The Real Truth 3,800 RPM Hesitation
12-07-03, 11:16 PM
#51
I'm a boost creep...
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Originally posted by GUITARJUNKIE28
from the schematic. where else?
from the schematic. where else?
12-08-03, 10:17 AM
#53
HAILERS
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Grounds.........Part of the problem is the owners who don't attach the ground wire in a clean manner. Then there are others like me who are perfect in every way, and our cars are lemon cars so to speak. The ECU grounds are located on top of the Engine in a circular connector attached with a bolt. In between the ECU and the ground end point, there are splices IN the ground wires IN the harness . Some are located IN the harness about a foot or less from the ECU. Others are located IN the harness approx where the harness crosses from the fender over to the engine. Some of these mechanical spilces are not perfect like their owners......hence the problem with ECU grounds. Any other questions? P.S. I've been inside the harness and seen the splices at both points mentioned above.
Last edited by HAILERS; 12-08-03 at 10:20 AM.
12-08-03, 11:33 AM
#54
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What years are the 3800 rpm hesitation most prevalent? Or is it common on all EFI setups? I am about to get a 90 on the road.... but need a new motor first.... I am tempted to wait on grounding anything until after it is running, just so I can see what fixes it on my car, assuming it becomes a problem in the first place. (current owner hasnt had any problems, other than the bad rotor.)
12-09-03, 09:48 AM
#58
Former Moderator. RIP Icemark.
Originally posted by tannji
What years are the 3800 rpm hesitation most prevalent? Or is it common on all EFI setups? I am about to get a 90 on the road.... but need a new motor first.... I am tempted to wait on grounding anything until after it is running, just so I can see what fixes it on my car, assuming it becomes a problem in the first place. (current owner hasnt had any problems, other than the bad rotor.)
What years are the 3800 rpm hesitation most prevalent? Or is it common on all EFI setups? I am about to get a 90 on the road.... but need a new motor first.... I am tempted to wait on grounding anything until after it is running, just so I can see what fixes it on my car, assuming it becomes a problem in the first place. (current owner hasnt had any problems, other than the bad rotor.)
12-09-03, 09:57 AM
#59
Rotary Enthusiast
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mazdasurplus.... can anyone contact them... i dont have long distance i have about 200 bucks icemark you think they can give me all the engine harness i need for the injectors for that much? and how new are they harness i have a 88 gxl n/a manual
12-09-03, 10:02 AM
#60
Former Moderator. RIP Icemark.
yeah, anyone can contact them.
Their stock comes and goes (they buy dealers old stock and stock from dealers than have closed doors), so it is almost impossible to know if they will have the harnesses you want, without checking with them on what they have in stock any given week.
Their stock comes and goes (they buy dealers old stock and stock from dealers than have closed doors), so it is almost impossible to know if they will have the harnesses you want, without checking with them on what they have in stock any given week.
12-09-03, 10:28 AM
#62
HAILERS
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If one READS 
(sticks tounge out) the FSM, one will find on page 4A-69, the On Vehicle Inspection of the injectors:
1. Disconnect hte vacuum hose from the boost sensor.
2. start the engine and increase the engine speed.
3. Check the operating sound of the secondary injectors OVER 3500 RPM.
It's the six port induction system that comes on at 3850 rpm on a series five.
I've taken the pressure sensor hose off and plugged it and gone for a drive. With a meter connected to the fuel injector secondary wires you can see the voltage drop when you reach 3500 rpm. And you can drive as slow as you want to the 3500 to see it trigger, if you have the pressure sensors hose disconnected that is. It'll trigger everytime at 3500.
(sticks tounge out) the FSM, one will find on page 4A-69, the On Vehicle Inspection of the injectors:1. Disconnect hte vacuum hose from the boost sensor.
2. start the engine and increase the engine speed.
3. Check the operating sound of the secondary injectors OVER 3500 RPM.
It's the six port induction system that comes on at 3850 rpm on a series five.
I've taken the pressure sensor hose off and plugged it and gone for a drive. With a meter connected to the fuel injector secondary wires you can see the voltage drop when you reach 3500 rpm. And you can drive as slow as you want to the 3500 to see it trigger, if you have the pressure sensors hose disconnected that is. It'll trigger everytime at 3500.
12-09-03, 10:54 AM
#64
HAILERS
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Engine - Surge or Stumble During Acceleration
Category Applicable Model/s Subject Bulletin No. 042/88
4 1986-87 RX-7 SURGE OR STUMBLE Issued 2/11/88
DURING ACCELERATION Revised
DESCRIPTION
If you encounter a 1986-87 RX-7 vehicle with a surge or stumble during acceleration at more than 2500 rpm, this may be due to an improper ground between the emission control unit and the air flow meter. Test for the symptom according to the procedure shown in this Service Bulletin. (Refer to Service Bulletin Category 4, No. 036/87.)
The ground circuit of the emission control unit has been improved since November 1, 1986.
CHECKING PROCEDURE
Use an ohmmeter to check the resistance between the 2C terminal of the emission control unit and the boost sensor/(pressure sensor) ground terminal (BrB). If the resistance is not 0, proceed
REPAIR PROCEDURE
1. Connect the ground wire (BrB) of the boost sensor/(pressure sensor) and the bolt of the water filler neck with an additional wire as shown.
NOTE:
Do not ground the ground wire (BrB) of the boost sensor/(pressure sensor) to the body panel. For correct operation, ground the wire as shown.
2. Use electrical tape or tie-wrap to attach the additional wire to the engine harness.
THE ABOVE FROM THE SERVICE BULLETIN. A ll this should have been resolved after 87 if you ask me.
.
Category Applicable Model/s Subject Bulletin No. 042/88
4 1986-87 RX-7 SURGE OR STUMBLE Issued 2/11/88
DURING ACCELERATION Revised
DESCRIPTION
If you encounter a 1986-87 RX-7 vehicle with a surge or stumble during acceleration at more than 2500 rpm, this may be due to an improper ground between the emission control unit and the air flow meter. Test for the symptom according to the procedure shown in this Service Bulletin. (Refer to Service Bulletin Category 4, No. 036/87.)
The ground circuit of the emission control unit has been improved since November 1, 1986.
CHECKING PROCEDURE
Use an ohmmeter to check the resistance between the 2C terminal of the emission control unit and the boost sensor/(pressure sensor) ground terminal (BrB). If the resistance is not 0, proceed
REPAIR PROCEDURE
1. Connect the ground wire (BrB) of the boost sensor/(pressure sensor) and the bolt of the water filler neck with an additional wire as shown.
NOTE:
Do not ground the ground wire (BrB) of the boost sensor/(pressure sensor) to the body panel. For correct operation, ground the wire as shown.
2. Use electrical tape or tie-wrap to attach the additional wire to the engine harness.
THE ABOVE FROM THE SERVICE BULLETIN. A ll this should have been resolved after 87 if you ask me.
.
12-21-03, 11:17 PM
#66
Mazda4Life
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I'm planning on having an 'electrical day' in the next week or two where I'll pull and replace the major power lines in the car; the positive loop from battery to starter to alternator, redo my past 4-gauge grounds and review and redo all other grounds (when I first installed them I didn't solder them.)
12-22-03, 02:37 AM
#67
Lives on the Forum
12-22-03, 11:56 AM
#68
Refined Valley Dude
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Congrats on getting your goddamn site back up!
We've been WAITING and WAITING and WAITING... I was about to mail you my own credit card just to get it all over with. 
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