Runs fine at idle, but seems to starve when the gas is hit - Page 2

gtboiii11 · #16 08-14-2005, 10:07 PM

the truck will start with a bad pump!!! the pump is losing power and not pumping enough fuel pressure, this is exactly what happened to my truck, i would take it over 2000 rpm and the truck would stutter and stall out, due to the weak fuel pressure provided by the pump, th enegine is not getting the proper gas to stay running over 2000 rpms!!! forget the cpi !!!

BlazerLT · #17 08-14-2005, 10:42 PM

Quote:

Originally Posted by gtboiii11

the truck will start with a bad pump!!! the pump is losing power and not pumping enough fuel pressure, this is exactly what happened to my truck, i would take it over 2000 rpm and the truck would stutter and stall out, due to the weak fuel pressure provided by the pump, th enegine is not getting the proper gas to stay running over 2000 rpms!!! forget the cpi !!!

Bullshit, it also can be caused by the fuel pressure regulator blowing fuel out its seal at higher fuel pressure.

Stop acting like the fuel pump is the only cause to a performance loss on a CPI engine.

Until we verify whether or not he is spraying fuel all over the inside of the upper plenum, you have no right to say I am friggin wrong.

You don't see me saying it is not the fuel pump do you.

You don't have enough information to say that my idea is wrong so shut the hell up.

kthx.

gtboiii11 · #18 08-15-2005, 02:15 PM

your just a punk ass kid who got your truck off your mommy and daddy and really dont know much about it. You have the same answer to every damn question, you either say ignition switch or cpi. And you are always certain your right.

Rick Norwood · #19 08-15-2005, 02:22 PM

Quote:

Originally Posted by gtboiii11

your just a punk ass kid who got your truck off your mommy and daddy and really dont know much about it. You have the same answer to every damn question, you either say ignition switch or cpi. And you are always certain your right.

BlazerLT, Pull the plug on this guy.

s10blazerman4x4 · #20 08-15-2005, 02:25 PM

Originally Posted by gtboiii11
your just a punk ass kid who got your truck off your mommy and daddy and really dont know much about it. You have the same answer to every damn question, you either say ignition switch or cpi. And you are always certain your right.

Quote:

Originally Posted by Rick Norwood

BlazerLT, Pull the plug on this guy.

I agree Rick

hazzzmattt · #21 08-15-2005, 02:33 PM

go with the fuel pump and youre gonna be right. the fuel pressure test is gonna tell the tale. that's the right move, dont guess. youre gonna see the fuel pressure start to drop off at about 1500 rpm then youre gonna slam a pump in it then its gonna be fixed.

Rick Norwood · #22 08-15-2005, 02:38 PM

I've seen the same thing with a plugged fuel filter. Idle all day, but won't take the high RPM's When was the last time you changed your fuel filter?

calebcoe · #23 08-15-2005, 04:08 PM

I just changed the fuel filter the other day, the thing is that i could barely blow through it, so it really does make me wonder if it burnt out the pump. And as for you guys arguing, thanks for all the input, but you doods should just fight!

jsgold · #24 08-15-2005, 04:25 PM

To put my two cents in, get a fuel pressure tester. Best tool you could have with these trucks. Check and see what it is doing. Don't cost a lot and I think you can rent them at Advance. Then while you are at it go ahead and check for CPI problems/injector problems by removing the Vortec plate and remove the round assy under it. Can't hurt. Also, one thing I don;t think anyone has mentioned, the TPS (throttle position sensor). If it is goofed up would that not cause problems with higher speeds?

Flatrater · #25 08-15-2005, 08:59 PM

Without performing any tests it is imposisble to rule anything out as the cause.

But fuel pressure as well as fuel volume is critcal for this engine to run right. A 5 psi loss can cause this problem. You can also have the correct pressure but not enough volume of fuel. The pressure I believe should be around 55 psi and you should be able to fill up 1/2 od a soda can in 30 seconds time. That will tell you you have the correct pressure and volume.

Fuel filters and CPI's. Over the years I have done many CPI's in these trucks for the same complain as yours but a CPI is not the first thing I would try. CPI's are a costly item and that puts them dead last on my list of things to replace. Only when I run all the tests I can and have no bad results would I lean towards a CPI unit. Fuel filters would be one of the first because they don't cost alot and they are what traps all the dirt and sludge. Fuel filters can be installed wrong. They should have an arrow showing flow direction, installing the filter wrong would also cause a power loss.

Cats, TPS, O2, and coolant sensors can affect the engine. A partially plugged cat will give you decent idle but in the higher RPM's you would see a decrease in power and might mistake it for a trans slip. An O2 sensor that is skewed will affect fuel trim levels and it can add fuel or cut back fuel which would be felt more above idle. The TPS is an input to the computer which is used to determine fuel injector pulse along with the O2 and TPS.

I would first rule out the basics. The biggest mistake that techs make is to forget the basics and head right for the CPI unit only to find out after replacing it they still have the same problem. I will agree with BlazerLT 90% of the time their is a problem with the CPI, they are prone to failure but as a tech I only have one try to get it right. Since there realy is no test to rule out the CPI you need to rule out what you can and then you can look at the CPI as your problem.

BlazerLT · #26 08-15-2005, 09:05 PM

Quote:

Originally Posted by gtboiii11

your just a punk ass kid who got your truck off your mommy and daddy and really dont know much about it. You have the same answer to every damn question, you either say ignition switch or cpi. And you are always certain your right.

Because you know why, more often than not I AM right. If you have a problem with MY advice, that is fine, but don't cut up my help when you don't even know if I am wrong.

This is your first and final warning about the insults, I never insulted you.

gtboiii11 · #27 08-15-2005, 10:05 PM

first and final warning about insults? what are you going to do come to florida and do something? i think not, but you are the one who said that i was wrong when I GUARANTEE that i am right on this one, i have had every problem in the book with my truck, and with his described syptoms it is 100 percent the fuel pump, ill put my truck on it!!!

gtboiii11 · #28 08-15-2005, 10:07 PM

why waste 300 dollars of the guys money on a cpi when it is the pump for 70 dollars

FormulaLT1 · #29 08-15-2005, 10:10 PM

This thread served its purpose. If the thread starter has anymore questions feel free to PM a moderator or start a new thread. Lets all try to get along please, no insults is not too much to ask.

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