iluvmy3rdgen

I have been trying to search why my car won't start put I think I got myself into a jam. Over the winter I went non-sequential and simplified my engine harness and now my car won't start. I don't know where to start, it's getting fuel and I'm almost 100% that it's getting spark. Please help name some things I can do to see why my car isn't starting.

Mr rx-7 tt

iTrader: (5)

You guys that don't list your location (where you live) make a mistake. There may be someone in your area that can help you with rotary knowledge and experience.

iluvmy3rdgen

10992, which is washingtonville, ny.

I'm gonna go ahead and try a compression test tomorrow hopefulyl everything turns out for the best, and I'm gonna try and unflood it again. BTW the Power FC is reading 4.98-4.99 for all the sensors in sensor checks, I don't know if this is normal or not. The car is grounded very well I'm just stumped.

Lawyer

5 volts is Vref, so I would say that is good, with KOEO.

RotorJoe

This is why your car is flooding. If the PIM voltage is 4.98 it pins the map sensor and the car ECU thinks you're at full boost at start and idle. One way to check that is turn the key to the on position and look at the boost under the monitor section of the comander. If it reads 1.2 then (or what ever map sensor you have) that's no good.

Did you mess with any of the connectors on the ECU side inside the car?

iluvmy3rdgen

I had the ecu unplugged from the car for a few months then plugged it back in. I finally got it started with some carb and choke and i was able to have my foot 50% throttle and keep it at 1k rpm. The air and water temp readings on the power fc read ----- so I think that may be the problem. I tried unplugging the ISC and nothing changes. What Should I look at next.


I replaced plugs, checked compression, checked for vacumn leaks. Is there anyway my pfc lost it's memory. The tps sensor seems to be off my about half. At full throttle it only revs to 4 grand at most with no power.

iluvmy3rdgen

bump

RotorJoe

The PFC will highlight the sensor when the circuit is open. You need to track down each sensor that is highlighted. OHM through from the ECU to the sensor connectors and find where the disconnect is. The Z section of the manual is a life saver.

This is exactly what I went through when PIM was reading 4.98 volts for me.
When I disconnected my S-AFC, I just unplugged it at the harness, not knowing at the time that it was tied into the boost sensor, PIM then read 4.98 volts. I was able to get the car started however I had to damn near floor it to keep it running. Can we say smoke show? Only then did I see that I was at full boost in the ECU's eyes.

I don’t think it’s your TPS but check it anyways.
No the PFC did not forget a thing. It knows all still.

When I pulled my engine one of my buddies disconnected the ECU and all the harnesses in the drivers compartment. I was not able to get my car started (no spark) and my fuel temp sensor was highlighted. My spark problem was a connector in the engine side but the fuel temp sensor was new. It turned out I didn’t have a connector seated all the way and it was not making a connection. Once I pushed on it and hear a click, I went back and checked the fuel temp sensor. Fuel temp was not highlighted. The car fired right up like it used to, new motor and all.

Long story short, check all connections. Make sure you have them all connected and seated well. If all good then, then start OHMing through the entire harness. Again the Z section in the 3rd gen manual is a must (wiring diagram). Some signals go through a few connectors.

Also double check your simplification of the engine harness, make sure it is correct. I haven’t done this (although it had been done to my car) so I am not much help there. That's why I didn't want to replace my harness, I thought it would open a whole new can of worms.

What other sensors are highlighted or abnormal with the key in the on position?

Sorry for the long response.
Good Luck.

iluvmy3rdgen

Yeah If I get it started sometimes it smokes like hell and boost is reading 1.2 with key on. The highighted sensors are:

PIM
VTA1
VMOP
WTRT
AIRT
FUEL

RotorJoe

You're going to have to start tracking those down.
I did an ok (so so) write up in the PFC section to track down the fuel temp sensor (FUEL)

PIM is your boost sensor. It comes to one wire on the ECU, I don't remember off the top of my head which one though.

VTA1 is the TPS. I forget if that is narrow or wide though. You may want to bring that back into spec. from the manual. One should read around 1.7ish (volts) and the other should read .6ish (volts). These numbers are in the manual so don't quote me.

VMOP is your oil metering pump. This should read 2.somthing volts ish and rise with RPM and load. Again don't quote me on the number.

WTRT is the water temp sensor on the back of the T stat location. Green connector. This one and the fuel temp connector could be reversed. But I doubt it due to the fact that they both are highlighted and reading almost 5 volts.

AIRT is the blue connector on the UIM underneath.

I think you have a harness not making a connection somewhere. You need to start checking for continuity between those sensors and the ECU. As you start to back track you will find the disconnect.

iluvmy3rdgen

I checked the wire going from the water temp sensor to the ecu and it's getting low resistance. So that wire is good but I haven't checked the other one yet
could a bad ground or bad power wire cause all these sensors to be fubar'ed?

iluvmy3rdgen

I checked continuity between the water thermosensor and the ecu and it's fine so my question is if there is a bad ground or no power would it cause all these sensors to malfunction? I'm checking the wiring diagram and it seems to all point to br/b and br/w wires.

iluvmy3rdgen

Ok, today I checked the engine harness and all the wires and sensors and they are good, no breaks or shorts. Can a bad ground or power wire do this?

Derex'7

iTrader: (16)

haha bump in this guys question I'm in the same exact boat right now going to recheck and backprobe the ecu connectors but could a faulty ground or port power wire be the culprit?