Hi guys, like the tittle says, bought a new ECU to resolve my MAP sensor issue, now the problem persist but with the new ECU when disconnect the MAP plug the CEL not come on.

With any other sensor disconnected the CEL pop on, less the MAP. With the old one all works as it should.

The ECU still in warranty, This sound like a defective ECU? Should I return it for exchange?

Thanks

 

1 isn't your car turbo'd 2 thought you had a s300/RTP 3:where was this ecu from

4:at least post info regarding the car for all I know it's a got a rotary in it.

 

Yes, Turbo and EcTune. The ECU is from Advancedignition in AZ.

No haha. No Rotary

LS VTEC 81mm SRP 9.0:1 darton sleeves, Eagle rods.
b16 head P/P, Supertech springs, valves and retainers
P06 VTEC EcTune
850cc injectors, walbro 255lph, AEM FPR
SC34E
Dyno Tuned.

The car shut down when disconnect the Map but no CEL, if disconnect any other sensor the CEL pop on immediately and can retrieve the code.

 

They probably disabled the CEL?

 

He said the CEL will come on with any other sensors disconnected. So no disabled CEL.

 

I only bought the ECU from them, the ectune license, program and ostrich still the same I have before in the other ECU. No CEL disabled.

We also try with crome pro, that is what I use before and no luck!!

RonJ@HT, help me in other thread to check all voltages and continuity and apparently all is fine with the car. The guy from AI, have no problem with change the ECU but he is 100% she test fine in his car before send it.

 

To say the true I don't give a sh** the CEL.

The problem is with both ECU's, I have low voltage in the red/green wire at MAP plug.

With the switch ONII using SG1 as ground I have 3.52v at RED/green, When it should be 5.0v.

Any advice I will try it.

 

Was your voltage test at the ecu or sensor plug?

Did you try using either chassis or the battery negative for a ground instead of SG1?

Have you done a resistance reading on both the red/grn and grn/wht from the sensor plug to the ecu?

If you're getting the same results with a second ecu I would suspect the wiring.

 

At sensor plug with engine ground:

Yel/Red = 5.0v
green/white=00.1v
red/green=3.52v

At sensor plug using SG1 as ground

yel/red=4.99v
red/green=3.52v

At ECU plug D MAP disconnected using SG1 as ground:

D19 yel/red= 4.99v
D17 red/green =3.52v

This is the thread where RonJ@ht help me:

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/map-voltage-problem-3196749/

 

I didn't look at your link to your other thread but I will.

Based on what you just posted as far as voltages...I think the problem is in your ecu jumper harness.

Your volatage referance (red/grn) and signal (yel/red) are backwards.

Double check me on this. On the OBD2A side, you should have red/grn (D3) going to D17 on the OBD1 side. Yel/red (D4) should be going to D19.

It sounds like you have D3 to D19 and D4 to D17.

Keep in mind OBD1 and OBD2 pin numbering is different.

12345
6789


13579
2468

 

You are right in the pins, but they are installed correct.

D3 = map signal
D4 = vcc1 sensor voltage

D17 = map signal
D19 = vcc1 sensor voltage

d3 + d17 = 3.52v
d4 + d19 = 4.99v

The funny thing is, this start suddenly like a TPS fail and getting worse to the point, I can't drive the car. And this car is build since 2010 nothing was touched.

 

If your engine harness to jumper harness to ecu pins are correct I'm confussed.

The voltage you're getting on the yel/red would be what you should be seeing on the red/grn, 5V referance voltage.

The voltage you're getting on the red/grn is what you should be seeing on the yel/red with the key on engine off. Signal votltage at atmosphere should be approxamitly 3.5V, but you said you get that on the wrong wire with the MAP unplugged which should read 0V on the yel/red.

Have you tried another known working MAP sensor? For testing purposes a stock one would be fine. From your earlier post stating unpluging the MAP and not throwing a code is still suspect in my mind to wiring.

Do you have a stock, unchipped ECU you can use for tesitng the circuit as well?

 

Yes, I have stock MAP. Need to borrow a ECU. I post the results later.

Check this, it's what I follow for voltages and test:

https://honda-tech.com/attachment.ph...1&d=1395634763

 

According to this FSM test, You need to have 5.0v at both sides of the plug with the switch ONII plug disconnected.

 

nub, What voltage need to reach:

A25 and B1

This two are ECU power, I get 11.88v this is right? or should be +12v.

Battery voltage engine off is 12.36v.

 

With the test you listed the 5V on both sides of the plug is based on using a factory test harness (07LAJ-PT3010A). Are you using this factory test harness? If not forget about that test.

SG1 is the sensors ground.
VCC1 is the 5V input from the ecu to the sensor.
MAP or PB is the output from the sensor to the ecu. The voltage varies with the change from atmosphere to the amount of vacuum from 3.5V to .5V


A25 and B1 should be battery voltage or within a couple hundreths.