Blms in 90s, can't go past 1/4 throttle???

[fullahotair]

Well i have finally been able to get a chance to drive my car, after 5 years!!!! So not all too surpising, I have a few issues, I was hoping you guys might help me out with. First off, a few mods to provide some info : new CPT61, 3" dp, Trans +, 4" integrated MAF (with updated TRANS+ chip), extender chip, 009 injectors... (all new)

Ok, So i can't get into the throttle anymore than say 1/4 throttle or the car cuts out, hickups, etc etc... at which point you can hear some turbo flutter. The blms for the most part are in the 90's. I have messed around with lowering fuel pressure, and moving the BASE setting to B but seems to be of no effect. The Int always seems to be higher than 128, but the BLM won't go there...

After doing some homework, I am going to look at the plugs/o2 sensor. The 02 sensor oddly enough generally seems to be reading lean, (<750) when the BLM is in the 90's.

I just put the headers and everything on, and haven't notice any leaks upstream of the turbo...

Any help with trouble shooting or pointing me in directions to look..would be greatly appreciated...

I have powerlogger files i can send someone if interested.
Thanks,
Nate

 

[fullahotair]

Ok, so after a few more test runs..i have realized that the car starts to break up when it approaches 0 psi.... Does this clue anyone in? I am going to do some homework on MAP sensors and the such now...


Thanks,
NAte

 

[fullahotair]

nevermind on the map sensor...just learned that means nothing to the ecm...darn it!!

off to trouble shoot something else...


Nate

 

[GSTOY]

What is your fuel pressure set to? Is it breaking up at idle, or while driving? You mention that you are getting to drive the car after 5 years....whats the story? Has it sat, or did you restore?

Sorry for the questions, just need further info to try to help

Steve

 

[GNVYUS 1]

Huh, sounds like a Maf issue if tip in is stumbling, I'd contact Bob Bailey and pick his brains since you have a few of his products on the car ( he's at Fullthrottlespeed ).

Post data of the Translator ( switch setup ) and the Powerlogger file info.
Also post your fuel pressure line off and any other info you can remember that the Powerlogger might not tell us.

It easiest to tell if a leak exists if you post your IAC and BLM #'s in park while it's warmed up. But your symptoms don't sound like a leak would affect your car like this.

It literally could be gas with a ton of condensation in it etc, I doubt it but how was the car stored ( garage ) and did you top off the tank, did you drain it etc.

 

[TLIMITED]

Well i have finally been able to get a chance to drive my car, after 5 years!!!! So not all too surpising, I have a few issues, I was hoping you guys might help me out with. First off, a few mods to provide some info : new CPT61, 3" dp, Trans +, 4" integrated MAF (with updated TRANS+ chip), extender chip, 009 injectors... (all new)

Ok, So i can't get into the throttle anymore than say 1/4 throttle or the car cuts out, hickups, etc etc... at which point you can hear some turbo flutter. The blms for the most part are in the 90's. I have messed around with lowering fuel pressure, and moving the BASE setting to B but seems to be of no effect. The Int always seems to be higher than 128, but the BLM won't go there...

After doing some homework, I am going to look at the plugs/o2 sensor. The 02 sensor oddly enough generally seems to be reading lean, (<750) when the BLM is in the 90's.

I just put the headers and everything on, and haven't notice any leaks upstream of the turbo...

Any help with trouble shooting or pointing me in directions to look..would be greatly appreciated...

I have powerlogger files i can send someone if interested.
Thanks,
Nate

If you have a fuel pressure gauge with a hose on it that you can lay up by the windsield while driving,check fuel pressure when it starts breaking up.I had the same problem last year,the fuel pressure would drop off when it would start breaking up and it was at 0-2 pounds of boost just like you are describing.Turned out to be the fuel pump.Hope this helps!!!!!!

 

[fullahotair]

1. I have been doing a body off resto on the car. So the car is good shape, fresh hoses, plugs, wires, etc... The motor is from a donor car. I saw it run before i pulled it. No known issue prior to that. New hoses, injectors, intake gasket, header gaskets...

2. Fuel pressure is about 44 to 45 line off (Extender chip is to be at 45), and drops about 5 psi with line off. the fuel pressure fluctuates with throttle as it should...i can check tonight to see what it does when it breaks up...i can duplicate the problem by loading the breaks in drive...

3. New fuel pump, just put that in (before getting the car started), hot wired. (307).

4. IAC was at 19 at idle after a run, BLM was 108.

5. Trans Settings Dip switches on on off off BASE set at B (i put it there because i am running rich...didn't help much)

6. I realize it is running rich, but would a rich condition cause it break up when I approach 0 psi??

7. The car has fresh gas in it. I drove it the gas station to get it filled up..

8. I can the send the powerlogger file to anyone who would like to take a look...

Thanks guys, i appreciate the help!

NAte

 

[BlackBettie6]

alldata

i had a similar problem, it ended up being the fuel pressure regulator.take the vac line off of the regulator after its been run for a while and if it smells like fuel then its most likely your problem. hope this helps good luck man

 

[fullahotair]

thanks for replies... I checked the fuel pressure while the car was "breaking" up...the fuel pressure stayed fairly steady...it would blip between 40 and 42...

A few other things i checked tonight:

Grounds look good.

Coil pack falls within range hot and cold...11.33 cold/12.44 to 12.67 hot

When the car cuts out and stumbles....the fuel pressure blips with the engine, blipped between 40 and 42 psi (line on)

I unplugged the cam sensor, ran just as crappy if not worse, and ultimately stalled...ran too poor to drive...

I have powerlogger files upload on the fullthrottle site... Can't get the blms out of the 90's - Page 2 - Full Throttle Speed Tech Support

Anyone have any more suggestions on where or what to look for?

Thanks,
Nate

 

[notacarlo]

MASS AIRFLOW SENSOR

With the car idling.....tap the MAF with the handle of a screwdriver. If the motor stumbles then Bob's your uncle.


***ALSO CHECK***
Disconnect battery and re-seat the chip in the ECM.

 

[fullahotair]

Notacarlo...

What particular aspect leads you to the MAF? I am also looking to understand the "traits" of a malfunctioning sensor so it can help me in the future?


Thanks,
Nate

 

[notacarlo]

1/4 throttle death for one. It's just that it has happened to me soo many times and 8 times out of 10 in was a spent MAF sensor. They seem to operate fine in vac, but once you get into boost, they seem to lose track of airflow and the ECM has no idea where or how much fuel to add....so it doesn't. There's a pre-set table for idle/off idle fuel which is why the car seems to run fine. Once the air starts speeding up, the ecm relies on the sensor to meter then other fueling tables take over. So if it can't measure the increased volume of air the car will continue to use idle fuel tables. There's no fuel there.

It is just a good place to start while troubleshooting this problem. If it is the MAF, invest in a MAF Translator from Full Throttle and use the LS1 sensor. They are cheaper and abundant. Send your original MAF to Kirban for a credit as he has them rebuilt and then sold at a premium.

 

[fullahotair]

I see... I am already running the trans + with the full throttle 4" integrated MAF. I do have an LS1 MAF sitting on the bench...i could plumb that in to see if that makes a difference...


Nate

 

[notacarlo]

Do that for sure. Eliminate the possibility of it being the pipe/sensor. There were problems with that set up when they first came out. Bugs may be worked out now.

Wasn't aware you already ran MAFT. Still a strong possibility. Are the dips in the box set correctly? Have you added or removed fuel using the box?

If you use one of Mr. Baily's chips then the settings in the translator can be used. If you have one of Eric's chips the translator must be set a certain way and then never messed with.

You may already know all of this stuff, but like most of the threads on this site there may be someone who doesn't. So don't take it as I think you don't know your stuff.:biggrin:

 

[fullahotair]

Thanks for the reply….sometimes the most obvious stuff is the most overlooked, so I appreciate all questions no matter who trivial or elementary. As you said, perhaps a future reader will benefit as well.

I do have the dip switches and the BASE fueling set to recommended locations. (on on off off) (Base at 9,A, or B). I am also running the extender..

The only problem with plumbing in the 3.5” LS1 is finding a makeshift adapter to go from 4” to 3.5” just for testing purposes (i know you can buy silicone reducers)…hmmm

Thanks!
Nate

 

[TurboDave]

I see... I am already running the trans + with the full throttle 4" integrated MAF. I do have an LS1 MAF sitting on the bench...i could plumb that in to see if that makes a difference...


Nate

Is your translator version 6.25? What is your MAF BASE set to? What are your DIP switch settings?

 

[notacarlo]

can you remove the pipe and fit the LSI directly to the inlet bell of the turbo - wires may not reach

 

[fullahotair]

Hi Dave!

I got the Trans+ upgrade with MAF pipe...(can you put that chip in backwards and still have it run?? - 99% sure it is put in right...but just brainstorming)

The dip switches are on on off off

BASE settings - It is currently on B, of the (A, B, and 9 options)

The power logger files are on the fullthrottle tech site..(link posted above)



Notacarlo:
The turbo inlet bell if 4"....good idea though...

Thanks guys!
Nate

 

[Blazer406]

The only thing that jumps out at me.... is looking at the datalog 062308C.dat

Get to the area where the TPS is the highest... still not WOT... but close (4.23 v on the TPS)...

Examine the 02 volts... and the Injector pulse width at the same time..... the 02's are in the 800's there... and the pulsewidth is showing....32.69..... a frame or two later.... 02's drop to .027 volts... and the pulsewidth has actually increased to 38.50.

This makes no sense... If the FP is there.... and the pulsewidth hasn't drastically changed.... 02's shouldn't drop from .811 to .027........

It appears to me you might be having some sporadic issues with the 02 sensor.... as long as you are confident that the FP is still good when this takes place... during this run....

 

[fullahotair]

When i got the car to break up while loading the brakes, the fuel pressure would blip, but only from 40 to 42 or vice versa...I attributed that to vacuum fluctuations.... I can't see the fuel pressure while driving. If need be...I could plumb a line for the fuel pressure so i could see while it driving... Would you expect to see the fuel pressure go to 0 or extremely low?


It is a new fuel pump (walbro 307), the fuel Adj. is an accufab that i got off very stand up board member...

The 02 sensor is brand new as well...



Thanks again guys...

Nate