I'm having a little grounding issue....

My map sensor(hondata 4 bar) is reading 4psi at idle(obviously wrong) so my motor is running extremely rich.

Thought it was an easy fix so i chased the map sensor wires....everything good.

So after pulling all my hair out I pulled my harness out and removed every butt connector and replaced with solder and heat shrink and ran all the sensor ground wires EXCLUSIVELY to the thermostat ground no more piggy-backing.

Checked main relay grounds...all good.

When I turn the ignition off the oil pressure idiot light stays on lightly as well as the ECU

I relocated my battery to the back so my tranny is not grounded directly to the battery, but it is grounded to the chasis(not sure if that is an issue)

EG Chassis
H22 motor
Hondata

I just need other perspectives to throw some ideas at me.
Let me know what extra details you might need to get a better idea of what I've got going on.

Thanks!

 

Sounds like some place in the harness it has a double loop for some reason , if the car has a double loop then a sensor is the most sound to mind problem , next to a fuse!

If the hondata is ok and not burnt then this is a simple fix, first start with the basic ecu error code puller in the program! See what you can diagnose, then shut off any broken or un-needed sensor and open close loop! Check again! If not then check your injector sizing and map valtage percentage see if they rise up and down like a short or open end !

That's all I can see if u re did all grounds! Hope all go's well

 

actually i have not checked if it was in open or closed loop thanks!

yea I think ill pull the harness back out and make sure the map sensor wires are ran exclusively to the ecu.

are those hondata ecu socket testers specifically for pre-installation or can i check my ecu at any given time.

 

Test the ignition switch.

 

great idea! ^
do you think easiest way would be to just separate it from the mechanical portion and turn the electrical portion with a screwdriver?

 

tester only for obd-2

 

What does this even mean?

 

i think he means the hondata ecu socket tester might be for OBD-II only

 

O well it should fit the honda he bought it for, and or a jumper, im talking about the yellow and orange ones you can buy at autozone

 

You'll find a diagram for testing the ignition switch in the FAQs sticky. You may want to pull it apart and inspect the contact points.

 

ok so i traced every wire coming from the ecu.(tons of fun) made sure all of the main relay wires were correct. Ignition is good. Plugged everything back up and map sensor still reading 4 psi and idle, WTF! It's a hondata map with omni throttle body, so I think I'm gonna hook up the factory map with a vacuum and see if the reading is different.

Another thing I was kinda confused on was Logic Ground aka sheilded wire aka LG1.
Where exactly is that supposed to be hooked up at?
I have the sheild over the dizzy wires connected the the thermostat ground as well as the sheild wire around the ecu.

 

Using Honda Civic and Prelude ETM's for reference

 

Are you still having these^ problems?

Regarding the MAP sensor, what reference voltage is received by the MAP sensor plug and what output voltage is read with the engine off and key in ON(II)?

The ECU and main relay ground on the thermostat housing.

 

I don't know if the oil light staying on because I took my dash out and haven't hooked the gauges up, just trying to figure this map thing out first I guess.
when i get off work tommorrow I will check the ref volts for input and output on the map plug, that's pin 1 and 3 right?

I'm sorry but is this^ the answer to my LG1 question?

 

LG1 grounds on the thermostat housing.