05-12-2014, 11:48 PM | #26 |
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Re: Checking for spark?
Just checked out your build thread to see what kind of pump you're using and I think I found your problem, the truck isn't low enough..... Truck looks killer man! However I didn't find out what you're using for a pump. If you are getting fuel out of the filter, but not at the rail, something is seriously wrong since there should be no restrictions between the two. First and foremost, you should really get a fuel pressure gauge instead of just pushing in the schrader valve on the rail. That said, you should have pressure at the rail after the pump shuts off for quite a while. If the pressure is bleeding off, then you've got a leak somewhere. Could be the regulator like you said, but if it's not leaking fuel when you pull off the vacuum line, I would suspect it's going to be good. To be loosing pressure, you could have a stuck open injector, but you probably would have found that out by now, because it will hydrolock an engine in a pretty short amount of time. If that's not the case, then it could be the pump, if it's an intank pump, make sure the hose between the sender and the pick up tube is still on and the clamps are tight and there are no holes in it. Get a fuel pressure gauge and see what the pressures are actually reading and go from there. Just because you are getting a large amount of fuel out of the filter doesn't mean you have the correct pressure, and "large amount" can be a relative term, if you are not sure what the amount should be, it may just seem like you are getting the right amount when actually you are not. Also what I meant by the pump being wired backwards was the positive and ground wires on the pump reversed. They will still pump fuel running in reverse, but it won't be enough. Make sure the power is on power and ground is on ground.
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05-13-2014, 01:01 AM | #27 |
meowMEOWmeowMEOW
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Re: Checking for spark?
Have you hotwired the fuel pump yet so you KNOW you'll have full fuel to the rail? You can't blame the regulator if the fuel never gets to it.
So when the truck goes key-on, it runs for the 2 seconds, and is looking for Rpm's. It won't command the pump to run again, until it sees Rpm. The hotwire bypasses this. If you do this, and it still won't fire, next step is to verify fuel pressure (with a gauge). As part of this, if the crank sensor is not hooked up, damaged, etc....then that will trick the engine into not "Seeing" those rpm's as I mentioned above. This will cause the fuel pump to not run, and it will also cause spark symptoms.
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05-13-2014, 10:47 AM | #28 |
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Re: Checking for spark?
So i got a fuel pressure gauge and i get no pressure at all whether two seconds or crank. i do smell a fuel pretty strong in the engine bay, possibly injector/injectors are stuck open being that i have no clue how long this motor was sitting or last started
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05-13-2014, 08:29 PM | #29 |
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Re: Checking for spark?
I did also try to jump the fuel pump off battery. pump ran fine but still no fuel pressure at the test gauge.
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05-13-2014, 10:26 PM | #30 |
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Re: Checking for spark?
Not sure if you have a return on the fuel system if you do do did you cross the lines and your pumping into a check valve
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05-14-2014, 08:38 AM | #31 | |
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Re: Checking for spark?
Quote:
Next step i guess will be pull line from fuel rail and see if it is pumping gas to the rails. For piece of mind (im sure a waste of money) i did install a new pressure reg on the rail to eliminate that as a possibility. Now lets say i am getting fuel to the rail after testing it...what else in the rail could cause it to get zero pressure at the schrader valve? |
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05-14-2014, 09:04 AM | #32 |
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Re: Checking for spark?
Yeah, I would pull the feed line and make sure you're getting presure there, if you are, then there should be no reason not to get fuel at the gauge. Unless there's some junk in the rail, like a big bug crawled in there when it was sitting open. I wouldn't think it will be likely though. You could try removing the schrader valve from the rail to make sure its opening, they unscrew just like a tire valve stem an take the same tool. If you are not getting fuel to the rail but are getting fuel out of the filter you have a clogged or kinked line somewhere. They are bad about kinking at the flex part at the rail but you can't see it because of the outter covering on them. What kind of filter are you using?
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05-14-2014, 09:13 AM | #33 | |
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Re: Checking for spark?
Quote:
I am using this filter http://www.summitracing.com/parts/rus-650130 |
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05-14-2014, 10:27 AM | #34 | |
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Re: Checking for spark?
Quote:
We HAVE fuel pressure gentlemen! So i did try to start it for a couple times and nothing. Beacause it kinda (cough) started with starter fluid im guessing maybe getting new injectors? |
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05-14-2014, 10:29 AM | #35 |
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Re: Checking for spark?
Does it matter that i dont have the MAF hooked up and plugged in while just trying to start it?
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05-14-2014, 10:57 AM | #36 |
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Re: Checking for spark?
great news you got it figured out. I would bet your injectors are plugged up or stuck. They can be cleaned, you can clean them, send them off or you can get new ones.
It will run without the MAF you will get codes of course. The temp should also be in your MAF so it may think it is cold and throw a bunch of fuel in. Good luck, one step closer.
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Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!" |
05-14-2014, 11:12 AM | #37 | |
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Re: Checking for spark?
Quote:
Are you sure the injectors are firing? Can you hear them clicking on and off, or have a noid light to see if they're getting the signal to fire during crank? |
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05-14-2014, 04:42 PM | #38 |
meowMEOWmeowMEOW
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Re: Checking for spark?
If the tune is decent and VE tables are close, it should idle alright, just probably boggy and sloppy on the pedal.
The maf is just a quick molex plug tho, no reason not to have it for startup.
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05-15-2014, 07:43 AM | #39 |
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Re: Checking for spark?
I dont have a noid light but have an extra spark plug so i wrapped a ground wire tight around the treads of extra plug and had it plugged into the coil and tried to crank and see spark. i only checked three and none had spark. makes sense as to why starter fluid wouldnt fire it up completely. going to check the others this morning in this fashion. Please someone chime in if me checking for spark this was doesnt work, i dont want to be chasing an electrical problem if im wrong in this test..
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05-15-2014, 08:03 AM | #40 |
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Re: Checking for spark?
Noid lights are for checking for injector pulse. If it sputters on starting fluid, I would lean towards clogged injectors, since that is way more common than having more than one coil go bad all at once. Take them out and soak them in some Seafoam overnight and then put them back in and see if it starts. You can also check them with a 9v battery to see if you hear them click, just do it quick, don't hold the power on for very long.
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05-15-2014, 10:25 AM | #41 |
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Re: Checking for spark?
I agree, i doubt 3 coils to go bad at same time which leads me to believe it has to do with harness. i was meticulous about the pinout from lt1swap.com but i have heard from others the the (current performance) ls fuse box/relays might be wired wrong on their end to make it run. my harness looks like crap anyway and i think i might just call bill (bp-automotive) and just buy something i know will work. its just getting frustrating
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05-15-2014, 11:11 AM | #42 |
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Re: Checking for spark?
Didn't you say it tried to start on the starting fluid? If it tried to start, then I would think the wiring would be alright. If you suspect the fuse box, have you checked for power at the coils and injectors? If you have power on those pink wires, then check all the other pink wires for power and the two orange wires for constant power. If all your powers are good, make sure you have your grounds grounded good. This is most likely going to be something simple you are overlooking. You can basically take all the pink wires and the two orange wires and tie them all together, add power to them and if you have fuel and grounds hooked up, it will start (VATS deleted of course). I have started several on the garage floor this way in less than a half an hour. But before condemning the harness, have someone turn the engine over while you listen and feel the injectors to see if they are working. You can put a large screwdriver on one and put your ear on the handle to act as kind of a cheap stethoscope, and you should head an audible "click", you can also feel it. If you don't get that, then you need a noid light to make sure it's getting a signal, but if you have power to them and your grounds are good, they should work. If there's no signal to them, check your crank sensor behind the starter. Make sure it's plugged in, and if it is, pull the loom off of it and trace it for as long as you can to make sure the wires are not damaged. If you feel a soft spot in the wires it could mean the wire is broken inside the insulation. But before all of this, I would spray a little more starting fluid in it and see what happens. Open the throttle body and spray it in the intake, just don't go crazy, a second should do it (count one Mississippi), then try to start it and report back with what happens.
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My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
05-15-2014, 05:25 PM | #43 |
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Re: Checking for spark?
got mine started today..turns out it was because I didn't block off my egr port on the intake manifold
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05-16-2014, 08:15 AM | #44 | |
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Re: Checking for spark?
Quote:
I do have the big port blocked off on the side but not the tiny port on the top yet...think that matters? what did you use to block the one on top? |
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05-16-2014, 10:32 AM | #45 |
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Re: Checking for spark?
I have been thru a couple of these issues and they were both stuck injectors. It seems to be very common with these.
On my first one I unhooked the coil packs and raised the injectors out of the manifold. I hooked up one at a time and with my son cranking the motor I tapped the injector till it fired then went to the next one. It may not have been the safest... but I am cheap and it worked for me. That was 10 years ago. I think fuel has gotten worse around here with the amount of alcohol in it. Just recently my buddy had the same issue we tried that and got some to work but we took all his out stuck them in a coffee container and cover them with sea foam. He decided to strap them to his law tractor and mowed that "agitated" them and cleaned them up good. They fired up great and have been running ever since. Poor people have poor ways as the saying goes. Don't panic just slow down and you will get it. When I did mine there was not nearly as much information out. Good luck. Dave
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Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!" |
05-16-2014, 01:33 PM | #46 |
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Re: Checking for spark?
Probably...if the egr port in the intake manifold is not blocked properly it wont start....i used a 1 3/8' freeze plug and i also got about off kit for the ports on the exhaust manifold.
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1983 C10 Silverado 5.3 swap 1974 C10 lwb 5.3 swap(sold)...http://67-72chevytrucks.com/board/sh...d.php?t=614122 2001 BMW 530i 5 speed 2019 Nissan Titan SV Midnight 1979 Datsun 210 4 door 1980 Datsun 120y(back home in Trinidad) |
05-17-2014, 08:16 AM | #47 |
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Re: Checking for spark?
So i bought new injectors and will try to get them in this weekend (time permitting). At least i will be able to rule out stuck injectors at that point.
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05-17-2014, 09:07 AM | #48 |
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Re: Checking for spark?
why would you buy new injectors? the old ones can be soaked in seafoam and unclogged/stucked. i mean i know its quicker but man them things cost an arm and leg
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05-17-2014, 09:12 AM | #49 |
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Re: Checking for spark?
Cuz im in panic mode! Always empties my pockets lol
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05-17-2014, 10:45 AM | #50 |
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Re: Checking for spark?
Well....new injectors...still no start
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