[PandP]

I have had my focus 2L ESP (2000) for six months now. I was unsure on the car at first but now i love it, it has been superb. As it had no service history (or very little) i had the cambelt, pulleys etc done as well as a full service and new tyres. My family and i recently did a 500 mile round trip and it never skipped a beat.

Since buying it it has always had a slight issue with revs staying high when changing gear, mainly when cold. It also jolts a little when changing gear, again only when cold. There is a slight hesitation when going back on the gas, this i felt more so whilst doing the long motorway trip.

To try to cure this i replaced the TPS, that didn't do it so today i fitted a new MAF sensor, 6 miles from home and the car breaksdown. It has never broken down on me before. The car started to splutter then i lost all power and came to a stop. I couldn't get it start so i unplugged the new MAF and it started and got me home. It did splutter a couple of time though on the way back.

What could have caused this? The MAF is new from Eurocar parts. Was there anything i was supposed to do whilst fitting it? Would a dodgy MAF cause these symptoms? I filled up with petrol yesterday at the same place i always go and it drove back home fine. Would driving with the MAF unplugged cause a problem?

Sorry for all the questions guys i just want to sort this but unsure where to start.

 

[whynotthinkwhynot]

It sounds like they gave you the wrong part to me. What does ESP mean? Is your transmission an automatic?

 

[PandP]

I'm going to contact them but it looks exactly the same. ESP is electronic stability programme....so i'm told

 

[whynotthinkwhynot]

OK, well we usually recommend an ECU reset after MAF replacement. That could be it, but I don't remember it resulting in a complete fail like you experienced. Usually it doesn't run right.

All you need to do before returning the part is disconnect the neg battery terminal for 10 mins or so, reconnect, and start the engine without touching the gasoline. Allow the engine to idle for 6-7 mins. You might notice a slightly high idle in that time, but that is normal and will settle out when the ECU performs all it's tests. Do not touch the accelerator during this time. You will have codes- P1000- after this, but that will go away after some time. There are other tests that it performs while driving over 2 weeks or so.

 

[PandP]

Appreciate that i will give that a go when i go back out. I did debate on disconnecting the battery so will definitely do that. Thank you.

 

[PandP]

Battery disconnected, MAF connected, battery reconnected. Started the car, no gas and left it ticking over for over 6 minutes. I then turned it off, left it a few minutes, started it up, it sounded lumpy, revved it and it dropped near to stalling then picked back up. It did this a few times so maybe the MAF is not working?

 

[GhostTribute]

What is the part number on the top of the MAF, it should be the same as your old one. There are MAF sensors from V6 and V8 setups that look identical to the I4 MAFs. Only difference is the part number etched in the top.

For example;

3.0L V6 MAF - XF2F-12B579-AA
2.0L I4 MAF - XF3F-12B579-BA

These two MAF sensors look and mount identically but the calibrations inside are different.

 

[GhostTribute]

Also a note on the ECU reset.

Make sure all electrical circuits are off, lights, AC/Heater fan, defrost etc..etc..

Let the car idle for 5-10 minutes without touching the gas or brake pedals. Then take the car out for a quick stop and go drive and a blast on the highway. This will help the ECU reset properly.

If the car stalls out during this process, there is an issue somewhere in the metering.

 

[PandP]

There is no number etched in the top. The maf is an aftermarket part made by HAAS. None of the numbers on the box match up to my maf either.

I have removed the part and already my car seems to run better, doesn't try to stall after revving.

I have written to the company requesting a return so the options i have are either, put up with the slight hesitation (because a new maf may not cure it anyway), or return the maf for another ensuring that they check it is for my vehicle, or, pay the extra for the genuine part.

 

[GhostTribute]

So have you done any troubleshooting of your original MAF or have you just been assuming the issue and replacing parts to see if it works?

Is your check engine light on? Have you checked for any stored diagnostic codes?

 

[PandP]

To be honest i haven't done any trouble shooting, i have just aimed at those sensors i felt could affect it. I replaced the TPS and then went for the maf. I have never had an engine management light on. As the driver i feel when it plays up, maybe i should just accept it's not a new car and just put up with the slight hesitation.

Like i say i felt it more doing motorways. If i came off the gas for example at 70mph, when i start to apply gas again i almost get nothing then a little burst that you can feel. Almost feels like you are jerking the car.

Like i say i'm probably being too choosy for a car that's now 14 years old.

 

[GhostTribute]

How about regular maintenance?

Spark plugs, wires, test the coil.
MAF cleaning, air filter replacement/cleaning
PCV valve replacement/cleaning...

Have you done any regular maintenance lately?

 

[PandP]

The car had a major service only around 3 months ago. The garage which i have known for years went over it and pointed out all the new parts that had been fitted.

Which is the PCV? is that the IACV?

 

[GhostTribute]

PCV - Positive crankcase ventilation system.

There is a valve and hose located on the front of the engine block that blowby gases from the crankcase are sucked back into the intake manifold. Sometimes this valve can get clogged or the hoses will collapse and cause driveability issues.

IAC - Idle Air Control system.
Sometimes the IAC valve can get clogged up with oil/sludge and cause some issues. The issues with the IACV are usually more prevalent at idle, not so much while driving.

 

[PandP]

That does ring a bell with regards to the pipe. I am certain i read somewhere before about checking it for leaks.

So is this pipe behind the manifold, i take it is difficult to get to?

Sorry for all the questions but it would be good to check this just to see it's condition.

 

[reidk]

Here's a good thread about the PCV hose: http://www.focusfanatics.com/forum/showthread.php?t=190218
Some good pics here: http://www.focusfanatics.com/forum/showthread.php?t=251321

I'm surprised no one has said this, but a certain amount of this behavior (the revving, not the sputtering) is normal. It's actually caused deliberately by the computer, and the only way to be completely rid of it is to get a "tune" (computer re-programming). Do a search for "hanging revs" or "rev hang" and you'll find a lot of info. Since you described this as a "slight issue", it's possible that there was nothing for you to fix in the first place. (Sorry!)

Reid

 

[PandP]

Hi Reid,

Thanks for the link. Yes i think you could be right with regards to trying to fix something that isn't there. I did a 50 mile round trip today with my old MAF on and it ran fine. Yes i still got the slight hesitation now and again but everything else is fine. The new MAF is being sent back for a refund although thay want to investigate my findings first. Clearly the MAF is either broken or it's the wrong one or it would not have stalled my car on the busiest roundabout possible.

 

[reidk]

Glad to hear you've got it under control!

Reid

 

[PandP]

I will check the PCV hose tomorrow. Looks like a pretty common replacement part. Thanks for everyone's input with this, very much appreciated.