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...surging SE's

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Old 10-25-03, 10:10 PM
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...surging SE's

I know there's been many a thread concerning the GSL-SE's habit of suddenly surging at idle and then "hunting" up and down between 1200-2000 rpm. And I know the Mitchell Manual (1984 RX7 full manual, pg 240-241) has a Technical Service Bulletin that says sticky secondary throttle valves or a bad vent solenoid valve are to blame. I just never got around to doing anything but check the throttle valves before now. At $250+ (or so I heard) for the vent solenoid valve from the dealer - no way was I gonna buy one just to "see" if it would fix my car.

I finally found a used set (vent solenoid & vacuum valves) at RX-7 Heaven in Minneapolis and he only charged me $15! Next question is: are they any better than mine, or did the car they came off of have the same problem? Well I installed them today and everything "seems" okay. It's been surging off and on all this last week, but when I took it out for a spin today - it behaved itself. Of course, this is an intermittent problem which means it'll never ever do it when you want it to - it'll only do it again when you finally relax and figure you fixed it!

So I'll run around for a week or so, then dig this thread out of the dust and let you know if the problem has been solved.

Oh yeah, I posted an album of photos showing my car before, during, and after the paint job last year. You can check it out here if you want:
http://www.hpphoto.com/servlet/com.h...sword=60437016
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Old 10-25-03, 10:26 PM
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Like the colour and the matching lettered tires!
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Old 10-25-03, 11:26 PM
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you might also wanna do the easy stuff like reset the idle speed and mixture, and clean out the bac valve. they get dirty and can bind

mike
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Old 10-26-03, 08:29 AM
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Good to hear that you may have found a temporary solution, anyway. Your engine bay looks pretty clean, I did recognize the factory Mazda fuel injector feed hose, however - mine started leaking about 6 months ago and had to be replaced. Be sure to use fuel injection tubing, obviously.

The SE is an interesting animal to tune, but once it's dialed in, it runs great. Finally retuned my SE after new injectors were installed about a month ago - was waiting to make sure I didn't have any lethargic leaks that I'd have to dissassemble it for. Got the idle down to a very smooth setting and then checked it on the tach - 800 rpm! I was amazed, then bumped it back up to 900 to get that extra bit of smoothness out of it.

It's never idled this well before! New injectors made the difference, as it was surging at steady state driving speeds before and I couldn't get it to idle at 1000 smoothly no matter what I tried. Had the injectors tested, flow-balanced, and cleaned and made a world of difference.
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Old 10-26-03, 10:27 AM
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How much did that cost?

Longduck:

How much did it cost you to have the injectors cleaned, etc?

My fear about doing that is that I was pulling an intake off a salvage yard GSL-SE (for another car I have) and I couldn't get the electrical connectors to release. I ended up breaking them accidentally (on the harness, not the injector)...which was exactly what I wanted to avoid.

What is the trick to getting the harness connector off the injector?

I have two GSL-SEs that run and neither seems to have this issue (thank God). After removing those at the salvage yard, that hole setup is a pain in the rear to take apart. It is probably mostly my fault...I know there is a particular order to removing it, and I didn't have the reference with me.

Zookeeper, your car looks awesome. Did you do the paint job, etc. yourself? I think the red accents on the intake, tires and the few other select parts are just right.

Now that I think of it...both of you have gorgeous paint jobs.

I hope mine turns out that nicely.

FWIW, I am in San Antonio.

Brian T. C.
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Old 10-26-03, 12:21 PM
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I finally found a used set (vent solenoid & vacuum valves) at RX-7 Heaven in Minneapolis and he only charged me $15! Next question is: are they any better than mine, or did the car they came off of have the same problem? Well I installed them today and everything "seems" okay.
Hey I did the same thing on my car, I think it's been a year and it hasn't done it once since! (Knock on fake computer desk wood) I picked up a second set of valves real cheap and tried them, worked fine, so I am holding onto them for when the ones in the car fail again. take care.
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Old 10-26-03, 11:11 PM
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There is a local shop to me in AZ that does injector work, and they were doing 10 injectors for a Q45 for my brother, and 5 from me; discount price was $12 each for leak test, rebuild, new pintles, flow balance, spray pattern adjust and cleaning.

I think the volume discount helped with the pricing, but out of my 5 injectors, only 2 could be rebuilt correctly - the rest were trashed. This says something about old injectors in your SE's out there.

As stated above, the new injectors increased my idle due to (likely) better fuel atomization and flow balance, and I readjusted the idle to a smooth and even 900 rpm, just as the FSM states. I'm smooth sailing!
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Old 11-02-03, 11:50 AM
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Week 1

Originally posted by zookeeper

So I'll run around for a week or so, then dig this thread out of the dust and let you know if the problem has been solved.
So far, no surging. But it "tries" on occasion, the rpm will jump and then settle down again. It never goes into full blown hunting and surging though. I might need an idle and TPS adjustment now that I changed the vent solenoid.
Originally posted by Mr7
Like the colour and the matching lettered tires!
Originally posted by TexasGunRunner

Zookeeper, your car looks awesome. Did you do the paint job, etc. yourself? I think the red accents on the intake, tires and the few other select parts are just right.
Brian T. C.
Thank you both for the compliments. I try to keep the old girl looking as good as possible. And, no, I didn't paint it myself. Had it done at Rick's Custom Shop here in Abilene, TX.
Originally posted by LongDuck
Good to hear that you may have found a temporary solution, anyway. Your engine bay looks pretty clean, I did recognize the factory Mazda fuel injector feed hose, however - mine started leaking about 6 months ago and had to be replaced. Be sure to use fuel injection tubing, obviously.
Thanks for the advice. Reading about your injectors, makes me think I may need to replace mine someday.

I'll drag this thread out again in another week and letcha know how the surging problem is going...
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Old 11-02-03, 10:29 PM
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I've found that the surging (from 1200rpm to 3000rpm on cold startup) is often due to the sticking throttle body rods Tech Bulletin. Whenever I have the TB out for anything, I turn it on one side so that the TB throttle rods are pointing up and down, lube it up really well with any thin oil that you have around (not WD40, though, evaporative, and too thin), and then turn it 180 degrees and do it again to the other side. Gravity pulls the oil down into the aluminum TB holes where the rods turn and helps to keep the 'surging' to a minimum.

In colder weather (like now, November), the oil here tends to gum up and the spalling of steel throttle rods to the aluminum TB housing is what causes the 'sticking'. Once the rods start sticking in the TB, this is what causes the feedback loop between the idle compensator (BACV) and the engine computer. As the engine speeds up, the vacuum diaphragm opens for the cold start system, allowing more air in, increasing idle speed, which keys the BACV to close airflow, causing decreased idle speed, and so on, and so on...

When the throttle rods move freely, this prevents the delay in the movement of the rods and thus prevents the loop caused by the BACV and ECU. Use the lightest oil you have around to help with cold starting, and try to avoid revving it to attempt to clear out the problem - cold engine, cold oil is the worst possible time to be revving the engine greater than 2-3k rpm. HTH,
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Old 11-11-03, 02:34 AM
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FYI...

Two weeks, now, and no surging. I think the Vent & Vacuum Solenoid Valves have done the trick. Just an occasional "kick" up to 2k and then it settles down again. I think that's just TPS adjustment which I haven't had time to check lately. Or throttle rods sticking like Longduck mentioned...

Last edited by zookeeper; 11-11-03 at 02:36 AM.
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Old 11-11-03, 05:03 AM
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I never did fix that problem, it seemed to just go away... could have been when i installed my cone filter intake, tho i'm not sure.

I dont remember, honestly. it seemed to me that it just slowly faded until it didnt do it anymore.

then i blew the engine, and havent driven it since. so go figure, hehehe

Good to hear that that might be the easy fix!!
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Old 11-11-03, 05:48 AM
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Whenever my SE surges, I just gotta drive it hard for a short while. Then it goes away.... but of course it's a devilsh bug. Seems to happen sometimes when it's cold and the engine isn't too warm, and/or I got the clutch in.... WEIRD ain't it?

Of course, I never tried fixing/replacing the solenoid... haha I'm lazy/n00b like that. Good to know though, thanks for posting!
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Old 01-10-04, 06:27 PM
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When replacing the vent and vac selinoid valves can I use the ones from an 81. I have an se. They look the same so I figured that they are the same.
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Old 01-10-04, 08:34 PM
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Try it and tell us the verdict. These -SE's are a squirly one, waiting on an oil cooler and reaming out of rear yoke on my driveshaft (picked up a 79 driveshaft from JY for $12 so going to make it replaceable u-joints).
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