RX-7 Chris

iTrader: (19)

1984 GSL-SE stock except for a Bönez Street Exhaust System (cat).

My car idles perfectly right at 800 rpm once it warms up and the cold idle is also good. Overall the car is running great. I cleaned and redid all systems 2 years or so ago. I even had the injectors cleaned. Shortly after I got the car running great it went into paint. Paint took about a year and a half to finish and about 100 miles tops were put on the car then.

Problems:
1. When I stop, the idle drops below 500 RPM sometimes stalling.
2. If I don't start the car with the peddle floored, the car will floor.
3. Car floods regularly. Sometimes to the point where I have to pull the plugs and clean it out.
4. Real hard starting after the car sits over night in weather below freezing.
5. Extremely hard starting if the car sits for over a week.
6. Pressure building in the gas tank.

I looked through this: The Peritrochoid: Solving GSL-SE Idle Problems
Problem #8 fits one of my problems perfectly. Should I go through this procedure?

Do you think I should have the injectors cleaned again?

Any pointing in the right direction will help, thanks.
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I also have a problem with the Bönez Street Exhaust System mating flat with the exhaust manifold. It sits with about 1/2 a MM of space on the bottom side even after tightened down. If I replace the gasket (metal one), it will fix any exhaust leak. The car will be quiet for a week or two and then it will start leaking again. The motor and tranny mounts are new.

Any reason why it wouldn't align right? Anyway to fix the problem without cutting and rewelding the flange on the new cat pipe?

Rotaryhaven

iTrader: (17)

On the number one issue, I had that same problem. I replaced the BAC Valve and the issue went away.

As far as the flooding and all that, I did exactly what you did for awhile until December of last year. It froze (cold winter) and the car never started....Turned out to be the engine was tired. I ended up replacing the engine and so far, no issues.....

You might want to do a compression test on the engine. I believe it is tired....

RX-7 Chris

iTrader: (19)

I'll look into the BAC Valve.

The car has good compression. The motor has about 40k on a factory mazda reman motor.

Rotaryhaven

iTrader: (17)

I would just check the compression just to be on the safe side...I have seen engines personally go bad even at 35k. Just to rule it out.....

Yeah, every stop, my car would cut off, after the bac valve replacement, it quit doing that....

RX-7 Chris

iTrader: (19)

I messed with the car a little over the weekend. The BAC Valve is good. I messed with throttle stop screw and that solved the stall problem. I went a little too far with it so it now idles around 1100 RPM but is no longer drops.

Anyone else have any ideas?

andernamen

iTrader: (2)

Compression Check

RX-7 Chris

iTrader: (19)

I did a little searching and this is a similar problem to mine: https://www.rx7club.com/1st-gen-non-...gsl-se-973131/

I am currently running the Bosch O2 sensor. I'm going to order the NTK one and see what that does. Lately I've been getting around 15-16 mpg.

If that doesn't fix my problem, I'm going to send my spare set of injectors in to get cleaned.

RX-7 Chris

iTrader: (19)

I changed out the O2 sensor for the NTK and it made a huge difference in the way the car is running.

The flooding problem is for sure the injectors. The car had some bad gas in it and was driven a few miles with it before it was drained (by the painter). I figured I would run some fuel cleaner through the car before I pull the intake and have the injectors cleaned again.

I started with RP MAX-CLEAN FUEL SYSTEM CLEANER & STABILIZER which did seem to help. The next tank I used Seafoam. The car ran like crap for a day but after that it started running much better. So far the car hasn't flooded.

I also found that the battery does n't have the cold cranking amps that I need. If the temp is below 20f, the starter doesn't crank fast enough. I think this is the main reason for the hard cold starts.

I do still need to work a little more on the tune. Idle is a little high. I just need to spend an hour or so on it.

thorage327

I found an easy fox for that slow start issue! An aluminum flywheel! My car hated starting, and I was about to go buy a huge battery to supplement that old starter.

Changed out the flywheel, and it spins right up now!

RX-7 Chris

iTrader: (19)

I had a light weight flywheel on my old car, it was fun sometimes but not in traffic.

This car is a nearly complete restoration. I don't have any plans for performance parts.

RX-7 Chris

iTrader: (19)

Tomorrow morning will be a good test of the car. High temp of 17deg.

What I really need to do is clear out the garage and park the car there.

RX-7 Chris

iTrader: (19)

The car started right up this morning. I ended up driving to work in 3"+ of snow.

82transam

iTrader: (18)

Sounds like you got it sorted out then? Rotaries seem very sensitive to cranking speed. A weak battery, starter or crappy battery cables (or some combo of all 3) will make it a nightmare to start.

RX-7 Chris

iTrader: (19)

Very true. I didn't even think about that when I first started having problems. I guess I was too worried it was something more. I need to get under the car and clean the connection to the starter. There has been a couple of time when it cranks just fine then slows down for a couple of cranks only to speed back up.

I replaced the starter a couple of years ago (I know that doesn't always mean anything). I also replaced the battery cables with new mazda ones.

82transam

iTrader: (18)

Yeah it's worth looking at. I've had very mixed luck over the years with starters, some seem to last very well, and others die quickly. I also seem to have better luck with my T2 ones than I do the FB ones, but that might just be coincidence... And of course doesn't help if you don't have a T2 transmission.

RX-7 Chris

iTrader: (19)

I got gas last night and checked mpg. I was getting 16 in town but since I've been running fuel cleaner through it I'm up to 18.5

The car has started fine all week even when it was below 10deg.

RX-7 Chris

iTrader: (19)

I thought I had it figured out but I didn't because the problem started up again.

I ended up sending my extra set of injectors out to RC Engineering last week. I swapped them out over the weekend and the car no longer floods and starts right up in the morning. I also had some help fixing the exhaust leak. It turned out that the bend in the cat pipe was a couple of degrees too much and it wasn't lining up right. We heated the pipe and bent it back.

__________________

I'm still having a lot of trouble with the idle. I'm thinking of going through the full procedure in the FSM.

Problems:
1. When I stop, the idle drops to 500 RPM and sputters.
2. Sometimes the car will idle at 1100 RPM and sometimes at 800 RPM.
3. Idle jumps now and again. Revs from 800 to 1000 and back again.

Good:
1. The car revs fine.
2. has plenty of power and pulls really good.
3. Six port actuator valves are opening.

- Does anyone have any suggestions on things to look for?

- Anyone know where I can get a replacement idle screw (the one in the throttle body)? Mine is a little stripped and it leaks air around it causing a small vacuum leak. I can't remove it completely.

Rotaryhaven

iTrader: (17)

probably need a used throttle body....

RX-7 Chris

iTrader: (19)

I'm going to try the procedure in the FSM before I get a used throttle body. It seems like everyone wants $75-$100 for a used throttle body that may not be any better than what I have.

I'm going to test the BOV as well.

RX-7 Chris

iTrader: (19)

I'm still having flooding problems with this car. I'm so tired of it. I've been driving my 45 year old truck because it actually starts every morning.

I've gone through basically everything.
-replaced the throttle body
-sealed the gas tank because rust kept clogging the fuel filter (good now)
-had the injectors cleaned
-tested all the sensors, etc per the FSM
-good compression
-new top of the line Interstate battery
-cranks very quickly now even when below zero.
-replace O2 sensor 6 months ago with NTK
-no air in coolant
-oil change less than a 1000 miles ago
-new plugs, cap and rotor
-msd blaster II coils

This afternoon I'm going to check the fuel pressure and vacuum.

The car will run great, pull strong. Sometimes the car will idle perfectly at 750rpm (very smooth) and then a few minutes later it will start bouncing between 500 and 1200 RPM. It will never actually stall. If I rev on it for a minute or two, sometimes I can get it to idle smooth again.

The car will sputter and not start even it I just shut it of 15 minutes ago and was completely warmed up. If I pull the main fuse under the dash while I continue to crank and immediately put it back in, the car will start right up. No smoke out the back. Acts like there wasn't even a problem.

When the car sits overnight, there is a 50% chance that it will flood bad when I start it. Some times it will start fine like there was never a problem.

Could the problem be the ECU itself?

Cameron38

iTrader: (2)

Welcome to the world of SE idle problems... I've found this car likes to be run at least once a week. If it sits, my idle will sometimes stick or do the bouncing thing.

Smokeyfb33

iTrader: (8)

I am chasing down SE gremlins as well...

I like the details of what you have done, I have done a lot of similar things. But, I have also replaced all the gaskets and orings I can possibly find. Every vacuum line I have is upgraded to silicone too. I really started making progress after going through and checking all the vacuum solenoids one by one. I was able to find many small problems. The ACV valve and the check valves are pretty important too. That whole system is a secondary Idle control.

Id recommend going through with a really fine tooth comb, check for anything that doesnt work as it should of 30 years ago. If I had a guess, I would say you have some type of air problem. Not enough most likely, so those times cranking it in the morning or when warm it floods easily because it doesnt get a good A/F mixture to fire up.

Ive had idle symptoms all over the place. Currently my car runs and drives great, pulls very nicely. But my idle is odd. %80 of the time it runs and idles perfect at 800. But then I get the odd occasion where it goes from 800-1000 and cycles every 10 seconds or so. My other problem is idle with AC on, it can be as low as 500 sometimes and all the way up to 1500. I have a strong inclanation that the rest of my problems are in the vac solenoids or with old sensors (o2, intake temp, ect).

Good luck with the progress! Keep us updated!

RX-7 Chris

iTrader: (19)

I have also gone through and replaced all the vacuum lines (rubber) and replaced all the gaskets that I can get to. I've gone through all the vacuum solenoids and they all seen to be working. I'll recheck them anyway.

LongDuck

Search on 'GSL-SE Surging' - I've done write-ups on this in the past.

It's due to the steel throttle rods sticking in the aluminum throttle body due to dissimilar metals. Once it starts, and the rod sticks, it causes a feedback loop in the idle compensation air circuit, which is why it goes from 600rpm to 1200rpm or more as it swings.

Removing throttle body and lubing those rods inside and out fixes it for about a year or so.

RX-7 Chris

iTrader: (19)

Thanks. I'll look into it.

I swapped out the ignitors just because I have extras. The idle now sits at 1200 rpm. I'm not sure if maybe one of the ignitors was on its way out. Later that day I swapped out the ECU, etc that are under the passenger floor because I have an extra one of those as well. I figured it couldn't hurt. I still need to check the fuel pressure.

A friend of mine came over (FD owner) and we looked the car over. I really need to check the fuel pressure. We concluded that it has to be flooding on start-up and not while it sits. The car hasn't completely flooded since we swapped those parts but it still smokes when it is start after sitting long enough to completely cool off. The smoke is definitely fuel because the exhaust smells like raw fuel when started even with a cat.