Title is self explanatory, D16Y8 inside 93 del sol. I was having issues with low power and the engine surging under medium to heavy throttle. So I sent the P28 ecu out to get chipped and pinned, that comes back but the issue remains. Jump forward to me testing the MAP and TPS sensors to find that instead of the 5ish volts they should be getting, I only get readings of maybe 0.004 volts instead.

I checked all wires on each sensor and even went back to the pins at the ECU and tested them but still got the same extremely low voltage.
Anyone have thoughts on either why the engine is hesitating or to why the voltage readings are so off.
Anything is appreciated

 

You need a new ECU.

 

Who modified your ECU ???

 

H-A motorsports, shipped it out and had them do it, it was struggling before and I thought that might be a fix. I went to start it this morning and now it just cranks with no start

 

try a known working ecu.

 

4 options:
0.004V on MAP and TPS: (listed in order of probability)

1) you are testing the voltage incorrectly (where is the negative terminal of the meter? how are you gaining access to the pin? is the key on when you do the check? are you checking the correct pin?.... it's a long list of things I've done)
2) thermostat ground is very bad or disconnected
3) your ECU is cooked
4) sensors are both cooked (VERY unlikely to happen at the same time unless something happened to have caused it)

 

I tried testing the connections each way, back- testing, alligator clips and even splicing into the wires. At first I checked the ones which were supposed to be 5 volts but got nothing so i tested each one and same result.
Problem is I don't have another P28 or obd1 ecu, i have a P2P from a 2000 civic dx and don't have any friends either with one.
I will check the thermostat so thank you for saying that
The ECU originally had some kind of salt looking corrosion on one or two edges but not the board its self, cleaned most of it before sending the ECU out but now there is some inside floating around so I will give that a cleaning
I have spare MAP sensors from another D series and it gives me the same result, the 0.004 volts is regardless of the sensor being plugged in or not.

 

you do realize you're not telling us what wire you're testing on the map and tps plug right? Did you check the ecu pin that supplies the 5v?

 

The 5 volt sensor power bus (yellow-blue wire) may be shorted to ground. This 5 volts also goes to the IAT and ECT.

 

The map sensor has its own 5V bus, should be yellow/red. Check that one too. I’m leaning taped damaged ecu on this one.