Quote:
Originally Posted by Esel Mann
Norm,
You sure that aux fan is adequate and pulling air over the entire engine like the main fan did? What you have doing primary duty is an aux. or auxillary fan. Typically from a system perspective, the function of auxillary differs from primary. Even when the fans are identical, their placement can dictate what and what they cannot do.
Fuel boiling at the rails on start-up seems unlikely. At that point everything is "cold". Fuel boiling when running could be due to not enough circulation? Hence maybe your pump is approaching the end of life or there is some sort of issue with the pressure regulator(s)?
I presume you've got some sort of euro 928, hence no Ox and no cat? So the negative impact on av-gas would be minimal? What about the fuel injectors? Any possibility of av-gas blend causing problems there? (I have no clue but it did come to mind for some reason.)
Ethanol is known to attack seals of earlier cars. You may want to give everything a good look over. Maybe there's a seal for something or other in either the pressure regulator(s) or the fuel pumps for which the ethanol (over time) has essentially rendered non functional ?
Does the 928 have an idler valve like the 911's? If so has it been verified that it is functional? I have to presume it is because your description indicates a start-up problem, hence if it is the idler valve, you would still stall if idle, engine warm.
You should not be having combustion/starting issues for an ethanol blend which is fresh and under driving conditions. This is also true for mowers, chain-saws, and vibrators. I run using FL gas. Though I am in Orlando and not FT Lauderdale. No issues thus far. Though I do so with 911's and not a 928.
Which brings me to..... the following which you may want to additionally consider, or not consider:
- For the station where you regularly filled up, how often was/were the deliveries for the premium (I presume your were filling up with premium)? What I am getting at here is, maybe premium is no longer selling too well at your station and hence has been sitting for a while? Ethanol is a great absorber of moisture, hence if their tanks are regularly replenished, you can be certain there is going to be more water in the gas.
- Is there any potential that there is some sort of ingress point for water/run-off to enter into the station's tank? For example old tank(s), or even inadequate water/run-off drainage for the tank area. We have been experiencing some good rainfall here recently. I could see water getting into those tanks if the station owner cut corners with their fuel station.
- Is there any potential that someone is stealing the gas (at the station) and replacing it with water?
- Have you or perhaps someone you know used the same gas from the same station from the same grade? Did they have problems?
- Your profession is aviation, hence I presume you leave the 928 for longer, ish periods of time? Is there any possibility with the 928's age, that this is correlated?
- Have you posted on the 928 forum the problem? Perhaps another 928'er had a similar/identical problem, identified it, and solved it.
I hope you are able to identify the root cause and solve this problem. 928's are becoming rare and I'd hate to see one less on the road. They're absolutely beautiful. I wish I could find a white one down here in FL which was well maintained and cared for. So far no dice. But I did recently pick up a nice 964.
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Now we are getting somewhere.
* The Aux fan can indeed control the temp of the radiator. I have it rigged to run full time; To do this, all you need to do is jumper the connector at the drivers side front of the radiator. This is a valid point, but the temp gauge has stayed in the same place as it was before I removed the belt fan. I don't think that underhood temperatures are causing this.
-Beechcraft Bonanza's and other airplanes with an engine called the Continental IO-520 for years had problems with hot starts. Why? The injector tubes were mounted right on top of the engine, and the 8.5 liter air cooled six cylinder engine would bake them with heat after shut down. The gasoline in the lines would vaporize, and if you tried to start the engine a few minutes later, you had a terrible time. That was on pure Avgas. The 928 has its fuel rails right above the heads, so there is no shortage of heat. I checked tonight with a pyrometer; the drivers side fuel rail indicated 161 degrees right after shut down!
* ROW '85 928, injectors rebuilt/flow matched three years ago. NO O2, no cats. I ran pure 100LL for a month in 2003, and wound up with what I suspect was plug fouling. It ran too cool, and the lead started to build up. That is why I want to mix 90 octane NO ETHANOL Sunoco with Avgas; proper octane and no alcohol.
* My S2 does have the idler valve, and it is working. I have done the WD-40 fix as depicted on Rennlist to it several times, it works. There is an idle issue with the car, and it has to do with the throttle cable, which is gummed up and needs to be replaced. I pressed very gently on the throttle during cranking and it made no difference.
* The station I fill up at is the same one that I have been using for several years. It is on Wilton Drive in Fort Lauderdale, has a lot of traffic, and they had to replace their tanks about 5 years ago. The pavement in front of the place is fresh and white.
* My girlfriend fuels her VW CC in the same station and hasn't had any problems. Hmm- this is a good point.
* YES, normally, I leave my car sitting for a week at a time. I generally have a week on, week off schedule, but I've had vacation these past two months. Admittedly, I'm getting senior and I bid my schedule cleverly in order to do this. This means that the car has been used about 5 miles per day during this period.
[Since I fly for a UNIONIZED carrier, I basically will do no flying for my airline from September 25th until November 20th. How many of YOU get to spend two months off with your family? Think about it. A UNION did this for me.]
[TWO months off each year....to work on my Porsche~]
sorry-
* I did a search, and there are a few vapor lock stories on the 928 channel, and Rennlist is the same.
-What I have been told by small engine mechanics and boat mechanics is that their business is through the roof! They are repairing engines left and right, and the big problem is the 10% ethanol gasoline. It is DESTROYING the cheap Chinese carburetors on all of these, and even the better ones, and they are making a lot of money replacing them. I have already gone to PURE GAS for my boat, for my generator, and for all my power tools. I'm sure that this stuff is causing the problem that occurs about one time in ten in my car. Porsche says that up to 10% ethanol is acceptable in their cars, and 0% methanol, but I'm not buying it. My fuel pressure is fine, my injectors are fine...folks it is the vapors. It is the gas.
And if it isn't I'll know real quick won't I!
Thanx for your help Esel Mann; If you ever work your way down here, let me know. I do my timing belts every 45k at Zotz Garage on 436, and my FAA doctor is up there, so I come up twice per year with the car. Fly safe!
N!