HA! I broke the code! How to fix Start/Stall problems!

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F-Type

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Gothenburg - Center of the Universe
I broke the code! I think! :)

Having had these start/stall issues with my octane the last couple of days, with the engine running no more than 0-3 seconds each try.

I think I found the reason why.

It is called fouled spark plug, and is caused by the insulator between the firing tip and the body getting coated with residue that is conductive, causing the voltage to leak this way instead of generating a spark.

Apparently fouling is more common during break-in of an engine. I am not certain why, but could be because the engine should be run more rich during break in, with more gas/oil passing through causing oil buildup on the insulator.

I went out into the garage just before writing this post, took my two plugs and had a look at them, they both looked very shiny on the insulator, pretty much like they had gas on them. I cleaned them in the simplest way with some alcohol and brake cleaner (yeah yeah, it's what I had at hand, its over midnight here right now ;). Popped one back in the truck, pulled the cord. Guess what! The engine started right away and ran pretty clean for 20 seconds or so . Tried again, same thing, engine started right away on first pull. Much better than before I cleaned the plug. Swapped plug, tried again, same thing, much better result. And this by just a very quick and simple clean of the spark plug. Tried probably 6-7 times, each time the engine started on the first pull and ran about 20-seconds.

For those of you who've seen Hemistorms videos (I've probably not seen them all) he said he had a "gremlin plug", that gave spark when he checked but wouldn't work in the car. Well, for sure he had a fouled one. He also said to get a bunch for break-in. Quite right, they apparently get fouled quickly during break-in. Cleaning could be a temporary solution. Sand blasting is a way of cleaning, I read somewhere. I just might try that tomorrow, as I don't have any new plugs at hand, and the ones I have on order is a week or so away.

Here's a photo of one of my plugs before cleaning, look how shiny/glazy it is, and this plug has been lying in free air for 4-5 hours since I used it earlier tonight, still this shiny. After cleaning the shinyness was gone.

DSC_0923.JPG

And here's a couple of links to info on fouled plugs:

http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqfouled.asp

http://www.aa1car.com/library/spark_plug_fouling.htm
 
well, glad to here it works for u now :D

yes, snad blasting is a good way to clean em'. that's what ive alsways done for small engines. I'm not sure how easy it is using just a standard sand blaster, though. ive always used a special gun( u can get them at hardware stores, all u need is and air compressor)
 
Well Guys!

Today my Octane ran like an old well used one, not like a new Octane that just starts and stalls! :D:D:D:D:D:D:D:D:D:ercm:
Well, almost like an old used one, mine still some break in left to do ;)

I did three things to make it work, of which the first two definitely made a big difference, the third one was just for extra safety to really minimize possible causes.
  1. I sandblasted the spark plug using a simple "spot" sandblaster (is that what they're called in english?) just put the end of the plug in the hole of the rubber top of the blast gun and blasted 20 seconds or so. Then cleaned out all blast sand and dirt thoroughly.
  2. I used a 7,4V LiPo for the CDI.
  3. I used gas with only half the amount of oil, this to make an extra effort to avoid build up of residue on the spark plug.

In my opinion, having tried around a bit, it is equally important to use the LiPo battery as to have a good spark plug. Now, it could be that my standard batteries are poor, but swapping them around the servos still work fine, so I don't think it's poor batteries.

Using less oil in the gas isn't something that should make an immediate difference, I just did that because I notced it was enough to try a few times with a cleaned spark plug to have a film of oil left on the spark plug when I took it out.

It is important to run the engine hot in order for residue build up on the spark plug to get burned away. This is perhaps why fouled plugs are more common during break in, the engine never gets really hot as you run slowly for a number of tanks.

Now it seems like I have some work to do with the cluch, or whatever it might be, the car hardly moves up a slope at full gas, clearly something i slipping somehwere.
 
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Glad you're making some good headway on this F-type! The octane community needed some good news badly! The modifications you're doing are logical. Just keep an eye on the engine while running less than recommended oil mix. You might be fine, but since you are running outside of spec you need to take extra care.
 
Yepp, I am back on normal mix again, I ran less than half a tank on the lean mix, just to make sure the car ran fine, it did and it still do. :)

I'll start a new thread shortly about the clutch issue I mentioned. The guy who had this car before me (I bought it second hand) must have had a screw or two loose.
 
Ok, so today I got my two new spark plugs that I had on order.

Don't really know what to do with them!? I mean, the two sandblasted ones I have are working great :)
I guess I keep them for a rainy day, or a fellow Octane owner not owning a sandblaster ;)
 
Having cleaned the spark plug, the car has been working a lot better, but not without some irratic behavior. At one point, I noticed the spark plug was quite loose in its cap, and that's where the ground connection is. So, I added a separate ground wire from between the spark plug and the engine top, and to the CDI. WOW, that made a huge difference, and today the car made its first wheelie :) Not a big one, but the front wheels raised a couple of inches.

Then however, the engine started running "bad", and now it is a lot more like a "gas" issue rather than electrical. The rpm was varying a lot when running it slow with constant throttle, like the car was struggling to reach the RPM I called for. Also when trying to increase speed the car accelerated slowly and irratically, the car could once in a while get kind of like a kick for a fraction of a second. I tried tuning a bit, both up and down from factory setting, but it did not seem to make a difference.

Any ideas what the cause of a behaviour like this could be?
 

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