Identifying Sensors - 1993 Geo Metro 3 cyl TBI 5 speed

After much questioning of people on this forum and on

http://www.teamswift.net ..... in the Geo Metro 'General
Electronics and Repairs' portion,

I was able to identify almost everything under the hood of my
1993 Geo Metro 1.0 L, 3 cylinder, TBI, 5 speed manual vehicle.

Here it is..............

Left side of engine compartment facing engine:

http://img257.imageshack.us/img257/8738/leftsidetbiandparts8xj.jpg

The MAP Sensor is on the Firewall right behind the TBI.

Right side of engine compartment facing engine:

http://img483.imageshack.us/img483/917/rightsidetbiandparts5ee.jpg

Fuel Pump Resistor:

http://img493.imageshack.us/img493/4283/fuelpumpresistor6en.jpg

More to come as I continue with this quest........

If anything here is incorrect, please let me know!

DoctorBill

The fuel pump resistor you labeled is actually the fuel Injector resistor. Also, the Idle Speed Control valve you labeled is an A/C idle adjust valve. The actual ISC Solenoid is below the plastic air shroud, and has 2 vacuum lines coming off of it, in front of the throttle cable. The vacuum line filter.. That's a dryer for the MAP sensor, which is hidden behind the wiper motor in the picture.

The fuel pump resistor you labeled is actually the fuel Injector resistor. Also, the Idle Speed Control valve you labeled is an A/C idle adjust valve. The actual ISC Solenoid is below the plastic air shroud, and has 2 vacuum lines coming off of it, in front of the throttle cable. The vacuum line filter.. That's a dryer for the MAP sensor, which is hidden behind the wiper motor in the picture.

The fuel pump resistor you labeled is actually the fuel Injector resistor.

Yes YOU are correct in actual fact, but The Chilton Manual calls it the
Fuel Pump Resistor (p6-29). Anyone reading this - please note this
fact.

...the Idle Speed Control valve you labeled is an A/C idle adjust
valve.

Someone mentioned that it is for the A/C, but hinted it does its thing
for normal idling, also. Is it in fact non-functional if the A/C is off...?

The actual ISC Solenoid is below the plastic air shroud, and has 2
vacuum lines coming off of it, in front of the throttle cable.

Are you sure of that? If you look at the second photograph, someone
told me that THAT is the EGR Modulator - or are you talking about
something else? On page 4-6 of the Chilton Manual is a diagram of a
device that looks like what I labeled the EGR-Modulator.... (???)

There is nothing else near the throttle cable - in front or beside it.

I want to get this straight!

The vacuum line filter.. That's a dryer for the MAP sensor, which is hidden behind the wiper motor in the picture.

You are quite right! I went out and checked that tube! It goes to
the MAP Sensor. These photos must be studied closely...even if one
takes them one's self!

I will modify the labeling on the photo....

DoctorBill

PS - been having trouble logging on to ImageShack.com to get to my
photographs. ???? I have to delete it and then reload the modified
one.

that white thing in the line to map sensor is a filter. and the isc solenoid is below the throttle body on the rear of the manifold by the firewall. you can't see it in the pic. its almost directly below the intake air temp sensor. should be a solenoid with 2 large vacuum lines and 2 wires

that white thing in the line to map sensor is a filter. and the isc solenoid
is below the throttle body on the rear of the manifold by the firewall.
you can't see it in the pic. its almost directly below the intake air
temp sensor. should be a solenoid with 2 large vacuum lines and 2
wires

Does it go electrically to the ECM?
Would it be called the "Idle Speed Control Valve" in Chilton's Manual -
with R/W and W/BL wires to it?

There is a small (approx 1 inch dia by approx 2 inch long) black
canister type thing back there with two hoses - one going into each
end *on the sides*..... I did not see any wires - but the weather and
the light is bad today, so I will check it out later.

Do they go bad? If so, I will try to find one at the local P-n-S (my
new home-away-from-home!)

I will try to photograph it.

I sure would like to get this bugger working again.

BTW - I tried to update the picture but imageshack.com has a message
saying they are fixing the 'database' and will be up tomorrow.

At that time I will fix the pix....

DoctorBill

PS - Why am I trying so hard to get this car running?
I seem obsessed with this Geo Metro!
Am I crazy!?
I NEVER have done this with any other car!
Instead of "Mental" maybe we should call it 'Metronal'...

when they go bad it will usually stick at a high idle, shouldn't keep it from starting. whats compression on your motor?

when they go bad it will usually stick at a high idle, shouldn't keep it from starting. whats compression on your motor?

Not happening.

Long story short......

CEL gave MAP Sensor code (31). Engine started dying. Had to pump
gas pedal to get power. Power faded in mid pedal. Coughing and
sputtering at stop signs. Pedal pumping to get going again.
Dying at odd times. Wait and ran for a while....

Disconnected MAP and engine ran fairly well. mpg went from 47 to 24.

Found '94 MAP Sensor and replaced mine. CEL coded OK (12).

Now won't idle or run with MAP in place - BUT...

Disconnect MAP and it runs and idles fairly well again!

Go figure!

I am putting together a plan of attack.
1. Check Timing.
2. Check Cylinder pressure.
3. Check Vacuum.
4. Check Fuel pump pressure.
5. Check TPS for readout.
6. ???????

But - it has to be electrical or the damned thing wouldn't
improve with the MAP Sensor plug off! How can it run fairly well
w/o the MAP and not at all (w/o pedal pumping) with it on?

Can't be the Fuel Pump! Nor Fuel Filter (changed it).

Something is boogering up the fuel mixture!

DoctorBill

The big one to the right side(when looking at the engine) is the EGR valve. Looks like a goofy hat. It also has vacuum lines coming off of it. The ISC solenoid is behind the throttle body. You'd pretty much have to remove the bottom air shroud to see it. The A/C idle control valve is completely shut off when the A/C is off. It will affect the idle if it's leaking. Will the car run fine if the MAP sensor is plugged in, but the vacuum hose is off of it? Your dryer could be full of water. As we all know, water doesn't compress, and could be throwing the reading off, causing a fu@#ed up mixture. Try blowing it out. Just with your mouth(yea, I know, gross). An air compressor will destroy it.

also check the ground wire that bolts to the back of the intake manifold behind or next to TB. should be 2 or 3 wires on it, if its loose or dirty can cause some of these problems. also check the ground connection behind the radiator overflow bottle. you can pull straight up to remove it

also check the ground wire that bolts to the back of the intake manifold behind or next to TB. should be 2 or 3 wires on it, if its loose or dirty can cause some of these problems. also check the ground connection behind the radiator overflow bottle. you can pull straight up to remove it


Hello, forgive me if I post incorrectly here as it is my first attempt. I have a 1993 Geo Metro which will not start. I suspect a broken harness connection somewhere, but need some advice:

No power getting to the fuel pump relay or spark to cylinders.

Diagnosis: Checked all relays and fuses and all appear good. I jump a hot 12v wire directly to the fuel pump wire (pink at FI relay) I hear the fuel pump whirl. I used a timing light to check for spark at the plugs and no spark when engine cranks. The FI relay does not "click". The adjacent relay clicks fine, so I swapped the two with same result. This is what leads me to believe there is a broken wire somewhere in the harness which provides power to the FI circuit. I did notice the oxygen sensor wire was smashed & shorted to ground, so I fixed that. Any ideas for further diagnosis?

You need to click the "NEW THREAD" button at the top of the thread menu screen and create a new thread. the first thing to check is for a broken timing belt. The easy way to do that is to take the cap off the distributor and see if the rotor is turning when cranking the motor.

also check the ground wires i mentioned above, if they are broken or bad connection it can cause same problem and take cap off and see if rotor turns while someone cranks engine over, that will tell you if timing belt if good or not

Speaking of MAP Sensors......Are you supposed to be able blow air through them? I tried on mine and nothing. My car seems to run better with it plugged in though.

MAP sensor measures vacuum.
Blowing in it will/can damage it...

i have a 92 geo metro .(i thought xfi)on the left looking at the engine under the air filter is what looks to be the coolant temp switch.a item with threads showing then the nut then a copper lead off the top.BUT NOTHING IS CONNECTED TO IT AND I CANT FIND THE WIRE TO IT.chiltons is no help.i asked another site they said if im gettting 48 mpg go to the frigde and drink a beer..well i need to find this all out . did full tune up and all cylanders at 195 psi (cherry).i had thought i might have a replaced engine other than a xfi. not sure yet.http://s675.photobucket.com/albums/vv112/dags123/?action=view&current=100_0722.jpg
try this link if it JUST brings you to photo bucket look at the top of the page if it says dags123. or search,,, dags123 ... PLEASE ..clik it it should bring you to the home page its the first 3 pix as seen the air filter top right.looks like it s in the left side of the throtle body.. so i need to find the wire. and or were it ends up incase its broken off some how.. pictures will help ..i tried to upload 2 pix at less than 100 kb. but cant. thank you for your time

That's a coolant temperature sensor for air conditioning. Most cars have it, only A/C cars have it connected.

on the title of the thread it should say92 ge metro ""XFI"" not tbi lol...
thank you for your reply so much. i asked this in another forum and was told dont worry about it get a beer.lol. any how now the big question as i thought the same thing.(coolant sensor)
a xfi never had ac sssoooo ,could it be said this is not a xfi..i had questioned wether i had a swaped engine because i had 195 psi on all cylenders.(cherry)i did compression tests on like 10 cars this month to finally choose this one.did full tune up . has alot better power now but my best 100% highway is only 48 mpg far from xfi mpg i thought id get..do i need to do that rolling test to test gearing(engine makes 2 full revolutions an d after marking the tires the tires should go areoun almost but not a full revolution) i thinki gotthat right
or can i check id on the engine block number.(what numbers do i look for)

thank you alot for your reply. your further insight is greatly antisipated..have a GREAT day ,,,,,,,,,,,,,,bill

It's very possible that XFIs had that sensor too, sometimes it's cheaper to just build them all the same even if a couple of parts aren't going to be used in that particular car. My XFI got 52 mpg with the timing advanced, 35 psi in the tires, and a lot of highway in the mix. 48 isn't far off from that when you consider that every car, driver, and road is different. A lot of people you see quoting mileage are running dangerous air pressures and unrealistic driving practices like pulse and glide or 50 mph. 48 is far above what any car available today will do, not bad with an 18 year old car.