heavy85 Posted March 2, 2008 Share Posted March 2, 2008 Well as it says there was a slight break in the weather today so last night I took it off the jackstands and today was the day. To date I've only started it in the garage a couple times for less than a minute each time. So I rolled it out of the garage & it started up just fine. Wanted to get it up to temperature before taking a drive so let it idle and after a minute or two it died. Sigh. Thought it might be too low on gas since I only had a little to put in so I dump whatever I had maybe 1/2 gallon out of the mower gas jug in it. Started right up and again ran for a minute or two then shut off. Feels like it's running out of fuel - kind of sputters for a few seconds then finally dies. So took a trip to the gas station to fill up the jug then added maybe another 2-3 gallons of gas. Again started right up then died after a minute or two. Tried immediately and it would not restart. Hot wired the fuel pump and it started and I pulled it into the garage - at least the clutch pedal seems to work good . Several hours later rolled it back out and again hot wired the fuel pump. Started right up and ran until I shut it off, maybe 10 minutes or so. Let it get up to temperature and everything was fine. (BTW where on the stock temp gauge does the stock f-body fans turn on?) So what would be telling the fuel pumps to shut off? I had VATS programmed out and that shuts off after just a few seconds anyway. I'm stumped so any ideas what could be cutting fuel? I'm tempted to test drive tomorrow with the hot wired fuel pump since it's suppose to be nice again but really want to figure this out before I do any significant driving. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
rsicard Posted March 2, 2008 Share Posted March 2, 2008 Check the fuel pump circuit and oil pressure switch Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 4, 2008 Author Share Posted March 4, 2008 Does the oil pressure switch shut fuel off if it does not trip? I know I have oil pressure from the gauge and idiot light. Where is the switch on the block ... I'll have to check the wiring and probe the switch to see if it changes state when the engine starts up. If there any other PCM inputs that would cut fuel if they are not hooked up? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted March 5, 2008 Share Posted March 5, 2008 The fuel pressure sensor doesn't send signal to the PCM. This means it can not tell the PCM to cut off the fuel. Do you have an auto or manual trans? Do you have a scan tool? If so try to read the the DTC off the PCM. As far as I know there is nothing except for the VATs will tell the PCM to shut off fuel. However there is something call a limp mode that the PCM puts the car into when it detects something wrong like water temp too high, abuse mode detected etc. In this mode the PCM will fire only 4 cylinders until the problem clears itself. Have you check the fuel presure? Quote Link to comment Share on other sites More sharing options...
Bigdeezs Posted March 5, 2008 Share Posted March 5, 2008 Have you check the fuel presure? yep...I think all the sitting my datsun did left a bunch of gunk in the tank...my friend with his LS1 Datsun had the same issue...debris messing up fuel delivery. Now my fuel pressure is a bit low (50psi) Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 6, 2008 Author Share Posted March 6, 2008 Need to get a fuel pressure gauge but it doesn't run rough like it's on 4 cylinders it just all of a sudden sputters to a stop like you turned off the fuel pump. If it was crud in the fuel system how would hot wiring the fuel pump fix the problem? I know some engines cut fuel if the oil pressure switch sees low pressure as a fail safe like in a roll-over but does the LS look at oil pressure for this reason? Anyone know where the oil pressure switch is located so I can check the wiring? It's a T56. Also need to hook-up the OBDII port so I can check the codes ... maybe after the kids are in bed tonight. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted March 6, 2008 Share Posted March 6, 2008 Cameron, I can guarantee you 100% it's not the oil pressure. I started my LS1 with the oil pressure sensor unplugged. So it's not the oil pressure. On the passenger side of the oil pan there is an oil level sensor. This might be what you are talking about that will stop the engine in the event the oil is empty or what not. Well according to my info this sensor feeds the BCM (body control module) and the BCM turns on a warning light for low oil on the gauge somewhere. In your swap you don't have the BCM so that's not it either. I highly suggest you find someone close to you with any type of scanner like EFI Live or HPtuner or whatever. With the scanner you can see all the info on all the sensors on the engine. From my experience on these LS1 engines if you have sparks then it's most likely fuel relate problem. Please give me more info on your setup. Maybe I can pin point the problem. GL V. Quote Link to comment Share on other sites More sharing options...
jonus079 Posted March 6, 2008 Share Posted March 6, 2008 so the ecm is shutting down the fuel pump?? sounds to me like over heat protection. perhaps the coolant temp sensor is bad?? anyway the factory setting with a 2002 camaro ecm is 140 seconds, about 2 mins. there is also a delay before you can restart the engine. time it and if its the same then its in protection mode. Quote Link to comment Share on other sites More sharing options...
jonus079 Posted March 6, 2008 Share Posted March 6, 2008 my mistake. its actually 409 seconds before shut down at factory settings. hopefully that helps. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 6, 2008 Author Share Posted March 6, 2008 my mistake. its actually 409 seconds before shut down at factory settings. hopefully that helps. Thanks for the info. Unfortunately it's definitely less than 409 seconds. Is there anything else that will trigger shutdown? Vin - I'm still not convinced it's not oil pressure as it starts up just fine it just shuts down after a few minutes ... like after it would reach some sort of 'shutdown timer'. Got the OBD port installed tonight so will borrow a scanner hopefully in the next few days and see what code I'm triggering. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
Bigdeezs Posted March 6, 2008 Share Posted March 6, 2008 I have to agree with Vin...there is no oil pressure safety on the LS1. I had as LS1 running with no oil pressure for a short period (had the wrong pickup tube o-ring) and it had zero oil pressure...also the sending unit only feeds the oil pressure guage nothing else and there are no other oil pressure related sensors. Quote Link to comment Share on other sites More sharing options...
jonus079 Posted March 6, 2008 Share Posted March 6, 2008 i looked over the engine protection and abuse management and i don't see anything else that would shut down the engine. however keep in mind that anyone with the software can change the protection time. maybe its possible they did this when they removed vats? as for the oil pressure sender, the parameters i saw were onlyt used to trigger a warning light. i may have missed something but when you hot wire the pump does it continue to run properly?? Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 7, 2008 Author Share Posted March 7, 2008 i may have missed something but when you hot wire the pump does it continue to run properly?? Perfectly ... at least it idles and revs good. Have not tried to drive it yet so I can't say what it does under load other than it acted fine when I pulled it in the garage. I'm borrowing a scanner and fuel pressure gauge from a guy at work so I'll hook that up this weekend and see where I'm at. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
Here comes trouble Posted March 7, 2008 Share Posted March 7, 2008 One minute run ....huh ! ..........With the price of gas, I can only afford to run an engine 3 minutes and 23 seconds. I need a gas govenor like you have. Hope you have the problem fixed. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 9, 2008 Author Share Posted March 9, 2008 Well I hooked up a fuel pressure gauge and scanner today. No codes which is odd because I was expecting fuel tank pressure sensor code at least. Fuel pressure ~60 PSI. Played with it a little and it seems to be fairly consistent that when I rev the engine as it comes back down to idle the fuel pressure starts to drop and eventually levels off to less than 20 PSI at which time it sputters to a stop. I did not try to idle for a long time to see if it would have stayed running if I didn't rev it. I'm stumped. Anyway I hot wired the fuel pump and took it for a spin for the FIRST time EVER with the LS installed. You still cannot wipe the smile off my face . First and second I can leave two stripes at will. Third I can leave stripes without a lot of effort. I did not push it 4-6 as it was the first outing. I've never owned let alone driven a truly fast car before (other than FSAE) so this thing is just insane ... comical really ... makes me chuckle. I'm sure at some point I'll get used to the power but man this rocks. Also on a positive note there were no unusual noises, no rattles, nothing broke, no vibrations, and nothing on fire. Could not have asked for more out of the first drive. Cameron PS to Here Come Trouble - it's worth a second job to pay the gas to drive an LS Z Quote Link to comment Share on other sites More sharing options...
Blown77Z Posted March 10, 2008 Share Posted March 10, 2008 I'm glad you got yours on the road at least, hehe. Mine's still up on jackstands waiting for it's wiring to be completed. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted March 10, 2008 Share Posted March 10, 2008 I suggest you to double check your fuel pump relay and your wiring to it. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted March 14, 2008 Author Share Posted March 14, 2008 It's fixed but ... not sure why? I hot wired it today and hooked a volt meter up to the PCM out to the fuel pump. Steady 14.5V for a ~15 minute drive. Hooked up the PCM to the fuel pump and she ran fine for until I shut it off. All I did was look at the wiring to make sure it was there and correct and pulled, tested, and re-installed the fuel pump relay. Scares me 'cause it's bound to happen again since I didn't really fix anything. I'm afraid ... I'm going to keep the jumper hot wire in the car for a while just in case. Man it takes off like a rocket if you can find traction. Tops out fourth gear before you blink. I might have to go down to the 3.7 or 3.5 gears from the 3.9 that's in there now. Can't wait for the first test and tune (autox) April 6 to really see what she has. Cameron Quote Link to comment Share on other sites More sharing options...
jonus079 Posted March 17, 2008 Share Posted March 17, 2008 ...I can't wait to take that first test drive..... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.