bad maf, bad ecu? wtf? (bogging under boost)NOT SOLVED

[stephen p]

ok, so my car runs like ass. it was running ok, but just slow. now, whatever the problem is, has gotten way worse. i did the boost leak test. and all is good. so here's the deal now it's gotten to where when you give it gas, and it goes to boost, it it's like it hits a wall, it will boost to 15 lbs, but it goes no where at all... the only way the car is drivable is to drive out of boost, and feather the gas. i put in a walbro 255 last night, and the filter is new. any ideas, before i go throwing parts at it? it's throwing a fuel trim code

 

[LiquidX]

You did plug in your MAF connection right? If the MAF isn't plugged in, the car will run like crap.

Do you have an AFPR? The 255 pump will over run the stock FPR.

 

[stephen p]

the maf is plugged in. and i have the stock fpr. but since i got it a week ago, it has ran like crap, and had no power. i changed the fuel pump night before last, and it made no difference, good or bad. the car did start running REALLY shitty untill last night. and i've had several dsm's with stock fpr's and 255 pumps.

also, the car will run ok on like 5psi if you feather the gas. but when you go WOT, it falls on it's face as soon as it goes into positive pressure.

 

[LiquidX]

How are your plugs looking? It's possible one or more is fouled up bad and the excess pressure isn't allowing the spark. Someone else may want to verify that though.

 

[stephen p]

i pulled the plugs 4 days ago or so, and they all had a nice brown burn pattern, but i do have a new set, it could not hurt to throw them in, but generally when plugs go bad, it starts running rich, you can smell fuel, and it idles crappy. i think it's going lean, and i don't smell fuel

 

[LiquidX]

I'm about at the end of my knowladge on this, but is your timing jumped at all?

 

[stephen p]

cam timing is dead on. checked that last night.. thanks for your help though.

 

[stephen p]

ok, so i changed the plugs a few minutes ago, because i read, that plugs and wires can be the cause.. well, no dice. brand new ngk's (the guy who i got the car from gave me a spare set) gapped at 0.28 the plug wires look brand new, and the guy said he replaced them very recently.

also, when the hesitation i'm getting does not feel like fuel cut. but it's more just bogging down really bad

so, so far.. compression test is pretty much 150 all the way down (with in 3psi) cam timing is dead on. plugs and wires are brand new, and fuel pump is a brand new walbro 255. boost leak tested to 20 psi.

throwing a cel code p1070 fuel trim bank one

 

[stephen p]

ok. well, i just got from pull-a-part, grabbed a $25 dimante maf, and it runs a tremendous amount better. it still launches like dookie. and has a little bit of stumble around 4k, but i'm just going to chalk that up to the car needing a tune. i'm sure when i get my afpr, afc, and injectors it will be a screamer

 

[LiquidX]

Good to hear it's running better. You said you have a code, did you search that to see what others have come up with, with what may be the real problem?

 

[jdodds]

if you have a 6 bolt swapped in, check your base timing. I was having troubles with mine recently and once I adjusted the timing, it ran a ton better.

 

[stephen p]

i still have a 7bolt. i don't think crank walk is an issue with auto cars. and i have not checked to see if it was throwing a code again, but the fuel trim code was probably from the maf

 

[stephen p]

ok, well before i set this car on fire, does any one have any more ideas? i thought it was fixed, but i guess not so much. it's up to it's old tricks, and is now fuel cutting at 15psi, and it was not doing that before. and at 10 psi, it just boggs, and won't pull itself past 5k.

 

[LiquidX]

Check out the old code and see if there is a new code. Compare if you can, and find out what others say about the thrown code. It aint fixed until it's fixed. On my car I was having random misfire codes thrown and now it's in the shop getting a new engine... Not saying that's the reason but you never know what *could* happen. So deffinatly see if there is a code and do some research on the old code.

 

[Talonfiend]

ok, well before i set this car on fire, does any one have any more ideas? i thought it was fixed, but i guess not so much. it's up to it's old tricks, and is now fuel cutting at 15psi, and it was not doing that before. and at 10 psi, it just boggs, and won't pull itself past 5k.

97 awd auto car
evo3 16g
hardpipe kit
255 Walbro
front mount
full exhaust
road surge manual shift box

i'm sure when i get my afpr, afc, and injectors it will be a screamer

You need something to tune with, this is why your hitting fuel cut. An evo3 16g flows way more than a T25.

 

[stephen p]

yesterday morning it was running 15 psi, with no problems. the problems seem intermittent.. i doubt the car is going to forget it's untuned and run fine one minute, and run like crap the next. also, i've had untuned dsm's with 16g's before. they ran fine. something is wrong. and it's running just as shitty, if not shittier on 10 psi

 

[Talonfiend]

Yup, something is wrong. Things will be better once you get your other parts...

 

[LiquidX]

Did you figure out where the problem lies with the thrown CELs?

 

[saechao04]

You may check how your injectors are flowing if they are stock and never been replaced. I would also look at the fuel filter as its a 12 year old car now and probably never been replaced.

 

[LiquidX]

You may check how your injectors are flowing if they are stock and never been replaced. I would also look at the fuel filter as its a 12 year old car now and probably never been replaced.

He would just need to run injector cleaner for them and he has a new filter to boot.

 

[saechao04]

He would just need to run injector cleaner for them and he has a new filter to boot.

He did not mention he has a new fuel filter.

 

[Nick2gGST]

did you check the flux compacitor? jk...I did a fuel pump on my old car and had this EXACT same problem..when you changed your fuel pump what did you use to clame your sending and returning and evap lines? the issue with mine was a SLIGHTLY crimped hose. i fixed it and still ran like crap for a while but eventually got back to normal.

 

[stephen p]

fuel filter is new, and i just used the factory clamps on the lines, the problem existed before the fuel pump

 

[Talonfiend]

When are you getting your injectors, AFPR, and AFC? That's when you will stop hitting fuel cut. You got the boost up to 15psi, I guess you forgot about the boost creeping or spiking. Seems you need to TUNE your car.

Oh and guess what you car will run fine then turn to shit. When you disconnect the battery you reset your fuel trim then your ECU makes the adjustments. Stop being a tool and get your setup correct.

 

[stephen p]

on <10 psi it's bogging down, and not falling on it's face.. i want to get the stock fuel system right before i go tuning the thing, because when put on a safc, injectors and my afpr, IT'S STILL GOING TO RUN LIKE SHIT, BECAUSE SOMETHING ELSE IS ####ING WRONG. fuel cut is the LEAST of my concerns

yes, it needs to be tuned. but the current problems are not tuning related. no shit it won't run 100% untill i get it tuned, with bigger injectors, but it's still got bigger problems than that, and i need to address those first

stop being a tool, and realise that there are other problems