Losing boost at anything over a quarter throttle

[Robertjw]

Need some suggestions, I had a new fuel pump put in a couple of days ago. Last night I was driving and at WOT my boost gave out now it gives out all the time except if its about a 1/4 of the way down. Could my computer being reset have anything to do with this? I tried reading some old post but couldn't get anything concrete to try to fix this. Please any help would be great and I don't have and logs or a scanmaster yet so it's kind of hard to figure things out thanks in advance

 

[Chuck Leeper]

Check the hose clamps on the piping...
" Please any help would be great and I don't have and logs or a scanmaster yet so it's kind of hard to figure things out"...Stay out of WFO operation without scan tool info. Loss of boost may become the least of your concerns, if you don't know what's going on.

 

[pacecarta]

check for the obvious stuff like blown off up pipe or intercooler hose , disconnected MAF sensor
if all hoses and pipes are good youll need to know your O2s/maf reading are when this happens
put a fuel pressure gauge on it (temporary windshield mounted gauge) and verify that pressure goes up 1-1 with boost

no scanmaster is not good
you may have already popped the headgasket
any water in the oil , air blowing out the oil fill tube/ air breather?
any funny pft pft pft.... sounds under hood?

 

[Robertjw]

Yea I hear the pft pft sound when it starts to cut out like it shooting air back through my air filter. I just had my head gasket done like a month ago so I don't think it's that

 

[Robertjw]

At least I hope not ill have to check to see if there anything but oil on the dip stick today

 

[pacecarta]

Yea I hear the pft pft sound when it starts to cut out like it shooting air back through my air filter. I just had my head gasket done like a month ago so I don't think it's that

trying to find the logic in this statement ...
gave up

did you use the cheap foil faced header gaskets . you may have blown out a header gasket
best gasket is.the way they came from GM... no gasket

 

[forcefed3.8's]

Is the fuel pump keeping up? MAS no good.

 

[haywire4130]

At least I hope not ill have to check to see if there anything but oil on the dip stick today

Your oil wont necessarily have coolant in it if your gasket is blown, especially if youre hearing a pft pft... check for coolant leaking or gasket pushed out between cylinders 1 and 3 right below the drivers side header flange.

 

[turbo nasty]

I was psi testing my GN from the compressor inlet with the rockers pulled several years back and the up pipe to IC hose connection would breaks seal at 17 psi and then reseal at 15ish.
I never knew this was happening when driving and it lead me to erratic boost, transitional KR, etc.

Secured connections and all was well.

 

[LEGACY_GN]

trying to find the logic in this statement ...
gave up

did you use the cheap foil faced header gaskets . you may have blown out a header gasket
best gasket is.the way they came from GM... no gasket

I think he is referring to the blow back from the turbo through the air filter when you let off the gas and close the throttle. Sounds like a fuel issue to me. Running out of gas and cutting out.

 

[lrayzer]

Last time that happened to me it was a clogged fuel filter, maybe they did not clean the tank and disturbed a great amount of sediment during the pump change.

 

[Chuck Leeper]

Bottom line: Get a scan tool and then ask for help, once you have some data.....

 

[Robertjw]

Thanks for the advice, to chuck sorry but I just don't have the extra 250$ right now to get a scan tool I was just looking for some things to check on my own. And yes, I do understand that having a scan tool for these type of cars is a need but I just spent 1500$ or so on the pump and head gasket to get it running so a scan tool was at the bottom of the list I think it's something to do with my fuel because that's all that's recently changed.

 

[turbo nasty]

Devils advocate here...the HG would have not blown if you had a scantool.

Scanmaster or equiv is like the first thing...TR 101 basics and concepts

 

[Robertjw]

Yeah, i get that but little did you know i just bought the car and these where the things wrong with it to get it running so either i by a scan tool for a car that doesnt run or i get it running like i think a sane person would want to do first but thats just me. Sorry for being a rookie with this stuff and not posting DaTa but im not rich and i bought this car for cheap so thanks for all the help and suggestions some of you provided me with.

 

[earlbrown]

Try to keep the spending on your car as low as possible.

When you get fed up and sell it for a loss, it'll minimize how much money you hemorrhaged fighting with it.

There are cheaper ways to scan than the scanmaster, but not being able to monitor an engine that's already not running is like saying you can't afford oil so you're just going to run it dry.

 

[LEGACY_GN]

A scan tool is important but I think everyone is being a little harsh. I didn't have one for the first 5 years I had my car and I ran 11.40's with it. My friend tuned it and I didn't mess with it after. Set it and forget it. Find someone that can do that for you and you'll be good. Get on the local forums. Thankfully everyone in Houston is extremely helpful. I was ready to sell mine after the first year as I didn't know all the tricks and standard issues with these cars. My cam wiped 6 months after I got the car. Through friends we got it rebuilt and back on the road.

 

[earlbrown]

I will admit it was harsh... but your example isn't exactly apples and oranges. You were driving a mechanically sound car in a good state of tune with out a scan tool. In that instance you're fine until something acts up.

In the OPs case, the car isn't running right and it's no where near uncommon for these cars to have several issues at once.

Either get tired of blowing it up, put a carbed 350 in it, or try to enjoy breaking parts and spending money instead of driving. Unfortunately the car is going to insist on that. These cars will not run right unless everything is in line.

 

[Robertjw]

Well for the people that would like to help my situation. I know that its not fuel related i hooked a fuel gauge up and watch it as i was going into boost and the fuel went up 1-1. I dont see any leaking fluids or loose connections with the hoses to the turbo or my headgasket. Any other things i could check. My neighbor just happend to have an otc2000 scan tool with the gm chip does anyone know about this tool like what it can do or not do?

 

[LEGACY_GN]

Just to verify, you did check all the hoses to the intercooler right? It happened when you were at WOT, and that's when hoses blow off or come loose. Check them real well and make sure they're all tight because it really sounds like that.