I get 6mpg. Car runs rich, really rich. 43psi fuel pressure.
SES light isn't functioning at the moment, put in a new IAC, new TPS doesn't act right so I am using the old one, car idles at 1K, car drives very fast, has a surging effect if I have the throttle at a certian position when trying to maintain a slow speed, like 25mph.

I have 2 computers, both run the same in my car, 4 different proms ran pretty much the same.

I put one of my computers in a friends car with an SLP Prom I have and her car ran pretty good, didn't seem to have any problems. Didn't want to put her ECM in my car for fear that my car might damage her ECM.

Any help is appreciated, going broke putting $10+ each day in gas and getting only 50 or so miles from it.

 

Zepher,

The MAP sensor can be checked with a vacuum source and a digital voltmeter. The sensor should output a 0-5VDC signal at the 'B' terminal. The output voltage is based on absolute pressure at the hose connection. The sensor should output full voltage (5.0VDC) when there is one BAR (barometer, or atmosphere) of pressure applied. This means there is basically no vacuum (0" Hg) and the Absolute Pressure is at 14.7 PSIA.

When the Absolute Pressure decreases (due to vacuum) the voltage output on the 'B' terminal should decrease as well. Test the sensor down to about 20" Hg of vacuum, or 0.33 BAR (4.9 PSIA), where the output voltage should be aroud 0.8-1.2 VDC. The voltage should vary in direct proportion to the Absolute Pressure, or amount of vacuum applied. If the MAP output "jumps" or "sticks" at a given point, the sensor bridge circuit or the mechanical diaphragm is failing. Since there is no good way to repair a MAP sensor, replacement would be your only option.

Of course, the hose connecting the sensor to the intake manifold needs to be intact, free from cracks, leaks, splits, or kinks. The electrical connector needs to be clean and tightly seated.

 

Thanks.

So how do I go about testing the MAP sensor when it's off of the car? Or do I leave it on the car with the ignition on and have a vacuum source attached to it with my voltmeter stuck into the terminals of the connector that is plugged into the MAP?

Thanks again.

 

Zephyr,

The easiest way is to reconnect the sensor to the car's wiring harness and vacuum line. Back-probe the connector and test the voltages.

 

From watching your video it sounds like you're running a really lumpy cam. What are the specs on it? I'm going to go out on a limb here and say you're going to need some custom prom work. Problem with a lumpy cam is the ecm senses the vacuum pulse from each cylinder instead of reacting to the engine as a whole. What were the 4 different proms you've tried?

 

You'll just be guessing and throwing money at it if you replace the MAP sensor. Even if it's bad, it still won't make up for the fact that you need a scanner on it and chip work to get it dialed in. I'd recomend getting a scanner on it ASAP and going from there. Then you will straight up KNOW what is wrong...

 

Cam specs are 272/284 Advertised and .454/.480 @ 112 LSA.
Crane Cams PowerMax 2050.
The 4 proms were stock burns, 350 A4, 305 A4, 350 5 speed, 305 5 speed.

The only settings I changed with the chips were, 19lbs injectors on the 350 chips, and Manual settings for the Auto chips.
I did turn off the VSS, EGR, and VATS on all the chips.

I am going to wire up the VSS to the ECM as well as hook up an SES light and the ALDL and have my friend bring his scanner by again. Last time with the old ECM we couldn't get any data, Scanner said "No Connection", so we were thinking the Serial Data Port on the ECM was bad, which is common from what I've heard.

Oh, I did get a new MAF Sensor today. One of my friends works at a Firestone Service Center and the Service Manager gave me a warranty replacement on mine since it was an AC Delco unit.
Still runs the same with the new MAP sensor.

Thanks for all the tips.

 

How does it idle? Not to alarm you, but my IROC got like 6 mpg after a fuel injector started leaking. To make a long story short- it now has a 350 going in it, one year later.

BTW: I want to see pics of your car after it's painted. Looks just like I want mine to (except I'm keeping the '84 powerbulge hood). Send me some when you do!!!

 

Idles at 1K. Idle is pretty smooth. Just kinda high.
Car has a lot of power, just runs rich and blows smoke out the tailpipes when I get on it.