Jaiyurai

iTrader: (30)

So the dilemma is still here..

I have a E6X on a 13BRE FC. The ECU does not have a internal map sensor.

I've tried 4 different map sensors and another E6X ECU. I was almost sure the harness was the culprit, so I went and ordered a new terminated harness.

I braided, heatshrinked, loomed it and installed it. Hoping it would be fixed, its still doing the same thing.

I've tried 3 different GM 3bar map sensors and 1 GM 1bar map sensor. All reading differently. But none change readings during cranking and idle. Because the readings won't change, it's causing my timing to be screwy and dumping fuel.

I tried plugging in another E6X ECU from another running car and the same readings showed. Nothing changed.

I am getting 5 volts in the power wire, but the signal wire is getting 2.4 volts. I've checked all the connectors and rechecked the wiring harness.

Anything advice would help. The car is done, but this haltech problem is probably the only thing keeping me from bringing it to Sevenstock.

Thanks guys.

- Kevin

RETed

Last ditch option...
Try the zero throttle map function?


-Ted

C. Ludwig

iTrader: (27)

Have you actually applied vacuum and pressure to any of those sensors with a pump to check if they are reading when not hooked to the engine? Possible you have the vacuum line run to a nipple on the manifold that's blocked off and not receiving a signal?

After using two ECU. two wiring harnesses, and countless MAP sensors I doubt it's a Haltech problem.

Claudio RX-7

iTrader: (1)

Ludwig is right, are you 100% sure the nipple you are using has vaccum at all? try a different one, like the ones on the back of primary runners of the manifold, and not the ones on the sides of the throttle body.

Because 2 harness, 5 sensors, and 2 ECUs cant possibly be sharing the same problem.

Heck, with the power on, and any map sensor connected, grab the hose and suck on it with your mouth, it should change the reading a little bit.

Jaiyurai

iTrader: (30)

I tested each of the map sensors with a vacuum pump and none of them change on the haltech window.

Yes, I have tried different nipples on the back of the manifold. And none change.

What I don't understand is why the signal wire is getting 2.4 volts on a voltmeter. Is that correct?

Here's what each MAP sensor reads out.
Sensor #1 (3bar map, came with kit) - -14.6psi
Sensor #2 (3bar map, bought new) - +5.4psi
Sensor #3 (3bar map, borrowed from friend's FD) - +26.6psi
Sensor #4 (1bar map, bought from Autozone) - -0.5psi

Now these readings don't change at all during key on, cranking, and idle.

Claudio RX-7

iTrader: (1)

What do you mean with these readings? each map sensor reads differently? Also, map sensor values at cranking and key on engine off shouldnt change that much. But at idle they should be around -7 to -5psi, also tell me something, can you actually start the engine and it will run? I have the feeling that you have a massive vaccuum leak that is preventing any accurate readings on the map sensor, have you checked for that? Also, did you switch ECUs? or even try your ECU on another car? Did you also change the harness?

I would take your ECU and map sensors and try them on another car all together that you know works fine. If the ECU and MAP sensors work perfectly, im thinking that your problem is engine hardware.

Jaiyurai

iTrader: (30)

Those readings are from each MAP sensor that I tried on the car. They all read differently. They stay the same when key is ON, during cranking, and when the car idles.

Yes, I can get the car to run. But it idles rough and the MAP sensor readings are throwing off the timing advance and fuel.

Yes, I have tried my ECU on another car. The other car started up perfectly and ECU worked normally.

I have checked for vacuum leaks. I've sealed everything.

I bought a brand new harness and installed it because the one I bought with the used kit looked poor and fishy.

What exactly in engine hardware could do that? Here are the specs of my car:
1989 Turbo TII
13BRE 2rotor Cosmo running 91 octance and 2-stroke oil
Vmount Intercooler with a hybrid S5 turbo
stock TII igniter coils
no emissions, no p/s, no a/c
block plates on everything

So what engine hardware could be the problem? And I'm still wondering why the signal wire to the MAP sensor is getting 2.4 volts.

YayeR

Are you 110% sure your block-off plates are sealed? If you don't have any, put some RTV where the plates touch the manifolds.


As far as the signal voltage, how are you checking? Are you stabbing the wire with the connector hooked up, or what's your method?

Jaiyurai

iTrader: (30)

I checked the block off plates twice already. i'll do it again tomorrow for a third.

for the signal voltage. I'm removing the connector from the MAP sensor and using a voltmeter to check continuity and voltage. The 5v is reading correctly, ground wire is good, but the signal wire receives 2.4 volts when unplugged from the MAP sensor.

RETed

What you just said doesn't make sense.
The MAP sensor is a pressure transducer.
It needs to be powered (i.e. +5VDC) and ground for it to output a valid signal.
It sounds like the wires are crossed in the harness?

Try and verify the wires from the MAP sensor run back to the correct pins off the Haltech?


-Ted

C. Ludwig

iTrader: (27)

Seeing voltage at the signal pin when the connector is unplugged is normal and correct. There is feedback through the ECU when the sensor is unplugged. You'll see the same thing on the Spare A/D pin when it is not connected.

Have you tried resetting the setting in Main Setup? Assuming you want to use a 3 bar sensor change the load sensing to something else, say 1 bar sensor. Cycle the ignition switch to save the settings. Now go back and change load sensing back to what you want and cycle the key again. I've had issues like this where the MAP sensor decides to not read at random moments while I'm connected to the ECU using Halwin. For some reason I've never had a problem with the DOS software.

Claudio RX-7

iTrader: (1)

Yeah, ive also seen sensors or options in the software the dont reset when you change them, and required me to completely disconnect the ECU from the harness and then it worked. I would also, make sure the pins have contiunity with their corresponding wires on your harness just to be sure.

Because if your ECU and map sensors work perfectly on another car, the problem lies in your car.

Also, i always always put a thing gasket with RTV on the block off plates, this ensure vaccum free operation, and snice you have no accesories on that motor, its possible that one might have escaped you? i have seen it happen. Although a big vaccuum leak is very noticeable. But im leaning to harness issues.

YayeR

I like RETed and Claudio's idea of checking the continuity.

Unplug both the MAP sensor and the E6X plugs and test the continuity of the three wires. You may have a mix-up, or a break. It's worth a look. Confirm pin-to-pin continuity, refer to the abstract of the wiring diagram below.

Claudio RX-7

iTrader: (1)

Yeah, pin 11 on the haltech connector should have continuity with the yellow wire on the map sensor connector and nothing else, pin 18 is 5v and should be the same for the tps connector, and the black/ground wire is common for most of the other sensor grounds.

Jaiyurai

iTrader: (30)

Thanks everyone. Continuity was fine, but I did a stupid idiot mistake. The wire combination going into the MAP sensor was backwards. My mistake. The 1bar map sensor I have on the car is working fine.

But a new problem arised. When going to start the motor, I was testing the coils for spark by plugging a plug at the end of the wire to the shock tower. The trailing coils fire fine but I get nothing from the leading coils.

When I turn the key to the on position, I will get a spark from the leading wires. But during cranking, no spark. I checked the single wire going from the leading coil back to the haltech and everything seems okay. So my guess would be in the haltech program.

Any clues?

Thanks everyone!