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Old 07-03-2012, 05:04 PM   #1
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Default engine randomly sputtering, dying, sitting, then drives fine?

So it has happened to me three times now in the last couple weeks. Ill be driving home from work and the engine will sputter a few times, then continue driving fine, sputter a few more times, drive fine, then sputter and die. AFR goes very lean during sputter so its obviously a fuel starve issue. So all three times I pulled off the side of the highway, turned the car off, let it sit for 10 mins or so while I checked vacuum lines I thought might be the issue, then it starts back up fine and drives fine the rest of the trip home (about another 30 mins of highway cruising) the next day everything is fine, next few days everything is fine, then it happens again on my drive home today. in between the events, car drives totally fine. It has only happened about 5-10 mins into my drive home at the end of the day. First time it happened I thought the fuel pump finally craped out (I still have stock fuel pump) but then since it started back up eventually and drove fine I dont know what it is. It has been abnormally hot here (105F when it is normally low 90's max ) and my car sits in the sun for 10 hours while im at work (6-4) Is there any way the heat is causing some sort of vapor lock in the fuel lines?

Summary: drives fine, sputters, dies, cranks very strongly but wont fire, sits 10 mins then cranks right up and drives fine for days in between events.

Has anyone else had a similar experience? Im guessing i couldnt just have a clogged fuel filter since it is just a bag type thing in the tank rather than some cars with a inline force through type filter?

Thanks for any suggestions.
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Old 07-03-2012, 05:43 PM   #2
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Fuel pumps can be intermittent. You have an MS. log it?
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Old 07-03-2012, 06:38 PM   #3
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The older Mitas dont have the inline filter?!

A big log would be nice to see. Also could be TPS, CPS, crank key.
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Old 07-03-2012, 08:57 PM   #4
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Quote:
Originally Posted by krissetsfire View Post
Fuel pumps can be intermittent. You have an MS. log it?
This^. What you describe sounds exactly like many "crap I'm running out of gas" or "crap my pump isn't running" I've seen. Since you're starting up fine and driving a good distance after the occurances than the latter is more likely.
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Old 07-03-2012, 09:24 PM   #5
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Plus he said he has the stock pump in there still. It's past time to swap that bugger for a Walbro, or better.

I have a slightly used(bench testing) Walbro 255 Inline pump that won't help but you should pick it up anyway,.lol
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Old 07-03-2012, 10:13 PM   #6
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I do have an MS but dont currently have a laptop to hook it up to. Ill have to see if i can bring my laptop home from work and take a look. Ive been meaning to get a Walbro but figured I would need another tune once its installed and wanted to wait til I got a replacement turbo and just get one tune all at once but i guess that might not be an option. I didnt realize pumps go out intermittently but looks like its time to quit being a cheap ***. Thanks for the advice
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Old 07-04-2012, 02:25 AM   #7
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You shouldn't need another tune with a FP change if the regulator can handle the pressure. Something to research but at the most you would only need an adjustable FPR to reset to correct (or modified) base pressure.
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Old 07-05-2012, 08:07 PM   #8
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So doing some research has left me confused. Some people say just get a 255 others say its too much and will overload stock fpr so to get the 190. But then do I need HP or not? Currently running 460's with a t25 at 8 psi getting 175 whp. Future plans include t28 aiming for 225-250 range. Which pump would y'all recommend? Thanks
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Old 07-06-2012, 04:11 PM   #9
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DSM's stock can handle around 225-250 on the stock pump and that's only 100lph @43psi base fuel pressure. The 190 being an upgrade to even that, I would say you're safe with the 190 - unless you plan on increasing boost later which I would say get the 255 and an adjustable FPR to compensate the base pressure accordingly.
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