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Old 12-18-2007, 02:55 PM   #1
MM951
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Default What would cause all 4 injectors to dump way too much fuel?

I reinstalled my computer, replaced the FPR, and replaced the plugs. I'm still dumping waaay too much fuel. From what I understand a bad FPR (too much fuel pressure) would make the injectors stay closed.. anyone know what would make all 4 injectors dump too much fuel?
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Old 12-18-2007, 03:03 PM   #2
Mike Murcia
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Temp sensor unplugged/bad?
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Old 12-18-2007, 03:06 PM   #3
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Are your chips installed correctly? If they are backwards your injectors will squirt like a fire hose filling your cylinders.
Don't ask me how I know this...
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Old 12-18-2007, 03:24 PM   #4
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I've actually heard that a faulty FPR will produce too much fuel.. can someone confirm this?
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Old 12-18-2007, 03:28 PM   #5
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The regulator is supposed to fail in a closed position which will result in very high fuel pressure. Have you checked that yet (fuel pressure)?
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Old 12-18-2007, 04:10 PM   #6
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i have three or four known good regulators-used- if you want one cheap to try out.
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Old 12-18-2007, 06:26 PM   #7
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New temp sensor, didn't touch the chips but I will pull the computer again and double check.

I understand when the FPR fails it usually results in over pressure, but I heard if ithe injectors have too much pressure they won't fire. am I wrong?

I did replace the stock 2.5 fpr (that I think failed) with a new 3bar , but I doubt my chips are tuned for that (europroducts?) I figured I could use the arc-2 to get it in the ballpark until I can get Maxtune. I wonder if thats the problem now..

Dan, thanks for the offer, if I find out I need to use a 2.5 bar fpr for now I'll let you know
thanks!
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Old 12-18-2007, 07:02 PM   #8
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switching to a 3bar FPR when you have chips for a 2.5 will cause it to run pretty rich
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Old 12-18-2007, 07:41 PM   #9
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i swear your problem is exactly what my car was doing after i installed my vitesse stage 3 kit(which had nothing to do with my problem)john helped me through it and turned out to be one of the computers...my car was sputtering and dumping fuel and smoking very bad....just a thought
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Old 12-18-2007, 07:56 PM   #10
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clogged injectors not atomizing the fuel properly?
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Old 12-18-2007, 08:13 PM   #11
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Quote:
Originally Posted by dougoh View Post
i swear your problem is exactly what my car was doing after i installed my vitesse stage 3 kit(which had nothing to do with my problem)john helped me through it and turned out to be one of the computers...my car was sputtering and dumping fuel and smoking very bad....just a thought
You know.. I didn't want to spend the money on a computer to have it not be the problem.. but I just realized I could always resell it if it isnt the case. Might as well try it out instead of wondering if its the case .I'll pick one up..

Quote:
Originally Posted by rhesus View Post
clogged injectors not atomizing the fuel properly?
When I pulled the rail they all had a consisent spray

thanks guys
mike
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Old 12-18-2007, 09:17 PM   #12
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3 bar fpr with chips for 2.5.

You just stated the obvious.
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Old 12-18-2007, 09:44 PM   #13
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I had a similar problem (way too rich, ran poorly) - it turned out my DME temp sensor wires were shorted out. Another place to check: O2 sensor

Good luck
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Old 12-18-2007, 09:47 PM   #14
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Define "Way Too Much Fuel". Using a 3bar FPR with a chip for a 2.5bar FPR will increase fuel delivery by roughly 9%. Are the injectors spraying full blast 100% all of the time, or spraying a bit more than expected causing the car to run rich?

Are you seeing this across the RPM or just idle? At idle, if the vacuum line between regulator and manifold is not connected or is bad, then the car will run pig-rich (it will be lean under boost).

A faulty O2 sensor, giving a constant lean signal will cause the DME to try and richen the mixture.. Unplug the O2 sensor, what happens?

If the injectors are spraying 100% all of the time, you could have a bad DME or a shorted wire to the injectors..

It's a bit too early to start changing parts. Define the problem a bit better, isolate it (idle, PT, WOT) then it will be a bit easier to find the cause.
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Old 12-18-2007, 10:06 PM   #15
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Quote:
Define "Way Too Much Fuel". Using a 3bar FPR with a chip for a 2.5bar FPR will increase fuel delivery by roughly 9%. Are the injectors spraying full blast 100% all of the time, or spraying a bit more than expected causing the car to run rich?
By "Way too much fuel" I mean it cranks and doesn't start because the plugs are getting fouled. Now that you mention it, it does seem like the injectors are firing 100% all the time.

I do remember my injector duty cycle gauge was showing ~10-30% duty cycle at low loads/rpm...When cranking it doesn't show anything. Does that make any sense? I wish I was looking at it when it started to run on 3 cylinders and then die.

Some background:

Last week I went for a drive , the car started running like crap (wouldn't rev, no power, back firing), then started running on 3 cylinders, then died and wouldn't restart. I have spark and my noid light shows proper voltage getting to the injectors.. Each injector has ~4.5ohms

I suspected a bad FPR , replaced the 2.5 bar one with a 3 bar (I will be buying chips to match the 3 bar soon, just figured no point in buying a 2.5 only to replace it after a month) and replaced the plugs. Still no start.

thanks everyone
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Old 12-18-2007, 10:06 PM
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