got it home now need help with codes, black smoke

[old_blue]

As I mentioned before I just picked up my 88 a few days ago and it had a surging problem and didnt run well. It would blow black smoke like crazy on take off in first gear.

I knew it was probably a vacuum leak and could hear a slight whistle. I pulled the upper intake and found the lines to the MAP/BAP and charcoal canister were done. Put it all back together and no surging and it pulls hard through the RPMS. but....

When I get on it in first gear I see a puff of black smoke out of the exhaust. I pulled the codes and this is what I got.

engine off-
22 and
either 1 and 22 or 122.... there was a slight pause after the one which felt longer the in between the 22

engine on-
4

Now I know per jrichkers guidelines there is no vehicle that has both 2 and 3 digit codes but I did this several times and that is what I got.

22-MAP (vacuum) or BARO signal out of range - MAP ---- replaced MAP...vacuum lines hooked up correctly-- no change in code.

122-TP low (possibly grounded or open circuit) - TPS ---- now this one I cant figure out. It is a speed density car and I dont know how to adjust the TPS.

I am wondering if fixing one will delete the other. I took the negative terminal off the battery to reset the system for an hour. then I hooked it back up and ran the motor for a few minutes. turned it off and I still got the same codes.

I dont see 1 or 4 in the code book or a 10 or 40 so I dont know what these codes are. hop jrichker can step in and assist.

thanks Jon

 

[jrichker]

Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is pretty much the same sensor for both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the atmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury - dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it. There a very few DVM with a price tag under $40 that will measure frequency, but there are some out there.

The MAP/BARO sensor is mounted on the firewall behind the upper manifold.

Baro or MAP test using frequency meter - run the test key on engine off. The noise from the ignition system will likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the MAP/BAP to reduce the jitter in the meter's readout.

If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer

Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery cable. It should be less than 1.5 ohm.

The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.

 

[old_blue]

dvm= digital volt meter?

Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery cable. It should be less than 1.5 ohm.

So I unhook my sensors and check the wires to each connection???
example- hook red wire from voltmeter to black/white of egr, then the black wire of the voltmeter to the black/white wire on the negative battery terminal??


my tps has a black and looks like purple strip/ then there is a orange and then green wire.

 

[old_blue]

Also I just read that I need to run the car for 10 minutes after reseting the computer but the codes should still be gone after taking the battery off for 5+ minutes?

any advice on the other codes? or should they not be there?

 

[old_blue]

not sure if I have the volt meter setup correctly but it starts out at 1ohm. then when I make any of the above connections the will start to drop to 0ohm

not sure if I am doing it correctly though

jrichker, you may have to walk me through this a little more. what should I have the dial turned to on my DVM?? I have the black wire on the Com. and the red wire on the omega sign. anything else I should be doing?

 

[jrichker]

Disconnect both sensors from the chassis side wiring harness..

Key off engine off.
Set DVM or meter to Low Ohms and short the red lead to the black lead by pressing the probe tips together. Note the reading, it should be 1 ohm or less. If it isn't replace the batteries in the DVM or meter.
Leave the DVM or meter set to low Ohms.
Stick the tip on the red lead into the TPS chassis side connector that is connected to the black/white wire.
Stick the tip on the red lead into the MAP chassis side connector that is connected to the black/white wire.

Note that it really doesn't matter which test lead goes to the black/white wire on the MAP or TPS

Check the resistance between the black/white wire on the TPS and MAP chassis side connectors. It should be no more that 1 ohm higher than the reading you got by shorting the probe tips together. If it is, you have wiring problems or a bad connection.

Disconnect the battery negative lead from the battery.
Connect either test lead to the disconnected battery cable. It should be no more that 1.5 ohm higher than the reading you got by shorting the probe tips together. If it is, you have wiring problems or a bad connection.

Reconnect the battery negative cable to the battery.

Key ON, engine not running.
Measure the voltage on the orange/white wire on the TPS and MAP chassis side connectors. Use the black/white wire as a ground. You should see +5 volts +/- .5 volt. No +5 volts and you have wiring or computer problems.

Reconnect both sensors to the chassis side wiring harness.

 

[old_blue]

My dvm starts at 1 ohm. then when I connect it to the black and white wire it will drop to 0 ohms. same thing when I touch the two probes together.

 

[old_blue]

key on test I get about 9 volts

 

[jrichker]

key on test I get about 9 volts

Stack 3 new flashlight batteries top to bottom, positive to negative. Measure the voltage of the stack of batteries. That stack should read 4.5-4.75 volts. If it doesn't you DVM is flakey.

If the DVM checks out good, then the 9 volts means your computer is probably flakey if you made the test reading correctly. The +5 volts is from the power supply circuit inside the computer. Jack that up to 9 volts and all kinds of strange things could happen.

 

[old_blue]

hmm it is a multimeter I picked up from homedepot. I dont use one often enough to know what I am doing with it. I may have it set incorrectly.

is the 0 ohms good for the black and white wires? I know you said under .5 but didnt say how far under LOL.

It does run alittle rich still and a little black smoke when I get on it in first gear. passed emissions today though.

ok I did the battery thing and it came it was 4.7v like you said. I did the key orange wire and it was 4.9-5.0 depending on whether I could hold the wires still long enough.

could this mean just a bad tps sensor then???
I really appreicate all the help, just alittle slow on the wire department.

 

[jrichker]

Since your car is an 88, I will assume that it is not a mass air car or mass air conversion. If it has mass air, the map/baro sensor vents to the open air. All speed density cars connect the map/baro sensor to the intake manifold vacuum.

The code 22 is probably a bad sensor. Time for a trip to the auto parts or junkyard if all the voltage & resistance readings check out.

The code 122 is a code 1 and a code 22 run together.

 

[old_blue]

gotcha, thanks. I replaced the bap already. should i replace the TPS too?

 

[jrichker]

gotcha, thanks. I replaced the bap already. should i replace the TPS too?

There are no computers that have the 2 digit codes and the 3 digit codes in the same unit. The code 122 was a misread and does not point to the TPS as being a problem. You will probably want to dump the codes again and see what you get.

 

[old_blue]

gotcha.

did you ever post pics of your new ride??? I didnt see them if you did.