Question about 1994 Geo Metro

6 Answers

Which sensors tell the ECU to send a pulse to the single TBI injector?

ECU and injector are both new. On startup I get a pulse to the injector to spit. After that no pulse feed line pressure is good. Compression and spark is good. Timing belt is good. Relays are good.
Last time I asked this someone got really over zealous and wanted to take my car apart and put it together in an hour. Please answer just the question

Posted by on

  • Jeff Armer Apr 12, 2015

    Do you hear the fuel pump running ? The FI relay powers the fuel pump also ,through the fuel pump relay !

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6 Answers

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  • Geo Master
  • 5,309 Answers

You want a simple answer but there is not one. The ECU looks at many things to determine what (if any) pulse is proper. Any sensor which sends no information or info outside of normal limits can prevent pulse. No info from crank/cam sensor is common issue, Bad EFI fuse or relay can do this. Bad ECU ground or other ground (Fuel rail) can do this. Many sensors can be tested with ohm meter.

Posted on Mar 27, 2015

  • 4 more comments 
  • jamguivit Mar 27, 2015

    Actually the camshaft sensor was suspect before I asked the question. I don't expect an easy answer but I do appreciate not taking my engine apart. Tested TPS ohms are in spec in the haynes manual. Not sure how to test MAP sensor besides replacing. Any ideas how to test camshaft position sensor?

  • David Harrelson
    David Harrelson Mar 27, 2015

    Using digital meter (old style unit use too mach battery) check for continuity. Cam sensors are very common failure part. Haynes manual should tell how to test MAP, but I think generally you use ohm meter and suck or blow into hose port and see if reading changes smoothly as you increase pressure (using handheld vacuum pump is better if you have one. I suspect cam sensor.

  • jamguivit Mar 27, 2015

    Haynes doesn't tell how to test and oriellys can only test ohms. Will see if I can get a vacuum pump but right now concentrating on cam sensor. Thanks for the assist

  • _-__-___-_
    _-__-___-_ Mar 28, 2015

    he wants either spoon feeding, or just a single guess. he does not want to diagnose it.. that is a give. i gave him a list and he didnt like it, so I will asnwser your quesiton, the injector is dead because the ECU has bad inputs, or the Injector is bad. or the ECU injector driver is bad. he has the G10 TBI engine, we know them very well. seems, too well for OP.

  • jamguivit Mar 28, 2015

    Cadaver you want to take my car apart and put it back together in an hour. Little over zealous or tweeking flip a coin

  • _-__-___-_
    _-__-___-_ Apr 20, 2015

    You want a simple answer but there is not one.

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  • Geo Master
  • 20,706 Answers

Http://www.aa1car.com/library/2003/us60324.htm

read how EFI works.
the how to do the tests.
or guess.
your call.

Posted on Apr 13, 2015

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  • Contributor
  • 43 Answers

What wild guessing>?
or how to fix cars.? EFI.
the answer is same on all EFI engines. !
The ECU injects based on inputs.
(this is like EFI basics 101, day 1. need Block diagram?))
the dead injector has many causes, must list them all for you.?
did a NOID light test fail? this is first test on all dead injectors , unless you have tools and can check fuel pressure.
I don't want to overload you with facts, or tests. as there are many.

The ECU cuts injector dead (noid DEAD) for (inline injector resistor blown (side show1)
CMP dead
Ignitor reads dead.
DTC errors, fix those yet?

Posted on Apr 11, 2015

  • 2 more comments 
  • Jeff Armer Apr 12, 2015

    A regular test lamp works just as good ! I started working as a tech.1984 at a chevrolet deal , have worked for cadillac,pontiac ,gmc , for thrity years !

  • dimbulb
    dimbulb Apr 14, 2015

    got 12vdc on both sides of your injector resistor block key on.

    ?

    seen here, ?

    http://www.fixkick.com/INJECTORS/the-pul...



    if not the the resistor is gone.

    or fuse "FI" is blown'

    or Main relay bad.

    if that works then the noid lamp test, is next.



    all 4 ways to do noid tests per FSM is here, and lots of DIY ways.

    http://www.fixkick.com/INJECTORS/NOID101...



    this page is for G16

    but the G10 is exactly the same but with the silly resistor block

    added just for fun.



    this post assumes, engine runs in test fuel , as stated in other posts.

    and that fuel pressure is at spec.

    the ECU cuts fuel for the following reasons. (above is other reasons.)

    1: lost 12vdc to ECU.

    2: lost cmp sensor sigs.

    3: lost tachometer signals (ignitor dead or its brown read back wire cut at C1-26 pin on ECU) or the noise filter fell off car. (dang)

    4: ECU not grounded.

    5: fuel injections are cut if the TPS signals(wrongly) at wide open throttle.



    how is this post , better? (or too tech heavy)-?



    if not clear , ask questions, can peel the onion deeper, on demand.

    good luck.

  • dimbulb
    dimbulb Apr 14, 2015

    50 years, and retired eary, at 60, you figure it out.

  • dimbulb
    dimbulb Apr 14, 2015

    Sonny!

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  • Geo Master
  • 2,963 Answers

I bet you live in a salt zone. With the age of the car you have may have connection, contact extensive corrosion problems. Check all of your connections, clean and scrape to bright metal both sides. I used electronic point/connection cleaner too. I had a serious problem with cold start.
The very difficult to get to Thermal sensor connection got this treatment. Cleared the codes,
Wala, instant start, just like new.

Posted on Mar 28, 2015

  • jamguivit Mar 28, 2015

    Seattle area so yeah. Will look at contacts

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  • Geo Master
  • 11,105 Answers

The ECM turns the injector on , check for control ! You have two wires , one is power the other is control. It depends on how it is set up , is it power side switch or ground side switch Ok after looking at a wiring diagram I see the ECM supply's a ground ! An it gets power from FI relay in fuse / relay box an check FI fuse 15amp in the same place !

Posted on Mar 28, 2015

  • 24 more comments 
  • jamguivit Mar 28, 2015

    Yup what I found too.

  • Jeff Armer Mar 29, 2015

    Do you have voltage on one side while cranking the vehicle over ? you need to do while cranking to see if the power drops out. On the other wire the computer supply's a ground an you need to test this side while cranking the engine over also but use a test light with the clamp to positive battery post an touch the other to the wire going to pcm ,if there is control the light will flash or more like flicker !

  • jamguivit Apr 01, 2015

    I get flicker on start but not after

  • Jeff Armer Apr 01, 2015

    Check for 5volts at the TPS -throttle position sensor ,there are three wires ,the one you want to check islite green with a white strip ! If no 5volts the 5 volt reference circuit is down causing your problem ! One of the sensors is shorted on 5volt ref. circuit !

  • jamguivit Apr 01, 2015

    Cool gonna check tomorrow

  • Jeff Armer Apr 01, 2015

    You live in Seattle ! cool I lived down the road for 12 years , Vancouver ! Love those Seahawks !

  • jamguivit Apr 02, 2015

    Not a big football fan unless I'm playing but the Hawks are doing a lot even off the feild. Kudos to all of them

  • dimbulb
    dimbulb Apr 12, 2015

    if engine runs on test fuel, does it? then you lost injections, so? the NOID light test is next, is the fuel injector resistor blown open or pins rusty, , got 12v to the resistor, and is resistor ohms not infinity, and is inector coil not infintiy,? ohms? all these will cause the NOID lamp test to fail, as will many inputs to the ECU or even a bad ECU. the test are easy but seems you just want to guess. replace all those parts. 1 by 1. The ECU also custs fuel for (tacho/igniter read back pin dead) and cuts fuel for TPS stuck at wideopen throttle. (if the 5vdcref is dead, (all loads pulled at source , that is a bad ECU) !

  • dimbulb
    dimbulb Apr 12, 2015

    got 12vdc at bottom of FI relay? above? and not 0v at injector cranking at point between injector and resistor block>? using any volt meter? we check this first if you dont have a tech1 scan tool. like we have. the scan tool will show all reasons for the ECU to not inject. lacking this tool, the tests are tedious, if you need a list of all things that can kill injection, its not a big list. and was posted to you . already.

  • dimbulb
    dimbulb Apr 12, 2015

    a NOID light can be made for $1 , google how to use a NOID light, or youtube it. i

  • Jeff Armer Apr 12, 2015

    your a b**** head ! you asked you !

  • Jeff Armer Apr 12, 2015

    https://youtu.be/FAipVwCdwSQ

  • dimbulb
    dimbulb Apr 12, 2015

    correct any NOID lamp works even home made, 50years , kid)

  • Jeff Armer Apr 12, 2015

    Remove the injector test lamp from the fuel injector electrical connector.

  • Jeff Armer Apr 12, 2015

    Turn ON the ignition, leaving the engine OFF. Measure the voltage from the fuel injector connector cavity 1 to ground (harness side) using a DMM. Is the voltage near the specified value? Connect a test lamp from the fuel injector electrical connector cavity 2 to B+ (harness side).

  • Jeff Armer Apr 12, 2015

    Does the test lamp flash while engine is cranking?This is GM factoy service info !

  • Jeff Armer Apr 12, 2015

    POP'S I replaced your ancient older then dirt self !!!

  • Jeff Armer Apr 12, 2015

    Noid lights are out pop's !

  • dimbulb
    dimbulb Apr 13, 2015

    yes any 12vdc test light works, low current. unpowered, kid.

  • dimbulb
    dimbulb Apr 13, 2015

    i use a scope, as it finds all causes.

  • Jeff Armer Apr 13, 2015

    Yea me too ! snap on verus !!!!!

  • Jeff Armer Apr 13, 2015

    I just thought what's this guy going to know about a noid light , an making one , come on now !

  • _-__-___-_
    _-__-___-_ Apr 20, 2015

    he thinks injection is simple, so wants simple answers. or wild guessing. i think he posted that it runs in test fuel for 3second, but does not inject, and fuses good, and scan codes show 12s cranking, so the next test is what. got 12vdc on both sides of the injector block resistor? on fire wall? key on? in not the resistor is bad.

  • _-__-___-_
    _-__-___-_ Apr 20, 2015

    as seen here

  • _-__-___-_
    _-__-___-_ Apr 20, 2015

    http://www.fixkick.com/INJECTORS/92-94EF...

  • _-__-___-_
    _-__-___-_ Apr 20, 2015

    and in all cases, old cars, bad connections galore (per rust belt comments below, are you?)

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  • Geo Master
  • 10,875 Answers

Camshaft sensor sends code to spit gas at times when the camshaft is at intake valve open

Posted on Apr 14, 2015

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1 Answer

My 1993 Geo tracker fuel systen is not working, the injector is not spraying. now it is sprayin on the inside of the carborator and filling the carborator up.. how do i fix this problem//


there is no CARB on this car.
that must be the throttle body engine, TBI EFI.
1 injector engine not the 4 MPI engine.
G16a is TBI G1b is TBI and both sold day 1 , new.
its is supposed to spray, but you forgot to say when.
just key on over and over not running, (not spray is correct)
it sprays cranking and running,, that be its job1.

lets say it sprays key one.
That means:
1: injector leaks.
2: injector - o-rings are bad. (cracked)
3: ECU injector drivers shorted (bad ECU)
you can look at the inject on this car, air pipe off TBI horn.
see if the seals leak or injector tip leaks ?
if the injector actually leaks.
unplug the injector connector (4pin plug)
leak now.
yes, injector is bad or just o-rings
no, the ECU is bad. (common on this car)
i can even tell you which transistors are bad.... etc.....ask.

both engines covered here.
http://www.fixkick.com/INJECTORS/injectors.html

Dec 09, 2015 | 1993 Geo Tracker

2 Answers

1993 Geo tracker fuel injector is not working right. i have to pour fuel into it. any suggestions on what i should do?


Important to know if it's not working at all, or if it is working some, just not enough? If not at all, then you need to check the injector wiring circuit, it's pretty simple really, just a hot wire with key on, and a ground wire that goes into the engine computer. Test with a voltmeter, best practice.

You should probably first check fuel pressure. The injector won't work unless the fuel pressure inside it is at the specified pressure. If the fuel pressure is too low, you have a bad fuel pump or a clogged fuel filter. If the fuel pressure is correct, you could have a clogged injector. The best way to clean that is with the injector off the engine.

Dec 09, 2015 | Geo Cars & Trucks

1 Answer

What generates fuel injection pulse on a 1994 geo metro base model? I have replaced alternator, TBI injector, and ECU. Checked relays, fuel pump and filter. Feed and return line are clear. On startup I get...


The PCM (ECU does that) its part of what is called EFI, electronic fuel injection, it's a computer, that gets inputs, and uses those inputs to injector perfectly at ALL times.
what engine? 3cy. or 4? is it TBI injected or MPI injected
1 injector or 4? we need to know that first.
does it run on test fuel for 3 seconds.
when was last time it run perfect, last week last year. what?
first off stop guessing, you can go broke that way.
want to diagnosis it? the steps are easy. if fuel is good..
  1. fuses good.?
  2. CEL lamp glow keyon, if not ECU is bad. or bulb , it must glow.
  3. compression over 150PSI on all cyl. (w.o.t = wide open throttle)
  4. do a 60k, mile tune up yet, filters, spark,. and cam timing belt.?
  5. if not, why wait?
  6. 6: is spark good tall cylinders not just 1? is the timing way off if yes, the cam belt did slip, do not fiddle tiiming, fix the belt. first.
  7. ok it now magically runs on test fuel for 3 seconds and sounds great. so we do fueling last.
  8. fuel pressure tests are next. takes $20 gauge got one?
  9. ill stop here, as fueling tests are long play.l..... ask. if you can get to step 9,

I think all 94 metors are TBI engines, one injector
up to 1997 inclusive.
then the 1998 offered 4cyl, MPI injected engine.


have you learned how to use flash codes (DTC) yet?
insert jumper , key on, see CEL lamp glow and flash 12s'
the crank for 5seconds, see if the flashes go to 41 or 42?
bingo if yes.
the TBI allows the mech to watch injection, at the TB.
with top hose off. you can watch it inject as person 2 cranks.
does it?
the ECU brain cuts fuel at the first sign of:
  1. lost spark (to stop fires)
  2. lost Cmp sensor, same .
  3. TPS ground wire busted and ecu things foot is W.O.T (super secret unflood mode) (or TPS cracked in half inside)
or total loss of fuel pressure.

Mar 27, 2015 | 1994 Geo Metro

2 Answers

Fuel Injector keeps spraying after engine start.


yes, that is how the engine keeps running.

Mar 14, 2015 | 1992 Geo Tracker

2 Answers

What activates the fuel injecters


The crank position sensor (and or) the cam position sensor send a message to the computer. The computer then activates the fuel injectors and coils.

Mar 03, 2015 | Cars & Trucks

1 Answer

Injector not fireing


you have a TBI 8valve engine. just like my 91
the injector , not firing, so by guy method.
1: it dont click? (sonic ,stethoscope)
2: the noid dont flash. (use a noid lamp and win)
3: it dont squirte, watching it with eyes, cranking,

if the noid fails, that means ECU is bad or one of 3 inputs to ECU are dead.
if noid works, that means, the injector is cogged, it has 10 micron screens that are easy to clean. or there is no 35 PSI fuel pressure.

here is the page just for that.
  1. THE ECU IS PROGRAMMED to cut fuel if there is no spark preventing TV like crashes and burns. (and other fire reasons)
  2. the tests are all easy. no order but #1 is #1
  3. fuel pressure at spec.
  4. injector coil reads 1.0 OHMS.
  5. injector clean. (there is only one, so all hope is just here)
  6. noid lamp fails , so is CMP dead? or TPS TP pin stuck high or , ecu throwing code 41./42s errors, BINGO!

http://www.fixkick.com/INJECTORS/injectors.html

or no starts

http://www.fixkick.com/INJECTORS/injectors.html

May 06, 2014 | 1992 Geo Tracker

2 Answers

91 chevy 1500 p u the tbi is not spraying fuel out the 2 injectors spray starting fluid in the throttle body and it will start


Check all engine grounds as the ECU relies on the control unit to find a ground and pulse the injectors. Also check the crankshaft sensor to make sure its pulsing when rotated. It should produce a 5 volt reference as it moves. Also check that you have fuel pressure as the pump also relies on a good ground to power up. Everything is controlled from the ECU.

May 06, 2014 | Cars & Trucks

1 Answer

Fule injectors have no eletrical pulse


No pulse from the injectors signals that the ecu is not sending those signals. Could be the crank sensor is bad or the ecu itself is bad. Have it checked out.

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1 Answer

My 1990 Mitsubishi Montero Sport will crank but will not start. I tried to use starting fluid through the air filter shaft but the car still won't start. The car has been stalling before when I am idle and...


Given the year of the Montero I expect the ECU has failed or the component within the distributor which tells the ECU when to send a spark. Check for spark or fuel injector pulse. To check fuel injector pulse rent NOID lights from auto parts store. If no pulse I expect the Distributor if no fuel I expect the ECU
Best regards,
Tom

Aug 20, 2010 | 1990 Mitsubishi Montero

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