[blainsbrains]

Hi guys and gals!

My focus is idling slightly rough in Park and Neutral. It kinda sounds like a carburetted car from the back with it's new "blub, blub, blub" sound. In F or R it bucks, stumbles and misfires under load. It never had this problem before having sat for 1 1/2 yrs.

I was fixing my girlfriend's old car, an 03 SE Wagon. I had to perform a complete brake job in my spare time. So the car sat for a year and a half while I plugged away.

I changed the fuel filter since I was underneath. I also changed the engine oil and filter. Brand new battery also.

Everything looks to be installed properly, eg I don't see any loose/bad vacuum lines. Also I did not replace the spark plugs although for the 1st 5 min of running that didn't seem to matter.

When I completed the repairs a few days ago, I started the engine and was thrilled it started right up. Now I wasn't able to bleed all the air out (probably bc of ABS) so I took it for a 5 min ride around the block. It ran just fine...for a couple minutes.

I limped it back home and the next day put in injector cleaner and 5 gal fresh gas. Would old gas (probably with water in it) cause my engine to sputter and buck, even if I mixed 5 gals of fresh gas in?

 

[amc49]

It could..............if ethanol in the local fuel then there may be water in it. Add more fuel to dilute it more. No drygas or other, if ethanol in it as the ethanol IS drygas.

Post the exact engine type although likely a zetec. If so the REAR PCV hose where it attaches to the lower intake manifold commonly rots to open up vacuum leak or close to affect idle quality. Even more if it runs fine cold then begins to idle funny once warmed up.

 

[blainsbrains]

AMC, not sure exactly which engine but I remember the vin code is 3 and it's a DOHC.

I was thinking about a vacuum leak but wouldn't that mess with the engine from the moment I started it? Who knows, the hydraulic damper is shot so maybe something I THOUGHT I'd plugged in snug came loose? I'm also going to check error codes with a scan tool.

So about the gas: there was 3/8 tank of old, I added 3/8 tank brand new. So now the gas tank is about 3/4 full. If it's the gas, then I'd probably be better off draining and starting over. What's the best way to do that?

 

[amc49]

Code 3 is zetec...........

 

[blainsbrains]

Fouled Injectors?

AMC,

I drained the old gas and installed a new fuel filter. When I disposed of the old gas (cut with new gas, mind you) it was the color of dark urine.

I then poured 5 gals of 93 octane with 1/2 bottle of Royal Purple detergent. BTW, this new gas is from a chain and the color was crystal clear- I looked. The car is still fumbling.

I'm wondering if that old gas fouled a couple injectors. I changed the plugs and wires because they were due- 195K miles. 1 and 3 spark plugs were dry and 2 and 4 were wet and smelled of gasoline.

Idle is rough and has a fast "blub blub blub" sound in Park and Neutral. In Rev or Drive, the engine loses power and stalls. Putting the gas pedal down to the floor doesn't get the RPM's anywhere near what they are in Park.

 

[zacautomotive]

Do you have codes?

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[blainsbrains]

Hi, zacautomotive no I don't. The car brakes catastrophically failed on the car over a year ago. It sat while I rebuilt the brake system and I had to change the battery. The computer is still in open loop mode. It was driveable for 5 minutes with the stale gas, but now it runs like $h!#

 

[zacautomotive]

Hi, zacautomotive no I don't. The car brakes catastrophically failed on the car over a year ago. It sat while I rebuilt the brake system and I had to change the battery. The computer is still in open loop mode. It was driveable for 5 minutes with the stale gas, but now it runs like $h!#

I wonder if there is an issue with the ignition coil spark plugs shouldn't be wet. You could pull the spark plug wires if you can keep it running and check for spark on each of them.

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[amc49]

Indeed the plugs should not be wet. If again ethanol used in the local fuel the fuel pump could be dead and working erratic too. Sitting in water pulled in by ethanol kills them left and right, the most common cause of pumps going bad now is ethanol. It is transparent as long as the car gets driven daily, let car sit though and watch the troubles multiply quick. Nobody will tell you that of course when they crow about how wonderful the stuff is. Garbage in my book.

 

[blainsbrains]

LOL, well I suppose ethanol is better than lead in the gasoline. The gas currently in my tank is fresh at 92 octane and with 1/2 can Royal Purple detergent.

I'm thinking given the car DID run ok for a few minutes and THEN died, it's a gummed injector. But I have nothing to lose to check the coil. Besides, I'm pretty savvy with electronics and prefer to test parts rather than replace them willy-nilly.

So what's the best way to check if the spark is up to snuff?

 

[zacautomotive]

LOL, well I suppose ethanol is better than lead in the gasoline. The gas currently in my tank is fresh at 92 octane and with 1/2 can Royal Purple detergent.



I'm thinking given the car DID run ok for a few minutes and THEN died, it's a gummed injector. But I have nothing to lose to check the coil. Besides, I'm pretty savvy with electronics and prefer to test parts rather than replace them willy-nilly.



So what's the best way to check if the spark is up to snuff?

with the car running simply pull a spark plug wire one at a time of course see if there's a spark jumping and make note of the idle change for each one. For the fuel injectors if they're accessible use a long screwdriver put the tip of it on the injector and the other end to your ear and listen for the noise of the injector firing.

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[amc49]

Injectors do NOT run for a few minutes then suddenly gum up to not work right, they pretty much are messed up or they are not. Spark check is worthless if the spark is weak instead of not there at all and a good way to blow out the ignition section of the electronic ignition (which is inside the PCM on these) because excess spark length can make the unit try to establish spark so hard it fails the spark unit. Missing is much more common, you get spark at a check but it is not strong enough to make the engine run right.

The quickest check anyway is to yank coil and look at it in bright sunlight for fine hairline cracks anywhere on it top or bottom. Find them and coil is junk. Moisture gets in to short the coil windings and then the engine misses. VERY common on these and the coils change as much as you change the oil sometimes, not really but it's almost that bad. The coil connector wiring must not be frayed or cracked either and again common. Past that the plug wires must be 5000 ohms or less per foot of length or they are bad and can do it too. DON'T run resistor plugs AND resistor wires, a bad combo that causes trouble.

 

[blainsbrains]

@AMC

Thanks for the advice. I was thinking pulling spark plugs while the engine is running would do damage. I did that to a mustang years ago and wound up bricking it. I could have sworn that's what I thought happened, the spark backfed into the control module.

Ok, I'll remove remove the coil pack and give it a thorough inspection and I'll break out my Fluke and test the impedances.

BTW, what about that capacitor? I can check the connections and I can check it with my DMM but I have no idea what value it should be, like 1 uF?

 

[zacautomotive]

Didn't say anything about checking for spark strength. I was talking about seeing if there's any output at all. I have a spark strength tester were you adjust the gap to check for voltage output. Are you telling me that you don't ever check to see if a coil is dead on output? Takes all of 30 seconds to do. If a car won't even stay running it doesn't say hey this thing has a weak misfire that says cylinders aren't firing at all.

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[blainsbrains]

@zacautomotive, I like the idea of the tester. I've seen those, it's a little plastic body with a screw to move the air gap apart. The side is graduated with KV tick marks. One side goes to the ignition coil and the other side gets grounded. Neat idea, thanks ;-)

 

[amc49]

Zaca, not knocking you there at all and 100% correct on that last post, I DO do the exact same. Just wanted to point out that an absolute spark check is not the same as a partial spark check and most have no access to a spark intensity tester.

The rule of thumb I use is 3/16" for a checking gap and no more or ignition module damage. But you must hold that gap constant and the issue doing it in the real world. You can do the exact same with an old plug cleaned up and the gap spread way wider than ever used real world, the spark jumps that and consistent as well as cheap toolbox tool.

If plug is or has been fuel wet, or carboned black then the spark commonly jumps down the side of the plug porcelain and you think there is no spark when there might be a lot of it, and harder to see in daylight too. That fools a lot of people too.

 

[blainsbrains]

@AMC

Thanks for the info. I'm an electronics tech so I really like the idea of the spark checker that has the KV marks on the side. I'm thinking to properly use one, I'd need to know the nominal voltage on the coil's secondary winding. I discovered I can buy one of those testers for a few bucks at AZ or AAP. So, could you please point me to the voltage specs?

 

[blainsbrains]

Cracked Coil

@ AMC

When I first looked at the coil pack, I didn't notice anything unusual. When I pulled it out to perform DMM testing, I hosed it down with brake cleaner. Once the dirt and oil was gone, then I noticed a couple of cracks.

You nailed that one. As an EE Tech, I rarely ever see units that have only one thing wrong. I'm going to replace the coil and see if there's anything else going on. With unburned gas going into the cat, who knows what else I'll find.

 

[amc49]

Man, those coils are simply crap. My belief is that they compacted that design just a bit too much and then the heat down beside head cooks the plastic similar to the way the positive battery cables (located very close to same area) cook in the last 4 inches on them. I open up any space I can in that channel there, the battery cover is gone and the cables run different to get more fan air in there (already 220 degrees at that).

After changing enough coils of several brands on my 2 cars I retroed back to Contour zetec coils, which are similar but having a Contour too I never failed a coil on that one. That coil though takes a bit of modding on the Focus coil bracket to fit it as it has bigger windings in it than the Focus one does and why Focus is smaller. Since going to Contour part I have not failed one yet.

Can't say I've seen any voltage specs on the coils and if they did they may well be suspect anyway as coil voltage is something that gets stretched all over the map of reality and the spark gauge will not be nearly dead accurate as to markings either. Doesn't matter as more airspace (gap) is good until you blow the module out trying to jump it.