HELP NINETRES!! Car randomly dies when boost hits.
I know, I know 
... 
09-23-2012, 12:38 AM
#24
We should have the car back together sometime this coming week for some testing.
09-26-2012, 02:10 AM
#25
RRrrrrrrr. So frustrated. Tested the car tonight, still cut out on me. Here is what we have done so far:
--Upgraded to the 145amp truck alternator
--Upgraded the charge back wire between the alt and rear battery from 4g--->to 0g.
--Cleaned up and verified all grounds looked good
--Re-wired Fuelab fuel pump. It used to use a hotwire kit I had, that ran alllllll the way up to the alternator. Now we used all 8g wire, and used a heavy duty "starter type" continuous solenoid, all rear mounted. We still are using the single factory pigtail on the bulk head, with the small signal wire running to the solenoid.
Thoughts:
1. Maybe need to add a wire between the starter, and PCM power wire to ensure PCM is getting constant voltage.
2. Maybe something is wrong with the pigtail where we are pulling our fuel pump signal from. We are going to try to jump the signal post on the solenoid, to the RED cable on the battery right near it. Then....if the car doesn;t cut out....we know its something with the pump signal we are using.
3. Does the stock PCM consider oil pressure at all when determining to cut the fuel pump??? I know some cars do this. Maybe I have a bad sensor or connection on my oil pressure sensor that is causing the PCM to think I lose oil pressure momentarily and it's cutting the pump for a split second.
I don't know. So bummed right know. The car is just DYING to get the tune finished and make some serious power.
--Upgraded to the 145amp truck alternator
--Upgraded the charge back wire between the alt and rear battery from 4g--->to 0g.
--Cleaned up and verified all grounds looked good
--Re-wired Fuelab fuel pump. It used to use a hotwire kit I had, that ran alllllll the way up to the alternator. Now we used all 8g wire, and used a heavy duty "starter type" continuous solenoid, all rear mounted. We still are using the single factory pigtail on the bulk head, with the small signal wire running to the solenoid.
Thoughts:
1. Maybe need to add a wire between the starter, and PCM power wire to ensure PCM is getting constant voltage.
2. Maybe something is wrong with the pigtail where we are pulling our fuel pump signal from. We are going to try to jump the signal post on the solenoid, to the RED cable on the battery right near it. Then....if the car doesn;t cut out....we know its something with the pump signal we are using.
3. Does the stock PCM consider oil pressure at all when determining to cut the fuel pump??? I know some cars do this. Maybe I have a bad sensor or connection on my oil pressure sensor that is causing the PCM to think I lose oil pressure momentarily and it's cutting the pump for a split second.
I don't know. So bummed right know. The car is just DYING to get the tune finished and make some serious power.
09-26-2012, 06:53 AM
#26
Ninetres, dont take offense to this, but you're shooting in the dark. If I read your post right, you're saying that fuel pressure isn't dropping on the dyno via the underhood gauge. You need to log fuel pressure and/or signal wire with some type of analog output to a PC or oscilloscope and verify that there is no momentary loss of power or signal to the fuel pump etc. That will tell you for certain if you have a fuel pump/wiring issue. You can also verify with the oscilloscope realtime voltage to the fuel pump etc. as a multimeter is only RMS (average).
Second, you need a PC logging the run via HP Tuners/EFI Live to verify that none of your sensors are doing anything wierd when it starts to cutout on you. Does it only do it on 1 boost level and not on a lesser boost level?
I troubleshoot for a living and being a little more methodical about your approach will go a long way to solving this. Good luck!
Second, you need a PC logging the run via HP Tuners/EFI Live to verify that none of your sensors are doing anything wierd when it starts to cutout on you. Does it only do it on 1 boost level and not on a lesser boost level?
I troubleshoot for a living and being a little more methodical about your approach will go a long way to solving this. Good luck!
09-26-2012, 08:12 AM
#27
Ninetres, dont take offense to this, but you're shooting in the dark. If I read your post right, you're saying that fuel pressure isn't dropping on the dyno via the underhood gauge. You need to log fuel pressure and/or signal wire with some type of analog output to a PC or oscilloscope and verify that there is no momentary loss of power or signal to the fuel pump etc. That will tell you for certain if you have a fuel pump/wiring issue. You can also verify with the oscilloscope realtime voltage to the fuel pump etc. as a multimeter is only RMS (average).
Second, you need a PC logging the run via HP Tuners/EFI Live to verify that none of your sensors are doing anything wierd when it starts to cutout on you. Does it only do it on 1 boost level and not on a lesser boost level?
I troubleshoot for a living and being a little more methodical about your approach will go a long way to solving this. Good luck!
Second, you need a PC logging the run via HP Tuners/EFI Live to verify that none of your sensors are doing anything wierd when it starts to cutout on you. Does it only do it on 1 boost level and not on a lesser boost level?
I troubleshoot for a living and being a little more methodical about your approach will go a long way to solving this. Good luck!
I bought HP tuners a few days ago and still need to load it onto a lap top.....and start learning how it works. Happens at all boost levels.
09-26-2012, 01:37 PM
#28
FormerVendor
iTrader: (64)
Join Date: Feb 2008
Location: Bakersfield, CA
Posts: 1,074
Likes: 0
Received 0 Likes
on
0 Posts
What size injectors are you running on this car? I assume speed density tuned.
Ive ran into this problem where the computer hits an internal limit that shuts it off like you turned off key under high boost.
What I have to do on alot of our shop cars that have made 900+ rwhp, is scale the injectors back say 25-50% depending on the size and then scale the VE/fueling etc tables the other way and put everything back in line. Then the computer doesnt hit this shutdown. So your lying to the computer that the injectors are alot smaller than they are and then scale the fuel tables etc.
Ive ran into this problem where the computer hits an internal limit that shuts it off like you turned off key under high boost.
What I have to do on alot of our shop cars that have made 900+ rwhp, is scale the injectors back say 25-50% depending on the size and then scale the VE/fueling etc tables the other way and put everything back in line. Then the computer doesnt hit this shutdown. So your lying to the computer that the injectors are alot smaller than they are and then scale the fuel tables etc.
09-26-2012, 02:24 PM
#29
TECH Addict
iTrader: (22)
Join Date: Sep 2004
Location: tennessee
Posts: 2,639
Likes: 0
Received 0 Likes
on
0 Posts
seems i read (key word read ) on here along time ago someone was having an issue like this and it was the crank flexing and causing the cps to lose signal. just a very uneducated guess lol.
09-26-2012, 02:53 PM
#30
FormerVendor
What size injectors are you running on this car? I assume speed density tuned.
Ive ran into this problem where the computer hits an internal limit that shuts it off like you turned off key under high boost.
What I have to do on alot of our shop cars that have made 900+ rwhp, is scale the injectors back say 25-50% depending on the size and then scale the VE/fueling etc tables the other way and put everything back in line. Then the computer doesnt hit this shutdown. So your lying to the computer that the injectors are alot smaller than they are and then scale the fuel tables etc.
Ive ran into this problem where the computer hits an internal limit that shuts it off like you turned off key under high boost.
What I have to do on alot of our shop cars that have made 900+ rwhp, is scale the injectors back say 25-50% depending on the size and then scale the VE/fueling etc tables the other way and put everything back in line. Then the computer doesnt hit this shutdown. So your lying to the computer that the injectors are alot smaller than they are and then scale the fuel tables etc.
09-26-2012, 04:39 PM
#31
9 Second Club
Go back to basics.
Exactly how does the cut manifest itself ? Is it only on boost, at a certain speed, rpm ? etc
Does the rev counter still work during this, or does it immediately fall to zero ? Do dash lights indicate a full power cut, or just an engine cut ?
If you cannot log, wire up a simple test lamp to ensure power is maintained to places it needs to be maintained. ie coils, injectors, ecu, fuel pumps
Is there anything silly in the ecu like a fuel cut for a speed limiter ? boost limit ? etc
A failing fuel pump or power dropout to the pump might stop the engine slightly slower than say a power cut to the ignition or ecu.
Exactly how does the cut manifest itself ? Is it only on boost, at a certain speed, rpm ? etc
Does the rev counter still work during this, or does it immediately fall to zero ? Do dash lights indicate a full power cut, or just an engine cut ?
If you cannot log, wire up a simple test lamp to ensure power is maintained to places it needs to be maintained. ie coils, injectors, ecu, fuel pumps
Is there anything silly in the ecu like a fuel cut for a speed limiter ? boost limit ? etc
A failing fuel pump or power dropout to the pump might stop the engine slightly slower than say a power cut to the ignition or ecu.
09-26-2012, 08:57 PM
#35
What size injectors are you running on this car? I assume speed density tuned.
Ive ran into this problem where the computer hits an internal limit that shuts it off like you turned off key under high boost.
What I have to do on alot of our shop cars that have made 900+ rwhp, is scale the injectors back say 25-50% depending on the size and then scale the VE/fueling etc tables the other way and put everything back in line. Then the computer doesnt hit this shutdown. So your lying to the computer that the injectors are alot smaller than they are and then scale the fuel tables etc.
Ive ran into this problem where the computer hits an internal limit that shuts it off like you turned off key under high boost.
What I have to do on alot of our shop cars that have made 900+ rwhp, is scale the injectors back say 25-50% depending on the size and then scale the VE/fueling etc tables the other way and put everything back in line. Then the computer doesnt hit this shutdown. So your lying to the computer that the injectors are alot smaller than they are and then scale the fuel tables etc.
Go back to basics.
Exactly how does the cut manifest itself ? Is it only on boost, at a certain speed, rpm ? etc
Does the rev counter still work during this, or does it immediately fall to zero ? Do dash lights indicate a full power cut, or just an engine cut ?
If you cannot log, wire up a simple test lamp to ensure power is maintained to places it needs to be maintained. ie coils, injectors, ecu, fuel pumps
Is there anything silly in the ecu like a fuel cut for a speed limiter ? boost limit ? etc
A failing fuel pump or power dropout to the pump might stop the engine slightly slower than say a power cut to the ignition or ecu.
Exactly how does the cut manifest itself ? Is it only on boost, at a certain speed, rpm ? etc
Does the rev counter still work during this, or does it immediately fall to zero ? Do dash lights indicate a full power cut, or just an engine cut ?
If you cannot log, wire up a simple test lamp to ensure power is maintained to places it needs to be maintained. ie coils, injectors, ecu, fuel pumps
Is there anything silly in the ecu like a fuel cut for a speed limiter ? boost limit ? etc
A failing fuel pump or power dropout to the pump might stop the engine slightly slower than say a power cut to the ignition or ecu.
Correct. It had the synergy 2-step on it, but we removed it entirely to eliminate it being a factor. Still happening.
09-26-2012, 09:26 PM
#37
in my old car we did a wire tuck with the harness under the drivers strut tower. Something got to the harness under the strut tower in the wheel well and caused the same issue. Don't quite remember what wire it was but just driving around the car would stutter and die just going down the road. Your's is in boost but it definitely sounds wiring/pcm related. have you messed with or modified with that side of the harness?
09-27-2012, 12:31 AM
#38
TECH Regular
iTrader: (2)
Join Date: Feb 2004
Location: 1985
Posts: 426
Likes: 0
Received 0 Likes
on
0 Posts
Seems like you've looked at a lot of things, but since you haven't found it with the current suggestions...
Ive seen this happen on cars with bad battery mounts ( where it is moving under power and the terminals are hitting something, causing a temp power spike and kills engine power )
Ive seen this happen on Fuelab, Walbro, Aeromotive ( all pumps ) defective pump ( usually cause the pump burned up ) either previously insufficient wiring / lines, or bad luck pump.
Seen this with truck alternators on cars and power steering lines being so close that the engine rise under power is pulling the PS lines up to the output power from the Alternator, causing a short to ground and cutting engine power. Make sure to have that Power line covered well.
Seen this with cars that have bad motor mounts: wires pulling or stretching from the engine moving in places that look fine when at rest.
Seen this on boosted cars tuned to run the MAF, when the range is out run and the car is in a fail state the secondary VE hasn't been tuned at all and the fueling is so far off that the car will die, or come damn close to it
Good luck buddy! Make sure to come back and let us know what you find!
Ive seen this happen on cars with bad battery mounts ( where it is moving under power and the terminals are hitting something, causing a temp power spike and kills engine power )
Ive seen this happen on Fuelab, Walbro, Aeromotive ( all pumps ) defective pump ( usually cause the pump burned up ) either previously insufficient wiring / lines, or bad luck pump.
Seen this with truck alternators on cars and power steering lines being so close that the engine rise under power is pulling the PS lines up to the output power from the Alternator, causing a short to ground and cutting engine power. Make sure to have that Power line covered well.
Seen this with cars that have bad motor mounts: wires pulling or stretching from the engine moving in places that look fine when at rest.
Seen this on boosted cars tuned to run the MAF, when the range is out run and the car is in a fail state the secondary VE hasn't been tuned at all and the fueling is so far off that the car will die, or come damn close to it
Good luck buddy! Make sure to come back and let us know what you find!
09-30-2012, 12:57 AM
#40
Defective fuel pump. Not only did we see that pressure drops like a rock to zero, but the pump also took a complete **** during our testing. I'll withhold the name brand until I see how they handle it. Only been on the car for a month but I've had it sitting in the box longer than the 2 year warranty. I've read about a LOT of people having them fail....even several for the same person. I also read their customer service is very good.....but not sure how they will respond since its "technically" out of warranty.
I'm not even 100% sure I want to run this pump after reading about all the failures. Might spring for a Magnafuel.
I'm not even 100% sure I want to run this pump after reading about all the failures. Might spring for a Magnafuel.