1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Idle gremlins galore

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Old 08-09-01, 11:33 PM
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8krpm is not enough

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Question Idle gremlins galore

Well guys and girls I've got a rather odd idle gremlin that I can't seem to solve. It seems centered around the BAC / ACV, since I can plug the hose that feeds it w/ a rolled up napkin and it seems to clear out the majority of the idle issues.

When the hose isn't plugged:
there's an occasional 2000rpm hangup, where the car will just hang at 2k rpm, no matter what gear, rolling, or standing. This is kind of annoying in traffic while rolling and the car suddenly decides it wants to be at 2k. When sitting idle, the car will occasionally surge between 1500-2krpm and just bounce up and down like that. It's almost like too much air is getting in to the system or something. I've adjusted the TPS, the throttle plates look clean, the secondary throttles seem to move ok, the BAC / ACV is clean and moves ok.

I'm stumped. but there's more!

When I plug the hose, it solves most of the problems, but there's still some surging at low rpms. It almost feels like the clutch is slipping, but it's only present at lower (under 2500) RPM's. As soon as I get the tach up there, the surging feel goes away.

WTF?
HELP!

--matt
Old 08-10-01, 08:41 AM
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Go to : http://www.nellump.com/peri/epi/firs...slseIdle.html, bunch of great info Solving GSL-SE Idle Problems. Really helped the POS Racer, good luck!
Old 08-10-01, 12:45 PM
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8krpm is not enough

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would you believe that page is printed out and sitting next to my haynes manual in the garage?
Old 08-10-01, 12:50 PM
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You know that’s the same place I keep mine! Plus I keep a copy by the nightstand!
Old 08-11-01, 04:57 PM
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Anyone else have any ideals for speckamp?
Old 08-11-01, 07:29 PM
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Angry Same problem

I have the exact same darn problem on my SE as well! It really sucks, is annoying, embarrasing, and also makes the car harder to drive. I know at least one other person who has had the same problem. I have that page printed out as well, sitting with the collection of Hanyes/Chilton/Mazda Shop manual but I'm stumped as well. So I just want to say that your not the only one. The day I figure it out (if ever) I think I would be willing to pay for a big front page section on USA Today newspaper telling everyone how to fix it
Old 08-11-01, 08:17 PM
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I'm thinking its the ThrottleBody, the reason for me is, I have 2 of them, 1 for summer, the other for winter. the summer one I removed the secondary plates.
and has these same symptoms, high idle, surging.
but when I put on the winter one, I only swap the TB and
the problems go away for me. I've looked, measured, and tested
both to see if I could find out what was diff between the two, with
no luck so far
Old 08-12-01, 01:07 AM
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8krpm is not enough

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There was an article somewhere that said that the secondary throttle plates might have had someting to do with that.

Anyone know what the hell that coolant line to the throttle body is for? The bypass for my heater hose lays against it, and I don't know if that's what causing some of the idle bs.

still hunting, tho w/ a better adjusted TPS, it's getting better,
matt
Old 08-12-01, 07:11 AM
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Lightbulb More Idle info

I was going through my bookmarks the other night and I came across the following in 1st Gen RX-7 F.A.Q.

"My 85 (100K miles) occasionally acts up in this manner, with an oscillating idle or a "stuck fast" idle. Whenever it happened though, by the time I pulled over, popped the hood and had a look it stopped spontaneously. Last month I played around with the throttle body linkages and found that if the the car was idling happily (warmed up) and the secondary throttle (??) was held open (this is the throttlish thing on the Driver's side of the main throttles, which is spring loaded on the front of the car and actuated at the back - have a look) a tad, the engine would appear to be doing a bang-bang (cut the gas??) control of the rev's which leads to the erratic problem described. This probably isn't the only way to cause the control system to misbehave like this, but it is probably common. In my case, I cleaned and lubed the linkage, spring return mechanism and the the throttle plates and "bearings" as best as I could, then worked the linkage until things freed up. SInce then - no symptoms, although I can still cause them by opening the second throttle linkage a bit.
The manual was underwhelming in its coverage of this, so I feel good about it as a cause. "

"R&T May 1990 (Sticky GSL-SE throttles?)
Mr. Tom Gilmour writes that his '85 gsl-se occasionally hunts between 1200 and 1500 rpm, causing an annoying on-or-off throttle condition at cruising conditions. Mazda said that they had a service bulletin concerning the hunting idle that advised checking the same solenoid or a sticking throttle shaft. Mr. Gilmour solved the following as follows:
Take the air feed tube and the choke body to reveal the throttle body. Next, while holding the butterflies open, clean out the throttle body with Q-tips dipped in carburetor cleaner. This will remove the carbon buildup that prevented thte butterflies from actuating smoothly and closing completely. After this, Gilmour's car apparently runs like new.
The reason for hunting idle is the throttle-position sensor, which tells the computer that the throttle is closed when, in fact, it is not. When faced with this conflicting information, the computer isn't sure what to do-hence idle uncertainty. Cleaning the carbon deposit should solve the problem. "

ok, thats the two articles I found pertaining to idle problems. Anyway, I bought some carb cleaner and I'm going to take some q-tips and give it a shot. I'll post the results when take it out for a ride. I also bought a new O2 sensor just to see if it helps at all, just to rule that out.

Matthew

Old 08-12-01, 09:17 AM
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I put an Oxygen Sensor in mine last night, it really seemed to smooth out the idle. The original Oxygen sensor looked like the tip of it had been melted off! Also messed with the TPS, seemed to Ohm out correctly, and had a nice and smooth transition as you moved it in and out. Figure I’ll take a peek at the throttle body today, and see if it may have a bit of crud in it.

Fixin to take the POS Racer out for a run, I’ll let you know how it does!

Last edited by P.O.S. Racing; 08-12-01 at 09:34 AM.
Old 08-12-01, 07:18 PM
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Well the Oxygen Sensor has made a difference in how the POS Racer runs, nice smooth idle at about 900RPM. Power comes on strong from idle until the buzzer sounds! Seem to be getting to the buzzer quicker also ! Another thing I did while working on the POS Racer was to put a couple of small hose clamps on the hose to the air supply valve, just to insure it wasn’t leaking.

Still have two things it does that seem strange:

One thing she is still doing is just a bit off idle it sounds like it’s missing; give it a tad more gas and it sounds fine?

The other is when I come off the gas it will drop down below 600RPM, it then bounces back to 900RPM. Hasn’t stalled on me yet, just seems weird.

Any Ideals?
Old 08-14-01, 03:00 AM
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8krpm is not enough

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ok, adding O2 sensor to list of things to do

POS, try adjusting yer dashpot, or clean the, oh crap, I can't remember which TLA the valve is that catches the idle when you let off the throttle. F, look through the page David wrote about solving GSL-SE idle problems, there's a section in there for that particular problem.

--matt
Old 08-14-01, 09:57 AM
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**** this ****.

Miones doing the same thing, and it's not even a GSL-SE, just a GSL. It will suddenly feel like my clutch is letting go in 2nd gear and makes a sputtering sound like its running out of fuel, then when I let off the pedal, it jumps from 750-3,000 rpm and in between like it's on crack, then it'll suddenly go away for no reason...I know how to fix it TAKE OF THE PIECE OF **** STOCK CARB AND SHITTY *** UNCLE SAM INFESTED BULLSHIT EMMISIONS CRAP So, I have dual 36 DCD's coming in with complete setup...BYE BYE shitty carb!! Hello 50+ HP and no goddamn emmissions! I know it's using the bigger hammer theory....but what the hell, works fine for me, LOL!!!!!!!!!!
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