Started to experience this in the last month. 08 XkR

 

 

Both times that I had my severe misfiring that turned out to be bad injectors, I had the same problem when I stopped the engine and then tried to restart.

 

+1 what's the voltage on the battery that's always a good starting point

 

Its yanking your crank.
Keep driving it, if there is real problem it will let you know soon enough.
Worst mistakes I have made in automotive repair has been trying to catch a problem before it occurs.
Its better to wait till whatever is going to fail to fail, then you simply fix the problem, at that point the diagnosis has been done for you free of charge. And as a bonus you did not replace something good from the factory with an inferior part.

Oh btw, I think its your tune that is causing the problem.
A factory program has a lot of leeway for certain conditions, those are the very things you tighten in a tune and then there is no margin of error.
Fuel pump, injectors, starter all possible culprits.

 

Thanks for the replies!
I have have a new Agm battery put in 4 month ago, so def not that.
Definitely not the tune , has nothing to do with starting, and been running for over a year in my car, have the same tune in customers cars , tune works great as it should.
Things I recently did: I have replaced the rubber coupler on top of the throttle body , new one fits good and tight. For last month or so on and off tried running with e25 ethenol blend, but don't see how it would effect starting either.

 

In Australia we have a cheaper fuel alternative containing ethanol called E10 yes it's cheaper however I have seen it destroy all sorts of engine components including coil packs , O2 sensors and catalytec convertors

PS alex you do realise one of the down sides to ethanol is it's harder to start on the cold start

 

E10? I'd assume it is petrol with 10% ethanol. Yes, it's garbage. Yes, it is nearly the ONLY option in the entire USA. It is VERY difficult to find petrol without ethanol anywhere, and when you DO find it, it's always a low-octane.

 

I wasnt aware of the cold starting issue with ethenol. Ran with only 25% ethonol though. Restarting the car after 15 minutes should not make the car cold though. Last time it did it car was restarted after 2hours.

 

Go to just about any marina and you can buy Ethanol free gas all day long. Some of the larger marinas are now keeping 89 and 93 ethanol free also.

 

In California? Where at? We have plenty of Marina's in San Diego

 

Yes, because there are So Many marinas in Utah. The whole state is surrounded by ocean! Don't even say Salt Lake, most of it is less than three feet deep and it eats everything that gets into it.

"It's an island, surrounded by water. Big water. Ocean water."
- Certified Lunatic

 

Don't you guys have some decent reservoirs? Anywhere bigger stuff stays in the water should have dock based pumps at marinas and most have shore side pumps as well.

 

There are about three in the state. Course since boating season is only from June through September and they are all at least 100 miles from me, sort of inconvenient. I can get clear 85 octane down the street from me, but that's only good for lawn equipment and such. I don't put ANYTHING with ethanol in my small engines. I had a bad experience more than once with it.

 

You are pulling our legs? You the guy thats into lap times has never heard of ethanol free or pure gas.
Ok I'll bite.
Harley guys can tell you, they always want the pure stuff, and if you get in line behind them, you will actually get 100% 93 or whatever your local limit is.
Another way to explain it- it pisses them off when the guy in front gets low-grade of 87 octane, because when they have to fill their tiny tank they will get 50% 87 octane.
Ethanol eats old harleys.

Use this site.
https://www.pure-gas.org/index.jsp?stateprov=CA

I keep high octane racing fuel on hand to start my old vehicles.
Do you have racing fuel by you?

 

Come on South. We have no problems finding ethanol free fuel, it just cost. Even Ingles (super market chain) has a 90 octane pump. Lot easier to get my car to than trying to drive onto a dock.
Suggest asking lawn service guys. Ethanol and two stroke engines are not a good combination.

 

Thanks for the chart . As I look at it , it appears that the closest 91 oct. for me is about 30 miles away. Funny considering I live near a major river that there isn't something closer. It also looks like Stewarts chain seems to have this as a standard offering. s much as I didn't like the introduction of E10 years ago that's all that we've been using here. Never had a problem yet even in small engines. Just need to prep for it. My BIL still buys liquid lead for his 63 stock Corvette. He just adds it at the pump.

 

This is just all-around bad advice. Sure, it is possible to overreact as a result of hyper vigilance, but ignoring issues until something actually fails is how you turn good car into an unreliable car.

Consistent hard starts are usually a battery issue. If not that, then it is symptom of various fuel system issues: Inspect fuel pressure regulator, check that your fuel filter isn't plugged, run injector cleaner, and switch from your regular gas station if you have one.

 

Ethanol alone won't cause hard starts in a modern car. While this stuff is vile and destroys fuel systems, there has to be other underlying issue for this to case hard starts.

If your car sits a lot and you live in Ethanol country, then you have to use fuel stabilizer. Otherwise it will separate and then you will get hard starts, corroded gas tank, and destroyed fuel pumps.

 

Agreed, if it were only a fuel mixture/grade issue others on the forum would be complaining of the same symptoms. As SinF states, there must be other (at least one) issues at play here.
Checking all of those noted items is in order as well as keeping an eye out for thrown codes. That said, there are times when intermittant problems can be so elusive that waiting for total failure is the only way to ID the cause. My only advice is to keep looking but don't rule anything out.
Some may dispute this approach but, I run fuel system/injector cleaner on occasion generally as a preventative measure.

I know, nothing others haven't already said or come to mind anyway.