the long black cover just below the Volvo ID plate in your photo, but I doubt very much there's anything wring with the MAP sensor.

During cold start, the engine runs in "open loop" mode - it estimates the amount of fuel to inject based on throttle position, MAP value, engine speed and ECT - Engine coolant temperature. Of these, the ECT is a well known common failure item on the 4 cylinder engines - and a pig to get to from memory...behind the thermostat housing I recall. If the ECT sensor is reading incorrectly, the computer could think you're in the sahara or the arctic circle - and the fuel it delivers will be way off what the engine needs. Once the engine gets to temperature (after a few minutes) the engine goes into "closed loop" where the mixture going out the exhaust is measured for oxygen content and the computer can compensate for a faulty temperature reading. Just a guess at what may be going on. Another known fault is the fuel pressure regulator diaphragm leaking - take off the rubber vacuum hose (the thin one) with the engine running and see if there's any fuel in the vacuum side. Our 2003 S40 had both of these faults around 100,000km... I also recall that the ECT sensor isn't the same as the temperature gauge in the instruments - it can seem normal but still use the wrong temperature for fuel management...you need to have a scan gauge plugged in to the OBD2 port to pick up the difference.

johna

Don't think an early 1997 model has OBD2, right? You can get a cheap cable of eBay and download VOL-FCR software to read codes.

Hershey

Hi Johna

I am not sure if my 1997 Volvo V40 wagon has OBD2. Whats more I can't even find the outlet port for the diagnostics at all.

Can't find anything on my Haynes manual and did a google search and on the OBD2 website my 1997 Volvo is definitely not listed.

In any case I still have the start up issues, and despite taking my car to two European service centres they have not been able to help me. One Volvo service centre saying they would charge me $120 to look at my car but could not guarantee they could find the parts if need to fix the issue. I took my car to them and they had it for two days and did nothing, no testing nothing.

johna

No OBD2 on early models. I believe the diagnostic port is located in the footwell by the centre console. There is some software called VOL-FCR you can use for the early models. Then you can get a cheap VAG COM KKL cable from eBay.

timbo

@Hershey your spoilt for choice of Volvo specialists in Melbourne, take it to masons prestige, voldat or berry motor group they will all be able to diagnose/sort out the issue and source parts for it easily

Hershey

Thanks Tim

All the garages you mentioned are many k's from me as I live in the outer western suburbs. Do you think I should just bight the bullet and go to Volvo in Port Melbourne as they are a lot closer. In any case, I have to get onto this issue as my 1997 Volvo V40 has only done 250,000 k's and the engine has no oil leaks.

Hershey

Ex850R

Midas in Yarraville know Volvo's.

Swedish Prestige is in Tullamarine.

Volvo Port Melbourne will charge double the hourly rate and don't actually know the old cars ..

Ex850R

Also Seal Motors Airport West Paul is old skool Volvo mechanic

Hershey

Yes I agree about Volvo

but thanks for Paul @ Seal Motors :)