ShadowZ

I have a '99 with 1.8 motor, Toyota COPs and turbo, running a MSPNP.

Here's the issue: I parked the car 4 days ago after driving home from work; the car has been running pretty much flawlessly with the MS tuned with VEAL. The next day I started the car up and noticed that it was misfiring pretty noticeably, so I took it for a quick drive around the block and the misfiring didn't go away through the rpm range. I thought that the tune may have gotten corrupted somehow, so I ran VEAL again and it enriched the entire fuel map by and avg of about 10 pts. The fuel map is incredibly messed up now, so the tune that I attached has that awful map that resulted from running VEAL after the misfire started.

I figured it had to be something other than the MS at that point, so I checked each of the COPs and spark plugs. All 4 sparked without a hitch when I pulled each individual coil and spark plug and cranked the motor. I checked the fuel system and didn't notice any leaks or anything out of the ordinary. I pulled the filter off the turbo and it looked like it was rotating normally.

Fuel, air and spark all seem to be there, I'm wondering if there may be something wrong with the MS picking up a signal or a sensor going out. I'm not ruling out that it couldn't be a mechanical/electrical problem that is causing the misfire, though.

I ran a quick log driving down the street, and I'm hoping that someone will be able to see something in the log that I'm missing.

Thanks in advance for any help!

Reverant

iTrader: (10)

Using test mode, test all 4 injectors by replacing them with a 12V test light.

ShadowZ

I checked each of the injectors using test mode, but only injector 1 and 3 showed voltage, no matter which injectors I had selected to test. Maybe I didn't set up the test mode correctly?

ShadowZ

I checked all of the wiring connections for the injectors and COPs, checked all vacuum lines.

I put everything back together to see if anything changed with the misfire, and when I started the car, the motor started idling at 3000 rpm, and the misfiring is still there. I immediately thought that it could be a vacuum leak, but I've checked all the lines and can't find one.

I'm totally at a loss what the issue is now...

Matt Cramer

Are 2 and 4 getting power?

ShadowZ

Just did a test right now, and injector 2 and 4 are not getting any power.

I disconnected the COPs and pulled the connectors off the injectors, then cranked the car and measured for 12v. 1 and 3 got a solid voltage, but 2 and 4 were basically 0.

Matt Cramer

Check your fuses and wiring then.

ShadowZ

Fuses are all good, and I pulled the injector harness off the car and went through it wire by wire, an it looked like all the connections were fine.

Braineack

iTrader: (62)

what are you testing for voltage, the white/red wires right? you're saying that 2&4 don't have 12v on the white/red?

just turn the key on and check...it's a constant supply.

ShadowZ

On the injector connectors, there's a white/blue wire that is shared by all 4 connectors. The other wire on each connector is a different color for each one.

I was looking through a wiring diagram, and it looks like the white/blue wire connects to the main relay and the 4 other wires go straight into the ECU.

I need to check them individually again, but should both wires in each connector have a constant 12v?

Braineack

iTrader: (62)

no. one is power, the other is a switched ground from the MS, that activates the coil.

all injectors should see 12v, and the MS provides the ground.


this will determine if it's an issue with the injector drivers on the MS, or the engine harness/fuses.

ShadowZ

Did another test with a better 12v test light, and the white/blue wire is getting 12v to each injector, but the other wire for each connector is not getting 12v. Now it looks like all 4 injectors aren't getting a signal from the MS, but the white/blue wire is getting a solid 12v.

I checked the voltage of each one with the COPs unplugged, while cranking the motor.

ShadowZ

I'm assuming that since the 4 wires that go straight into the ECU didn't have 12v, that the issue is with the injector drivers or something in the MS?

Reverant

iTrader: (10)

Remove the ECU, switch the ignition on, measure the voltage on pins 4W,4X,4Y,4Z on the harness connector.

ShadowZ

I pulled connector 4 out from the MS and checked the voltage on each of the pins on the MS. 4Z didn't have 12v when the ignition was on, but 4W, 4X, and 4Y had 12v.

Reverant

iTrader: (10)

You better check that then, as you understand, this has nothing to do with the MS.

ShadowZ

Only 3 out of the 4 pins on the MS had 12v, aren't all 4 supposed to have 12v?

I measured the MS and wiring harness side of each of the connections, only the MS side had 12v, but it was only on 3 of the injector pins.

Reverant

iTrader: (10)

Wait, you are supposed to check the wiring harness-side connectors, not the MS-side connectors.

ShadowZ

Right, I checked both. The wiring harness connector didn't have 12v to any of the pins. Are they supposed to? I thought that the MS would supply the power?

Reverant

iTrader: (10)

Yes, they are supposed to, with the ignition on. Power is provided to the injectors through the white/blue wire, and the MS activates the injectors by grounding them.