2G fuel issue

[exiletalon]

new engine, stock fuel, 10 psi, 91 octane, S16G. fuel cut at 4-4500 RPM- WHY?, i dont understand what could cause it. Many have told me O2 Sensor, could it be anything else. NEW injectors, same turbo!- 2000 mile old O2 sensor, is it possible it doesnt work already?

 

[sweet97]

What size injectors? At WOT the o2 is not affecting fuel and fuel cut is caused by the ECU "seeing" too much airflow. have you modded the mas, hacked it al all? Mark
Do you have any fuel control or is this completely stock?

 

[exiletalon]

What size injectors? At WOT the o2 is not affecting fuel and fuel cut is caused by the ECU "seeing" too much airflow. have you modded the mas, hacked it al all? Mark
Do you have any fuel control or is this completely stock?

The entire fuel system is stock, however, I have a 190lph, WeaponR AFPR, and a re-wire kit waiting to be installed, but boost is set to stock levels. I havent done any mods to the MAF since I bought it, the previous owner may have.- I will check!
Is it possible that the ECU is shooting wrong codes? or a more complexe issue.

Also, do you think that the O2 sensor has anyhting to do with this?

 

[sweet97]

It's not the o2 as it does not effect WOT and you should not get fuel cut at partial throttle. What size injectrs and did you get the chip to compensate for them? Again you are too rich. That also means the CU is "seeing" too much air causing the cut. What size injectors and what amount of inj. compensation? Then I can give you a base setting to try. mark

 

[exiletalon]

It's not the o2 as it does not effect WOT and you should not get fuel cut at partial throttle. What size injectrs and did you get the chip to compensate for them? Again you are too rich. That also means the CU is "seeing" too much air causing the cut. What size injectors and what amount of inj. compensation? Then I can give you a base setting to try. mark

I have NO chip, I have NO modifications of any sort that effect the fuel installed.

stock FP
stock 450cc
stock fpr
stock fuel lines
NOT re-wired
NO chip
NO computer
NO fuel modifications!

 

[sweet97]

SORRY, WRONG THREAD!
Somehow the ECU is "seeing" too much air flow. Could be the colder air temps. Try backing the boost back a bit if possible and see if it resolves it.

 

[CanadianTSi]

Positive you have no boost leaks?

 

[dsm-onster]

Positive you have no boost leaks?

Yea. You probably have a boost leak. To hold 10psi the turbo has to be sucking way more air past the MAF than stock to maintane the pressure in the intake mani.

Do a few spirited runs. Pull your plugs and see if they are black. This would indicate a really rich mixture. And help support this theory.

O2 sensors never have anythiing to do with fuel cut as explained by sweet97.

Are you sure it is fuel cut? You should be picking your teeth from the wheel, if you're getting true fuel cut. It will feel like you hit a pot hole from the Underworld!

 

[exiletalon]

It feels like I hit a wall at like 4500 RPM, so I let off. Before I got a new motor, I had this problem, and my whole engine would instantly overheat! Thats why my engine blew and I now have a newer engine half the miles, but still the same problem. I dony want to kill my new engine the same way!- I have 0 PSI above stock levels. ( I was told it was 10PSI)
So then it is surely not my o2 sensor then?

 

[Ginglingston11]

when my motor is still cold and i go to drive it, besides the fact that its hard to shift, if i really get on it on the highway i will hit fuel cut HARD in 3rd gear only and i have never gotten a chance to check my dash what my rpms are at. also when my motors hot in 3rd gear also at about 2500-3000 rpms i can hear a low backfire like im shooting a flame, but none of my friends have been behind me when this happens. now i dont even think about drivin that car til it gets hot, cause just like someone said i dont need to be picking my teeth outa my steering wheel.

 

[dsm-onster]

It feels like I hit a wall at like 4500 RPM, so I let off. Before I got a new motor, I had this problem, and my whole engine would instantly overheat! Thats why my engine blew and I now have a newer engine half the miles, but still the same problem. I dony want to kill my new engine the same way!- I have 0 PSI above stock levels. ( I was told it was 10PSI)

Over heating is not a symptom of fuel cut. It was likely your engine shaking so hard it was pulling something loose or something? Why did you rebuild? Spun bearing, blown rings, or what?

So then it is surely not my o2 sensor then?

Yea, whoever told you that knows just enough about DSMs to NOT listen to!

 

[sweet97]

Your mod list says you have an EVO3! You don't have the MAFT set correctly! Don't you have a boost gauge, aftermarket?
Anyways you need to give your translator settings. If you have the stock injectors they are too small for the EVO3 you list or even for the s16g possibly. The motor will run hot if the timing is low. If the translator is set wrong you will knock and have timing pulled and if run hard like this the motor will run HOT! but if 450cc's you need to have the translator set on:
AUX=4
BASE=2
IDLE=where you get the most vacuum for starters
MID on "0"
WOT="0"
What are your settings ? Thanks, Mark
PS: PLease correct/update your mod list.

 

[exiletalon]

Your mod list says you have an EVO3! You don't have the MAFT set correctly! Don't you have a boost gauge, aftermarket?
Anyways you need to give your translator settings. If you have the stock injectors they are too small for the EVO3 you list or even for the s16g possibly. The motor will run hot if the timing is low. If the translator is set wrong you will knock and have timing pulled and if run hard like this the motor will run HOT! but if 450cc's you need to have the translator set on:
AUX=4
BASE=2
IDLE=where you get the most vacuum for starters
MID on "0"
WOT="0"
What are your settings ? Thanks, Mark
PS: PLease correct/update your mod list.

I am sorry, This is not the vehicle that is listed in my profile!- Sorry, I did not clarify that. This car was given to me from a friend, This problem was present when he owned the car. Then the motor blew, ( which is when he gave it to me!) I replaced the motor with a newer 97' 7-bolt. It has a 18G, but the fuel system is entirely stock. I have BOOST, EGT, A/F, OIL PRE, WATER TEMP. gauges. I know that the fuel is an issue, but the problem he had was there before the 18G. He was told the wastegate was busted. So he installed the larger turbo. He kept boost stock, the boost gauge even says so. I have stock 2G MAFT.

 

[Newlogics]

I am sorry, This is not the vehicle that is listed in my profile!- Sorry, I did not clarify that. This car was given to me from a friend, This problem was present when he owned the car. Then the motor blew, ( which is when he gave it to me!) I replaced the motor with a newer 97' 7-bolt. It has a 18G, but the fuel system is entirely stock. I have BOOST, EGT, A/F, OIL PRE, WATER TEMP. gauges. I know that the fuel is an issue, but the problem he had was there before the 18G. He was told the wastegate was busted. So he installed the larger turbo. He kept boost stock, the boost gauge even says so. I have stock 2G MAFT.

Does the car idle/run smooth besides the fuel cut?

 

[sweet97]

Thanks! I feel better now!! Thought I was more nuts than I am! The 18G alone will cause fuel cut at 10psi in the winter(cold air is denser) given your location. Under boost it will also run lean which will heat the motor too high(possibly). What do the gauges read under boost or right after?
All you need is the correct fuel-pump, 650c inj's and some fuel control.
You will have to perform the usual maintanaince. Change fluids, tune up. Change thermostat to correct range if needed. Start with the gauges and what they read. Thanks, Mark