jkostac

Trying to diagnose an electrical problem and really can't get to the bottom of it without wire colors, connector locations and pinouts. I'm trying to teach (or show up) my son and failing miserably. I found the Dropbox service manual, but that only has body electricals.

El_Cheapo

So what is the problem that you're trying to fix so we can get you the right diagrams?

jkostac

2007 TL-S, 215K miles, front head was swapped and remachined by a reputable local shop. Compression with 5-10 psi between cylinders 4, 5, and 6, similar to cylinders 1-3.
Was running strong for 3 months, better than it ever has. Out of the blue with no symptoms:

Starts bogging down and sputtering when pressing accelerator, gas smell and smoking at the exhaust, gas smell in oil.
Checked spark plugs: plugs 4-6 wet, plugs 1-3 dry
Coils 4-6 verified with test lights and swapped with other cylinders.
Front cam is in proper time
Permanent DTCs:
--P0113 IAT high voltage
--P0108 MAP high voltage
Temp DTCs:
--Random and specific misfires
Isolated sensor grounds were verified back to ECU (green/yel wire)
Just bought a Picoscope, need to learn how to use it.

peter6

For the engine controls, take a look at (probably best idea to download it and view it then):
https://mega.nz/file/I1g0SLZR#wXh1b4...n7WHCtMoCmNFfc

jkostac

My son has shifted to “parts canon” mode. He replaced the IAT and MAP sensor, no change, ECU is next.

Is there any benefit to using a 2008 ECU on a 2007?
OE ECU PN is 37820-RDB-A53, he bought it with a 37820-RDB-A55 in it, and the 2008 has a PN of 37820-RDB-A61.

zeta

iTrader: (1)

I'm thinking he cannot use the 2008 37820-RDB-A61 ecu in the 07 TL-S.

If you check the 'Vehicle Fitment' tab on the links below for each year & ecu p/n they are individually specific to each other.

37820-RDB-A55 Genuine Acura Engine Control Module (acurapartswarehouse.com)


37820-RDB-A62 Genuine Acura Engine Computer Control Module Unit (acurapartswarehouse.com)

Score one for the parts cannon!

jkostac

Thanks for the info. I do remember seeing the suffix change from the 2007 to 2008 ECU but I was wondering if there was any functional changes, or was it just a rev control, OEM-manufacturing, best practices type of thing. Does Honda do a rev bump for every new model year? Sometimes firmware revisions bump the overall assembly rev., depends on the company.

peter6

Did you check voltages and grounds at the sensor connectors and signals at the ECM connector?

If you're throwing ecu at the car, it wouldn't hurt to open up the old one and check for moisture damage.
Might also try to reflow (flux + melt the solder) on the ECM connector pins.

jkostac

No moisture damage and through-hole pins are solid. Honda makes a good circuit board, class 3 solder joints, conformal coating (which I prefer over silicone potting)

I have an Autel that can do real-time monitoring of the sensors. IAT and MAP looked good before and after new sensors.

Woman at the salvage yard seemed quite knowledgeable about Hondas and Acuras.
She suggested I check the internal fuse box for issues, which I did, regretfully. Almost zero slack on the wire harnesses, but I did get it out and opened it up on the kitchen table. NPF.
Side note, I see why Tesla wants to simplify automotive electrical systems and switch to 48V. Why wasn't this done sooner?

jkostac

Enough with the parts canon. I don't think it's flooding, I think it's oil.

When rev the engine after swapping ECU

With camera in spark plug hole, cylinder 6 with what looks like oil dripping down from the head

Cylinder 5, similar

jkostac

And cylinder 4 after I got it to move down a bit.


so now the question is, what would cause oil leaks into all three cylinders of a freshly rebuilt head?

El_Cheapo

This thread is all over the place. 🤷