Definately have an issue with my unitronic tune. chime in unitronic

[Mindfault]

My vvt isnt deleted, so ill be checking the n112 and n80. But what am i looking for? Corrosion or what with the resistors and what not?

[groggory]

Ensure the resistors are properly connected. Personally, I used the postreleased resistors that are now available on IE's website.

The bummer about the resistors is you can't ohm them out if you've soldered them in. I don't think it's safe to connect an ohm meter to your ECU generally. Ohm meter's use voltage drop to measure resistance.

[Mindfault]

Yeah, i have a high impedance dmm, so i think that should be fine with the ecu. Anyway, ill check out the deletes and see if they are good connections. Ahh. Headaches i tell you. But thanks for all the info man. I appreciate it a ton!

[groggory]

Yeah, i have a high impedance dmm, so i think that should be fine with the ecu. Anyway, ill check out the deletes and see if they are good connections. Ahh. Headaches i tell you. But thanks for all the info man. I appreciate it a ton!

FYI...It's only high impedance when you're reading voltage. When you're reading resistance it definitely loads the circuit.

[turbo2.24.1990]

Well it is, but we discovered here and at nefmoto through people who spent hours watching flow execution that the MAF is the true source of load calculation in a motronic system.

Think of it like having CIS or CIS-E, but no airflow meter. What kind of crap is that? How would it ever work?

I have a UNI 630 tune scaled for a 2.75" ID housing (TT housing or VR6) with an OEM AWP sensor. It works phenomenal, and the car ran 100% garbage with no MAF.

It made power, but it had so much in the way of hesitation and misfires that it took so long for the power to come on it was essentially worhtless.


Now the car is so smooth and it absolutely rips into boost the boost builds faster and harder, it's smoother and no hesitation.


What does a MAF do? Determines the MASS of an AIRFLOW. Without an accurate measurement of the charge, or mass of the flow, you are guessing and adding/subtracting fuel here/there afte the fact, which is AFTER the fact and causes hesitations, light misses, a slow climbing tach, flatspots..... etc. etc.

DougLoBlue gained 50whp plugging in his MAF on maestro.

I can tell you running my lil 3076 @ 18psi now with a MAF, it feels like it gained about something similar powerwise.

Ask UNi if your tune was scaled for a MAF. I think UNI maxes with an S4 MAF or 3" housing anyways, they don't offer a file with scaling for a 4" MAF if I recall.

However, until you overrun the MAF, you need it.

My understanding? Timing is extremely load dependant. My timing values bounced all over at idle, add a MAF? Theyre very very stable now. The misfires associated with that timing bounce? GONE! Same at part throttle.

Mafless rev it in neutral hold at 3k. Don't move foot at all.... notice small oscillations

MAF rev it in neutral hold at 3k dont move foot at all... VERY steady, almost NO oscillations.

Something is happening there, and that is just neutral.


Historically look at bosch. You had L-Jet, and D-jet. Or luft jetronic, and druch jetronic. 1967-1979 or so. My 1975 914 has a Luft-jetronic. Luft, air mass. Druck Jetronic, or pressure jetronic.

http://en.wikipedia.org/wiki/Jetronic


Bosch figured out over the years, you truly need BOTH of these to accurately control an engine, have it make big smooth power and run great at part throttle. WIth a turbo car, your asking for a serious amount of resolution to go from -HG to +22psi, and how do you know the actual MASS or lb/m the compressor is pushing in? A maf.

really makes me think about going back to a maf on my cts 3076-I really haven't had any problems though.

[Mindfault]

^right me too. if i have to end up sending my ECU back out to unitronic to get the rev limiter tuned right, ill probably be going 3" MAF. is there any other reason why i would be hitting limiter at 7640 RPM rather than 8500 like i specified? oh and thanks grog. i wont be using the DMM on the ecu itself. i will be checking continuity between the Ecu harness connector, and the connector for the o2 sensor. but correct me if im wrong, doesnt the tune delete out the n112 and all of that? so even if it wasnt resistored i feel like it wouldnt affect the fueling because it is deleted and the ecu doesnt rely on the information anymore. i may be wrong about that, anyhow i will still check my resistors.

[groggory]

For awp

Front o2 sensor

o2 harness plug
Pin 3 is heater +
Pin 4 is heater gnd

Heater + is 12v with ignition keyed on

Ecu pin .. Harness Wire color .. o2 connector number ... o2 sensor wire color

52 .. grey/red .. 6 ... Red
71 .. black .. 2 .. Not connected
51 .. grey/white .. 5 .. Yellow
70 .. green .. 1 .. Black
5 .. white .. 4 .. White

Relay 87A .. blue/red .. 3 .. Grey

[Mindfault]

So i will be checking continuity between T121-52 and T6c/6. T121-71 and T6c/2. T121-51 and T6c/5. T121-70 and T6c/1. T121-5 and T6c/4. Where do i check from T6c/3. To e30? Where tf is that?

[Mindfault]

relay 87a is up under the dash or what?

[Mindfault]

87a is just a connection, do u know exactly where that is? thanks man

[groggory]

I don't know where 87a is, sorry

[20vturbslo]

Here's the data... My Analysis of logs

Can I send you my advanced measuring blocks for analysis?

My vvt isnt deleted, so ill be checking the n112 and n80. But what am i looking for? Corrosion or what with the resistors and what not?

Just for reference, the N112 is the Diverter valve, and the N80 is the EVAP valve?

I have a Uni2+ tune and my car has been running poorly, a lot of misfires and lack of power, I know my IATs are sky high at the moment due to an inefficient air to air intercooler. But could it be directly related to a bad MAF?

[Mindfault]

Yeah, they are valves but i have mine deleted, and resistored.

[groggory]

Can I send you my advanced measuring blocks for analysis?




Just for reference, the N112 is the Diverter valve, and the N80 is the EVAP valve?

I have a Uni2+ tune and my car has been running poorly, a lot of misfires and lack of power, I know my IATs are sky high at the moment due to an inefficient air to air intercooler. But could it be directly related to a bad MAF?

Sure, start a thread and pm me a link

[Mindfault]

Okay so i did some test today on that circuit. What i found was 52 and 6 had continuity,
71 and 2 had continuity,
51 and 5 O.L.,
70 and 1 O.L.
5 and 4 have continuity. Wtf is up?


Should i just re wire those 2 wires? Hopefully those 2 pins in the ecu arent shot. Groggory, chime in

[groggory]

Re wire those those puppies!

As a double check... Did you verify the wire colors matched that you were testing continuity on?

Don't forget appropriate heat and abrasion sleeving. Solder joints with heat shrink

[Mindfault]

Yes, i tested them multiple times. I will be waking up early to go to the parker store and get a oil restrictor for my buddies 2nd gen eclipse 6267, and then i will be buying heat shrink and some more insulation for the wiring.

Shoul i just cut, and make 2 points, or should i use a tool to pull the pins out and wire the new ones in? It would be a hell of a lot easier to cut and solder. Think thats what ill do then ill checl the resistance. Hopefully this works out :-) thanks man, ill buy u a beer if we ever meet

[groggory]

Yes, i tested them multiple times. I will be waking up early to go to the parker store and get a oil restrictor for my buddies 2nd gen eclipse 6267, and then i will be buying heat shrink and some more insulation for the wiring.

Shoul i just cut, and make 2 points, or should i use a tool to pull the pins out and wire the new ones in? It would be a hell of a lot easier to cut and solder. Think thats what ill do then ill checl the resistance. Hopefully this works out :-) thanks man, ill buy u a beer if we ever meet

Awesome. I'm not one to turn down beer.

I would snip the wires about 10 inches from the ECU and about 5 inches from the o2 sensor plug. That's what I did. I ran them in their own heat sleeving and then wrapped that sleeving in some corrugated tubing. Then ran that in parallel with the OEM o2 sensor loom.

Make sure to zip tie them together plenty. The turbo is near there and it's toasty warm.

I have a feeling this is going to fix your problem.

[Mindfault]

I ****ing hope so man, this has been a long time coming, if i wasnt so busy/lazy i would have done this a longggg time ago. We will see though. And if that is the case i have 3 extra good ecu's lol. Thanks a ton man. I will post in the afternoon about it. Its gonna be hot as satans ******* tomorrow too :-/ but all good if she runs right!

[groggory]

I ****ing hope so man, this has been a long time coming, if i wasnt so busy/lazy i would have done this a longggg time ago. We will see though. And if that is the case i have 3 extra good ecu's lol. Thanks a ton man. I will post in the afternoon about it. Its gonna be hot as satans ******* tomorrow too :-/ but all good if she runs right!

That's awesome. I potentially diagnosed your weird ass issue after you went through all those ECU's :-p

[Mindfault]

Yeaup. I have continuity to both connectors now, now i will log and see if the o2 sensor is reading

[groggory]

Yeaup. I have continuity to both connectors now, now i will log and see if the o2 sensor is reading

Awesome. Note, if you're been running really rich there is a good chance your o2 sensor is all gunked up. You may need to replace the front o2.

Let's see some logs of

Start the car up and drive the car around til it's up to operating temps while running this log...

block 001/ 031 / 032

Then do two third gear pulls

pull 1,2 : block 001/ 031 / 032

then do two third gear pulls

pull 3,4 : block 002/ 031 / 115

...let's see how things are looking. Post up the complete raw data.

[Mindfault]

Alright, will do. Im trying to get ahold of a computer now

[Mindfault]

Well, block 031 is still showing 1.0 on both of the columns:-/

[Mindfault]

meh.. :-(

[Mindfault]

So what do you think groggory?

[groggory]

Key on the car with o2 electrically unplugged.

Check voltage from ground to o2 sensor pin 3

Check voltage from o2 sensor pin 3 to 4

Report back

Also, were you looking at block 031 with the engine running for a couple minutes?

[Mindfault]

Okay. I will check thanks bud

[Mindfault]

Yeah it was running for awhile

[Mindfault]

Okay, here is the outcome. Pin 3 to ground is 3.24 volts, and pin 3 to 4 is .736v

[groggory]

Okay, here is the outcome. Pin 3 to ground is 3.24 volts, and pin 3 to 4 is .736v

Looks like you need to go find out what junction 87A is. Your o2 header positive wire is not receiving 12V. Without the heater you will continually fry o2 sensors. The heater is required to get the sensing element up to temps quickly. Without the heater exhaust gases will kill the sensor.

Your mission. Trace out the Blue/Red wire and find the elusive junction 87A. Figure out how to get 12V to the blue/red wire at key-on. Being that you are getting 3.24V to the wire it makes me believe that there is a corroded or loose terminal, damaged wire in terminal, bad relay contact, or corroded loose fuse somewhere.

[Mindfault]

ahhh. this is craziness. where the hell is 87A? is it infact a relay?

[Mindfault]

without the heating circuit, the o2 sensor should still read a/f ratio though

[groggory]

without the heating circuit, the o2 sensor should still read a/f ratio though

Theoretically it works. I don't know of anyone who knowingly runs a wideband o2 sensor without a heating circuit. lol.

My vote goes to figuring out where the blue/red wire goes in the loom.

From memory, I think I saw it runs under the window cowling, under the ECU, down the waterfall plenum, and I'm not sure where it goes from there. So go look in your waterfall plenum and see if you see the blue/red wire in there.

[Mindfault]

im pretty sure it goes into the box next to the waterfall. the one with i think 2 relays in there. and it seems like the junction is a relay, because it says "87a" which is a leg of a relay. but it's so F'ing hot here. i dont wanna be outside tearing thrtough wiring harnesses. haha. this is just crazy though