Hey HT

I have a 1996 civic ex M/T. I have been losing my mind over this no start issue. The CEL cam on and told me, IAT and ECT sensor. So I replaced both of them ran fine one day then the next, CEL back on again. I cleaned the FITV in the interim (just an FYI).

Basically what I am asking is this. All the CEL codes I get come from the "D" connector in the ECM, is it possible to have a short somewhere? I have tested resistance at IAT and ECT sensors.. I am losing my mind.. Any suggestions would be awesome!!

I have checked the g101 ground, as well as all other grounds.. Can not seem to find any opens.


Live Data reads

IAT -40
ECT -4
TPS % 98.9
Map 7.3






Thank you

 

Wait, your live data reports the TPS at 98.9%, with the car not running? That...doesn't make sense.

Is your car a no-start no-crank, or a cranking no-start?

 

Reset the ECU. Crank engine for 30 seconds. Pull codes. Post them.

 

Sorry.. I should have stated it runs, then I shut it off, won't restart, has to wait for IAT to "cool" down.

I reset the ecu and the codes that came up IMMEDIATELY today were..
p0113
p0118
p0123

Also today the temp gauge didnt work.. All sensors plugged in, cannot see any breaks in the harness...

Thank you again

 

I also probes the "D" connector at ecu as per Honda manual. Got proper voltage. Just an update

 

All of these codes point to a wiring issue. You have a wiring crossing into either the ground or to each signal wire going back to the ecu.

 

Should I start at the c115 connector?

 

Nope

 

What do you suggest then RonJ?

 

I think its best to start start from one sensor and trace the wires back to the ecu. And FYI 96 ex civics never came with an FITV.

 

Find the wiring diagram and perform both a resistance test and a voltage drop test for every wire. You can decide which sensor to start with.

 

I thought the same thing!! Well this vehicle had one. Clearly the guy before me jacked that all up. I ran test at the sensor for the TPS. All test came back to spec. I probes at the ECU for the IAT that came back to spec. Looks like it is time to trace some wires. Car ran clean today. Noticed when I moved the main barness under the Intakr, everything on my live data chaned. Went from 73deg at IAT -40 when wiggled that harness. Does ground come internal at PCM for the IAT?

 

The fact your data stream changed while shaking the wires tells you there's a wiring shaffed/broken/melted or such. Time to open up the wire loom and look for obvious signs of damage.

 

Agreed Joey. I will keep you all posted. I can access those from underneath right? I don't have to remove the intake manifold correct?

 

Post crystal clear pictures of the connectors plugged into the IAT, ECT, and TPS. The pictures should allow verification of each sensor and show the wire colors at the rear of the connector. The IAT and ECT have 2-wire connectors and the TPS has a 3-wire connector.

 

Will do tomorrow AM. @RonJ

 

 

Looks like it may be the wrong plug for the ECT sensor, though I can't see the wires clearly. Look at the diagram I posted. The plug should have Red/Wht and Grn/Blk wires.

 

You're correct @RonJ. Red/yellow Green/black. Different plug somewhere?

 

^These are the ECT connector wire colors?

 

I spy custom wiring............you better double check that...

also spy exposed wiring........

 

Yes.

 

Oh there is plenty of "custom" wiring. This car has it all.

 

Sorry RonJ I stand corrected. They are red/white green/black

 

Than you better double check for any exposed wiring, like what I'm seeing in your pictures.