Having some odd troubles, can anyone advise?

[ZeroLux]

Superk has his two cent troubleshooting list!

Distributor... Sneaky suspicion its this
VAF- mine went bad... Wasnt a way to test it. Horrible stutter
Fuel filter/strainer
Thurnongulator
O2 sensor. Unplug them and see if its different

Ok, let's look at that list:

Disty- what specifically could be wrong with it? Could it be as simple as the new cap and rotor I put in are junk?
VAF- let's hope not. I know those aren't cheap. Any way to test for that? Took a look inside of mine when I had the filter box off last time, it's extremely clean, has the bullet shaped dome pointing out on both sides iirc.
Fuel Filter- dumbass question but where is it located in the MX3? the one for the RX was a pita to get to, underneath the car.
Thurnongulator- you know as well as I do that those things NEVER go bad. ever.
O2 sensor- I had thought about this, but how would that effect it on a cold start if they have not even been able to warm up yet? don't want to have to replace those either, I'm finding prices around $170 a pop around here.

I'm bored sitting around the house tonight and starting to feel better (YAY MEDS!) so I was thinking about going for a short ride for the heck of it. I'll take along my cam to get some vid of how she's acting and post that up shortly.

[SuperK]

well, you can always unplug the o2 sensor and see if it changes the symptoms, both the front and back.
The strainer is on the fuel pump, but you want to make sure you replace the fuel pump gasket, and be very careful with the screws, they have a tendency to rust and stripped out. the fuel filter is attached to the... transmission, near the firewall.
VAF - there's no way to really test it that I know of, mine looked amazing but sucked tremendously. I have a spare you can test if you'd like. Usually it causes the car to lurch, so low possibility IMO

distributor - cap and rotor wont' really do anything unless your old cap was cracked significantly. These distributors are known to go bad.

O2 sensors I would source from rockauto.com, not locally. but like I said, if it changes when they're unplugged, that should be enough to tell you whether you should replace them.

[MrMazda92]

Hah! You guys are crazy.

Sorry, but I usually own cars until the wheels fall off. Don't see the MX as being an exception any time soon.

So to answer those questions:

1. Lurches primarily in 1st, SOMETIMES I feel it in a low 2nd gear.

2. I watched it last night, I was fluctuating between 2500 and 3000 on the tach in 1st trying to keep power but it kept wanting to drop around 900-1100 rpm's pretty quick for no reason.

3. Engine isn't missing. (I looked last night, nobody stole it ) Runs smooth at idle, runs smooth in all gears past the issue, gets up to speed fine.

I'll check out the spark plugs and probably do a compression test at the same time (just for sanity's sake), have not done the fuel filter- but wouldn't FF problems manifest at higher rpm's and not lower? The RX7 I have here had a bad FF about a year ago, plugged with rust, it would do fine until I wanted to cross 4k then it would cut out from fuel starvation. I also saw a few things online last night on the Probe forums about the air intake pipe might have a tear in it or a vac leak somewhere. I've checked all I can, did not see any leak but I could have missed one I'm sure.

If needed I can get out there sometime and take a video of how she's acting and post that up.

This completely screams IAC to me, it's like when I drive my car without warming it up properly. Have you tried giving it a ridiculously long warmup? Like 10 minutes idling in the driveway type of ridiculous... I'd try that before you tear into it too much more, it's a simple enough test that will help determine if it's deeper routed than the IAC.

[ZeroLux]

I could drive it around town in 100 degree heat for hours, still no change.

I'm starting to go back to thinking it's a clutch issue, even though I was told by someone that it's not. I did a second gear start today, went without much issue other than having to rev higher than usual.

If it's glazed/slipping but only in spots, I could see how it could do this and NOT appear to be a blatant clutch disc problem.

If this is the issue, this is going to suck. I don't have anywhere near the means or location to be performing a clutch swap, and there's not much chance of me paying some shop to do it either. Anyone here live in the greater NC area and REALLY like beer?

[SuperK]

Unless you want to make a trip to chattanooga

[Inodoro Pereyra]

I could drive it around town in 100 degree heat for hours, still no change.

I'm starting to go back to thinking it's a clutch issue, even though I was told by someone that it's not. I did a second gear start today, went without much issue other than having to rev higher than usual.

If it's glazed/slipping but only in spots, I could see how it could do this and NOT appear to be a blatant clutch disc problem.

If this is the issue, this is going to suck. I don't have anywhere near the means or location to be performing a clutch swap, and there's not much chance of me paying some shop to do it either. Anyone here live in the greater NC area and REALLY like beer?

It's NOT a clutch issue.
Check IAC and vacuum first, and don't despair. There are plenty of options before you kill yourself.

[Ryan]

Just to throw more stuff to check on the list:

Throttle position sensor, make sure its in spec. There is a thread in the FAQ for it....

Make sure your throttle cable has a teeny bit of slack, simple to check.

Make sure your ignition timing is still in spec (borrow a timing light)

Vac leaks (probably been mentioned, I didn't read the whole thread thoroughly)

Crawl under your car and look for the neutral switch. Its a little green thing, with two wires going to it. Not the one on the front of the transmission, the one pretty much directly on the bottom. Make sure both of those wires are still intact in the sensor. They like to break off, being in such a hazardous location...

Make sure your clutch switch (not starter interlock) is showing the correct open/close circuit when you press it.

[SuperK]

You wanna try a diff IAC? I have the TB, which will get you the IAC, TPS and jazz. 25 bucks and I'll ship it to you.

[ZeroLux]

I appreciate the offer, I'll keep that in mind.

I am kind of wishing I had bought the other GS I found for sale locally a few months ago, at least then I'd have a reference/parts car to work with.

I have been starting off in 2nd most of the day, seems like the problem shows up there too but to a lesser degree. Are we certain this isn't a clutch issue?

Will continue analyzing options this weekend, finally feeling a bit better, just hope it does not rain for two days straight.

[Inodoro Pereyra]

The issue is there. It's less noticeable if you start in 2nd gear, because you have to step more on the throttle to get the car moving. Meanwhile, you're giving the clutch a beating.
SO FAR it's not a clutch issue, although if you keep starting in 2nd gear, it may soon be. My advise: start working to take care of the problem, before you start breaking other parts of the drivetrain.

[cWs306]

Does it do this lurching and what not when u drive and give it more gas then normal? my car did that for the first while then i realized it had to be COMPLETELY warmed up. pretty sure my ecu was still in warm up mode, so it was sending to much fuel. also try unplugging the plug from the throttle body, its white. itll kill the "warm up mode" see if your lurching stops then.

[MrMazda92]

Does it do this lurching and what not when u drive and give it more gas then normal? my car did that for the first while then i realized it had to be COMPLETELY warmed up. pretty sure my ecu was still in warm up mode, so it was sending to much fuel. also try unplugging the plug from the throttle body, its white. itll kill the "warm up mode" see if your lurching stops then.

Mine does That's why I warm it up for a ridiculously long time.

[cWs306]

hahah yaah, i do warm mine up like crazy now. and drive it nicely for the first 5-10minutes. when it first happened i started freaking out and pulled over. then i realized i just had to be gentle at first.

[ZeroLux]

Warm up has never been an issue on my car, that I know of. I don't instantly beat on it from a cold start, and where I live isn't exactly cold right now

I have done a lot of reading the last few days online, starting to think it might be my TPS out of whack. Is it safe enough to disconnect that and give it a test to see if I get the same results? Also, someone mentioned before something about calibrating it... could not find the FAQ on that, anyone know where it is?

I am hoping this is the solution.

[SuperK]

You need a set of feeler gauges. pretty much you're testing for continuity between certain distances iirc. I set my TPS several times on my GS.

to quote troubleshooting from some REALLY REALLY OLD GUY


TPS Adjust (mechanicl)
Engine off.
Detach TPS connector.

Wire Colour & Purpose
P= +5V reference
Y= TPS position signal to ECU
BR= TPS idle switch
BK/DB= sensor ground

Connect ohmeter to 2 bottom pins (BR and BK/DB) and you should get continuity. If not, loosen 2 TPS retaining bolts and rotate until continuity has just barely been achieved. Semi tighten 2 TPS bolts.
Insert .006" (0.15mm) feeler gauge between the throttle stop screw and throttle lever. This should not break the continuity. If it does break continuity, slightly adjust TPS rotation again to regain the continuity. Insert the gauge in and out a few times to verify.
After confirming continuity with 0.15mm feeler gauge, insert a .020" (.50mm) feeler gauge. This should just barely break continuity but completely. If not re-adjust TPS rotation again. Re-confirm by re-inserting feeler gauge.
In essence, continuity on initial connection to TPS.
Continuity with .15mm gauge inserted.
No continuity with .50mm gauge inserted.
Tighten down TPS retaining bolts.
Re-connect TPS connector.

Once you've adjusted the idle and or TPS let the car run for 15 minutes sot he ECU can learn the new settings.

Idle Setting
Before adjusting remove the screw and ensure its clean and not damaged.
The screw on the top of the throttle body is what your looking for. Start by adjusting it about 3 turns out then start the engine. With the engine warmed up turn it in till the engine starts to die then gradually turn the screw out untill you read 650 RPM in Diag mode (Ten and Grd jumped). If you turn it too far out your engine will be less responsive so if it feels sluggish afterwards readjust the screw.