engine knock? help me please...
12-07-03, 07:25 AM
#1
Full Member
Thread Starter
Join Date: Nov 2003
Location: Boulder, Colorado
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
engine knock? help me please...
Hi guys!
I have problems.
I have a 93 rx-7. It has a new engine that has around 30,000miles on. everything is stock except air intake filter; however the turbo boosts upto 14psi with metal scraching sound. If I have a full boost at 1st gear, I do not have any boost at 2nd gear. why does it happen?
I also have an engine problem. I was driving normaly 80mph at 5th gear. It was about 3000rpm. I tried to accelate but suddenly I felt a little bump from the engine and could not accelate. It was like the engine stops. I have experenced this twice for now. Is this an engine knock? Why does it happen?
What is the cure for this problem.
any information would help me. Thank you!
I have problems.
I have a 93 rx-7. It has a new engine that has around 30,000miles on. everything is stock except air intake filter; however the turbo boosts upto 14psi with metal scraching sound. If I have a full boost at 1st gear, I do not have any boost at 2nd gear. why does it happen?
I also have an engine problem. I was driving normaly 80mph at 5th gear. It was about 3000rpm. I tried to accelate but suddenly I felt a little bump from the engine and could not accelate. It was like the engine stops. I have experenced this twice for now. Is this an engine knock? Why does it happen?
What is the cure for this problem.
any information would help me. Thank you!
12-07-03, 08:18 AM
#2
Rotary Enthusiast
Ummm, everything is stock except intake filter? And you are boosting 14 psi? Are you getting this info from a boost gauge or are you guessing, because if you do have boost gauge and it's telling you 14 psi, well, start saving money for a new motor. ergo: your engine problem.
When you say full boost in 1st but not second, what rpm are you shifting, because if you are shifting less than 7k rpm (from 1st to 2nd), the primary will not come on line in 2nd. Another thing is try to shift at 3k rpm from 1st to 2nd, this should allow the primary to come online in 2nd.
When you say full boost in 1st but not second, what rpm are you shifting, because if you are shifting less than 7k rpm (from 1st to 2nd), the primary will not come on line in 2nd. Another thing is try to shift at 3k rpm from 1st to 2nd, this should allow the primary to come online in 2nd.
12-07-03, 09:50 AM
#3
It's called "Fuel Cut".
Originally posted by neevosh
This is what the fuel cut #'s are.
RPM ABS. CUT OFF(PSI) SEA LEVEL CUT OFF(PSI)
1000 26.5 11.8
1500 26.5 11.8
2000 26.5 11.8
2500 26.5 11.8
3000 26.9 12.2
3500 27.1 12.4
4000 27.5 12.8
4500 28.0 13.3
5000 26.9 12.2
5500 26.0 11.3
6000 25.8 11.1
6500 25.4 10.7
7000 25.4 10.7
Mazda took into account that there may be boost spikes at transition and raised the cut-off pressure. Also, boost has to be sustained above the cut-off pressure for a certain period of time before the fuel cut takes place.
This is what the fuel cut #'s are.
RPM ABS. CUT OFF(PSI) SEA LEVEL CUT OFF(PSI)
1000 26.5 11.8
1500 26.5 11.8
2000 26.5 11.8
2500 26.5 11.8
3000 26.9 12.2
3500 27.1 12.4
4000 27.5 12.8
4500 28.0 13.3
5000 26.9 12.2
5500 26.0 11.3
6000 25.8 11.1
6500 25.4 10.7
7000 25.4 10.7
Mazda took into account that there may be boost spikes at transition and raised the cut-off pressure. Also, boost has to be sustained above the cut-off pressure for a certain period of time before the fuel cut takes place.
12-07-03, 12:43 PM
#4
Rotary Freak
Join Date: Aug 2002
Location: nyc+li, ny
Posts: 2,690
Likes: 0
Received 0 Likes
on
0 Posts
search around here a bit to learn just how bad your symptoms are and then find yourself a competent rotary mechanic in your area to look at the car.
14psi on a stock car/ecu is a very bad thing. the stock ecu only correctly handles boost to 10psi. meaning you will/can blow your engine by running that much boost.
14psi on a stock car/ecu is a very bad thing. the stock ecu only correctly handles boost to 10psi. meaning you will/can blow your engine by running that much boost.
12-08-03, 12:01 PM
#7
Senior Member
Join Date: May 2002
Location: Austin Tx
Posts: 494
Likes: 0
Received 0 Likes
on
0 Posts
Prevent the fuel cut..
Without it your car would probably be attached to a tow truck right now. You need to controll that boost. Get a profec B or make your own boost controller. Do a search for rx7 homemade boost controller on google. Its easy and will save your motor.
Without it your car would probably be attached to a tow truck right now. You need to controll that boost. Get a profec B or make your own boost controller. Do a search for rx7 homemade boost controller on google. Its easy and will save your motor.
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
07-01-23 04:40 PM
stickmantijuana
MoTeC
5
09-10-15 07:58 PM
Frisky Arab
2nd Generation Specific (1986-1992)
13
08-18-15 05:30 PM
