2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Still have 3800 RPM hes. after grounding and new fuel filter.

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Old Jun 15, 2004 | 07:36 PM
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Still have 3800 RPM hes. after grounding and new fuel filter.

I still have the hesitation after Replacing the fuel filter, and most gorunding. I grounded the leading and trailing coils, pressure sensor,and put a big ground on the body. I ran direct wires from the negative battery terminal to everything. I have new plugs and spark wires as well. I also reset the ECU. Should I ground to the ECu and then see if it is still there? I'm just wondering after I've done these things why its still there. Acceleration did improve and become smoother though, quite noticeably.

Please help me.
-Ian

Edit: I have an 87 base. 170k on odometer, original engine.
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Old Jun 15, 2004 | 07:51 PM
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Mine is the same...it comes and goes...It really pisses me off!!!
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Old Jun 15, 2004 | 07:52 PM
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My speedo hasn't worked for a while until lately...my Ode says 80000...but that's not right...unless it broke and sat for 10 years until I got it!
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Old Jun 15, 2004 | 07:53 PM
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Take it to a mazda dealership to get the name on the part, It was $400, i had it replaced when i 1st got the car, its a computer thing i dont rember the name of, Maby someone could clue you in, btw go to a junkyard to get it.
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Old Jun 15, 2004 | 07:57 PM
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do you know what the part went to, or attached to?
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Old Jun 15, 2004 | 08:15 PM
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Yeah...we need a little bit more info Mephis...
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Old Jun 15, 2004 | 08:24 PM
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a lot of 2nd gen rx7 have a hes. at 3800 rpm because this is where the secondary fuel injectors come in. Does is do it when u floor it or only when slowly increasing your speed?
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Old Jun 15, 2004 | 08:27 PM
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Both, Would this be due to them being gunked up? my primaries are fine. the car hasnt beeen driven hard for a while, about 2 years. I drive it now
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Old Jun 15, 2004 | 08:31 PM
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Originally posted by Molotovman
Should I ground to the ECu and then see if it is still there?
Grounding the ECU is just cleaning the ECU mounts & where it bolts to the body.

Other things to test:
https://www.rx7club.com/showthread.p...hreadid=271785


Originally posted by jacobcartmill
I finally got my 3800 rpm hesitation fixed (actually it didnt really hesitation, the secondaries wouldn't come on at all and it would just bog over 3800 under a load) i bought that resistor pack and replaced it. NO MORE PROBLEMS. please ask any questions you have and i'll be glad to help you replace this unit.
Also:
https://www.rx7club.com/showthread.p...hreadid=184591

Originally posted by kitchen
I JUST FIXED MY 3800 RPM HESITATION!! I AM SO HAPPY!

I did the trick where you solder a wire to the pressure sensor and ground it to the radiator. Works perfectly. No more annoying hole in my power band!
Also:
Originally posted by kitchen
I adjusted my TPS and my 3800 RPM hesitation went away.

I'm kicking myself for not having done it sooner!
Also:
Originally posted by Flobb
When this happened to me it was because the injector kept coming unplugged. The plastic plug had cracked and kept vibrating its way off the injector. Finally ended up that I was having some other work done on my car and the guy just used some kind of glue to stick it back on. I don't know if it will ever come off now, but it worked.

Last edited by vaughnc; Jun 15, 2004 at 08:41 PM.
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Old Jun 15, 2004 | 08:33 PM
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Isn't there paint there? Should I remove the paint and re-mount it? I am going to grab some injector cleaner and dump it in. Mine hesitates both times too! Wether I am driving sedately or hard...it does it intermittently now. It did it all day yesterday and has not done it once today...I am just confused now.
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Old Jun 15, 2004 | 09:46 PM
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****Grounding the ECU is just cleaning the ECU mounts & where it bolts to the
body.***

OH BULLSHIT. GET THE HELL OFF THIS FORUM SINCE YOU DON'T KNOW A DAMN THING.
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Old Jun 15, 2004 | 09:52 PM
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Damn Hailers, check your blood pressure...
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Old Jun 15, 2004 | 11:24 PM
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yea soe of the people on here have wrench turning skills and some think they do. i recomend doing at least 3 extra grounds, batt to the body, body to the motor and ecu to the body. i do 2 grounds on the motor to the body(1 on each side) and 2 on the ecu in difrent spots to difrent body locations... i want to make sure its grounded damit! I know on a friends t2 's that is the 1st thing he does and its CHEAP i mean whats a few ft of nice guage wire run 10$? i also put ringlugs and solder them on with shrink so they look really good.
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Old Jun 15, 2004 | 11:46 PM
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i have the same problm on my gxl . and the problem is that the wires that goes to the secondary injectors get so hot and worned out that it changes the resistions of the injector thus giving lease fuel. i have to replace the harness and put a bunch of electrical tape and wire protectors.(ps. its the wire that runs right on top of the motor Mazda wasent think britly on that , hmmm rotary run hot uhh its ok nothing will happen. )

i got 140,000 miles original engine. and now all the antifreeze is leaking into the housing yah

Last edited by fc3s-gxl; Jun 15, 2004 at 11:49 PM.
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Old Jun 16, 2004 | 01:11 AM
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You can lay the ECU on foam rubber and it won't act any different. The ECU does not ground its internals thru the ECU chassis. The grounds for the ECU are located on the rear rotor housing on a ring terminal.
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Old Jun 16, 2004 | 01:20 AM
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You can lay the ECU on foam rubber and it won't act any different. The ECU does not ground its internals thru the ECU chassis. The grounds for the ECU are located on the rear rotor housing on a ring terminal.

The factory installed a ground from the battery to the chassis and to the engine. Follow the negative cable from the battery.

The coil/ignitor assy gets grounded thru their mounts to the chassis. Running another cable from the coil/ignitors chassis to the battery negative post is.......pure superstition (a belief or practice resulting from ignorance).
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Old Jun 20, 2004 | 09:51 PM
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Mine was really bad tonight, but my car wasnt all the way warmed up. Also, wheres the best place to ground to the engine block(most accesssable). And what is the best way to read the secondary injectors?
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Old Jun 20, 2004 | 11:42 PM
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check out the actuators for your fifth and sixth ports
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