Truck randomly shuts off/afr bouncing around all while cruising.
08-04-2012, 10:52 PM
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Truck randomly shuts off/afr bouncing around all while cruising. 2 weeks ago I was tuning the ve for the first time since the swap snce I run maf only so I never needed ve but felt what the heck Ill tune it. Anyways it happened twice that day. I would slowly climb the rpms higher and higher until the afr error was ok. The rpms would climb then buck and everything would shut down. I come to a stop turn the key off then back on and fire it right up and go along my way. Thought this was just because my afrs were so bad for that bit until I got them all back alined then went back to my normal tune and all was well. Coming back from a 45 min drive last week I was pulling away from a light and everything shut off again. Come to a stop start it back up and all was well. I brought it home looked over everything nothing looked out of place or burnt. Then today I was on a poker run and it happened again. This time I turned it off then back on while still rolling but it wouldnt start. Come to a stop starts right up press the gas and it dies again. Pop the hood look around smell around. Tap on the connectors on the ecu but nothing out of place. Get back in starts right up and moves again to problem. Then after a while on more level roads i feel it start sputtering and notice the wb is going crazy 12:1-16.8:1 while just cruising. Im able to back off on the throttle a bit since the road is leveling out and the afr goes back to normal for a bit then starts acting up. It never shut down but I never really had to get on it much at alll since the roads were more level. I think those other times where it shut down the afr was just going crazy plus accel caused it to stall out? But the thing is at each stop we would park for 20-30 mins then go to the next stop. When back to driving the afr would stay normal just bouncing around 14.3-15.1 for the first 15miles or so then start acting up again.
Any suggestions. The wb is in the drivers side right after the collector, Thinking lazy o2 but it only has 3000miles on it, maybe leaky injector??? Possibly spark plugs even though it runs fine for the first bit until it like gets hot or something? When the wb bounces around its not a slow change. I have a digital lc1 wb andwhatever the refresh rate is how fast it ws changing going from the 13s to 16s to 12s and a couple 11s in there while just cruising on open country roads so defintely no pe.
Any suggestions. The wb is in the drivers side right after the collector, Thinking lazy o2 but it only has 3000miles on it, maybe leaky injector??? Possibly spark plugs even though it runs fine for the first bit until it like gets hot or something? When the wb bounces around its not a slow change. I have a digital lc1 wb andwhatever the refresh rate is how fast it ws changing going from the 13s to 16s to 12s and a couple 11s in there while just cruising on open country roads so defintely no pe.
08-05-2012, 08:57 AM
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Ill grab a fuel pressure gauge and go for a ride. I just put in a new aeromotive 340 and racetronix hotwire kit over winter so that whole system has less then 1000 miles on it so hopefully its not on its way out already haha.
08-06-2012, 05:36 PM
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Small update. Pulled the fuelrail and the checked the injectors, they were dry but it has been sitting for a day so that was expected. Ill have to jump the fuel pump and let it sit with some pressure for a little bit and see if they leak. Pulled the plugs and they all looked normal. Checked the grounds,(block to chassis, behind each head, original fuel pmp harness attached to the chassis by the drivers taillamp and the hotwire ground). All were tight, Still need to grab a fuel pressure tester and go for a ride and Ill also
datalog my voltage on that drive. Other then that its just more looking around which I did while I was under the engine and all the connections looked fine. Oh also switched the factory fuel pump relay with the horn one just incase.
datalog my voltage on that drive. Other then that its just more looking around which I did while I was under the engine and all the connections looked fine. Oh also switched the factory fuel pump relay with the horn one just incase.
08-08-2012, 09:40 AM
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Grabbed a fuel pressure tester. I varified the gauge by running a rubber tipped blow gun to it with the compresssor regulated to 60psi the fuel pressure gauge showed 60 so Im guessing its reading correctly.
Key on goes to ~ 65psi
running its sits at 75psi revving it backs down a bit then goes back to 75
As soon as I turn off the engine the gauge goes to zero. Bad check valve? I think it did that on the stock pump though too when I ran that last year. Always had to prime it before I cranked it or it would just crank a bit before it started, same as now with new pump.
Short drive not doing much
Im going to remove the return line and run a hose into a bucket to see if my return is blocked.
Key on goes to ~ 65psi
running its sits at 75psi revving it backs down a bit then goes back to 75
As soon as I turn off the engine the gauge goes to zero. Bad check valve? I think it did that on the stock pump though too when I ran that last year. Always had to prime it before I cranked it or it would just crank a bit before it started, same as now with new pump.
Short drive not doing much
Im going to remove the return line and run a hose into a bucket to see if my return is blocked.
08-08-2012, 06:48 PM
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Its not supposed to. Im running a vette filter with its built in regulator. So it should be what, 58-60 psi?
I put vicegrips on the nylon braided russell pro classic hose that is my return. Turned the key and priming it went to 90psi then slowly went back to 0 over about a minute. What would this mean? With the return not "capped" it instantly goes back to 0.
I put vicegrips on the nylon braided russell pro classic hose that is my return. Turned the key and priming it went to 90psi then slowly went back to 0 over about a minute. What would this mean? With the return not "capped" it instantly goes back to 0.
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08-09-2012, 04:50 PM
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Sounds like that is at least part of the issue. I know that this might sound strange....but you don't have the lines reversed on the filter, do ya? If not, I'd be changing the filter out any way...just as a way of trying to narrow the problem down.
08-09-2012, 06:29 PM
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Another vid is loading. Took the return line off to make sure that wasnt causing blockage and high pressure. Ran a line to a pan and fired it up. Still 75psi and once the truck was off the return drained for a good while. I would think the return would be shut off when the pump isnt pressurizing anymore? I ordered a new acdelco vette filter wont be in until early next week. Maybe the current regulator is somewhat stuck open where its causeing it to overpressurize by 15psi but also allow the main line to drain when shut down??
I made the mistake of having the feed and return reversed last summer when I did the swap found out that when reversed it doesnt let any fuel through.
I made the mistake of having the feed and return reversed last summer when I did the swap found out that when reversed it doesnt let any fuel through.
08-09-2012, 07:11 PM
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[QUOTE=tiresmokinV8;16606845] Maybe the current regulator is somewhat stuck open where its causeing it to overpressurize by 15psi but also allow the main line to drain when shut down??
That's my best guess.
08-09-2012, 07:21 PM
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So the return isnt like a valve with a spring that once it hits 58psi it opens to bleed off excess pressure? If this is so then once the pump is off the valve should close since theres no more excess pressure and nothing should be draining from that return line when I shut off the truck.
08-09-2012, 09:57 PM
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So the return isnt like a valve with a spring that once it hits 58psi it opens to bleed off excess pressure? If this is so then once the pump is off the valve should close since theres no more excess pressure and nothing should be draining from that return line when I shut off the truck.
Just guessing here...
08-11-2012, 08:47 PM
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Filter came in today and is installed. Had to return the fuel pressure tester yesterday since Oriellys only lends them out for 48 hrs. So Ill run there in the morning and pick up the tester again then intrument the truck for a drive. Hopefully something will get fixed .
08-15-2012, 12:38 PM
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Yea Ive been really busy the last few days, Since friday Ive had to replace the starter, Battery and waterpump on my Grandpas 91 century. All on seperate days of course, Seems it cant go a day without something breaking. Finally made a trip today, Duct taped the pressure gauge to my wipers, looked ghetto but no one could catch up if they tried anyways haha. Took a back road trip to a campground my family used to go to all the time with our travel trailer that I havent been to since 2001. 200 miles later Im happy to report its all good. Not a single stumble, Spent the first 1/4 of the trip redialing in the maf then ve, Idle and cruising its 62-63psi any gas at all it stay rock solid at 60-61. Wideband stayed steady around 14.7. On one windy road that was a posted 55mph I was stuck behind some focus going 35mph, At the first straight with dashed lines so I could pass I slammed it into 2nd and was gone! Never a dull moment when driving a lsx!
Hopefully all is good now, all that I changed was replace the filter with a new vette one which holds the correct pressure now but who knows the old one might have been bad the whole time?, I reset the fuel trims, Forgot to when i was tuning the ve and this all started but since then have done a write entire and it didnt solve it, I would think a write entire would reset the saved trims? Also put a new ring terminal on my ground wire from frame to battery on my remote mount kit, The one I had didnt fit the 2gauge wire so only about half the strands fit in it, I put the correct one on it now.
We will see if it stays golden, Still a blast to take trips in.
Hopefully all is good now, all that I changed was replace the filter with a new vette one which holds the correct pressure now but who knows the old one might have been bad the whole time?, I reset the fuel trims, Forgot to when i was tuning the ve and this all started but since then have done a write entire and it didnt solve it, I would think a write entire would reset the saved trims? Also put a new ring terminal on my ground wire from frame to battery on my remote mount kit, The one I had didnt fit the 2gauge wire so only about half the strands fit in it, I put the correct one on it now.
We will see if it stays golden, Still a blast to take trips in.
