I am going through the same thing.
I have added over 8 different grounds all over the place.
doesn't help.

I've been emailing with Dave at KD Rotary about this for a couple of weeks. I now think it is the injectors.

I am going to send them all out to RC Engineering next week. When i reinstall them, i am hoping everything will be cured.

will post results next week.

 

What makes you think injectors vs fuel pump. There a way to test either one of them?

 

Well, you can test the pump. If you go to Rob Robinette's site, it shows how to hook up a fuel guage. From there, you can test it based on the psi. i just haven't ordered one yet (which i plan to do).

As for testing the injectors, I measured the resistance of each injector. The book calls for 13.8 ohms at 65 degrees OAT. I tested my secondaries and they are 14.8 and 14.3 (and it was like 62 that day). the book says if they are not apprximately 13.8, replace the injectors. well, what is approximate? on a scale of 1-1000, "1" is not significant. but on a scale of 1-20, "1" is. So i called RC engineering and they said that the one ohm is not significant. They said anywhere from 12-16 ohms is fine as far as resistance is concerned. These guys have done rx-7 injectors before, and dave at KD Rotary sends all his out to them (he recommended them to me). Dave did say that he does run into injectors which need professional cleaning, although he did not say how many or what percent. Also, the guys aT RC Eng. did say that it is common to see very dirty injectors on 3rd gens. The very high heat under the hood helps contribute to crud getting caked on inside the injectors (is what RC Eng. said).

So why the injectors over the fuel pump? It is more likely and makes more sense, especially based on the symptoms i have. the bucking is occuring when you would think the secondaries are coming online. i tested the fuel regualtor, the fuel filter is new, all the grounds at the fuel pump have been cleaned, so i figure the injectors. If anything, injectors should be professionally cleaned (not the crap the the local quick lube runs through them - i tried that as well, but when you think about it, the car is running at idle, which means that the secondaries are never cleaned). Also, i went through and read a lot of books about injectors and fuel systems, and it seems to point to the injectors.

so anyway, i'm gonna try that and see what happens

 

Cool...can you post the info for the contacts to RC engineering.

I'll have to go and test my injectors as well.

 

http://www.rceng.com/index.htm


also, i checked my old emails, and dave at KD said that 14.8 ohms is high for the resistance (which makes sense based on what the caris doing) , although RC Engineering saud its ok, so......

either way, mine are going out there!

 

I have been avidly hoping that you guys were going to solve this ongoing problem as I have exactly the same situation here in the uk.
While driving slowly in traffic 1st, 2nd,3rd, the car seems to surge as if I am tapping the throttle. This seems to be in regular pulses of around 3 seconds on 3 seconds off.....is this the same sort of thing??
Have you got a standard air pump set up?
Someone must know!!
Chris p

 

The Mazda TSB(attached) on this says to clean and retorque the grounds although it did not fix my problem. I also put on the new TSB intake ground. Well it did fix the surging, but not the 3k problem. I've cleaned and added additional grounds. I suspect the problem is the Fuel injection ground. It's the only one I've not fixed. Sorry these pics suck. I'll have to try again.

 

Page 2 TSB

 

Page 3 TSB

 

I was just farting around on here, and couldn't believe this thread was still going so strong. Adding the new ground has completely fixed my problem, so I guess I'm lucky.

How much of a job is it to yank the injectors, though? I do think I've got a leaky/bad one as my car has always loved to flood real easily, which causes hard starting (duh) and fouls my plugs almost immediately. my gas milage has been down a bit lately, too.

uh...anyway, is it hard to remove em?

 

BUMP BUMP BUMP BUMP....

SO what happened to everyones CAR??

I got the same problem.. I replaced my ECU with a
Upgrade ECU and it surges. BUT only surges
when my Fan kicks on... When the Fan kicks off
IT idles like it should....

So what was the FIX????????????

Was it the GROUNDS???

I only added a 10gauge ground strap in the engine
compartement.

Was the FUEL PUMP relay the problem/fix???

IF SO Hwo do you by pass the relay??

So anyone ever adjust or check if its the TPS???

ODD thing is my car never did this with my STOCK ECU. Only the 3.5K hesitation that ever one had..
But with my upgraded ECU it surges and idles from 2k - 2.5K rpms.. and in gear it surges as if I am hitting the gas...

OR is it the FUEL INJECTORS??????
Does fuel injector cleaners you add to gas from
track auto work?? anyone know if its good or bad
for rotaries...

REVIVING THIS THREADD..

SOMEONE HELP.....

 

Read the first page, too much to continue. So I am not sure if this has been posted or not, but I had a similar problem with the car, and as it turns out, it was the plug/wires going into the TPS. Sometimes the problem comes back, and I have to jiggle the wires a few times and get them in a good position, then it works fine for a few months.

 

I'll have to try the TPS. Mine just continues to get worse. Now I'm getting surges in addition to the hesitations.

 

Did that already. I even have the new grounds listed in the TSB's. My O2 sensor is a 3 wire with a ground. None of this seems to help. The only ground I didn't get to is the one under the intake for the ignition and the ECU. Here's all the grounds I have:

Firewall to intake: New Mazda ground per the TSB
Exhaust to body after cat: New Mazda ground
Cat-back to Body: Extra ground added.
Trans to Downpipe: Directly bolted together
O2 sensor: 3 wire with ground
Battery to shock tower: Extra ground added.
Battery to engine bracket: Extra ground added.
Cleaned and retorqued main engine ground to trans bolt (seems oily now).
Main engine fuses next to battery: Cleaned up ground.

I sanded all the contact points and protected them with battery post protector spray.

I'm about ready to buy another car so I can park this POS and take it completely apart.

 

I have been having the same problem all summer. Still having it. A few things that were done: replaced TPS with a different one, fuel pump and regulator were dropping pressure so were replace, plugs replace, voltage was going to high charge so replaced voltage regulator and the alternator it comes with, new battery, wiring harness frayed wire patched, dashpots motion sticky and freed up, cruise control suspected of insufficient slack and re-adjusted, many swearwords hurled at it, big money paid to mechanic, still does the bucking hesitation surging swearword-inducing stuff. Latest thing is the mechanic noticed extra fuel smoke upon startup, and is now suspecting the injectors are sticking; currently trying running with extra Techron, but it still is mis-behaving. I am interested in the idea of grounding for the injectors; more details might be instructive.

 

Havent read all this post as im err drinking but id did read enugh to know that it sounds like a similar prob i had witch was cured with the altering the tps and replacing the lambda/o2 sensor.
Runs gr8t now.

No flames pls for not reading the post as i have drunken quite a few and am only tryin to maybe help.

 

This would have been good to have the mechanic do first, before all the fooling around. They put in two new grounding straps and the car has now been driven all around for a couple weeks and no bucking, sagging, oscillation, hesitation, and all that stuff.

Lost a summer of relaxed driving, but it is cruising now, well grounded.

 

Where did you put your ground straps in? Mine has just started doing this and I need to fix it quick!

 

The service manager says that comparing the actual wiring to the wiring diagram disclosed that there was supposed to be a (grounding?) wire between the computer on the automatic transmission and the computer controlling the engine.

The assumption is that there was an alternate ground path that almost made it work right, but that that alternate ground path had gone intermittant. With the new wire in place the problem went away completely and instantly.

That might explain in some cases when putting in other grounding straps may fix of temporarily fix the problem.