Lumpy engine fixed after flooding it

[marc2092]

My engine used to wobble a bit, especially getting up hills and moving off in first. Last night my engine flooded, since I adjusted a park on a hill then turned the engine off straight away. Anyhow, I got it started by pushing the accelerator down all the way while turning the key. Now the wobble has gone completely, and the engine is the smoothest it's been. Can't figure out why this might be. Could this have cleared something?

 

[Handy Andy]

Possibly, the "flooding issue" might have been a misfire, but not as a misfire the system would see from an emissions standpoint.

You did the right thing by forcing the throttle open and letting the crank try to pull thru whatever was left of whatever it was in there - to pump out into the exhaust side and finished the job.

Sounds like what you did was purge, or vacuum out - the intake manifold from something - usually gunk from the PCV valve and the oil it pulls into that plenum - where that PCV valve port sucks the vapors (supposed to be) in to be reburned.

No, no animals or possums were harmed in the starting of this thread...car? Wouldn't know...

In some rare instances the oil level and that crankcase vapor port and oil drain trap - get coked in - well, coke - the oil deposits and dried sediment it has in it.

They build up in the low spots where air that needs to pass finds other ports to get thru so one cylinder or several were starved for air - or starting to.

When the motor is tilted - that shifts any fluids along with it - so the up hill or down-slope affects even how the oil sits in the crankcase. Too close to the PCV valve- it will get sucked back into the manifold and thru the combustion chamber as it can.

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There are other ports too, including EVAP and EGR (if automatic equipped) on it - any one of those can get caked in oily dirt - so if nothing has ever been done to the manifold of the engines intake, it's been a couple of decades - then it should be a good indicator that you'll need time to take it off and inspect and clean it.

 

[marc2092]

Possibly, the "flooding issue" might have been a misfire, but not as a misfire the system would see from an emissions standpoint.

You did the right thing by forcing the throttle open and letting the crank try to pull thru whatever was left of whatever it was in there - to pump out into the exhaust side and finished the job.

Sounds like what you did was purge, or vacuum out - the intake manifold from something - usually gunk from the PCV valve and the oil it pulls into that plenum - where that PCV valve port sucks the vapors (supposed to be) in to be reburned.

No, no animals or possums were harmed in the starting of this thread...car? Wouldn't know...

In some rare instances the oil level and that crankcase vapor port and oil drain trap - get coked in - well, coke - the oil deposits and dried sediment it has in it.

They build up in the low spots where air that needs to pass finds other ports to get thru so one cylinder or several were starved for air - or starting to.

When the motor is tilted - that shifts any fluids along with it - so the up hill or down-slope affects even how the oil sits in the crankcase. Too close to the PCV valve- it will get sucked back into the manifold and thru the combustion chamber as it can.

View attachment 7824​

There are other ports too, including EVAP and EGR (if automatic equipped) on it - any one of those can get caked in oily dirt - so if nothing has ever been done to the manifold of the engines intake, it's been a couple of decades - then it should be a good indicator that you'll need time to take it off and inspect and clean it.

A very interesting read. Could probably do with giving the throttle body + manifold a clean. I think what actually happened is I inadvertently reset the ECU disconnecting the battery in the process of trying to get it to start. My car's now gone back to being juddery and lacking in power. Haven't got any issues with my idle revs so don't think it's a vacuum leak. My car smells of petrol quite often (especially when starting), so I'd be more inclined to think it's a rich fuel to air ratio.
Most annoying thing is the juddering when I release the accelerator pedal, and the hesitation when pulling off.

 

[Handy Andy]

To "reset the ECU" even if by pulling the battery, then this returns, ok, means there's something bigger in this.

I hope it's nothing more than a sticky throttle valve or - if possible - when you take the throttle off for cleaning - inspect the throttle plate - make sure - by finger pressure, you don't feel any sort of hard rough operation when you open and close the throttle using your finger pressure.

The reason for this concern is that at the age the Fiesta is in, broken teeth on the drive gears inside the throttle body, can make the system "jump" the start process and the hesitation - being that it may not necessarily be stuck, just the teeth in the gears are worn down and there is now some gap making the idle jumpy from the plate pulled open, then pulled shut - by the war of the vacuum and the PCM saying what it should be, so it may start to set a code soon.

But we haven't even begun the other areas of interest - like the IMVAT Intake Manifold Vacuum Temperature sensor or in your version; the MAF and MAP - the upstream side of the throttle body should not need much service, but the one if one is used, on the underside - might.

(Refer to the photo I supplied earlier - there is a connector on the intake just past the throttle mounting location)

Might also want to investigate the wiring and Grounding points on the harness - at the engine side and back at the frame / battery ground post side.