Rough idle after filling up

**fitdrive** · May 8th, 2013 07:50 AM

Guys, id like to ask for comments / reactions regarding our Ford suv.

It has rough idle / vibrations only when car as at stop or idle, but once i step on accelerator, no problems. No lag or power loss.

I already changed the fuel filter. Before, the fuel filter was changed, mas grabe ang rough idling. So I assumed it was dirty gasoline. Now, we had 3 refills of Petron Blaze. No more ethanol muna,

The rough idling subsided but meron pa din. And usually it happens pagka puno ng fuel tank at least 1st half, but when the gauge enters less than half, wala na yun rough idle hanggat mag-empty ang fuel tank, and then after full tank ulit, andun na naman.

I had it obd scanned (generic scanner, not Ford), during rough idling no Error Codes. Ang napansin ko lang during rough idle, sobrang amoy gasolina sa labas, at times it smells like burning rubber. I figure it maybe the emission sensors, like for example 02 sensors, pero no error codes. Pero yun nga parang the engine is running rich pag may rough idle, at medyo bagsak ang FC niya.

And here's one more thing, pag ayaw tumigil ang rough idle, i just remove the battery to force the system to reset the ECU. For 2 days, ookey sya, then balik sya ulit, basta whenever th gas tank is more than half full.

Sobrang gulo na po, pero ang labo talaga. Im planning to do an ecu reflash soon. Di kaya ecu na ito, corrupted or something.

Other things that planning to do before the reflash: (mahal kse

- Clean IAC valves
- Clean fuel injectors

**jick.cejoco** · May 8th, 2013 07:58 AM

Originally Posted by fitdrive

Guys, id like to ask for comments / reactions regarding our Ford suv.

It has rough idle / vibrations only when car as at stop or idle, but once i step on accelerator, no problems. No lag or power loss.

I already changed the fuel filter. Before, the fuel filter was changed, mas grabe ang rough idling. So I assumed it was dirty gasoline. Now, we had 3 refills of Petron Blaze. No more ethanol muna,

The rough idling subsided but meron pa din. And usually it happens pagka puno ng fuel tank at least 1st half, but when the gauge enters less than half, wala na yun rough idle hanggat mag-empty ang fuel tank, and then after full tank ulit, andun na naman.

I had it obd scanned (generic scanner, not Ford), during rough idling no Error Codes. Ang napansin ko lang during rough idle, sobrang amoy gasolina sa labas, at times it smells like burning rubber. I figure it maybe the emission sensors, like for example 02 sensors, pero no error codes. Pero yun nga parang the engine is running rich pag may rough idle, at medyo bagsak ang FC niya.

And here's one more thing, pag ayaw tumigil ang rough idle, i just remove the battery to force the system to reset the ECU. For 2 days, ookey sya, then balik sya ulit, basta whenever th gas tank is more than half full.

Sobrang gulo na po, pero ang labo talaga. Im planning to do an ecu reflash soon. Di kaya ecu na ito, corrupted or something.

Other things that planning to do before the reflash: (mahal kse

- Clean IAC valves
- Clean fuel injectors

have the evaporative emission systems checked. your charcoal canister might be overloaded (saturated with liquid gasoline. this usually triggers a DTC P0440-failed evaporative emissions system

**fitdrive** · May 8th, 2013 04:08 PM

Thanks boss. That's new to me: charcoal canister. I'll have it checked kse suspetsa ko talaga sa emission na. It's sending in the wrong data to the ecu, and therefore air/fuel ratio mix vslue na send ng ecu sa engine, mali.

**t2erns** · May 9th, 2013 01:23 AM

unlike other cars, fords do not easily flag a dtc. kahit na walang dtc scan mo mga data parameters and look for anomalies in the readings. best if your acanner supports mode 6 dyan mo makikita kung may nag fa-fail na sensor.

**t2erns** · May 9th, 2013 08:38 AM

could you post what vehicle are we talking about? i'm guessing it's a flexible fuel vehicle, maybe it got something to do with the pcm not recognizing the correct ethanol content (fuel composition) of the fuel and not re-learning after fill-up (need to drive around 7 miles to relearn) and thus pcm cannot utilize the right fuel trim.

http://www.motorcraftservice.com/vdi.../OBDSM1202.pdf
see page 62 if your suv is FFV

**fitdrive** · May 9th, 2013 02:35 PM

Exactly the reply I was hoping to read sir t2erns! Yes the car is an Explorer FFV. From dec 2011 to Nov 2012, we religiously loaded Seaoil e85 on it. Seaoil has the only e85 fuel loading station in the country. Sometimes, i gas up there among racer with modified e85 capable engines

Problem started when the Explorer is brought to Baguio. Like the gas guzzler car that it is, it's impossible to run a full tank e85 to and fro Manila. And so we loaded regular gasoline somewhere in La Union. After 2 weeks, the rough idle started to show. We had it serviced at ford casa, they only changed the oil, oil filter, air filter. As if asa pa kami lol. After 3 days it went back, and so we brought it a 3rd party service center, they recommended changing all the plugs. We changed it, and for 2 months no rough idle.

Then it went back again. I read somewherr na when ethanol stays too long in the engine, it attracts moisture in the air and therefore, engine may contaminate with water. Since e85 is 85% ethanol, just imagine the possibility of it attracting more moisture than regular e10. I had this theory coz the car is rarely used. It sits most of the time in the garage coz it's gas guzzler. Im thinking maybe there is some water contamination na.

Rough idle got worse, when my dad loaded regular gasoline from provincial gas stations either shell or petron, or kung san sya abutan. I figure it was the dirty fuel. And so i had the fuel filter changed. Imagine my surprise, the fuel filter located somewhere in the underchassis, was never replaced not even once, and this car had always been casa maintained for 8 years. That's how incompetent Ford casas are tsk tsk.

After replacing the fuel filter, rough idle is intermittent na lang, mostly after a fill up. Gumanda na din ang takbo ng makina. It's on a full Petron Blaze diet (0% ethanol) for a month now. kaya lang from time to time bumabalik ang sickness kaya that's why i eyeing the ECU or PCM, ano kaya ang solusyon dito. Reflash lang? The obd scanner that im using is generic but it doesnt report any error codes.

**t2erns** · May 9th, 2013 03:17 PM

please take time to read the link i posted it explains everything about the ffv. as much as possible use only one brand of fuel and when refilling be sure to drive it not less than 7miles. try to research also if there's a tsb for that, the tsb can only be addressed by computer reflashing (subscribe to alldatadiy.com for more info about your vehicle). i'll try also to look for myself when i get the time. don't depend too much on casa they still have a lot to learn about the car they are selling (LOL).

BTW when you scan the pcm, pay special attention to the long term fuel trim (LTFT) a good trim is plus or minus 10%