satch

iTrader: (1)

If you were to 'try' to place the wrench on the backside of the hinge/pivot bolt you would be in the that particular area though to loosen that bolt you would want to choose the opposite side.

clokker

iTrader: (2)

I guess I don't remember the stock alternator very well.
The 626 alt I have now has a capture nut in the rear ear of the body, so no need to get a wrench to the backside to remove/loosen.

dennis blackstone

dont ever service injectors , they are tired and old ...buy them new if you want your car to live a long llife

beefhole

iTrader: (29)

^That's pretty silly. MANY members here have had injectors serviced and they function quite well. It's worth it to get our old ones fixed for cheap especially if they function 100% again.

My 25 year old (serviced) injectors work flawlessly, thank you.

knifeman

I wasn't very clear on my description. I meant the nut on the back of the alternator. I guess maybe I need a thinner wrench.

NCross

iTrader: (18)

Have you compression tested the engine? Also having a bad fuel pressure regulator or a bad OMP will cause this. Your running 20w50? No or low oil film in the housings causes low compression and flooding. Your sure it's not a bad coolant seal? That will flood an engine more often than fuel when they're bad.

ericgrau

iTrader: (1)

They replaced the thermosensor and it starts fine now. Now I have a brand new problem (yay?), though hopefully it's not as serious. Whenever I start the car, cold or hot, the idle oscillates by about 300 rpm about once per full second. It also affects the car in gear at low throttle, causing the whole car to wobble as if my foot were moving the gas pedal even though it isn't. But the rpms don't change noticeably in gear since the engine is connected to the wheels of course. After 2 minutes the problem is gone and the car runs totally fine. After 2 minutes I've even tried to intentionally release quickly on the gas to see if it's the throttle cable dashpot and nope, it's smooth.

I'm guessing some kind of idle air control issue since it only happens at startup and only at idle or low throttle. But so far I'm batting 000 on my guesses.

satch

iTrader: (1)

Have you checked the TPS to make sure it is set right? And you might possibly have a vacuum leak. And on a cold start what does the idle start out as. Is it 1500 rpm, 1200 rpm or what? And if you unplugged the BAC does this change anything?

ericgrau

iTrader: (1)

It starts at 1500 rpm, which does seem lower than normal ya. I think it used to be 2500. Where's the BAC plug? I can forum-search/FSM/Haynes it and hunt it down but if you happen to read this before I can mess with my car then all the easier. Thanks for the help.

I noticed the issue is still there but not as bad when the car has only been off for 15 minutes, like to stop at a store. It's hard to tell though b/c while it happens every time the severity is inconsistent.

satch

iTrader: (1)

1500 rpm is rather normal except when the cold start 3000 rpm system is in force. The BAC is on the driver side of the engine and the BAC has three hoses running to it. Two are on the same plane and of equal sizing. Your problem sounds more like a misadjusted TPS though as the Green/Red wire should read 1 volt w/key to on and engine as hot as it can possibly get.

ericgrau

iTrader: (1)

Alright thanks I'll check everything I can tomorrow morning. IIRC TPS adjustment instructions are in the Haynes manual? Or should I dig up the right page in the FSM and print it? I know it's just a screw but I feel better if all my info is concrete.

satch

iTrader: (1)

Just backprobe the G/R wire w/the multimeter set to DC volts under the conditions predescribed and it's simple as pie (use the battery negative terminal for the ground source for the meter and twenty minutes of driving time should be sufficient to fully warm the engine as this is imperative when reading the TPS and adjusting it). If your problem subsides as the engine warms up then you'll have to let the engine cool down before you'll be able to decipher if you fixed it or not each and every time you try something different.

NCross

iTrader: (18)

Start up speed has nothing to do with the BAC. Check into your AWS solonoid. Located under the BAC by the oil filler neck, then check your neutral switch.

Things that seem the most obvious to me for the fluctuation problem, being an s4...
1.TPS
2.timing
3.vacuum leak
4.air mixture screw near air box

satch

iTrader: (1)

The BAC and Air Bypass Solenoid work in tandem on the high rev startup. If you unplug the Air Bypass, the car will still rev to 3000 rpm on a cold start where the coolant temp is above 60 degrees or so. And his problem is occuring during idle and the BAC will assist the idle speed if it is initially set to low.

RotaryEvolution

iTrader: (30)

a semi hung up thermowax will also cause the high rpm hunt, as the ECU tries to stall the engine into idle loop.

ericgrau

iTrader: (1)

Fully warmed up TPS measured 0.28 volts. I made 6 full turns to get it at 0.95 volts.

It all makes sense now though. On my driver's seat the mechanic forgot a flat-head screwdriver head electrical taped to a small wrench. How many flat head screws are there on an RX-7, especially ones that won't be tight enough to rip the electrical tape?

Upon immediate turn-off-turn-on the idle was flawless but I won't know for sure if this worked until tomorrow.

Before the adjustment the idle fluctuated between 1500 rpm and 1200 rpm once per 1-3 seconds. Then the dips to 1200 rpm died off and it idled smoothly. That is until I gave it a little gas then it did the 300 rpm dip again when I tried to hold the revs between ~1600 rpm and ~2800 rpm. Above ~2800 rpm it was smooth again. Then finally it made a gradual drop to 700 rpm and the whole issue was gone.

NCross

iTrader: (18)

The transmission must be in neutral to do this though, and the switch sends signal to the ECU to rich up the mixture. If the switch or AWS are bad you will send 3000 RPM worth of fuel to a 1500 RPM idle engine. This will definitely cause lopey idle. If the thermo sensor or ECU is bad it will always think its cold thus causing a constant hunt for idle due to different fuel amounts, timing etc... The AWS "feeds" air to raise the idle speed to 3000 RPM. That's why many people plug up the inlet of the AWS so you don't get the 3000 RPM start. That aside...


I still say one of these is your problem with a lopey idle. It's almost always the most obvious fix on these cars. Even if it' not the device itself it could be the ECU or the wiring in between.

1.TPS
2.timing
3.vacuum leak
4.air mixture screw near air box

ericgrau

iTrader: (1)

I can't attempt a cold start yet but after 30 minutes of waiting the warm start idle is as smooth as butter and I can't get it to oscillate even if I play with the gas pedal. Since that didn't happen before I think the tps was it.

I'm imagining this kind of scenario at the mechanic's, a guy talking to himself: "You're always forgetting something. Don't forget the TPS. Don't forget the TPS. Don't forget the TPS. Here I'll put a flathead dead center in the driver's seat then there's no way I'll forget the TPS."
Me: "What's this flat-head doing on the driver's seat? Hmm, nobody's standing at the counter. I'll just leave it on top of the counter and get going."

satch

iTrader: (1)

Might be wrong, but when he stipulates the engine would start at 2500 and now its at 1500 I believe he is referring to the car being in neutral right after startup and the 2500 figure he provides alludes to the high rev start while the 1500 figure relates to when the high rev does not occur so I don't think these are idling speeds provided while in gear. He recently had his Water Thermosensor replaced so that's likely not the problem but anything is possible. The Thermoswitch at the bottom of the radiator responsible for the high rev start sequence might be wonky though.

satch

iTrader: (1)

So you've adjusted the TPS to 1 volt and are awaiting a cold start condition to see if there is a change? If so, then what was the initial reading of the TPS voltage?

ericgrau

iTrader: (1)

0.3 volts. Post #41. Thanks everyone. I'll know for sure if this worked tomorrow but I think it's fixed.

satch

iTrader: (1)

What specifically do you mean by "semi hung up"?

RotaryEvolution

iTrader: (30)

stuck as in won't close fully, could be due to an accumulation of junk in the lines that allow coolant to pass through the core or the thermowax itself being jammed up.

i try working the throttle linkage backwards first to push the thermowax in, sometimes it works, sometimes it doesn't.

ericgrau

iTrader: (1)

The TPS was it. It starts and runs fine now. I could be imagining it but it seems to run smoother than ever.