fuel cut at high rpm
01-17-04, 03:46 PM
#1
fuel cut at high rpm
i took the gsl-se out for the first time yesterday for a ride since i had installed the new engine (used with low miles). it ran great but when i shifted out on second gear at 6000 rpm's, it hesitated like it was starved of fuel. it broke out if when i shifted quickly into fourth. it seems like it was starved for fuel for a sec. also, i do not have a part on the dynamic chamber. it is black and looks to be a one wire connector. kinda looks like the ground wire on an alternator. at any rate, i think it is the atmospheric pressure sender. i do not hav it. the male end is on the dynamic chamber but i do not have the female end. i may be wrong on it being the aps. anyone have any ideas?
Trending Topics
01-17-04, 06:02 PM
#10
it WILL run
Join Date: Dec 2002
Location: Raleigh,MS
Posts: 2,017
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by mazdaverx713b
why would it do it in third and not first or second? is it because it has to work a little harder to keep up with the added load? i was thinking vaccume leak or timing off a little.
why would it do it in third and not first or second? is it because it has to work a little harder to keep up with the added load? i was thinking vaccume leak or timing off a little.
but it takes more fuel the higher the gear becuase the engine has more load on it
01-18-04, 08:00 AM
#16
Senior Member
Join Date: Nov 2001
Location: Gig Harbor, WA
Posts: 566
Likes: 0
Received 0 Likes
on
0 Posts
That beggar has caused a lot of probs, kinda makes sense too if I think about it. Its an easy procedure, it WILL make it run better either way (that is if its out of adjustment) Here is this in case you need it. https://www.rx7club.com/showthread.p...ps+for+dummies
01-18-04, 10:06 AM
#17
84SE-EGI helpy-helperton
The connector that you describe on your dynamic chamber is for the intake air temperature sending unit. This is a thermocouple that transmits a signal to the ECU to adjust mixture level for the ambient air temperature. There's another one in the Air Flow Meter, by the way.
The Atmospheric Pressure Sensor is located adjacent to the ECU under the passenger floorboard, and sends a signal to the ECU to adjust mixture for increasing altitude, as in driving from the coast to the mountains.
Your description of the 'fuel starvation' at high load conditions may be volume related, so the other posts suggesting that you look at your fuel flow system (other than floats...) are spot on. I would check the following;
1) fuel filter - EFI fuel filter is huge and much more expensive due to high pressure, get the Mazda factory replacement and feel confident that it's in good shape,
2) fuel pump - check this via fuel pressure readings at the fuel rail leads to see if you're getting good pressure. Fuel dump over time is only really helpful on carb engines, IME, because an EFI system is moving a much higher volume of fuel at a much higher pressure - making it hard to accurately gauge flow rate.
3) fuel lines - if you have any leaks anywhere, it may be releasing fuel from the system and dropping pressure.
4) fuel pressure regulator - on the fuel rail at the rear, you'll see the diaphragm activated fuel pressure regulator that reacts to vacuum signal on the 'rats-nest'. If this vacuum connection is bad (bad hose, hole, missing, etc.) then you will not get higher fuel pressure change for increased load conditions <--- Most Likely Cause!
Good luck, and report back, HTH,
The Atmospheric Pressure Sensor is located adjacent to the ECU under the passenger floorboard, and sends a signal to the ECU to adjust mixture for increasing altitude, as in driving from the coast to the mountains.
Your description of the 'fuel starvation' at high load conditions may be volume related, so the other posts suggesting that you look at your fuel flow system (other than floats...) are spot on. I would check the following;
1) fuel filter - EFI fuel filter is huge and much more expensive due to high pressure, get the Mazda factory replacement and feel confident that it's in good shape,
2) fuel pump - check this via fuel pressure readings at the fuel rail leads to see if you're getting good pressure. Fuel dump over time is only really helpful on carb engines, IME, because an EFI system is moving a much higher volume of fuel at a much higher pressure - making it hard to accurately gauge flow rate.
3) fuel lines - if you have any leaks anywhere, it may be releasing fuel from the system and dropping pressure.
4) fuel pressure regulator - on the fuel rail at the rear, you'll see the diaphragm activated fuel pressure regulator that reacts to vacuum signal on the 'rats-nest'. If this vacuum connection is bad (bad hose, hole, missing, etc.) then you will not get higher fuel pressure change for increased load conditions <--- Most Likely Cause!
Good luck, and report back, HTH,
01-18-04, 11:36 AM
#18
LongDuck, thank you. i will definatly look at what you reccomended. i am kinda new to the egi system so please bear with me on some of my descriptions. if anyone is selling an intake air tep sending unit, i'd be interested as i have none. thank you all for the advice given. i will definatly look into the possible faults and report back.
01-18-04, 02:02 PM
#19
Senior Member
When Air Intake Temp units fail or have an open or short most vehicles run rich.
Many computers have predetermined values that they fill in when they doe not get a reading.
If that is the case on the RX7's then it is NOT your "cut out" problem.
The TPS can cause Havoc and it is a good idea to check that TPS voltage with a good quality meter.
Many computers have predetermined values that they fill in when they doe not get a reading.
If that is the case on the RX7's then it is NOT your "cut out" problem.
The TPS can cause Havoc and it is a good idea to check that TPS voltage with a good quality meter.
01-18-04, 02:26 PM
#20
KehoeAutomotive: thank you for the advice. i actually am missing the intake air temp unit. i have the male end of the connector. i need to get the female end that connects to the harness as well as an idle adjust part (i believe). it connects on the right side of the engine bay, near the strut tower. it has a black female connector with a boot and it is next to a green connector. also i remember i am missing a hose that is in the middle of the lower intake, facing the right. i am not sure what it connects to. it is large. possibly 5/8 in size. i am also missing a hose that is on the rear of the airbox. i have no idea what this connects to. please bear in mind i swapped a 13b back into this car. i couldnt have a 12a in a gsl-se.
Last edited by mazdaverx713b; 01-18-04 at 02:30 PM.
01-18-04, 05:59 PM
#22
Yea, I'm working on it...
Join Date: Dec 2003
Location: Click click fucking click, Africa
Posts: 1,220
Likes: 0
Received 0 Likes
on
0 Posts
Mine does the exact same thing, i got smaller jets and a bigger fuel pump....of course you got fuel injection so it may be diferent
01-18-04, 07:51 PM
#24
Senior Member
Join Date: Nov 2001
Location: Gig Harbor, WA
Posts: 566
Likes: 0
Received 0 Likes
on
0 Posts
[i]I have three Turbo 13BT motors on the floor. Will any of the parts off it work for you? [/B]
Last edited by Steve Shulz; 01-18-04 at 07:53 PM.
