yeah haha I meant less than. and that was just the plug with the key on no ecu involved

 

Sounds like something is corrupt then. How about disconnecting the plug at the CAS and perform the same exact voltage test just at the pigtail plug connected to the CAS. Also, do the ohm test mentioned in the other thread at the large ECU plug and compare those results to spec.

 

Will do, I am going to get another multimeter aswell because they are cheap, and one of the probes broke off of the one I have been using haha.

So when I check at the CAS I am checking the side that is part of the harness correct?

 

No, from the plug that comes from the short CAS pigtail. Focus on the ohm test first and then compare the results with the pigtail plug connected at the CAS and taking the same reading from the large ECU plug disconnected from the ECU. And one other thing. Take the voltage test one more time at the ECU, but with the large plug connected to the ECU. W/o checking I might have been incorrect to tell you to disconnect the plug at the ECU for the voltage test. For the ohm test it's certainly supposed to be disconnected. When I did the voltage test on mine the other day I left it plugged in so I might have wasted some of your time on that one and if so I apologize.

 

Ok this is kinda unrelated in a way but I have had an alternator that would make me lose spark when plugged in and the car would run perfectly if I unplugged it. Not sure how that happens, but get a known good one and try it out.

 

Think before giving advice
would be better to Unplug it and try, before buying another one... dont you think?

 

Can you break this down into simpler terms? I am having trouble understanding what I am doing here haha sorry

Ohm test the plug on the CAS, not the harness. which wires do I check? all of them?
Then plug them back together and test through the back of the CAS plug?

Then ecu voltage tests with the big plug attached, am I testing through the back of that plug aswell?

Thanks

 

When you do the ohm test you do it in pairs such as two specific wires at a time. When the plug is disconnected at the CAS there are four wires in total. The paired wires are Green and Blue, and then Red and White. One terminal of the meter would go to White and the other lead to Red with the meter set to ohms. Before doing the test touch both meter leads together and they should make the meter indicate zero. Then do the test one pair at a time, two pairs total. Do this test at the CAS first and then at the ECU. When doing the ohm test at the ECU the plug is to be disconnected from the ECU. No key is necessary.

At the ECU the meter probes are stabbed into the back of the ECU plug. Plug connected and key to on during the voltage test. But not during ohm test, so no key and plug disconnected at ECU for ohm test.

 

The only proper way to test the cas is to check with a scope. even then, its very rare for the cas to become funky. you can try to regap them.

try using multimeter with a continuity buzzer? you know... connect the two probes togeather and it beeps. what you can do it connect the probes to the home + and home -. spin the cas. should beep whenever a tooth passes past the pickup. same for the other teeth.

either way, i dont think its anything but the damn AFM. see if a budy of yours has a spare one, and slap it in yours.

 

I am leaning towards the afm at this point, it's just a matter of tracking one down, I thought they were a dime a dozen haha I guess not up here.

I just remembered though, when I checked the omhs of the afm I didn't check the plug, just the actual afm. should I check the harness to the afm?

 

try cleaning the contacts. sometimes unplugging **** will make an rx7 unhappy.

 

Should I test the voltages and resistances of the actual AFM plug?

 

Awesome I will try this

I will clean the contacts aswell

 

Ok, So I tested voltages with the ecu and plug connected (key on), I will post the spec number first then the number I got.

Pin 1O (12v or 1.5v)~ .8v
Pin 1Q (Below 1V)~ .68v
pin 1T (Below 1V)~ .68v
pin 1P (Below 1V)~ .68v
pin 1N (Below 1V)~ .68v
pin 1M (below 2v)~ .98v
pin 1U (4.4v)~4.28v
pin 1V (0v)~0v
pin 1X (0v)~0v

pin 2A (4.5-5.5v)~4.9v
pin 2B (3.5-4.0v)~3.49v
pin 2D (below 1v)~0v
pin 2E (4v)~3.93v
pin 2J (2-3v)~2.9v

pin 3C (12v)~12.2v
pin 3E (12v)~12.2v
pin 3F (12v)~12.2v
pin 3H (12v)~12.2v
pin 3I (12v)~12.05v
pin 3J (12v)~12.2v

I also Checked the resistances(ohms) on the big ecu plug between pins
1N-1P~150.9
1T-1Q~151

So everything looks normal with the exception of the milage switch, and the fact that I got a zero reading from the o2 sensor.
I can't seem to get the damned cas unplugged from the harness to do the resistance test, is there some secret ninja technique to this?
And can anyone point me in the direction of the "4 wire plug located near the Brake master cylinder/Main relay area" that satch was talking about?
Is that in the engine bay or cockpit?

Thanks again guys, I probably would have rage quit my car by now,
This is the first problem I have ever encountered with it that I couldn't figure out!

 

Measuring the CAS resistance at the ECU is the most important. If it's good there then it's good everywhere.

 

the only thing i can think of it being is the ecu is dead, coil pack could be bad, or AFM

 

so I swapped the AFM this morning same symptoms, I think we are narrowing this down haha
how can I check the coils without killing myself?

I have 2 ecus and I swapped one out, still same thing

OH! before I forget, if it is relevant at all my pressure sensor (near afm) is marked n327?

 

the easiest way to check your coils to see if they are sparking is with a timing light.

if you are not getting any spark, then i would suggest replacing your crank angle sensor. the cas is what sends the signal to your coils to make them spark on time.

 

Remove the plug wire boots from the leading coil and place them back on the bore that they were plugged into except leave a small space between the two to the tune of 1/8th of an inch. Then try to start the car and observe for spark.

What you could also do is to pull the plug off of the leading coil and w/key to on use a socket wrench on the bolt found on the alternator pulley as this will rotate the main pulley and rotate clockwise when looking at the pulley from the front and measure the voltage on the Green/Yellow wire at the leading coil plug which you disconnected and see if the voltage goes from 0 volts to 5 volts back and forth. This is necessary as this is the signal from the ECU to fire the leading coil. No signal means no firing.

 

I will do this tomorrow morning, also what is up with these plugs? I cannot get them to come apart haha am I doing it wrong?

 

GOT IT RUNNING!

My roomate and I pulled the car apart and cleaned all of the grounds, while putting the UIM back on I noticed one of the little wires on what I think is the IAT was broken (temp sensor on the drivers side of the dynamic chamber w/ green and black wires) I re-made the connections and plugged it in. Cranked...half started then flooded, I cleared the flood then remembered I had a vac line undone. Plugged the line in and viola! it runs....

so it was something pretty simple, and I suck hahahhaa

Thanks to everyone who contributed to this thread, you guys kept me sane and gave me alot of good info!

-Miles

 

All because of a vacuum hose? And which hose was this? You need to run laps!

 

it was probably a bad ground. lol

 

the vac hose wasn't the problem haha, after I fixed the IAT wires I forgot to reconnect 1 vac line, so the car started but then died.

and it may have been a bad ground, but that wire was the most obvious thing to me I was getting intermittent spark? I dunno I am just happy it's running again

 

nice