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Discussion Starter #1
Hello. So I'm still fighting this start on ether an run on gas problem. I tested fuel pump and if I turn the key on it quickly jumps to 19-20 psi. If I turn the key off it holds pressure and builds to 39 psi on second turn of the key. Is that normal? If I hit it with carb cleaner it fires up and runs and idles all day on gas but it just won't start on gas alone. Any help from somebody that has debt with these machines electrical problems would be greatly appreciated ....thanks in advance
 

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There is your problem. It should build up to 37-39 lbs on first turn of key and hold there. IIRC. Surely either a pump or pressure regulator issue.

What is pressure at idle? Mid throttle?

Does pump make any noise like screeching or anything like that?
How long will it hold 36-39 lbs?

The problem is it should build higher pressure initially.
 

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Discussion Starter #4
Thank you Walters.. I did not check long term pressure. Once machine us fired up on ether it runs fine and with normal throttle response.. I read in the service manual about initial Efi pressuring after fuel line disconnect. I'll have to retest after reading about turning the key on and off 6 times to purge any air. Also do u have any thoughts on the pick up coil or crank position sensor and it not sending signal to injectors to pulse and send fuel in unto more engine rpm? Maybe similar to machines that will start with a pull rope but not with electric start?..today will be a day for more testing. Also would the kill and reverse switch problems I've read about allow the machine to start on ether most of the time and then run? Thanks again .I'm not ready to give up the fight lol
 

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Not familiar with kill switch issues.

As I understand it, pump comes on briefly with key on to build initial pressure then shuts off until engine is cranked and efi sees either a certain rpm and/or ANY rpm trigger from a sensor. Then turns back on.

Doesn't explain why it likes ether though.

Crank speed. Is battery up to snuff? If weak it may effect fuel pump and starter crank speed. Checked charge, connections and load tested battery?

Diesel engines sometimes get ether dependent when it is used unnecessarily. We call them ether babies. They wont start without it even when it is not needed.

Any reason to suspect low compression?

Have you checked for diagnostic fault codes?

Report back.
 

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Discussion Starter #6
Checked codes none unless I disconnect something. Pleasure tested and both are at 180 give or take a 1lb. Machine never tasted ether till I bought it with this problem. Digital display shows about 480-550 rpm during attempts to start. When it starts on ether it seems like it builds rpm up then fires it's not a instant start up. Battery lives on a 2 amp charge thru all this and yes battery is solid. Would the fuel work half way? By that I mean pump till 20 lbs then stop or pump continuous no matter how long of a test line was hooked up to it?
 

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Discussion Starter #7
Also sorry I did not see ur question about starting after I turn the key a few times. No it has never started after that.2 times out of 100 attempts without ether it fired back up after I turned the key off. Almost without fail it will start on ether and then run fine. It doesnt always start on ether but u can hear the engine trying to fire. Ive been thru the wires and nothing other then the t bap wire harness seems to have failed. Im looking for a easy way to test the stator and cps. Ive found a few differnt ways but since u brought up the questions on my testof the fuel pump ive found something I may over looked. I want to make sure my tests are done ccorrectly.
 

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Aside from not building up sufficient initial pressure. Which one would suspect a pump or pressure regulator,.....I WOULD have to research more about the sensor the efi looks to to resume fuel pump operation and then also injector pulses. If the sensor was starting to fail and needed to see a higher rpm to turn on the pump than the starter could provide.....then yes the sensor is suspect too.
 

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I believe initial pump cycle is timed and not pressure dependent. After efi senses rpm and pump is turned back on, it stays on and any fuel beyond what is needed to maintain the specified fuel pressure is dumped back into the tank by the regulator. This is why a weak regulator may cause a failure to build initial pressure.
 

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Discussion Starter #10
Thanks for confirming my understanding of the system. Im having difficulty finding test info on 07's. I know many yrs cross eachotger just seems 07 is to close to the middle. Now to locate the senser test in the service manual.
 

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Discussion Starter #11
Well then I think that takes the fuel pump out of the equation.the engine seems like it has to get a running start the fire rock even on the ether a few times on the ether it would pop right off I couldn't let go the key fast enough.which is a sent them and a problem that I read about on a 05. That 05 pick up coil needed to be adjusted and oncethat was done he posted that tge machine fired up better then from the showroom.
 

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Discussion Starter #13
Haha sry that was a bad voice to text........ maybe what u r saying about the timed fuel pump would take a bad fuel pump or regulator out of the picture.... when mine starts on ether it kinda sounds it's picking up and building on top of rpm and then will turn into the engine running. Not ur normal turn the key and fires up.... I read a post on a 05 500 having pretty much the same issue as I but he was able to adjust the pick up coil and once that was done his machine then started better then it ever did. I'm not sure on my 07 800 that their is an adjustment. Twice on ether my machine shot to life with just a slight turn of the key..
 

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I would still want to check fuel pressure readings...at idle, while cranking, at part throttle running, and see if it holds pressure while off, etc.

Pressure should be higher after only one key on cycle.

Are plugs dry after cranking?(w/no start fluid)
 
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