How about injector seals into the head..............My problem lied in those and the only way i could tell was when one finally blew out completely. under low boost and vacuum car ran like a champ, then under full boost fuel cut. Put your boost leak tester on and wiggle the injectors around with your finger to see if they are sealed properly.........
Trying to Solve Fuel cut - at wits end - this one will stump you
- Thread starter ArmandoP
- Start date
sounds about right for such a large turbo IMHO...
Can you change the spring int he wastegate? If so, put a lower one in it and see if the boost comes down a bit.
Can you change the spring int he wastegate? If so, put a lower one in it and see if the boost comes down a bit.
Not seen it asked so i will, have you checked your wiring on the afm that two wires are not cracked and rubbing. Just a thought stupid or not.
there have been a few suggestions that i havent tried yet so i will try these today and update later today. keep the suggestions coming and i will keep updating.
injector seas have been replaced and tested. afm is definitely a lexus afm. more detailed response later today.
for the record, i tend to like to help solve these strange issues myself, but its never been MY car with the strange problem. lol.
injector seas have been replaced and tested. afm is definitely a lexus afm. more detailed response later today.
for the record, i tend to like to help solve these strange issues myself, but its never been MY car with the strange problem. lol.
If you wanna try another Lexus AFM I'm pretty much free anytime after 3:15PM M-F, all day on weekends, or I can bring it to the meet if you want. Your screen might be dirty or scratched (dunno if this is possible with Supras, but I've read about it happening on f-bodies)
honestly i think its just a problem with flow in that you have too much of it. yes with a lex afm you should be able to run into the high teens but there are some stars* next to that that your setup throws up.
1. BIC DDP - these are famous for the amount of exhaust gas they flow, I have seen a few stock cars throw this on and start hitting FC.
2. The turbo - this looks alot like my jt61gt but bigger. more flow at a lower psi.
3. Headwork - you said you have ported your head some. This is semi-rare in the supra world and just making things easier for the engine to breath can do the same thing as a bigger exhaust, increase flow out and in.
4. Exhaust - 4in is again on the larger side of things we see. Great for flow but not FC friendly.
5. larger ic and pipes - see items 2,3,4
Like most accidents its not that one thing is going to cause FC but I think its a combination of all those above items. get an safc,vpc, or maft-pro and see if you can tinker with things on that end.
1. BIC DDP - these are famous for the amount of exhaust gas they flow, I have seen a few stock cars throw this on and start hitting FC.
2. The turbo - this looks alot like my jt61gt but bigger. more flow at a lower psi.
3. Headwork - you said you have ported your head some. This is semi-rare in the supra world and just making things easier for the engine to breath can do the same thing as a bigger exhaust, increase flow out and in.
4. Exhaust - 4in is again on the larger side of things we see. Great for flow but not FC friendly.
5. larger ic and pipes - see items 2,3,4
Like most accidents its not that one thing is going to cause FC but I think its a combination of all those above items. get an safc,vpc, or maft-pro and see if you can tinker with things on that end.
Responses:
-The EGR is properly bypassed and properly sealed.
-I have no wideband installed or narrowband a/f gauge.
-Rich enough that it looks alarmingly like a diesel at WOT. (sorry guys but I have a port for the wideband, just have been holding cash to solve this problem first)
-I cannot backboost down to 12psi, as it is running on the wastegate spring only, no boost controller. I have however loosened the wastegate enough to where it is actually leaking into the downpipe a little bit and shouldnt be hitting 14psi in my opinion.
-Im testing boost leaks at 10psi on the autometer gauge
-AFM honeycomb is in good shape. definitely a lexus AFM, Ive only tried one set of electronics.
- Quin, Im willing to try it, bring it to the meet or maybe I cna make it down to you this weekend.
-Im fine with the explanation that Ive got too much flow and must upgrade the electronics, I want to KNOW that though instead of just guessing because its easier. I also dont want to inadvertently destroy the engine while installing a MAFT on an otherwise unhelthy setup.
-AFM wires are in great shape and not crossed.
-vaccum line between turbo and wastegate is in perfect condition
READ THIS:
There is no gasket ont he ISC valve. The waffle valve inside is facing the right direction. There has never been a gasket on there. After checking the TSRM though, it doesnt appear that there is a traditional gasket, only a rubber seal which is intact on mine. I will order a new one today just in case though. Please let me know if I am wrong in how Im reading the diagrams in the TSRM.
I havent had a chance to recheck codes, but I will later today.
This is a possible explanation. Im not averse to going at it in this way, BUT I want to make sure there is not something Im missing before I go messing with the ECU signal. Since so far 3 people have mentioned this, I will seriously consider this option.
Ill be back later today with codes and such.
-The EGR is properly bypassed and properly sealed.
-I have no wideband installed or narrowband a/f gauge.
-Rich enough that it looks alarmingly like a diesel at WOT. (sorry guys but I have a port for the wideband, just have been holding cash to solve this problem first)
-I cannot backboost down to 12psi, as it is running on the wastegate spring only, no boost controller. I have however loosened the wastegate enough to where it is actually leaking into the downpipe a little bit and shouldnt be hitting 14psi in my opinion.
-Im testing boost leaks at 10psi on the autometer gauge
-AFM honeycomb is in good shape. definitely a lexus AFM, Ive only tried one set of electronics.
- Quin, Im willing to try it, bring it to the meet or maybe I cna make it down to you this weekend.
-Im fine with the explanation that Ive got too much flow and must upgrade the electronics, I want to KNOW that though instead of just guessing because its easier. I also dont want to inadvertently destroy the engine while installing a MAFT on an otherwise unhelthy setup.
-AFM wires are in great shape and not crossed.
-vaccum line between turbo and wastegate is in perfect condition
READ THIS:
There is no gasket ont he ISC valve. The waffle valve inside is facing the right direction. There has never been a gasket on there. After checking the TSRM though, it doesnt appear that there is a traditional gasket, only a rubber seal which is intact on mine. I will order a new one today just in case though. Please let me know if I am wrong in how Im reading the diagrams in the TSRM.
I havent had a chance to recheck codes, but I will later today.
MKIIINA;1007267 said:
This is a possible explanation. Im not averse to going at it in this way, BUT I want to make sure there is not something Im missing before I go messing with the ECU signal. Since so far 3 people have mentioned this, I will seriously consider this option.
Ill be back later today with codes and such.
for reference, here is a 62-1 compressor map.
http://www.turbocharged.com/catalog/compmaps/fig10.html
mine is a hifi which is supposed to flow 5% less. unfortunately I have not been able to find a hifi compressor map. Probably because they now only make a 60-1 hifi (or so Ive been told)
http://www.turbocharged.com/catalog/compmaps/fig10.html
mine is a hifi which is supposed to flow 5% less. unfortunately I have not been able to find a hifi compressor map. Probably because they now only make a 60-1 hifi (or so Ive been told)
ArmandoP;1006635 said:
No, "Accordion" Hose Running to the turbo cool side inlet. If theres any holes in there you're getting a misreading at the AFM. I had 6 psi and was hitting FCO.
Errr... this makes no sense. This would ADD unmetered air, which would make you run leaner, and essentially increase the level that FC would appear.Zumtizzle;1007380 said:
You need a leak in the pressurized part of the IC piping to cause lower than normal fuel cut, as metered air escapes.
Armando, you're not putting enough pressure in the system when checking for boost leaks. Push that up to 20psi.
Zumtizzle;1007380 said:
excellent condition. replaced when I did the head gasket a year ago, no cracks or holes, etc.
what do you guys think about the possibility of my wastegate diaphragm in the actuator being damaged? I cant actually inspect it so Im considering ordering a new one and trying that next.
GrimJack;1007393 said:
correct I have tried this even in attempts to move fuel cut higher and it doesnt seem to do much. (using the capped port that was for the original BOV)
I will up the pressure on my next test.
ENGINE CODES:
checked codes...
34 - turbo pressure too high
42 - no speed signal (my speedo)
43 - no sta signal (this confuses me)
51 - cant find this code anywhere and cant search for it.
checked codes...
34 - turbo pressure too high
42 - no speed signal (my speedo)
43 - no sta signal (this confuses me)
51 - cant find this code anywhere and cant search for it.
i would try this,
replace the electronics with a know working set,
and if that fails, then i would unbolt the waste gate, and test once with no wast gate.
the stock setup hit's fuel cut between 10-13psi depending on rpm, and load. i want to say i typically saw it at 1400 Hz.
can you take some photo's of your inter-cooler pipe's and inter-cooler?
if you are using worm clamps, or thin couplers, i would replace them with 4ply couplers and T-bolts.
but as far as fuel cut is determined, it's the amount of air flowing past the meter, cfm then how much boost you are running.
like, you could be running 38cfm at 10 psi and not fuel cut, then change your exhaust, and now be running 43cfm at 10psi, making additional power and hitting fuel cut, or skimming the line. (just an example.)
replace the electronics with a know working set,
and if that fails, then i would unbolt the waste gate, and test once with no wast gate.
the stock setup hit's fuel cut between 10-13psi depending on rpm, and load. i want to say i typically saw it at 1400 Hz.
can you take some photo's of your inter-cooler pipe's and inter-cooler?
if you are using worm clamps, or thin couplers, i would replace them with 4ply couplers and T-bolts.
but as far as fuel cut is determined, it's the amount of air flowing past the meter, cfm then how much boost you are running.
like, you could be running 38cfm at 10 psi and not fuel cut, then change your exhaust, and now be running 43cfm at 10psi, making additional power and hitting fuel cut, or skimming the line. (just an example.)
You know, now that I am thinking Armondo... you have an internal wastegate huh?
Im thinking you're seeing fuel cut because of boost creep. The creep may be so very fast and violent that your boost gauge isn't catching it but the AFM is.
LMK.....
Im thinking you're seeing fuel cut because of boost creep. The creep may be so very fast and violent that your boost gauge isn't catching it but the AFM is.
LMK.....
code 51 is a switch signal,
either your a/c switch was on, or your foot was on the gas pedle, other wise, your tps need's adjustment.
try this...
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=125
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101
code's
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=26
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=27
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=28
either your a/c switch was on, or your foot was on the gas pedle, other wise, your tps need's adjustment.
try this...
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=125
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101
code's
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=26
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=27
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=28
Correct.pimptrizkit;1007445 said:
If Armondo still hits fuel cut with no wastegate, either the door is stuck shut (internal gate) or the wastegate port is too small.