Losing propulsion with 5.7 Turbo Tweak chip

JSTARGL231

New Member
Sep 11, 2018
5
3
3
40
Can anybody advise? I have a stock 87 buick GN with 5700 miles. Only mods are 100lb valve springs and deleted cat when installing new magnaflow exhaust. Installed new chip and let her learn before giving hard boost. 3 times I have given 80 to 90% throttle from a 20mph rolling start. She pulls great, then around 55 to 60 mph sudden cut out with a little clunk sound and feel associated with it. The engine doesnt die, no engine light comes on. I dont have scan tool and dont want one. Any ideas what is happening? Is there a boost governor of any kind? Stock injectors not enough fuel? Stock air intake not enough air? Any thoughts would be welcomed and greatly appreciated. I reached out to Eric at Turbo Tweak and he didnt have any idea what it might be. Thank you!
 

Turbo6inKY

Short Guy
Jun 18, 2001
1,561
393
83
41
Louisville, KY
blog.andrewdscott.com
Why don't you want a scantool?

Without one, you have no idea what's going on with the car. You're blind. Nobody here can help any more than offering guesses.

Trial and error is expensive. It could cost you that engine. Get a Scanmaster or even better, a Powerlogger, and get a log of the problem. We'll likely be able to tell you exactly what the issue is from that data. Without it, everybody's guessing. Guessing is bad.
 

JSTARGL231

New Member
Sep 11, 2018
5
3
3
40
Why don't you want a scantool?

Without one, you have no idea what's going on with the car. You're blind. Nobody here can help any more than offering guesses.

Trial and error is expensive. It could cost you that engine. Get a Scanmaster or even better, a Powerlogger, and get a log of the problem. We'll likely be able to tell you exactly what the issue is from that data. Without it, everybody's guessing. Guessing is bad.
I agree guessing isnt good. If someone had a very similar issue in similar conditions and could share their fix, it could be a pretty educated guess. My main reason for not wanting a scan tool and power logger is nothing more than wanting to stay stock. I dont want to see them in the car. I am not going to the track. I do however like proper performance on the street. My hope was that the 5.7 chip would plug in and I would be good with the improvement in idle and performance and could curtail my competitive nature there. I fear a scan tool and power logger is going to show me data. And then my damn blood will boil to go faster and my car will end up way too far from stock. My wallet will be out of stock, next thing you know money is missing off the dresser and your daughter's knocked up. Seen it a hundred times... So my plan is to put my new injectors in from Kirban. They are the enhanced OEM injectors they say are newer tech and run about 10% higher than stock. Not a huge change, but could be good. Will put the Tin man cold air intake in that I havent installed yet and see how she does. Yes I know that isnt stock, but I hate restricted air flow. I'll keep the stock stuff of course. I'll try to reset and reinstall the chip as well. After all that if problem persists I'll get the power logger and get it to you all.
 

RUQWKNF

KEEPER OF SECRETS
Staff member
May 26, 2001
2,434
310
83
48
NEED TO KNOW BASIS
s78.photobucket.com
First off, welcome aboard. I completely understand your story. You want to keep it as close to stock as possible without getting bit by the hot rod bug. I gotcha. But, without a Scanmaster, you are proceeding blindly and are on a dangerous course that will eventually lead to a blown head gasket or 2. Even on a bone stock car with low miles it will happen. I know you say you don't want one, but you don't have to hard mount it. You could simply plug it up, put it on the dash with some velcro, go for a drive and get the data, then remove it, wiping the Velcro residue (if any) off with some Simple Green or Goo Off. Easy peasy. It's not a permanent install. Some people simply stash it away inside the glove box. You gotta know what's going on under wide open throttle or disasterous things can happen. But I highly recommend mounting it where you can see it at all times while driving. Either on top of the dash, or using one of Kirban's steering column mounts. For years I just mounted it on the dash, but now I have this mount and it's great.

With that disclaimer out of the way, here's my best ass guess as to what's going on.

Symptoms: Runs great at first, but once it gets going good, it falls on it's face, pops and stumbles, stops pulling.

- If the car still has the stock fuel filter on it, even with very low miles, it is definitely clogged and starving the engine of fuel. This would show up as a lean condition under WOT (wide open throttle) when watching a Scanmaster driving down the road and punching it. The first screen shows your O2 Mv and degrees of knock. These numbers are real time and are what you use to help diagnose a lean condition.

- The spitting, stumbling and popping could be detonation, or it could be numerous other things, such as a failing TPS sensor, failing due to age coil pack or ignition module. It could also be a failing MAF sensor, or even something as common as low battery voltage from a failing alternator or dead celled battery. All of these can be diagnosed with a Scanmaster so you don't have to start throwing parts at it. IOW, the Scanmaster will pay for itself seven fold over the long run.

- The factory vacuum hoses are no doubt dry rotted at this point. You could have one that's even crumbled and broken / fallen off. As in disconnected and causing a vacuum leak. This will lead to a severe lean condition as you loose your fuel pressure rise under WOT. This is one of the most critical vacuum lines on the engine, as without a good sealed vacuum system, the fuel pressure won't rise and the engine will go severely lean under boost. I recommend to everyone, go over all of the vacuum hoses that originate from the vacuum distribution block on the top of the throttle body. If you see any signs of dry rotted, replace every hose.

- Check the hoses on the turbo and wastegate actuator, and the ones on the wastegate solenoid the same. If disconnected or if dry rotted, R&R them asap. It can cause an over boost condition.

- Don't trust the factory dash boost gauge. It will lie. Get a good boost gauge, if you don't already have one. Stock cars with a good chip and the fuel system addressed, can typically run 14-16psi with ethanol blended 93 pump gas, sometimes even higher, but that depends on the condition of the injectors and pump. On a seriously bone stock car, keep it safe at 12-14.

- As a start, I would change the fuel filter, any auto parts store will have what you need. Then change the spark plugs. Next would be to replace the fuel pump with a Walbro 340 255lph pump and a hot wire kit. And lastly, I would run some fuel system cleaner through the system like Chevron Techron. I understand about keeping it stock and even with low miles, injectors do go bad. So, replacing the injectors with a matching chip should be high on the list for the future.

- The stock chip has got to be replaced. It was programmed with higher and more aggressive timing tables for non ethanol blended pump gas back in the "80's / "90's. Keeping the stock chip and running 93 octane with it's blended 10% ethanol can cause detonation. Don't put it back in, no matter what.

- Even though an adjustable fuel pressure regulator doesn't look stock you gotta get one. The black Accufab one, is as close to stock appearing as you will get.

You can do these things to even a mint condition car without hurting it. If this is an investment for the future, the fuel system mods are just preventive maintenance that will protect your investment. And whatever you do, don't forget to run some zinc/phosphorus additive like ZDDPlus in the oil at all times.

If you haven't read up about the spring cleaning, I highly recommend doing so. http://www.gnttype.org/maint/basics.html

Don't mind the negative comments. These types of threads have been common for years. And I can understand and respect wanting to keep it stock. Unfortunately, it's so easy to hot rod these cars and make an extra 50 rwhp that you get the GoFastItis bug without even trying.

Get a Scanmaster, replace the fuel filter, inspect and replace those vacuum hoses, get some ZDDPlus for the oil that's in it now, put the TurboTweak chip in it are the very first things I would do. If at this point you see the car is running lean under boost, replace the fuel pump and put a hot wire kit t on it. That's what I would do if it was mine.

Hope this helps and again, welcome aboard.

-Patrick-
 
Last edited:

JSTARGL231

New Member
Sep 11, 2018
5
3
3
40
Scanmaster at minimum, you could put quick connects on wires or put it in the glove box... Mike
I was thinking glove box too. Thanks Mike!
First off, welcome aboard. I completely understand your story. You want to keep it as close to stock as possible without getting bit by the hot rod bug. I gotcha. But, without a Scanmaster, you are proceeding blindly and are on a dangerous course that will eventually lead to a blown head gasket or 2. Even on a bone stock car with low miles it will happen. I know you say you don't want one, but you don't have to hard mount it. You could simply plug it up, put it on the dash with some velcro, go for a drive and get the data, then remove it, wiping the Velcro residue (if any) off with some Simple Green or Goo Off. Easy peasy. It's not a permanent install. Some people simply stash it away inside the glove box. You gotta know what's going on under wide open throttle or disasterous things can happen. But I highly recommend mounting it where you can see it at all times while driving. Either on top of the dash, or using one of Kirban's steering column mounts. For years I just mounted it on the dash, but now I have this mount and it's great.

With that disclaimer out of the way, here's my best ass guess as to what's going on.

Symptoms: Runs great at first, but once it gets going good, it falls on it's face, pops and stumbles, stops pulling.

- If the car still has the stock fuel filter on it, even with very low miles, it is definitely clogged and starving the engine of fuel. This would show up as a lean condition under WOT (wide open throttle) when watching a Scanmaster driving down the road and punching it. The first screen shows your O2 Mv and degrees of knock. These numbers are real time and are what you use to help diagnose a lean condition.

- The spitting, stumbling and popping could be detonation, or it could be numerous other things, such as a failing TPS sensor, failing due to age coil pack or ignition module. It could also be a failing MAF sensor, or even something as common as low battery voltage from a failing alternator or dead celled battery. All of these can be diagnosed with a Scanmaster so you don't have to start throwing parts at it. IOW, the Scanmaster will pay for itself seven fold over the long run.

- The factory vacuum hoses are no doubt dry rotted at this point. You could have one that's even crumbled and broken / fallen off. As in disconnected and causing a vacuum leak. This will lead to a severe lean condition as you loose your fuel pressure rise under WOT. This is one of the most critical vacuum lines on the engine, as without a good sealed vacuum system, the fuel pressure won't rise and the engine will go severely lean under boost. I recommend to everyone, go over all of the vacuum hoses that originate from the vacuum distribution block on the top of the throttle body. If you see any signs of dry rotted, replace every hose.

- Check the hoses on the turbo and wastegate actuator, and the ones on the wastegate solenoid the same. If disconnected or if dry rotted, R&R them asap. It can cause an over boost condition.

- Don't trust the factory dash boost gauge. It will lie. Get a good boost gauge, if you don't already have one. Stock cars with a good chip and the fuel system addressed, can typically run 14-16psi with ethanol blended 93 pump gas, sometimes even higher, but that depends on the condition of the injectors and pump. On a seriously bone stock car, keep it safe at 12-14.

- As a start, I would change the fuel filter, any auto parts store will have what you need. Then change the spark plugs. Next would be to replace the fuel pump with a Walbro 340 255lph pump and a hot wire kit. And lastly, I would run some fuel system cleaner through the system like Chevron Techron. I understand about keeping it stock and even with low miles, injectors do go bad. So, replacing the injectors with a matching chip should be high on the list for the future.

- The stock chip has got to be replaced. It was programmed with higher and more aggressive timing tables for non ethanol blended pump gas back in the "80's / "90's. Keeping the stock chip and running 93 octane with it's blended 10% ethanol can cause detonation. Don't put it back in, no matter what.

- Even though an adjustable fuel pressure regulator doesn't look stock you gotta get one. The black Accufab one, is as close to stock appearing as you will get.

You can do these things to even a mint condition car without hurting it. If this is an investment for the future, the fuel system mods are just preventive maintenance that will protect your investment. And whatever you do, don't forget to run some zinc/phosphorus additive like ZDDPlus in the oil at all times.

If you haven't read up about the spring cleaning, I highly recommend doing so. http://www.gnttype.org/maint/basics.html

Don't mind the negative comments. These types of threads have been common for years. And I can understand and respect wanting to keep it stock. Unfortunately, it's so easy to hot rod these cars and make an extra 50 rwhp that you get the GoFastItis bug without even trying.

Get a Scanmaster, replace the fuel filter, inspect and replace those vacuum hoses, get some ZDDPlus for the oil that's in it now, put the TurboTweak chip in it are the very first things I would do. If at this point you see the car is running lean under boost, replace the fuel pump and put a hot wire kit t on it. That's what I would do if it was mine.

Hope this helps and again, welcome aboard.

-Patrick-
Patrick, This is over the top brother, thank you. I can deal with a negative jab, or two. I welcome it in fact. Humor is healthy. I do have new plugs and wires. Not sure if the coil pack is necessary on such a low mile car. Putting the new WIX fuel filter in tonight. I put Redline fluids in everywhere including their oil additive. Will get the scan master, put in the new injectors and cold air intake. I am taking the original wheels and tires off and preserving them. New Budnik GN 17's shipped today and putting Nittos on them. Can't wait. Will not put the stock chip back in. Will go ahead and get the fuel pump upgraded. The scanmaster is on the way. Thanks again for the warm welcome.
 

gsgnnut

Active Member
Mar 31, 2014
403
67
28
56
Probably a dumb question but you are running a good premium fuel right? The tt chip performs best with higher octane. Make sure you have proper fuel pressure too. Easy to test. I recently had a similar problem and a New tta fuel pressure regulator and fresh 93 cured it quick.
 

gsgnnut

Active Member
Mar 31, 2014
403
67
28
56
The sudden drop in power under boost is the ecu pulling timing due to a lean condition which among lots of other things could be low fuel pressure or not enough octane.