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Fuel system mystery

Posted by Bob in Everett 
March 14, 2013 01:54PM
If you think about it, if the injectors are leaking, then one would think there is fuel in the manifold although wouldn't it evaporate with a warm engine? You idea that it is firing faster at startup is consistent with excess fuel in the manifold except for the notion of fuel evaporating in a warm engine.

I wonder what would happen if you simply pulled a couple of spark plugs and insert a straw or something to indeed see if you have raw fuel dripping into the cylinder (but it may only be one or two injectors leaking-question: which ones?).

Of course, this still doesn't explain the chief symptom of poor cold engine performance.
March 14, 2013 09:48PM
Hi Guys
Mine has been getting gradually worse, taking longer and longer to start, to the point where it is now starting to display the same symptoms when cold and being impossible when hot.
Yesterday, on my way to work, I got a flat tire and pulled off to fit the spare.
The 10 or so minutes it took me to fit the spare made it impossible to start again, I ended up abandoning the car and using Swambo's car to work., as it just refused, point blank to start, keep in mind, the car was at running temp.
Returning that evening to fetch the car,. she fired right up from cold.
I know that I have no vacuum leaks, I have bought a set of new plugs as well as a set of new HT leads and will fit them this weekend.
Will let you know what the outcome is.
I remember from my workshop days, weak spark due to bad plugs or / and HT leads were often over looked and the culprit of hard starting, especially with the starter sucking up all the juice during cranking, which leads to another possible scenario, possible bad unloader relay, whose job it is to make sure there is adequate electrical current to all the other systems while cranking, what if this were breaking down, once warm........mmmmmmmmmm????

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
March 15, 2013 11:42PM
I once thought the same about my problem too but the stumbling when cold seems more like a fuel control problem with mine. I have made no progress but the winter weather has inhibited my enthusiam for being out of doors workking on it. I find that when warm, if it does not start in the normal time, if I keep the starter running while holding the throttle wide open, it seems to catch in a few seconds. It is weak at first but when it does get running, it accelerates so quickly that one must be alert to prevent reving excessively.

Bob

Bob in Everett
rkj
March 16, 2013 11:16PM
Quote
Bob in Everett
I once thought the same about my problem too but the stumbling when cold seems more like a fuel control problem with mine. I have made no progress but the winter weather has inhibited my enthusiam for being out of doors workking on it. I find that when warm, if it does not start in the normal time, if I keep the starter running while holding the throttle wide open, it seems to catch in a few seconds. It is weak at first but when it does get running, it accelerates so quickly that one must be alert to prevent reving excessively.

Bob

Be interesting to pull a plug (one of the middle cylinders) when it does not start and see if it's dry or not.... Rick
March 17, 2013 11:20AM
That is an interesting thought. The main problem is that when I am trying to start the car, it is because I need to go somewhere and would not likely have an extra 10 minutes to mess with it. Or it is in a parking lot at work or at the store, and this being the Pacific Northwest, raining.

My plan is to check the oxygen sensor readings and the distributor cap and rotor.

Also have been wondering how much the ethanol in the fuel might have to do with this. There are few places here that have real gasoline.

Bob in Everett
March 17, 2013 01:55PM
Ok, so here is the low down on the new plugs and HT leads.
Fitted them this morning, car fired right up from cold, took it for a good run out on the freeway to get it up to running temp and then parked it for half and hour or so, then went to see if it would give it's usual hot start troubles, nada, nothing, fired straight up at the first turn of the motor.
Turned it off and tried again, same result, fired right up with the turn of the key, without touching the accelerator.
So we shall see, will report back in a week or so, once I have checked it under varing and diffirent conditions, but it is looking promising.
The car deffinately has more pep, idles a lot smoother and quiter, and revs up easier and cleaner.

Measued the resistance in the old wires and the new ones, old wires had six times the resistance of the new wires, so just because they look good, don't mean they are doing their job as advertised.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.



Edited 1 time(s). Last edit at 03/17/2013 01:56PM by Flyboy.
March 17, 2013 03:41PM
Did you disassemble the distributor and rotor and clean them too?

I usually take mine off when I do the timing belt and wash them really good with dish washing soap and rinse with hot water. That seems to be helpful too. I may do that next.

Bob in Everett
March 17, 2013 03:49PM
No Bob, I didn't because;
1. Couldn't be bothered
2. Rotor is new and cap cleaned from last belt change not too long ago.
3. She ran so sweetly and started so easily after the plug and HT lead change, I figured it was not required.
:biggrin: :biggrin:

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
March 17, 2013 06:35PM
Coolness!!! Ugh, we were completely off base on this one. It was electrical not fuel system. Good ending though!!!

alan
March 17, 2013 11:15PM
It would seem so Al. I am cautiously optimistic, this coming week will be the acid test.
I will let you guys know all the findings at the end of the week.

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.



Edited 1 time(s). Last edit at 03/17/2013 11:16PM by Flyboy.
March 18, 2013 10:04PM
Your success with the wire harness is interesting. I have a new set of ignition wires I could try. I bought them a few years ago and put them on the car and it made no difference so I put them away for a rainy day. I had put new plugs in a few months ago and it made no difference.

If the weather ever quits dumping on us here I would be able to spend more time with the car. I took the snow tires off Saturday and within two hours it started snowing, it continued for three hours. Good thing the ground was warm enough to melt it.

Bob in Everett
March 19, 2013 06:55AM
Quote
Bob in Everett
I took the snow tires off Saturday and within two hours it started snowing, it continued for three hours.

Hahahahaha, ain't that always just the way.......:furious:

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
March 19, 2013 06:10PM
This forum has been busy! Good to know the problem was solved.
:cool2:
I took my kids to the snow last Sunday, to the highest place in mainland Portugal.
No need for snow tires, they plow the roads clean so people can use regular tires there.
Just felt like sharing...:biggrin:
March 19, 2013 08:13PM
Quote
Jose Pinto
This forum has been busy! Good to know the problem was solved.
:cool2:
I took my kids to the snow last Sunday, to the highest place in mainland Portugal.
No need for snow tires, they plow the roads clean so people can use regular tires there.
Just felt like sharing...:biggrin:



Obviously, in Portugal they don't use E30's for snowplows!!!:mrgreen:

alan
March 22, 2013 11:34AM
Ok, as promised, for your edification and perusal, here is the one week feed back report.

The little 318i is my daily driver, and I do an average of 70km a day to the airport and back, a mix of highway driving and traffic, pretty much 50/50.
Not once in the last week, since putting in the new HT leads and plugs has she refused to start at the first turn of the motor, and settles immediately into a steady 750rpm idle.
I have started her from cold, cool, warm, hot, and every time she fired straight into a steady idle, when standing at a light in traffic and the temps are way up (it's summer here, average temps 30C) I sub consciously find my right foot darting for the accelerator to catch her so as not to die, but she is rock steady at exactly 750rpm, then I just giggle at myself. Oh ye of little faith.
As I said before, measured with a multimeter the resistance on the old wires was six times higher than the new wires.

Change your leads, it is $40 well spent, use it, don't use it.
Just sayin'
Putting this one to bed.:dance:

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.



Edited 1 time(s). Last edit at 03/22/2013 11:35AM by Flyboy.
March 22, 2013 07:31PM
I must be buying the wire harness in the wrong place. Mine cost a lot more.

Next year I will wait till the first of April to take my snow tires off. Last night it snowed about 6 inches with only half of it meting by the morning commute time.

Bob in Everett
March 23, 2013 02:37AM
Bob, that was just a thumb suck, I paid ZAR 400 for mine and just worked on an exchange of 10:1 $/ZAR, not BMW stuff, I bought Bougi Cord.
But then again, the minister of fun does work for an auto parts outlet, and I get the stuff t staff price, which is like cost +10%, so I doubt you are being fleeced.

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
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