Injector Help?

Tony R

Tony R

New Build is For Sale.
Joined
Dec 23, 2007
Messages
808
I'm looking at a 04.5 lly for a local guy. It has a no start condition. You can get it running with a little shot of ether. I have checked the balance rates with EFI live and all the injectors check out fine. After it is warm it will start on it's own after some extended cranking. Is there anyway possible to check the return rates of the injectors to see if or which one is bypassing to cause this condition?
Is there a way to check rail pressure also When I turn the key to start my efi drops out till truck is running so I can't really see the rail pressure that it's giving while cranking.
 
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Try pumping the hand primer while cranking the truck cold. If the truck cranks then you have an air leak which would be my guess of what is really wrong with the truck. If the injectors are leaking off the balance rates should show it. You can take the return line loose on the drivers side rear of motor and catch the fuel in a container if there is a lot of fuel coming out while cranking then you have a leak on the injector returns or the pump return. Also use the dvt function to max out the rail pressure and make sure that you are getting 23000psi.
 
Thank you I will try that and let you know the results.
 
Hey Phale how exactly do I make efi Live command 23000 psi on the rail. I just got the efi from my buddy to try this. We tried it on his 04.5 but no luck. I went to the dvt function then clicked on controls and tried increasing in the desired fuel control but no luck. The truck does have a fass system on it, could that still cause a issue with the factory fuel filter. Also is there a way to monitor the crankshaft and camshaft position sensor's using efi live. This is all new to me and just trying to help a guy out. Thanks for the help!!!
 
Make sure that you have the box checked for the rail pressure control as well. Sometimes on the LLYs it can take a couple of tries to get it to work.
 
The fass should rule out any fuel filter head issues since it is putting positive pressure to the cp3. what is the rail pressure while cranking? there is a PID for crank and cam sensor pules missed as well.
 
I'll double check i and get back with you. I do remember the rail psi was very erratic last time I had it hooked up compared to my buddies truck. His stays within 200-300 psi of desired, this truck was all over the place. For some reason when I try to start efi live cuts out and I am unable to read cranking rail psi. I uploaded all versions of efi live to my laptop tonight and borrowed his flashscan hoping to get this figured out.
 
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the cutting out could be low voltage, make sure the batteries are charged. See what the RP reading is with the key on and the truck not running, if it is still really irradic it could be a bad rp sensor.
 
Check the relief valve on the drivers side rail. Take the u-shaped hose off, pinch it off and put a piece of hose on the rail nipple and run it into a bottle, start the truck and see if it is letting fuel by. Should not have any. I have seen this cause hard start/no start.
 
I checked the rail pressure relief valve and it's not letting any fuel bypass. I held the truck at wot and did get 23,000 psi. The rail psi is calling for around 4800 psi and the truck is holding 5005 psi. I left the paper in the truck with all the balance rates wrote down, but it was anywhere from the negative on some injectors up to 4 on some injectors. After it is warmed up you can tell it is missing and can hear a fuel knock. I'm lost to ideas. Leaning toward replacing all eight injectors?
 
anything over +4 or below -4 at idle in park designates a bad injector. before you go dropping a lot of cash on a new set, swap some of the injectors with high rates with some of the lower ones and see if the balance rates move with the injectors.
 
Here is a close estimate of rates
1 -1.70
2 2.50
3 -.36
4 -.30
5 2.20
6 2.98
7 -.40
8 -1.18 Why does some run in the negative and some run positive? Thank You phale I will try that as soon as i get a chance
 
All of those rates are ok. The numbers are how much the injector is adjusting fuel to keep each cylinder producing the same power as rest of them.
 
That was with the truck in gear and holding the brake, after the truck was completley warmed up. What could I try from here? Should I look at the cam and crank sensor? If these aren't reading right should I see some missed counts?
 
Injector rates look fine especially with it being in gear. There is a pid for both cam and crank pules missed. It could also be a pump going south, and it only supplies enough pressure with the added speed from firing on either.
 
Is there any way to test? Ihave a crankshaft sensor pulses missed but no camshaft sensor pulses missed pid on the efi live.
 
misses

Not sure on lly, but I have seen the same problem on lb7 trucks when the cam or crank pickup comes loose. Reluctor wheel
 
Last night the owner brought me two new batteries and a new fuel filter. I wanted to check the fass system on it and when I removed the stock fuel filter, I turned the fass pump on. I did not get no fuel coming out of the filter housing even with the key on. What is the module called that the inlet fuel line comes into then goes out of to the filter housing and what is the purpose? After I put the new filter on and gave it a small shot of either it fired right up. I took it for a test drive and sometime around 2200 rpm's the truck wants to cut out a bit. I let it warm up for awhile then shut the truck off and it starts right back up. I'm going to check it today after work to see if it will start. I was mainly wondering what that module does and if the fass was even supplying fuel to the filter.
 
That is the FICM (Fuel injector control module), the fuel just flows through it to help keep it cool.
 
If you take the line going from the FICM to the fuel filter loose and turn the key on does the FASS pump fuel?
 
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