The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support STM Tuned

2G Voltage Drop on Pin 81

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Danny_Mitch

Probationary Member
4
0
Oct 31, 2020
Modesto, California
Once I plug in the MAP sensor, voltage from pin 81 on the ECU will drop from 4.97v to 4.30v and the MAF and TPS will read that same voltage since they are also connected to pin 81.

If I leave the MAP sensor unplugged, the TPS and MAF will get 4.97v from the harness. This affects the TPS a lot because when the map is plugged in the TPS voltage can't go higher than 78%, but if the MAP is unplugged it will reach 98% at fully open.

I've checked the splices for the sensor grounds that come from pin 92 and they're in perfect condition.

I've been dealing with this for too long and can't seem to find an answer. The only thing i can think about doing next is locating the splice from pin 81 that goes to MAF, TPS, and MAP sensors in order to determine the issue.

Any suggestion on how to diagnose this would be much appreciated. The car is basically stock aside from a 16g turbo, FMIC, wideband and DSMlink v3.
 
Last edited by a moderator:
Do you have an after market MAP sensor or are you talking about the MDP sensor on the intake manifold?

If remember right 2G have the normal barometric pressure sensor in the MAF and a MDP sensor on the intake but no MAP sensor stock.

If the sensor is pulling the ECU +5v sensor line down it might just be bad.
 
Do you have an after market MAP sensor or are you talking about the MDP sensor on the intake manifold?

If remember right 2G have the normal barometric pressure sensor in the MAF and a MDP sensor on the intake but no MAP sensor stock.

If the sensor is pulling the ECU +5v sensor line down it might just be bad.
Sorry it is the stock MDP on the intake manifold. Is there a way to test if the MDP is bad?
 
Not really other than swap it with a known good one. Suspect you either have a bad one (most likely) or someone wired it in wrong. If it's pin 2 (black wire) and pin 3 (green-yellow) are reversed that could cause a voltage drop (but wiring it in wrong is unlikely unless someone wired in their own connector wrong).
 
Is there a way to test if the MDP is bad?

You must be logged in to view this image or video.
You must be logged in to view this image or video.
 
I forgot to reply, but thank you for the info the MDP sensor was bad and i replaced it with omni 4 bar so i can run speed density.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top