Bad Gas Milage Holley Projection Update - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 02-17-2003, 03:19 PM Thread Starter
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Bad Gas Milage Holley Projection Update

Well here is the deal. I cleaned the carbon off all the plugs. And I leaned out the fuel mixture on the computer. Last time I had got 5 mpg. Before this I had got 7.5 mpg. After this experiment to save money I just went and got gas. I got 3.3 mpg. Now my fuel gauge is usually acurate and it showed 3/4 of a tank. I got 10 gallons. Something seems a little wrong here. This week I drove the jeep as light as possible also. either the gas station ripped me off or something is terribly wrong with the jeep. Now I can't afford this anymore. I am out of ideas to improve it. Looks like I might be selling the jeep for a car, which is retarded since I took so long building it and it has brand new warn shafts ctms and xd9000i that hasnt even seen the offroad.

http://stream.asap.um.maine.edu/~pul...tegory=Archive

Here is a pic. read profile for a list of goodies. Let me know what you think it is worth.

Mike
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post #2 of (permalink) Old 02-17-2003, 03:38 PM
 
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Re: Bad Gas Milage Holley Projection Update

Keep the holley TBI, build a megasquirt controller (or buy one that is assembled and tested) for the existing EFI system you have installed. You should be getting over 10 mpg with that setup. Either that or take off the projection, install a mechanical fuel pump and put on a good old carburetor. Motorcraft 2100 (a 2bbl) or quadrajet if you like to climb things.

Keep the Jeep!
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post #3 of (permalink) Old 02-17-2003, 05:00 PM
 
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Re: Bad Gas Milage Holley Projection Update

I'd really hate to see you give up a Jeep you've put so much effort into. I've got my old Motorcraft carb and the original V8 intake I'd sell you for next to nothing plus shipping, or you could meet me somewhere between Groton, CT and Providence, RI if you're ever down in this area.

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post #4 of (permalink) Old 02-17-2003, 10:31 PM
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Re: Bad Gas Milage Holley Projection Update

I would make sure that your spark curves are correct before messing with the injection. Check the stock specs. for both centrifical and vacuum advance, and your base timing. Most of the time, with a carbed engine, when fuel econemy is poor, it turns out the vacuum advance is ruptured or not connected. Remember, before messing with the fuel system, always verify all ignition components are in spec.

Also note that most dist. specs are given in camshaft degrees, so doubble the specs. to convert to crankshaft degrees. i.e. If the centrifical spec for your dist. is 8-10 degrees at 2500 rpm, that would equate to 16-20 crankshaft degrees.
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post #5 of (permalink) Old 02-19-2003, 03:15 PM Thread Starter
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Re: Bad Gas Milage Holley Projection Update

Alright here is a little more info. After cleaning the plugs to like new after 1 time of driving it they are all carbon filled. even the end of my plug wires are black and near the spark plug threads. Hows it get there?? I dont know. I checked my oil and it is showing I am a quart high and it smells like gas. Now My ecu must be retarded because when i take off my airfilter it just looks like it is getting 2 much fuel. But I really do think there is so much fuel that it is getting into the oil somehow.
I am changing the distrib cap the plug wires are brand new accel's. The ignition module will be change next week. I will be checking the timing soon. Well keep the comments coming, I wish there was someone local to help out with this mess! Mike
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post #6 of (permalink) Old 02-19-2003, 03:33 PM
 
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Re: Bad Gas Milage Holley Projection Update

Change the oil. I don't know whether it's an explosive mixture or not, but it can't be doing your bearings any good being 5 parts oil 1 part gasoline. If you are so rich you are wetting down the cylinder walls, that cant be good for the cylinder walls and rings either. Obviously it's stinking rich and you are darn near killing your engine driving it in this condition. I feel bad if it's your daily driver, but you need to park it till you get this fixed. How hard to put a carburetor back on till you get this EFI problem solved? You must be throwing away half the gas you buy.
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post #7 of (permalink) Old 02-19-2003, 05:09 PM Thread Starter
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Re: Bad Gas Milage Holley Projection Update

Well it sucks because it is my daily driver. I only drive it 40 miles a week though. Luckily I have only put 120 miles on it here and another 120 since the projection. Wow $100 in gas for 240 miles what a deal. Well I custom bent the fuel lines when I put the projection on and I sold the carb and fuel pump.

I now have an edelbrok intake setup up for a 4bbl. So I can either get an adapter of some sort or pick up a 4bbl motorcraft somewhere and then a fuel pump at napa. In 2 weeks I will be able to get it back home to the garage and have 2 weeks to switch back to carb or figure out what the hell its problem is. At least my ignition system will almost have all new components. thanks for the help. any more comments on what to do would be helpful also. thanks Mike
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post #8 of (permalink) Old 02-20-2003, 04:50 AM
 
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Re: Bad Gas Milage Holley Projection Update

I hate taking my jeep to anybody to get it worked on but this sounds like a good reason to take it to a speed shop that sells and installs stuff like that. Talk to the hotrodders in your area and they should have a shop for you to get a hold of and maybe they will have a dyno they will tune it on. [img]images/graemlins/RockOn.gif[/img]
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post #9 of (permalink) Old 02-20-2003, 07:37 AM
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Re: Bad Gas Milage Holley Projection Update

I'm no expert on holley projection systems, so I'm speaking off the cuff here. First what have you done, if anything, to troubleshoot the projection system itself?

Does the projection system determine the amount of fuel based on an O2 sensor? If so, is it within specs?

Does the projection have a TPS? If so is it within specs?

If you have checked all of your ignition specs as suggested above and the TBI is just dumping fuel into your engine, there has to be something telling it to do so, or a malfuntioning injector or something.

Its sounds like you have maybe two problems that are feeding off of each other i.e.ignition/advance problems and the TBI itself.

The way I normally troubleshoot is to start right in the middle and then work my way one way or the other depending on the test results.

IF you have and O2 sensor, use your meter and make sure its within the proper specs, don't they work on a scale of 0-5v or something like that? I would think that your holley instruction sheet would have information on the proper readings for this.

Then start testing each component til you confirm that all are good, my favorite saying when testing a new system is "new doesn't mean good"

Confirm each part and go from there, If you don't have an O2 sensor on your system, maybe you should consider installing one, it would be a good way to test your air fuel ratio and troubleshoot....

You've probably already done all this, but I was in a typing mood this morning, so....... [img]images/graemlins/smile.gif[/img]

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post #10 of (permalink) Old 02-20-2003, 08:53 AM
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Re: Bad Gas Milage Holley Projection Update

Sounds like the injectors might be leaking after shutdown.
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