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

 

[Talonfiend]

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

This is coming from a guy who said he didn't have a boost leak and wow you did have a boost leak. You make no sense. How are you going to get the stock fuel system right when you installed a 255 Walbro with no AFPR?

Stop being a tool again, realize that you are experiencing fuel cut, and realize that you need an AFC.

Get a 1:1 raising rate AFPR you will need it for your 255. Get the 650cc injectors to get the proper amount of fuel.

What else could be wrong with your car? You no your hitting fuel cut so FIX IT!! If your still having problems go from there.

 

[stephen p]

it hit's fuel cut at 15 psi. and it was not even doing that untill a few nights ago. and right now, the boost is at at wastegate spring (just under 10) and it's just bogging, NOT fuel cutting on 10. fuel cut is violent. i have hit it before. also, i have had several dsm's with 255's and stock fpr. and the walbro does not really put out much more pressure it's the volume that makes it a better pump, and when i changed the pump, it did not affect any thing

it's not running like this because of no tune. something in the fuel management system is bad, and causing this, and an afc, injectors, and an afpr, WON'T fix it.. what ever sensor is bad needs to be replaced first. the problem needs to be corrected before i throw even more variables in there

oh and that boost leak? i fixed it, and it did not change shit. that was not the problem. it was a small leak

also, i have reset the ecu several times, and it did not change much.

 

[LiquidX]

He did not mention he has a new fuel filter.

It's in his first post


There are a few things you should do right now: 1. Reset your ECU (if you havent alraedy). 2. Get an AFPR (You should have one for the 255 regardless) and 3. Is your BOV over tightened or too loose?

My car bogged for a while and it was my BOV


We'll get this figured out. Are you still throwing codes?

 

[Talonfiend]

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

something in the fuel management system is bad, and causing this, and an afc, injectors, and an afpr, WON'T fix it..

You just contradicted yourself. Stop being stubborn, just get the proper setup FIRST then troubleshoot. I bet once you get the right setup up your car will be better. Good Luck.

 

[LiquidX]

I bet once you get the right setup up your car will be better. Good Luck.

He did say it was already doing this before the fuel pump though. If the o2 sensors are going won't that alter the fuel trims?

 

[stephen p]

You just contradicted yourself. Stop being stubborn, just get the proper setup FIRST then troubleshoot. I bet once you get the right setup up your car will be better. Good Luck.

if you had been paying attention to the thread, you would have seen that i changed the maf, and the car did a complete 180, and it ran awesome, the problem seemed to be 80% fixed, and what it lacked i could chalk up to needing a tune. and i put "SOLVED" in the title....

and then later that day, the car was up to it's old tricks again, so i put a "NOT" beside the "SOLVED.


you are a complete idiot if you think for once second, that putting an afc on would do any thing but complicate the situation. you can't go throwing another variable in there, when something in the stock system is not right

 

[Talonfiend]

He did say it was already doing this before the fuel pump though. If the o2 sensors are going won't that alter the fuel trims?

Yes, but the ECU would just run richer to save itself from running lean(causing detonation).

He's running an EVO3 16G w/ a front mount. He's getting more air, not to mention that its colder(denser) from the front mount. With the increased amount of air from the 16g and it being colder he needs more fuel. The 255 pump is great but its limited to the stock FPR(43psi). Had it been a 1:1 AFPR he would get more fuel for the increased boost. Anyhow the MAF sends a signal to the ECU telling it that there is too much air coming in. The ecu then see that there isn't enough fuel for the air coming in(lean condition). It pulls the timing. The afc will keep the MAF and ECU in check for the increased air and fuel.

But like Stephan P said there's something else wrong... I think its him. But we won't know till he runs the proper setup.

 

[Talonfiend]

if you had been paying attention to the thread, you would have seen that i changed the maf, and the car did a complete 180, and it ran awesome, the problem seemed to be 80% fixed, and what it lacked i could chalk up to needing a tune. and i put "SOLVED" in the title....

and then later that day, the car was up to it's old tricks again, so i put a "NOT" beside the "SOLVED.


you are a complete idiot if you think for once second, that putting an afc on would do any thing but complicate the situation. you can't go throwing another variable in there, when something in the stock system is not right

I feel so sorry for your car. So why did you get banned?

 

[stephen p]

i'm not banned. any mechanic will tell you that you to make sure every thing is working properly before you go adding a piggyback, and changing fuel and timing parameters. 10 psi, on the 16g is not more than the stock system will keep up with, and it is a problem that has gotten progressively worse.



also, why are you getting on source, and saying that i said "it won't hit fuel cut?" yes, it has just recently started fuel cutting on 15 psi, as stated, but it was not doing that at first, and it's still NOT fuel cutting on 10.. it's just bogging. not hitting a wall and cutting out!

 

[Talonfiend]

i'm not banned. any mechanic will tell you that you to make sure every thing is working properly before you go adding a piggyback, and changing fuel and timing parameters. 10 psi, on the 16g is not more than the stock system will keep up with, and it is a problem that has gotten progressively worse.

Ok you win, your right.

 

[brickyak]

Okay guys, this argument is going nowhere. The bogging down that you are getting is a symptom of the actual problem. Tuning a car that has a faulty part may temporatily solve the symptom, but at some point that component will fail. If a guy has a broken leg and you give him vicadin, he still has a broken leg. Here are a few things that might help you. You know you are having a fuel problem, so you need to look at everything involved in fuel delivery. Did you check your TPS to ensure it is within range? What is your fuel pressure at? Did you try cleaning your injectors?

 

[rick_dsm90]

Ok ive read through all this "purse slapping" and ive yet to hear anyone say anything about the ECU itself. You have a DSM so that means that you have a good chance at a shitty ECU or something someone might have "hacked" in some way. Im not saying that it is your problem but for some peice of mind and also to check off the list, pull your ECU and open it up and visually inspect it.

I had the same problem with my 1g and i couldnt figure it out for ever. then a friend came over and was like "dude check your ECU" guess what it was.....

 

[stephen p]

Okay guys, this argument is going nowhere. The bogging down that you are getting is a symptom of the actual problem. Tuning a car that has a faulty part may temporatily solve the symptom, but at some point that component will fail. If a guy has a broken leg and you give him vicadin, he still has a broken leg. Here are a few things that might help you. You know you are having a fuel problem, so you need to look at everything involved in fuel delivery. Did you check your TPS to ensure it is within range? What is your fuel pressure at? Did you try cleaning your injectors?

PRAISE GOD!

 

[Talonfiend]

I just can't wait till you figure out what the hell is wrong with your car.

 

[stephen p]

i just bought another tps, going to swap that in a few minutes and see if that's the problem

 

[stephen p]

i just bought another tps, going to swap that in a few minutes and see if that's the problem

 

[93blacktsi]

check your power transtior and your coil packs

 

[LiquidX]

i just bought another tps, going to swap that in a few minutes and see if that's the problem

Make sure you install it properly by testing the voltage.

 

[spaugh]

I agree with Rick_DSM90 check your ecu find one to swap it out with and see what happens.

 

[98gsxtuner]

Still regardless of what anyone says your gunna need a AFPR with that 255 that will completely over run the stock fpr. Believe me I know,the guy I bought my car from had a 255 with the stock regulator and I was running pig rich,now I have a Fuellab FPR and the car started running 10x better than it was.

 

[miniturbo23]

this is crap because my car has a similar problem but on a t25.. just wanna slap my mama! (mama=full turbo system)

 

[93blueGS]

You still running stock injectors, right? It may be going lean when you go into boost..

Get a logger and make a pull and see what it shows..

 

[miniturbo23]

what kind should i get?? I have AFC and a bunch of stuff to put in my car just waiting to buy new daily driver before i do and mess something up.

 

[stephen p]

well, i cashed in the warranty on the maf, swapped it out, and i could not find a tps, and i did not have a volt meter, so i just marked where it was, and moved it over a little bit, and once again the car has done a 180. it runs tons better than it did... NOW it runs like a car that needs a tune. before it would not run in positive pressure. now it is hitting 15psi again, and no fuel cut, and it pulls reasonably hard..


and you guys can say that a 255 will over run a stock fpr untill your ass bleeds, but it won't make it true.. i'm not saying in some situations it won't over run it, but i've had 2 1g's with a 255. (replaced because stock pump went bad) granted you won't be able to reap the full benefits of the pump, the difference in a walbro and a stock pump is VOLUME not pressure

 

[Talonfiend]

and you guys can say that a 255 will over run a stock fpr untill your ass bleeds, but it won't make it true.. i'm not saying in some situations it won't over run it, but i've had 2 1g's with a 255. (replaced because stock pump went bad) granted you won't be able to reap the full benefits of the pump, the difference in a walbro and a stock pump is VOLUME not pressure

Sure you don't need it.

But I was wondering, using the stock fuel lines and a 255 that pumps 2x the fuel vs. the stock pump.

How do you not increase the fuel pressure?

Using a 255 will increase your fuel pressure. AFPR will stop you from running pig rich in the lower rpm range.