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> L-Jet: Over My Head, Bad ECU, car's back on the road.
Mike Sanford
post Sep 23 2013, 10:03 AM
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I'm a little above my skill set playing with this stuff.

Took the wife out yardsale-ing Saturday morning. This is Tucson, maybe 85 degrees at 8am. Drove two blocks from home, stopped at one. Drove another 5 blocks, car acted as if it ran out of gas. Gas tank is full. Key on, pulled fuel line off of rail and opened air flow meter, squirts fuel. Pulled injector out of a cylinder, moved air flow meter, no fuel.

Shoved my analog voltmeter into injector plug, no sign of a signal at the injector.

Played on the internet looking up l-jet trouble shooting, decided to start with checking the relay because it seemed less intimidating. From what I'm seeing there should be voltage between 88a, 88b, 88c, and 88z and 85 (the ground). I have voltage everywhere except 88c. Come back inside, back on the internet, 88c looks like it powers the auxilary air valve. Would this cause the whole system to shut down? Is there something else I should be checking?

Thanks,
Mike
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timothy_nd28
post Sep 23 2013, 10:14 AM
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Everything sounds right. You will not have voltage at pin 88c unless the key is turned to the "start" position or the engine is running. 88c is tied to 88d which supplies power to the fuel pump. Also, the air flow meter does not send a signal to fire the fuel injectors.

Is the car still in its failed no start mode?
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Mike Sanford
post Sep 23 2013, 10:19 AM
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[quote name='timothy_nd28' date='Sep 23 2013, 09:14 AM' post='1930574'

Is the car still in its failed no start mode?
[/quote]

It's still dead.
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timothy_nd28
post Sep 23 2013, 10:22 AM
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Good, it's easier to troubleshoot it this way. With your multimeter, probe pin 88d on the dual relay with one meter lead. Put the other meter lead on the negative battery post. Have some one attempt to start the car, while you are watching the meter.
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Mike Sanford
post Sep 23 2013, 10:33 AM
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Home alone, but was able to watch meter through the window. About 9 volts.
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timothy_nd28
post Sep 23 2013, 10:37 AM
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Seems abit low. Check the voltage at the battery. Next, go ahead and put one meter lead on pin 86a and the other meter lead to the negative battery post. You will need to attempt to start the car while watching the meter again. What voltage do you have here?
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Mike Sanford
post Sep 23 2013, 10:46 AM
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Battery is at 11v, but there have been multiple attempts to start the car in the last few days. 86a is at 8v.

88c does power up when the starter engages.
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timothy_nd28
post Sep 23 2013, 10:49 AM
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Okay, now check pin 88y. You won't need to start the car for this test
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Mike Sanford
post Sep 23 2013, 10:56 AM
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11v.
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timothy_nd28
post Sep 23 2013, 11:03 AM
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How accurate are these readings? Are you still using the analog meter or is it digital?
Pin 88y is battery voltage on the dual relay. The test confirms that you do have the same voltage on that pin as you do on the battery. So far so good, but I don't like the voltage on pin 88d (9v). This shows you had a 2volt drop across the contact points inside the dual relay. If this is true, it's time for a new dual relay.
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Mike Sanford
post Sep 23 2013, 11:30 AM
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QUOTE(timothy_nd28 @ Sep 23 2013, 10:03 AM) *

How accurate are these readings? Are you still using the analog meter or is it digital?
Pin 88y is battery voltage on the dual relay. The test confirms that you do have the same voltage on that pin as you do on the battery. So far so good, but I don't like the voltage on pin 88d (9v). This shows you had a 2volt drop across the contact points inside the dual relay. If this is true, it's time for a new dual relay.


This is a cheap analog meter. 11v is kind of a guess, I'm using the 10v scale and its a about that distance past the 10, not yet maxing out. Just checked 88d again, and (this time) 8v is exactly what its pointing to.

I'll try to find my digital meter and double check my numbers.

Real time cross country electrical trouble shooting, more help than I expected this morning, I'm grateful for your time.
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timothy_nd28
post Sep 23 2013, 11:51 AM
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Not a problem. Anyways you have 11v going in and 8v going out, still shows a drop inside the relay and will need to be replaced. Time being, run a jumper wire from 88d to the positive battery post. Does the car run with this configuration?
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Mike Sanford
post Sep 23 2013, 12:06 PM
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QUOTE(timothy_nd28 @ Sep 23 2013, 10:51 AM) *

Not a problem. Anyways you have 11v going in and 8v going out, still shows a drop inside the relay and will need to be replaced. Time being, run a jumper wire from 88d to the positive battery post. Does the car run with this configuration?


Checked things out with the digital meter. 11.8 at battery. 11.8 at 88y. Numbers jumping between 7 and 9 at 88d.

Jumper kicks the fuel pump on, but I'm pretty sure that wasn't the problem. I'd checked it earlier this morning by pulling a line off the rail, and it was squirting fuel both with the key on and the AFM opened, and when cranking the starter.
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Mike Sanford
post Sep 23 2013, 12:10 PM
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QUOTE(Mike Sanford @ Sep 23 2013, 11:06 AM) *

QUOTE(timothy_nd28 @ Sep 23 2013, 10:51 AM) *

Not a problem. Anyways you have 11v going in and 8v going out, still shows a drop inside the relay and will need to be replaced. Time being, run a jumper wire from 88d to the positive battery post. Does the car run with this configuration?


Checked things out with the digital meter. 11.8 at battery. 11.8 at 88y. Numbers jumping between 7 and 9 at 88d.

Jumper kicks the fuel pump on, but I'm pretty sure that wasn't the problem. I'd checked it earlier this morning by pulling a line off the rail, and it was squirting fuel both with the key on and the AFM opened, and when cranking the starter.


Just to clarify, it wouldn't start with the jumper in place.
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rhodyguy
post Sep 23 2013, 12:14 PM
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Chimp Sanctuary NW. Check it out.
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great, straight forward advice!! nice work!
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timothy_nd28
post Sep 23 2013, 12:14 PM
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I identified a problem, but it maynot be the problem. With the jumper on and the fuel pump running 24-7 does the car run, or are we still in a no run mode? Also, do you have mechanical points or a pointless module?
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Mike Sanford
post Sep 23 2013, 12:19 PM
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QUOTE(timothy_nd28 @ Sep 23 2013, 11:14 AM) *

I identified a problem, but it maynot be the problem. With the jumper on and the fuel pump running 24-7 does the car run, or are we still in a no run mode? Also, do you have mechanical points or a pointless module?


With the jumper in place, we're still in a no run mode. Petronix instead of points.
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timothy_nd28
post Sep 23 2013, 12:24 PM
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K, verify you still have spark. Next pull off the ECU connector. With the key set to the "on" position, check pin 10 with the positive meter lead and put the negative meter lead on pin 5. What is the voltage? Do the test again, but now measure pin 10 to pin 16. Finally, check pin 10 to pin 17

If you have a strong 12 volts on all the above, set your meter to measure resistance. Measure the resistance between pin 1 on the ECU plug to the negative side of the ignition coil
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malcolm2
post Sep 23 2013, 12:24 PM
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QUOTE(timothy_nd28 @ Sep 23 2013, 01:14 PM) *

I identified a problem, but it maynot be the problem. With the jumper on and the fuel pump running 24-7 does the car run, or are we still in a no run mode? Also, do you have mechanical points or a pointless module?



Tim is so good, he changed his avatar in mid post!
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Mike Sanford
post Sep 23 2013, 12:40 PM
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This is the part that intimidated me, and why I started with the relay.

Have spark.

Pulled connector off or ECU.

How are the pins numbered?
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