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1g CEL 12 volume airflow circuit problems after a swap.

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Vladimir

10+ Year Contributor
197
2
Apr 28, 2010
Hollywood, Florida
Long story short, I was swapping my old setup in a new rolling shell. Everything was smooth until the start up. I have a v3 with ecm maf cable for my 3'' GM MAF. Nothing that I've tried made my car run smooth, it misfires,sputters, back fires, shuts off doesn't start, etc.... I get 0 HZ MAFidle and the car gives me a 0012 volume airflow circuit malfunction, sometimes I get codes for baro as well. The only time MAFidle moves is when I'm cranking but as soon as starts running (barely) it goes to 0. I have 2 of ecm cables that work 100% and 2 GM MAFS that work 100%. V3 was notified I'm running GM. All the connectors,wires and grounds are good with good continuity from ECU to the sensors. I got desperate and started cutting off wires pin 6 and 14 which didn't affect anything, so I cracked open the ECU and found out that a certain part of it was fried. Looks to me like the driver IC106 is fried. IC106 is only responsible for waste gate and fps solenoids, which I'm not even using. All my MAF readings are really low in HZ, so something definitely is not working.Car was running fine prior tho the swap. My Questions are:

Could the ECU be causing the issue?
Can the ECU be Fixed?
How much would it be to fix(approx)?
What caused it to fail?
Could the ISC be causing this problem?
If this is not the issue what is?

The car is a 1990 AWD talon with a v3 E2T34478 ECU (1990)

Below you will find pictures attached.


All help is greatly appreciated.

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If I'm correct that's the part of the ECU that drives the idle control motor the 1G I just bought had that same part of the ECU burned up but ran fine
 
It appears you have a short somewhere from the BCS or FPS. Do you have these on the car still? What condition are the connectors in? You may also want to trace the wires for these connectors as well. For good measure, you should also test the ISC.
While you are doing this, send the ECU to ECMTuning for repair. They would be able to get you the cost of repair.

Here are some additional resources:

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BCS and FPS are cut and completely removed from the car, all the related wiring has been isolated. Coolant temp sensor is working fine. The car was running fine before the swap. I have no clue as to why I the car is giving me a 0012 volume air code. All the pins and wiring along with the grounds were checked from the ECU to the maf sensor AIT sensor is working and getting a reading. When I look at the live stream my maf never gets above 300hz, MAFidle is at 0hz, mafraw never gets past 40hz. That is not a proper reading for 3'' GM. Airflow per rev is also ridiculously off. Car will not idle without opening the throttle 12%. Etc...

Thing that I don't get is the IC106 is not responsible for anything MAF related, could anything else be burned and not look burned in the ECU?

I will check the ISC when I get the chance but I don't see how it can be causing the maf problem. Also the weird thing is I get MAFidle when cranking but as soon as the car starts it goes to 0hz and stays there...

????????
 
Also the board doesn't look fried and discolored in any other places.
 
The driver pictured (IC106) is responsible for controlling the Fuel Pressure Solenoid (ECU pin 57), and the Boost Control Solenoid (ECU pin 105) as @2gmitsueclipse said. Typically, a short to ground on either of these circuits will blow the driver. Have you verified these circuits are isolated as you said? If so, what testing did you perform?

You mentioned a GM MAF, are you using a translator? How is it wired in? Solder connections?

I'm guessing you have multiple isolated wiring issues, as it seems your harness has probably been modified significantly from stock. Helping you troubleshoot remotely will be difficult, since we can't account for what's been modified from the stock diagram. Some pictures would probably help.

Worst case, you can always send the ECU to ECMtuning to have it checked. Judging from the jumper wire on the back side of the board, it has been repaired before.

There is quite a bit of good troubleshooting information here: http://www.galantvr4.org/ubbthreads/showflat.php?Board=UBB11&Number=1194088&page=0&fpart=1
 
The driver pictured (IC106) is responsible for controlling the Fuel Pressure Solenoid (ECU pin 57), and the Boost Control Solenoid (ECU pin 105) as @2gmitsueclipse said. Typically, a short to ground on either of these circuits will blow the driver. Have you verified these circuits are isolated as you said? If so, what testing did you perform?

You mentioned a GM MAF, are you using a translator? How is it wired in? Solder connections?

I'm guessing you have multiple isolated wiring issues, as it seems your harness has probably been modified significantly from stock. Helping you troubleshoot remotely will be difficult, since we can't account for what's been modified from the stock diagram. Some pictures would probably help.

Worst case, you can always send the ECU to ECMTuning to have it checked. Judging from the jumper wire on the back side of the board, it has been repaired before.

There is quite a bit of good troubleshooting information here: http://www.galantvr4.org/ubbthreads/showflat.php?Board=UBB11&Number=1194088&page=0&fpart=1


Wires leading to pin 57 and 105 were cut off from the solenoids and taped off then zip tied to hold the tape. Wire was cut, taped and tied on both ends at Pin 15 by the main connector on the ECU. Pins 6 and 14 were swapped previously by the previous owner (he probably run a (91-94 ECU, on a 90 harness), I swapped them back around soldered and heat shrinked them (continuity was checked).

The only major part of the harness that changed was that the 1g MAF was removed and a GM MAF was installed with the ECMTuning MAF cable. Also a GM IAT sensor was added to the intercooler piping and soldered into the ECM cable where it was supposed to go. The ECMTuning cable is connected to the original MAF connector (all the wiring is good and proper there, same exact way as my old setup).

The old owner of the car put a turbo timer on the car and messed with the ignition wiring. The ignition goes on fine, however the car doesn't crank with the key. I had to splice in into the YB starter wire, add extra wiring and create a circuit between the battery positive and YB starter wire., the push switch closes the circuit. In order for me to crank/start the car I have to turn the key in the on position press the clutch and push the switch (race car stuff :) ). (Ed: This means the ECU doesn't get a KeyStart signal)

I didn't have time to figure this problem yet. Could this possibly be related to the airflow circuit? Would be strange, in my opinion.

Also just now I was checking the wiring with the ECU connected in the car and noticed that my ISC 6 pin connector was fixed by the previous owner. So I took off the connector from the ISC and put a voltmeter on it. The 6 wires were cut around 6 inches away from the ISC and connected back with those blue crimp connectors. So when I'm checking them for continuity I notice that pin 1, 2, 3, 4, 5, and 6 are all beeping when I'm checking the pin 1 wire next to where it was fixed. That means that the wiring to the ISC is shorted right? (I'm going crazy starting to doubt myself).

Also I've noticed that when I connect the ISC back on with the ignition in the on position I sometimes hear weird tap or buzzing noises coming out of the ISC. So tomorrow I will definitely look deeper into it. But could this problem be causing my ECU volume air circuit code and prevent my car from reading my GM MAF properly?

Maybe that's why I only get MAFidle when cranking but 0hz when the car actually starts running?

Any thoughts? Anyone?
 
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