Inconsistent rough ride

byrnzy · 27-05-2014, 12:06 PM

Hi All

just wondering if anyone has had anything similar to the weird issue i am about to describe to you all. I have a 2007 MA Zetec, 2.3ltr 6 speed auto.

Over the last 2 years on approx 5 times the following scenario has occurred. The car would be at speed and all of a sudden a violent shudder will occur. Its hard to describe, but it is like the car is about to stall or is having a serious cough. On one occasion the car has stalled while doing a 3 point turn and it has taken a few tries to get it to kick over again.

Now, on each of these times the following items have had to occur.

1. The car must be full , with less then 20 kms driven since the tank was full. It has only ever had 98 Octane and it is 99% of the time Caltex.
2. The day must be warmish, ie Sydney 25 - 30 degrees or above
3. And the car must be parked on a hill with its nose in the air for some period of time , more then an hour or 2.

On one occasion, i was able to let the car idle in my garage when this situation occurred. The revs would drop, and it stalled once. After letting it idle for a while the problem went away, but that is once the fuel gauge had moved slightly.

The other night it was doing the same issue, approx 15 kms since the tank was last filled. Knocked it into Sports mode, and it played up in 3rd gear more then any other gear, but the revs never dropped. After a few more kms the car comes good and it is fine.

I know it sounds weird, but has anyone had anything remotely similar to this

thanks

cobrin · 31-05-2014, 09:19 PM

You may have more than one issue going on here so you'll have to diagnose what you can and eliminate areas as you go.

There's a few area's you can look at yourself if you think you can:

MAF SENSOR:
Clean the Mass Air Flow (MAF) sensor (with a can of MAF cleaner), not too close and don't touch or scrub it physically, let the product do it's job. Refit and test. Unless your vehicle uses a MAP sensor.

VACUUM LEAK:
Clean the throttle body butterfly with the same MAF cleaner, a lint free cloth and wipe the internal body and butterfly, just be careful you don't spray directly past the throttle butterfly cause the engine will start and run away initially when you do start it.

Again use the MAF cleaner, but with the engine running do a spot spray (short sharp spray) on the vacuum hoses at their connections. This is to look for a vacuum leak and if there is one the engine idle speed will increase momentarily, that's your source of a leak.

EGR valve clean and make sure the valve is connected and sealed appropriately.
Then there's the Idle speed control valve (or what your engine has).

IDLE SPEED CONTROL VALVE:
This you'll have to locate and check, they usually get dirty and the valve gets a bit sticky and doesn't regulate the idle speed. May lose some coolant as it's there to aid cold start higher rpm to bring the engine up to operating temp. Probably a Mechanics job.

When was the last time the fuel filter was changed? a restricted filter can give these symptoms too.

Coil packs/coil on plugs which ever you have could be failing. Physical condition and winding resistances will help.

Sparkplugs clean and gap OK?

Battery condition good?

That should keep you busy...

cobrin · 02-06-2014, 01:59 AM

Also forgot about a cam sensor or crank angle sensor.

byrnzy · 30-06-2014, 07:45 AM

Thanks for your response Cobrin.

I have not had a chance to do any of what you have suggested, due to both time and a heavy lack of ability, however the issue has once again risen over the weekend.

Car was parked on driveway with nose slightly higher then rear, very full (2.6kms since the fill occurred). It was parked in Sydney on Saturday, in full sun. Day was not overly warm. Car was stationary for approx 8 hours.

Come home to find a rather large puddle under the rear of my car. Probably just over a meter in diameter. Upon inspection it was fuel. Looked under car (once there was nothing ignitable around me) there was a large consistant drip of fuel from what appears to be a release valve / tube. Called NRMA, placed bucket under leak. Approx nearly a litre of fuel was captured in the bucket in 15 minutes till NRMA arrived.

NRMA had a look, first thing he said was open the fuel cap. I really dont understand why they have designed the fuel tank how they have, but explained to the NRMA person that it can not be done. Found in manual reference to fuel adapter that can be used with filling from Jerry can, opened up rear, but the adaptor was not there. Perks of buying the car dealer used i suspect. If anyone has a suggestion on where one of these can be purchased, it would be much appreciated.

Hosed down drive, and started car based on NRMA recommendation. Car started with no issue, and fuel leak ceased instantly. Drove car for a while to reduce amount of fuel in tank, and rough ride was once again there.

Once car had 15 kms on it, it has not missed a beat.

Wife ensures me that she is only filling it to the first click. Now she did fill the car just after 6 am on that day, so in theory the fuel could have been cold, therefore smaller in volume, and this could have expanded during the day. But what concerned me the most was the amount of fuel coming out of the car. Someone could have had a cigarette just walking past my house, and i could be typing a very different story today.

Does this sound normal for one, and does anyone have some detailed knowledge of how the fuel tank should react when over pressurisation occurs? Plan on taking it to mechanic today, will update if anything of interest occurs.

thanks

cobrin · 30-06-2014, 10:18 AM

Quote:

opened up rear, but the adaptor was not there

yeah that will have to come from Ford, or ebay OS. I bought a Mondeo in April and had a few questions, one of them was that funnel, the salesperson said it was there. On inspection indeed it was but it was new still in a sealed bag, I believe he had gotten one and put it in as it wasn't there. Got lucky on that call....

I get diesel a smell when filled and parked in the garage days after, no leaks but you can smell it.

well if you've got no issues when it's not "full" per se I'd be looking into the fuel pump/area...

byrnzy · 30-06-2014, 01:33 PM

Hi All

just spoke the the mechanic. Fuel tank and charcoal canister have been removed. Charcoal canister being shipped from Melbourne and will be fitted tomorrow.

So hopefully that is all it is, been quoted 300 - 350 for the work, but will wait to see if final invoice is any different.

Got to love those European Fords.

byrnzy · 11-07-2014, 07:43 AM

Car continued to play up with new charcoal canister. Was able to get it to mechanic while still playing up and fuel had leaked into canister, and was being sucked back into engine, so making it run rich, like a choke had been on.

New fuel tank installed yesterday. Car was re-fueled and left at a rather large incline for a few hours in the sun. No leaking occurred, so lets hope that was it.

There are 3 lines coming out of the tank, one to the engine and the other 2 are on opposite corners and they hook up to a common line that goes into the canister. Current thoughts is that one of these lines must have a faulty valve, that is deteriorating more over time, as the problem was becoming more consistent.