Distributor woes

[dude33694]

So I've pulled out the family beater and started using it as a daily driver, and its been almost as good as it once was. For the record, 1993 mx3 1.6l sohc, mtx, ~180k, recently replaced, clutch, headgasket, cv axles, water pump, distributor (2x) and ecu. Since I replaced the ecu I've had a code 3 but the car was doing fine, checked it a week later and had a code 8 as well.

Now the issue at hand is that the car only starts about half the time. For example, last night the car drove perfectly fine until about 10pm. I parked it and went inside for about an hour and a half. came back out, wouldnt crank. Engine was still warm so I dont think the outside temperature had that much to do with it. Cranked on it, listened for fuel pump, checked spark, all ok. Checked codes, I now have a 2, 3, 8, and 34. But the funny thing is, I went outside an hour ago and it started right up, better than usual. Drove to the store, let it run, dorve it home, shut it off and tried it again twice, and both times it fired right up.

Any ideas? I can't have it deciding to start based on the zodiac here and I'm to my wits end.

[Dark_Rider2k3]

Check starter wires?

[Ryan]

Aren't intermittent issues great?

This is the third thread tonight that I've suggested checking the battery terminals.

2 and 3 are distributor codes

8 is airflow meter

34 is idle air control

It sounds like you're forgetting to plug stuff in / have bad connections.

the airflow meters don't really fail, but should be like $20 bucks at a scrap yard, if not, we all have spares. I have a spare S code.

IAC doesn't really fail either, but thats super easy to come by in scrap yards as well.

distributor, once again, isn't really an issue in the SOHC MX-3. It was the only engine not to have distributor problems, for the most part.

[dude33694]

Dark rider, the starter actually works great.

Ryan, what does it take to reset the codes? I had hoped they cleared when you pulled them....

Sorry I'm spoiled by obd2

And I was also thinking bad connections somewhere. That's why I mentioned the clutch and cv axle replacement, knowing how deep they had to go in to get to it.

For the record I noticed the screw is missing for the IAC to contact the throttle linkage. would it cause the code?

And the code three is supposed to be for california cars according to the description... Can you verify or maybe explain that one to me? I'm used to seperate cam and crank sensors.

Sorry if this is elementary for you guys I'm just not THAT familiar with this car.

And in the meantime I suppose ill try to track down a loose or damaged wire.

[Dark_Rider2k3]

to clear codes, disconnect the negative battery terminal and hold the brake pedal down for roughly 20 seconds

[Ryan]

2 and 3 are codes caused by hall-effect sensors in the distributor. the NE1 signal (code 2) produces six pulses per revolution of the camshaft, and the G signal (code 2) produces 1 pulse per rotation. The reason for both is probably a resolution thing, but I don't actually know.

I don't believe the B6 has an actual crank angle sensor, its just another sensor in the distributor, but I might be wrong, its been so long since I had a b6.


If the throttle stop screw is missing that might mess with your car. You should definitely get that figure out. That would throw the IAC code, I bet.

[dude33694]

Yea I was going to head over to pull a part and grab the screw. Would I have any use for an rx7 maf? Not necessarily trying to bump performance, but the lady's uncle is swapping a 302 into an fc in the garage and has the maf on a shelf.

So since I haven't actually truly reset the computer since I started working on this thing, I'll go reset it and drive it. See what comes back.

Thanks for all the help! I'll follow up in a bit.

[Ryan]

if by maf you mean VAF, then yeah, its an upgrade, or you can sell it on club protege for a penny or two, or 4000.

[dude33694]

4000? xD

Yes I meant VAF. Maf justs seems to get the point across that its a device that measures airflow

Anyway I cleared codes and drove it a few miles. Still showing a 3 and 8 (so presuming vaf is shot.) Now the code 3 has only been present since I switched ECU's to a replacement and three different distributors (including the one that was on the car originally) have all turned back the same code. But given the intermittent start issue I'm really leaning toward wiring issues. Maybe the harness to the distributor is damaged.

[Ryan]

Mass airflow sensor.
Vane airflow sensor.

3 must either be the wrong ECM, or wiring in between, because honestly, code 3 isn't common the the SOHC.

Code 8 could be the airflow meter. Lots of guys don't know how to properly remove the plug, so it gets damaged, pins pet pulled out, etc.

[dude33694]

Thats what I figured. According to everything I have seen thats supposed to apply to a california or DOHC engine.

And I noticed the seal on the VAF has been cracked so there's no telling what couldve happened to it.

I'll see what I can find on using the RX7 unit instead.

[dude33694]

Couldn't find much about tuning. But if i remember correctly, all that needed done was some adjusting of the trapdoor itself.

Think I'll just pop it on and try it.

[Ryan]

Check http://www.clubprotege.com" onclick="window.open(this.href);return false;

I know for sure its on there.

[dude33694]

Ok. I will say I popped it on there and the maf code is gone. Problem is I didn't get to test it because the car isnt starting anymore. I tried to crank on the original vaf first and then the rx7 maf to no avail. Although I will say that the code would return immediately with the original vaf but hasnt yet returned on rx7 unit so I think THAT issue has been addressed. Code 3 is still present so I'm going to try another computer and see what happens. Thanks for following up on this man it's turning into a real headache.

Also, am I correct in assuming a little less fuel economy with the bigger maf?

*edit* Just did my reading on cp and think I know how to get the tuning about right. I'll tackle it in the morning. However I do remember that the ecu I purchased had an extra letter in the part number or something trivial like that. I'll have a look in a bit. However I did notice the collant sensor near the airbox side, front corner of engine is broken off....?

Think that has any bearing on this? And I have also noticed that while driving the temp gauge will start to drop under load. sometimes at 70mph it doesnt read any higher than the C line.

[Ryan]

Um, the little one wire sensor sticking out the front of the head is for the dash gauge....

the green one is for the ECM... and some motors have another one yet... I forget what its for though.