5.3 not running good while driving
Thread Starter
Staging Lane
Joined: May 2010
Posts: 71
Likes: 1
From: El Paso, TX
5.3 not running good while driving Good morning, I have a problem with a 5.3/4L60E that I installed in a 66 chevy truck. When the truck is on park, and you step on the gas, the engine sounds good, but once you put it on drive, and you step on the gas, if feels like the engine has no power, it moves, but that is it, if you step hard on the gas pedal, it does not respond as it should, and I am saying as it should because I have a 4.8/4L60E on a 76 Ford, and that thing has power, it moves the truck fast.... Now, the gas tank is from a jeep, and the pump is an in tank set up that I bought from Novak that fits in the tank... Is for an LS1 engine swap for jeeps, so it should give you the pressure. Could it be, that once you are in drive, the fuel pump does not have the pressure required? The check engine light is not on, so no codes. Could it be a bad pump?? Any one had similar problems?
Thanks for your help
Thanks for your help
it does not respond as it should, and I am saying as it should because I have a 4.8/4L60E on a 76 Ford, and that thing has power, it moves the truck fast
Thread Starter
Staging Lane
Joined: May 2010
Posts: 71
Likes: 1
From: El Paso, TX
No, when is on Drive, if you step on the has it does not revs up, and if you step all the way on the gas, it feels more like it wants to detonate. The tranny does shift, that is why I am thinking the fuel pressure drops and not enought fuel goes into the cylinders. Is there a way to test if the fuel pressure is constant when you are driving.
Thanks
Thanks
Connect a fuel pressure gauge to the rail and watch it as you drive. Best solution is use an electronic fuel pressure gauge and datalog it with the other parameters in the PCM, but most people don't have access to do that.
You need 58 PSI at the rail all the time or the engine will not perform as desired. Don't be alarmed if it fluctuates a bit as the engine revs under load, it simply needs to stay within 3-5 PSI of 58.
You need 58 PSI at the rail all the time or the engine will not perform as desired. Don't be alarmed if it fluctuates a bit as the engine revs under load, it simply needs to stay within 3-5 PSI of 58.
No, you'll need some kind of a gauge. It does sound like your fuel pressure is low. Not sure about the specs on the Jeep pump. What are you using for a regulator? Could also be the hose between the pump and sender has a hole in it or is loose and losing pressure inside the tank.
Thread Starter
Staging Lane
Joined: May 2010
Posts: 71
Likes: 1
From: El Paso, TX
According to NOVAK webpage it will deliver the 58 psi required, and they sell this pump for the LS swap.
http://www.novak-adapt.com/catalog/f...uel_module.htm
The regulator is located in the fuel rail. I am going to get e fuel pressure and test it.
I installed a fuel filter, one with 40 microns I believe, but I read somewhere the filters the trucks came with are not 40 microns. I will remove the filter and see if is dirty.
Thanks
http://www.novak-adapt.com/catalog/f...uel_module.htm
The regulator is located in the fuel rail. I am going to get e fuel pressure and test it.
I installed a fuel filter, one with 40 microns I believe, but I read somewhere the filters the trucks came with are not 40 microns. I will remove the filter and see if is dirty.
Thanks
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Within HP Tuners you can log injector duty % and see what it's at. The problem is you kind of need a baseline to determine what is normal for your engine, but for example on a stock (or any well designed fuel system) it should never go past 75 or 80% at wide open throttle.
My guess is you are hitting that far before you get to WOT. I would check static fuel pressure (pressurized with the engine off) and see how long it takes to bleed down, and running fuel pressure at idle. If it drives as bad as you say you probably won't have to drive the car to see it's low.
Things to look for off the top of my head are a pinched hose or fuel line, bad regulator, bad filter, bad strainer or poor pickup from the tank itself.
One thing to note: if you have a pressure AND return at the rail, the regulator is on the rail. If you ONLY have pressure, the regulator is elsewhere and the thing that looks like a regulator (pictured below and stolen from the Novak site listed above) is actually a pulse damper and never goes bad.
My guess is you are hitting that far before you get to WOT. I would check static fuel pressure (pressurized with the engine off) and see how long it takes to bleed down, and running fuel pressure at idle. If it drives as bad as you say you probably won't have to drive the car to see it's low.
Things to look for off the top of my head are a pinched hose or fuel line, bad regulator, bad filter, bad strainer or poor pickup from the tank itself.
One thing to note: if you have a pressure AND return at the rail, the regulator is on the rail. If you ONLY have pressure, the regulator is elsewhere and the thing that looks like a regulator (pictured below and stolen from the Novak site listed above) is actually a pulse damper and never goes bad.
Last edited by gofastwclass; Mar 20, 2014 at 03:50 PM. Reason: Added pic stolen from Novak's site
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Thread Starter
Staging Lane
Joined: May 2010
Posts: 71
Likes: 1
From: El Paso, TX
thanks for your hellp, I am going to check the injector duty % first, and then the static pressure. Also, going to remove the filter and check it.
The regulator is on the rails, it has a vacuum connection to it.
The fuel lines are braided from the rear to the rails, so the problem might be from the fuel filter to the fuel pump. Unless the pressure regulator is bad.
rpturbo, what do you mean, like having bank 1 o2, on bank 2??
fire67bird, is not a drive by wire..
The regulator is on the rails, it has a vacuum connection to it.
The fuel lines are braided from the rear to the rails, so the problem might be from the fuel filter to the fuel pump. Unless the pressure regulator is bad.
rpturbo, what do you mean, like having bank 1 o2, on bank 2??
fire67bird, is not a drive by wire..
Thread Starter
Staging Lane
Joined: May 2010
Posts: 71
Likes: 1
From: El Paso, TX
I just check the fuel pressure with engine running 46 psi, when I step on the gas the fuel pressure drops, is that normal for the fuel pressure to drop. Ok 46 is below the 58 needed, could it be a bad fuel pressure regulator??
Thanks for all your help
Thanks for all your help
Your problem could still be a leaking injector, damaged line, regulator, filter or the pump and pickup itself.
I would check those things in the order I listed which is also the cheapest and easiest then make sure they are in working order. Sometimes the high pressure line between the in tank pump and fuel line will get pinched or compressed causing low fuel pressure. I've seen people use incorrect fuel line which isn't rated J30R10 (submersible) and it deteriorates in a short time.
Might try unhooking the vacuum line to the regulator and see what it does. With the line unhooked, it will max out your fuel pressure, so if you don't get at least 58psi, then either your pump isn't putting out enough pressure, you're losing pressure somewhere or something is restricted (pinched fuel line, clogged filter, ect).
Might try unhooking the vacuum line to the regulator and see what it does. With the line unhooked, it will max out your fuel pressure, so if you don't get at least 58psi, then either your pump isn't putting out enough pressure, you're losing pressure somewhere or something is restricted (pinched fuel line, clogged filter, ect).
5.3L Flex Fuel engine 2001-2004, 48-54 psi with vacuum line disconnected
5.3L Standard Fuel 1999 to 2003, 55 to 62 psi with vacuum line disconnected
No...I could be wrong, but I'll bet you have a bad pump...
I had a customer install one of those pumps, and it wouldn't keep up with his stock 5.3.
