my rx7 has a weird problem it has the 3800 hesitation but its only if i stomp the gas if i go easy with the gas it goes past 3800 no problem but the second i push the gas all the way it hesitates what can be wrong? i checked and redid all grounds just changed spark plugs and coils did a tune up on it idk what it can be the other day it worked fine without any hesitation at all but now it keeps doing it only when i push the gas all the way i need help asap please

 

if all the grounds are good id check the map sensor and possibly the fuel system ( pump, filter, and injectors)

 

Check for a clogged catalytic converter.

Perhaps it is time to change your fuel filter and fuel pump strainer (fuel sock).

In case you're wanting to check for leaky injectors... Strap/secure the injectors to the fuel rails. Unbolt and remove the fuel rails. (There's an illustration of this in the 88' FSM. "Fuel and Emission Control Systems" 4A-70) - Obviously you do not remove the injectors or any of the fuel lines. Be sure to set some rags or something under the injector's fuel outlet nozzle, to absorb fuel in case they are stuck open. Jumper the yellow fuel pump test connector at the passenger side strut tower, near the AFM. Turn the key to "ON"... Not to "START". You'll hear the fuel pump running... Now go check the injectors to see if they are spewing/leaking.

If you do not have a Factory Service Manual, here is a link to the 1988 FSM "Fuel and Emission Control Systems": http://foxed.ca/rx7manual/manuals/19...SYSTEMS_NA.pdf

 

pop your fuel sock off and re try. i had the same issues with my fuel sock causing fuel starvation on wot and cournering

 

i just took off my fuel pump and the filter is brand new nice and clean and the pump is brand new can it be my fuel filter? or wat else can it be?

 

Could very well be the filter. Have you checked the pump output?

 

I think that hesitation is a precursor to spontaneous combustion, soon it will kill you. However being the good guy I am I care for your safety and am willing to come tow your car for FREE. That is right, for FREE. That way you can sleep easy at the thought that the devil 7 will no longer be lurking in your driveway waiting for some fateful drive to blow you up >.>

 

Change your fuel filter. Whether it is THE problem or not, it probably needs to be changed.

Also, check for a clogged catalytic converter. (As I advised above.)

 

check to ur secondary injectors. i had the same proble the turned up to be clogged with rust

 

The fuel sock is the cause of a problem for me. I removed it and tried to flush it out, no dice. Even though it looked clean it would actually hold gas. must be tiny invisiblefragments of something blocking it.
I ordered two from my dealer, put one on. all problems stopped with hesitation and stalling on bends. I think they were $10.00 apiece, I'd get a couple while they are available, unless they are fitted onto another Mazda model too, and the fuel pump, is that only for the NA RX7 FCs
Mike

 

i took off my fuel sock completely and left it out and still have the problem im gonna put the fuel sock back on i just wanted to see if that fixes it but it didnt and i took out my fuel rail and checked the injectors and they seem good but i did notice one of the secondary injector wires were not connected previous owner cut and crimped the wires and one came out so i rewired it and soldered and heat shrunk them and still has the problem would i need to reset the ecu or something for it to know the injectors r connected again? and i also noticed the ecu ground under the intake manifold is not there i see where its supposed to be but its not connected i cant see the ground wire it might not be visible with the manifold on or previous owner might of regrounded it but i grounded the ecu pins that were listed in another post i grounded them right next to the ecu witch was said to be okay on another post but still didnt make a difference? anyone know wat it can be? would it work with the ecu points grounded like i did? i also added an extra ground from the engine to the chassis

 

would the fuel filter do that? would it cause the secondary injectors not to go on? is there any way i can make the secondaries stay open all the time? and if so will my gas milage go to complete ****? its pretty bad now will it get alot worse?

 

I told you twice to change your fuel filter.


No.


Why would you want to do that?


YES.


Who knows...? That is determined by your ability to take in information to fix your issue.


Have you checked for a clogged catalytic converter yet?

 

Remove the vacuum hose from your pressure sensor. Cap off the vacuum line itself.

The secondarys will come on anytime you reach approx 3800 rpm when doing this. Now go for a ride and see if the problem persists. This is just to give us a clue. Not a permanent thing to do.

 

sounds like an AFM problem to me...

can you go WOT until it hits 3800 rpm? or will it bog if you go WOT at say 2k rpm?

 

i can go wot until 3800 right when it hits 3800 it cuts but anytime before that its fine

 

any check engine codes? is there an OMP code stored? is the Check engine light on?

 

its a 86 doesnt have a cel and i dont know how to check stored codes

 

Did you really check the ground on the rear rotor housing under the TB and UIM?

 

yes i did and the ecu ground wasnt grounded there the previous owner took the manifold off he must of took that ground off and forgot to put it back but online someone said that i could just ground the ecu points so i did that and it didnt do anything so tomorrow im gonna take my manifold off and see if the ground wire is there then ill ground it if it is and see if that fixes it

 

DOH! on my part, i was reading another car that was an 89.... should have read this was an 86...

it's 100% your secondary injectors, you can put in test lights in to the injector connectors(and you can get to the injector connectors without removing much)
you'll have to mount the test light bulbs were you can see them, and then drive the car to 3800 rpm, although hailers had a nice suggestion of making the car thing it is under load by venting the line to the MAP sensor.

i haven't tried it, but assuming this works, you can just rev to 4k at idle, and the secondarys should fire.

if they light up the bulbs, then they are badly clogged, but it's likely they won't light up the bulbs b/c of the missing ground(s).

 

IF driven gently a RX can be driven up to ??? five grand plus with only the primary injectors working and all will seem fine and dandy.

When you stomp on the gas below 3800, the primarys will be the only injectors working, but when you hit 3800 rpm the primarys duty cycle will be cut in half and the secondarys will now come online along with the primarys and the primarys and secondary duty cycles will be the same.

Your problem seems to be one or maybe both secondarys are not coming online at 3800 rpms. Just one not coming online would cause a big hesitation.

To more or less prove the wiring is good, you could pull the small ECU plug off and key to ON and see if there is batt voltage on all four of the green wires (green/white......green/red......green/black and plain green with no stripe). And when you see the batt voltage on the secondary wires at the ECU you could have someone wiggle the secondary injector wiring on the engine to see if the voltage comes and goes or not.

Eary 86-87 FSM had a secondary injecotor test where you idled the engine and then pulled the vacuum line off the pressure sensor and plugged that vac line. Then reved the engine to 3800 rpm and listened at the secondary injectors for a clicking sound (non turbo cars only). Kinda sensless thing to do since I can't see how anybody could hear a injector clicking at idle. But I could see the voltage drop at the ECU wires if I backprobed the secondarys with a meter plus you could hear the odd sound of the engine when the secondarys came online.

 

LOL, you don't ear it without the aid of a stethoscope... and with a steth, you can hear it VERY WELL... however finding a bulb with some wires to test for power at the connector can be done without finding and purchasing a stethoscope.