Now that it's warmed up I've got the bug to get my turbo vert back on the road. I'm probably gearing up for my first rebuild but before I do that I want to rule out other potential problems.

Real quick background is that it's a 89 vert with a JDM 13B swapped into it. I'm using an n370 ecu and an N/A harness with the pins swapped. The majority of my cars build is in my sig. Last time the weather was warm I had numerious problems. Occasional strong fuel smell while idling, very poor fuel economy, occasional smoking exhaust, sporadic reading on the OEM voltage meter....if that matters. Then before I parked it for the winter I suddenly got very bad idle and also very sluggish performance. I can provide more details about the car but it gets a little long winded and gets off track from the specifics of testing continuity.

I'm suspicious of an electrical problem because I tested two different CAS to be good. But when I swapped them the car ran great for a day...then went back to sluggish behavior.

Once the battery is charged I'll pull CEL codes again. I'll also recheck compression once I can idle the engine to warm it up. Last year when I checked it was 110,110, 110 and then like 80,50-60,80. Oh and I am planning to try some Seafoam to try and free the stuck seal or seals.

I want to make sure I'm checking continuity correctly. I made a jumper wire with a backprobe soldered to it to reach from the ecu side of the harness to the engine compartment. I made another backprobe wire to use on the engine side of the harness. I touch one backprobe wire to a multimeter probe and the second to the other multimeter probe and get a tone.

So far I've done this and have continuity for:

O2 sensor
2C on the ecu(black wire)

Intake Air Temp (engine)
2L on the ecu (green wire)

CAS pins:
3E (blue wire) and NE1 on CAS
3G (white wire) and G1
3H (red wire) and G2

Comparing the FSM on CELs (pg F2-22) and CAS (pg G-32)has me checking on Ne pickup coil and G pickup coil signals.

Can someone reassure me that I infact tested for continuity correctly, but also explain what task each wire performs? What does the green wire or NE2 perform? I haven't seen it listed in the FSM

 

You connect the CAS plug to the CAS.

You pull the plug off the ECU.

You ohm out b/t the 3G and the 3H and get the value given in the ENGINE ELECTRICAL section.

You ohm out b/t the 3E and 3H and get the value given in the ENGINE ELECTRICAL SECTION OF THE FSM

The value in each case is approx 110 ohms to 210 ohms. Done.

Screw continuity on the others. The water thermo sensor should read appox .4 to .5vdc hot. If cold it'll read b/t 2-3vdc. If it reads 4.5 to 5vdc the thing (water thermo sensor) has it's plug off or a pin in the plug pushed back. You do that with all plugs on the ECU and backprobing the wire. Green/White wire.

Either air intake or water thermo sensors have default values and won't make the engine run peculiar when defaulted to the ......default values. That's true if the engine is hot....not cold.

 

Thanks for the response Hailers.

I tested O2 only cause I found the harness dry and cracking off in my hand. While splicing an extension cable for the new sensor I figured checking couldn't hurt. From what I've read and been told that sensor isn't all that important.

I checked IAT simply because in the past I have left that unplugged when putting the TMIC back on. How it idles with that unplugged is similar to how it was/is idling now. I've swapped known good IAT sensors and neither car was effected.

I've read that water thermo sensor can create problems. The car did/does idle better when warm compared to cold. When cold I can't take my foot off the gas without it stalling. Checking the water thermo sensor is on my list, tho i replaced with a new one last spring.

I'll have time this weekend to do more work on it. I'm prob going to buy another N/A harness regardless. It's dry and cracking all over. I noticed yesterday that the engine side of the CAS plug is dried out. The insulation on the wires have cracked and I can see the wires between the cracks.

 

I checked resistances today

3G-3H=1.64 ohms
3E-3H=1.64 ohms

I tried jumping the battery today and it jumped just fine. I was alone so I had to leave both cars running while I got my car up to temp. Once it's warmed up it will barely stay idling. I turn the other car off and as soon as I remove the jumper cables my car dies. I got a friend coming over tomorrow to help me jump the car and also help me get compression numbers.

Once I've got the battery properly charged I'll check more electrical stuff. Anyone have any advice on any other electrical issues to check into. Tho it's looking more and more like a rebuild is in my future. From what I've read all my issues can be traced back to bad compression.

 

There has to be something your doing wrong with ohming out the CAS via the plug at the ECU. You leave the CAS plug on the CAS and remove the plug at the ECU. Then one meter lead on 3H and the other lead on 3G. The meter should read the FSM figues, not what your reading. Then leave the meter lead on 3H and go to the other pin I mentioned with the other meter lead. Car will not run if you figures were correct.

Since the engine runs, I suspect the CAS is probably ok.

Maybe your reading the ECU plug wrong??? You read from the wire side of the plug from right to left in a up/down fashion.

Is your alternator charging? Next time with the engine runing, put the meter leads on the batt terminals. It should read 13-14vdc idling for sure.

 

DOH!!! I had a stupid moment

My readings were 164.3 or NOT 1.64