david-b's 95 Eagle Talon ESi-T Motor Build

[ned032002]

So that may be what it stands for but what does it do in reference to performance?

[SilvrEclipse]

It reads intake manifold pressure. The ECU uses this information to know how much fuel to inject into the motor. The 4g63 uses a MAF to calculate fuel, while the 420a uses only a map sensor. Megasquirt also uses a map sensor to calculate fuel, this is what people mean when they say speed density. They get rid of the maf and only use a map sensor.

When I was asking Dave what sensor was it, I was referring to how high will it read. 2.5bar, 3bar, etc this is how these sensors are rated. 1 bar ~ 1 atmosphere = 14.7psi. So a 2.5 bar sensor is can handle 2.5*14.7=36.75psi - 1atm = 22psi. You have to subtract 1atm because of the atmosphereic pressure. So a 3 bar sensor will be good up to 29psi.

Hopefully somewhere in here was the answer you wanted Ned.

So Dave dont take that car over 22psi without upgrading the map sensor.

[vanilla gorilla]

The MAP sensor is also one of the things the ECU uses to determine timing adjustments. Wait till you have one go out and see how your car runs.

[ned032002]

I get it. Sometimes I just need knowledge spoon fed that's all.

[david-b]

Today I was hoping that the coolant leak was done with at the T-stat and I'd be able to get running better. Sadly, wasn't the case. As I pulled the car out from the garage, everything I did on Tuesday failed. FML.

Luckily, the extra T-stat housing I ordered came in today along with another package I needed for the car and it all worked out for the best. I pulled the manifold from the engine to pound in the runners. Bought a torch and heated them which helped some. Also dropped the $30 for a thread tapper thing to finally finish the 2 broken studs in the head. I had JB welded some studs in and those apparently failed. So did those right and holding very nicely now.

While it was off, was able to replace the -10an fitting that broke with a new one and take care of some other minor things that needed to be fixed.

The "Power Plant" as I called it all day. Sexy


I used some new maps and those are failing as well right now. Car idles, just badly. It's high, then low, high, low.... in the video below you can hear it pretty good. I took some logs and will be going through them and seeing what Jason thinks about them. I've been going over the car trying to eliminate all possible problems, like using new vacuum lines to MS and stuff like that.

Jason: I disconnected the IAC and it didn't help the idle any, but now when I let off the gas, the rpms drop right down to idle. I'll send the maps soon.

Video of revving. Can't hear on here but you can hear the turbo and BOV.

[SilvrEclipse]

Dave I just got a quick look at your log, your TPS signal is very rough, im guessing your not doing that with the gas and thats noise in the signal. Also your rpms are looking like their may be some noise in the signal but that could just be how bad the idle is. I would check out you TPS connection and see if you can get that better. You can change a gauge in megatune so that you can watch the TPS. It should either sit on 0% or maybe 1% but it should not be changing around while your not moving the pedal.

[david-b]

The TPS has always been like that. Even after replacing the TPS sensor itself. It sits at about 2-5% at idle. Shows 0% when motor is off, and goes to 100% fine. The SAFC showed that as well as the Palm logger. Never was able to find out why though. That's the third TPS this car has had. And there's no tension in the throttle cable. I've calibrate the TPS numerous times and even disconnected it yesterday and it ran even worse after doing that.

The rpms are up and down like I said earlier. They're not consistant and do back and forth the entire time.

[SilvrEclipse]

Im pretty sure thats your problem Dave. That TPS going up and down like that is causing the accel enrich to cut on and off, you can see it in the pulse width. Mine is just a straight line at idle. You must have noise in your signal some where. I would check all the wires at the TPS with a volt meter so see whats causing the signal to be like that. It could be the power source not being consistent or something.

If the TPS is only noisy when the car is running then its deffinately something causing noise. You may can set all of your accel enrichment to 0 and it might help for the time being, that would let you drive the car some but you cant leave it like that. Other things use the TPS and it needs to be accurate. Make sure to turn over run off also

[david-b]

Like I said that's been going on for as long as I can remember. Not sure if it did it before the TB got bored. But I don't think that would have any thing to do with it. What could be causing the noise though? Bad power wires or something? Could I just run new power wires to the TPS and try it like that as a temp fix?

[donmaton86]

Edited by Mod

[david-b]

Did some work today on the TPS sensor.

-Tried backup TPS and still got noise while motor was on
-Redid TPS wire at ECU coming from MS (possible bad connection, not the case)
-Car idles good without the TPS... but at 2200rpm
-Found ground wire and connected to new ground
-Push TB stopper out some so the butterfly wasnt resting right on TB. Calibrated TPS in MS, then pulled out the stopper so it was reading 0%, but still jumps up to 5%. Also kept dying this way.

I didn't have a chance to set the accel enrich to off... got text after I already left. I did get some more logs that I will post up. I'm really at a loss right now on what to do.

On the good side, finally got the car up to 200* and the fans turned on for the first time.

[ned032002]

So no coolant leak I'm assuming?!?

[SilvrEclipse]

Dave - The TPS and Map sensor run off of a 5v source, I would check this power wire with a volt meter while the car is on and off to see if the voltage is causing the problem. If the input voltage going into the sensor is going up and down then the output will do the same. Also test on the signal wire to see if its oscillating. If the 5v source is in fact oscillating then you could use a 5v regulator from radio shack as a temp fix for now.

I looked over your log and its still the same thing, the TPS is tripping on the accel enrichment causing the car to run rich.

[david-b]

The TPS wire was reading 4.95v when car is in ON (motor not running). Sadly, I couldnt get the voltmeter working after I did that test.

I read online that it's a common problem with the TPS and MS. I'm going to use the ground sensor wire at MS and twist that with shielded wire from the TPS pin on MS and run both to the TPS. Where can I find another 5v source be from? Is the MAP off the same 5v source as TPS or is it coming another location?

I'm going back tomorrow afternoon so need as many ideas as possible.

Also, had a mechanic check out the GA.... not the security.

[david-b]

Oh, as far as I can tell, no coolant. There was a little spot under the car when I moved it but could have been overflow or when I spilled some.