Just recieved my 86 gxl from a relative so it has been siting in a garage for several years and not ran for some time. As of now ive got it running great and most of everything works on the car but i just started noticed the constant hesitation at 3500 rpm lately because i jsut started driving it harder. Ive looked on the forum and gather my links but still had a few questions before i start fixing the problem. And wait for it to stop raining.

1. The groud that is added to the FPS does it needed to be grounded to the block in the same area as the original ground? are there any other good spots to add a ground maybe closer to the fps?

2.Might there also be any pictures of a ground being added there? ive found pictures of all the other grounds for the car.

3. The hesitation is constaly always jsut around the 3500 rpm range every time i drive it, rarely could i get past 3500 and maybe those rare times i was going downhill. If i was to check all the grounds and add one to the fps and no change, should i go stright to checking the injectors?

 

1 question:

Does your car rev over 3500 rpm? It seems from the last point you made that it does not rev over 3500 rpm.

The 3800 rpm hesitation that everybody talks about is just that, a hesitation. The car will accelerate through 3800 rpm, but accelerate less rapidly through this point. It makes it feel like you are letting off the gas momentarily.

If what I wrote is not your problem, then the answer you are searching for is simple! Ground the lead to the CHASSIS anywhere you can get a good metal on metal connection.

 

don't check your grounds, clean your grounds. (especially the one under the intake manifold)

check for vacuum leaks

see if your secondary throttle plates are working properly

check the 5/6th port actuators.

try switching out your secondary injectors with known good ones.

and I prefer my grounds to be all looped back to the block.

I did all these and got rid of the worst hesitating Rx7 I've ever been in, IE - mine.

 

Yeah it never goes past 3500 really, maybe jsut a little bit up to 4000.

Im going to clean all the grounds, run a ground from the fps to the chassis, and check all the vaccum lines for leaks.

Ill take off intake to check if secondary throttle plates are working properly.

How do i cehck the 5th and 6th port actuators? if not ill search the forum.

Ill consider running to the block, after i see how hard it is to reach the ground on the block under the intake.

Thanks for the info guys.

 

Wow!

That is not a hesitation. If your car won't rev over 4000 rpm, it is not the regular hesitation.

It could be fuel related! Is your fuel filter and fuel pump sock new and clean?

How are your plugs and wires?

Does the car idle normally?


I think you are on the right track by checking the throttle plates, I would check the 5th and 6th ports also.

Again, this is not the typical hesitation that grounds cure. This sounds like you have something else going on!

Any other info you can provide?

 

If the car idle is okay or close, it is not a Vac leak. When you go wide open throttle, the computer does not read any sensors (I believe) which means that the air is no longer metered. Vac leaks would not matter in this case.

^-- if that was retarded, please call me out on it!

 

More information: The car will rev past 3500 jsut fine when im in park, but when im driving it it will not go past 3500. And when i do rev it that high it tends to blow smoke and it really doesn't do that much. It also feels good and sounds pretty good. Most of my rotary friends think the car drives great and feels great but we never really ran it high rpm then.

If it revs fine in park, where should i start? going to clean and do all the ground stuff anyways before or after i fix.

he car was sitting for some time so i had to replace the fuel pump, still using a stock one. New fuel filter and the flow seems to strong (i haven't put a tester or regulartor on it, i think i have one im going to put on to test). The plugs and wires look and feel good. The idle is fine and revs pretty good. But the air ratio screw on top of the intank manifold i believe needs to be adjusted because it was moved. Im what is the best settting or best way to test that.

 

Reading more, now i believe it could be my actuators not operating properly? Im gonig to check them and prob clean as well.

 

No. If your actuators were stuck closed, you would feel strong low end torque and the car would get way slower at 4000, but it would still get to redline just fine. It sounds like your secondary injectors are not firing at all, or you have a clogged cat.

 

Do all the usual checks - ground etc - but definitely check out the fuel delivery (pressure / filter ,etc). Consider replacing the secondary injectors if all checks out - it was my solution.

 

Im going to try some secondary injectors from my friends 2nd gen in the next day or two, but its been sitting so i hope they work out. But before that im going to manual check to see if injectors click on and also look on FSM for the flow test or whatever it is.

As of today the car still lags at about 3500 if i let off the throttle alot and figddle with it i can get it to go past 4000 rpm and after that it seems to rev fine. It really struggles to get past 3500, and say im going downhill its alot easier to pass 3500.

 

So far i cleaned all the grounds, added a ground to the fps, checked actuators both more freely and one i can see is working the other is hard to see. I haven't gotten around to checking the connection on the secondary injectors or swtiched them out yet.

As i was leaving my friends house last night when it was very cold, after letting the car warm up a bit i drove it home and tried to run it past 3800 about 8 times or so. Only 2 of the times it got stuck at 3800 and wouldn't go any higher and the other times it drove well above 3800 just fine with no hesitation. This morning it was back to normal and wouldn't drive past 3800 at all. What might make it run so much better just because it is colder?

 

thats bad ground, revs fine under no load but under load the bad ground dont give the right voltage under the load they need, mostly the injectors, even more so if they are cold.

clean all your grounds or re ground them.

wire brush the contact area and clean the connector too or replace the connector with a new one, if you want you can go nuts and loop them all together in a circle.

ground locations underhood.

1. under airbox
2. under UIM
3. behind coils (larger ones)
4. irons
5. wherever else

and adjust your TPS when it has come up to operating temperature (when the upper rad hose is hot)

 

two days ago i clean most of the grounds. The one under the UIM, the one by the coils, the one for the battery where it is the bolt near the driver's shock tower, and i also added a ground to the brn/blk wire to the FPS. I added it in and ran it to a bolt near the passenger side shock tower. After i did all of that i felt no difference the many times i drove it till last night when it was cold.

Could the ground i added to the FPS not be installed well?
How do i adjust the FPS once its at operating temp?
Could my FPS be bad or could it actully be the vaccume line that runs to it is bad?

 

Make sure the injector connectors at the secondary injectors aren't baked by exhaust heat and falling off.

As for grounds, all you need to know is this:
http://www.aaroncake.net/rx-7/grounding.htm

Also check the pressure sensor at the passenger shock tower. Testing procedures are in the FSM.

 

FIRST OFF I OWN AN 86 GXL
I am not saying this is your problem but seriously check it out . Your problems sound alot like what my car was doing .
I had 3800 hes problems a while back . One thing I never see mentioned in the forums and I am not saying its not out there somwhere . Is the Fuel Injector resistor pack . Disconnect it and test it for continutity also test the secondary injector wire connections for continutity .if you don't know where the resistor pack is its located underneath where the air filter box would be attached to the right wheel well . That was what was wrong with my car . I figured that out after regrounding everything under the hood and the ECU adjusting TPS 5th 6th ports and air actuators make sure your boost sensor works to . But this really sounds altot like what I had go wrong . Have fun