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88 FC cranking but wont start

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Old 11-28-11, 12:36 AM
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Originally Posted by satch
And this test was done w/the key to on? And you have to make sure the Main Pulley rotates as the alternator belt is turned. Was this part done correctly? If the pulley didn't budge then the test will not indicate a proper voltage reading.

EDIT: I also made a typing mistake and meant to state that the G/Y wire should have zero volts which briefly then indicates 5 volts then back to zero volts and not the reverse as previously stated.
Yes It was hard to turn and I could hear the rotor rotating in the housing.

Im not the best with a Multimeter so just to make sure im doing things right ill tell you how I do it, I poke a little hole in the wire then put the black pin inside the whole while the red is touching the negative terminal of the battery? That sound right or am I doing it wrong? It would be a good thing to know before I go any further with testing.
Old 11-28-11, 12:54 AM
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Originally Posted by mario4817
Yes It was hard to turn and I could hear the rotor rotating in the housing.

Im not the best with a Multimeter so just to make sure im doing things right ill tell you how I do it, I poke a little hole in the wire then put the black pin inside the whole while the red is touching the negative terminal of the battery? That sound right or am I doing it wrong? It would be a good thing to know before I go any further with testing.
The Black meter lead goes to ground and not the other way except if you did it like you did, which is the opposite of what it should be, the only real change would be that the voltage reading would show a negative sign in front of the voltage reading and of course there is no such thing as negative voltage. You can always use the battery to practice on. With the White two wire plug removed from the leading coil just stick the Red meter lead into the front of the two wire plug where the G/Y wire resides and the Black lead to ground. You also need to make sure the Main Pulley doesn't move just a, bit but you need to rotate it a fair amount to get the voltage reading to change from 0 volts to 5 volts briefly.
Old 11-28-11, 02:18 AM
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Got it, Does the black wire ground anywhere where there is metal or do I have to ground it on a battery terminal?, will be retesting tomarrow after school
Old 11-28-11, 09:55 AM
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Originally Posted by mario4817
Got it, Does the black wire ground anywhere where there is metal or do I have to ground it on a battery terminal?, will be retesting tomarrow after school
It depends but the negative battery terminal is always a good choice especially since it's close to where you are working.

If you still can't get the zero to five reading then disconnect the CAS pigtail and clean it and reconnect it and look for spark as previously done. If that doesn't work then disconnect the CAS once again and plug in the spare and w/key to on spin the CAS and not only should there be spark but the injectors should click as well.
Old 11-28-11, 10:59 PM
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OK, so knowing how to test right I went through everything again and got some different results
The Black/Yellow wire is getting 12v with the key to on.

With the key to on: The Green/Yellow wire still does not read anything but 0v I can see the main pully moving througholy. Does the main pully have to move constantly? because I am moving the pully by strokes not at a constant speed.

With the key to on and it plugged in: The solid Brown TPS wire going from the TPS to the clip is not getting any reading other than 0v, I used The mulimeter properly as said, and even used the test light and nothing. BUTT i noticed that the TPS bracket had a bolt missing! and the TPS was really loose and not hitting that throttle bar (or whatever you call it) and the TPS wasnt moving its sensor I guess. So I fixed it and its really solid and is hitting the throttle bar to make it move. Tested the brown wire again after fixing and still no reading.. After fixing the TPS I tried starting it and no good.

With the key to on: Cleaned the pigtail end of the CAS (even tho it looked pretty clean) and tried for spark and maybe a reading on the Green/Yellow wire and nothing still. Got my spare CAS from the Turbo II and hooked it up to the car, Tested for spark like satch said and listened for and clicking noise of an injector and heard nothing.
Old 11-29-11, 12:08 AM
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Originally Posted by mario4817
OK, so knowing how to test right I went through everything again and got some different results
The Black/Yellow wire is getting 12v with the key to on.

With the key to on: The Green/Yellow wire still does not read anything but 0v I can see the main pully moving througholy. Does the main pully have to move constantly? because I am moving the pully by strokes not at a constant speed.

With the key to on and it plugged in: The solid Brown TPS wire going from the TPS to the clip is not getting any reading other than 0v, I used The mulimeter properly as said, and even used the test light and nothing. BUTT i noticed that the TPS bracket had a bolt missing! and the TPS was really loose and not hitting that throttle bar (or whatever you call it) and the TPS wasnt moving its sensor I guess. So I fixed it and its really solid and is hitting the throttle bar to make it move. Tested the brown wire again after fixing and still no reading.. After fixing the TPS I tried starting it and no good.

With the key to on: Cleaned the pigtail end of the CAS (even tho it looked pretty clean) and tried for spark and maybe a reading on the Green/Yellow wire and nothing still. Got my spare CAS from the Turbo II and hooked it up to the car, Tested for spark like satch said and listened for and clicking noise of an injector and heard nothing.
It's a bit strange you measured 5 volts on the Brown wire for the TPS before and now you have zero volts. There is a Green check connector with four wires near the leading coil. Three are Yellow based and the 4th is Black/White. W/key to on check for battery voltage on the B/W wire. If there is no voltage on it then the COMP fuse might have blown once again. If there is voltage on this B/W wire then a possible cause of your problem relates to a loose engine ground or a loose connector above and to the right of the ECU (connector is Orange). And when you tested the Brown TPS wire before was the connector plugged or unplugged and was the key to on?
Old 11-29-11, 12:37 AM
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Originally Posted by satch
It's a bit strange you measured 5 volts on the Brown wire for the TPS before and now you have zero volts. There is a Green check connector with four wires near the leading coil. Three are Yellow based and the 4th is Black/White. W/key to on check for battery voltage on the B/W wire. If there is no voltage on it then the COMP fuse might have blown once again. If there is voltage on this B/W wire then a possible cause of your problem relates to a loose engine ground or a loose connector above and to the right of the ECU (connector is Orange). And when you tested the Brown TPS wire before was the connector plugged or unplugged?
Well the first time I tested the brown wire I tested wrong, but then I cleared things up on the "how to test" you explained, and did it the right way and got nothing.

When I tested the brown wire and got 5v it was connected, but I think I put the red pin to ground to the positive side of the battery and the black pin into the brown wire and got a 5v(prob more) from doing that. When I tested it today I put the black pin on the negative terminal and the red pin in the wire i was testing, and it came up with nothing. with it plugged in of course and the key to on. And as I said I even used a test light and that came up short also. I checked all the fuses after completing all my tests today and all were good.

I will check the green plug tomarrow as soon as I can, as well as the orange clip.

Thanks for your patience
Old 11-29-11, 04:10 PM
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And one other thing. If the B/W wire doesn't have power then proceed to check the four wire plug at the Main Relay ( relay has two plugs to it, and mounted to the driver side fender near the trailing coil). There will be a White/Blue wire in this plug and it should have constant power (no key necessary). If it does not then chances are the White/Blue wire which is powered by the 30 amp COMP fuse has come loose underneath the Engine fuse box.
Old 11-29-11, 04:14 PM
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The black /white wire is getting 12v, should I now check the orange clip next to the ECU?

Last edited by mario4817; 11-29-11 at 04:18 PM.
Old 11-29-11, 04:25 PM
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Originally Posted by mario4817
The black /white wire is getting 12v, should I now check the orange clip next to the ECU?
I would check the Brown wire at the TPS one more time and you could use the alternator casing for a ground if need be. As I stated previously, if the meter leads are accidentally switched the net result is the voltage reading would have a minus sign to it, but it would still give you an accurate number, so I am a bit confused as to how it indicated 5 volts one day and then 0 volts the following time.
Old 11-29-11, 04:44 PM
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Yup tried the Brown wire again and im not getting anything close to 5v, I am getting a steady .13v on it tho if that means anything lol I got a picture of the brown wire im testing just to make sure its the right one... and if im testing the right thing.... ha... ignore the temporary bolt to secure the sensor in place.

Im testing that middle wire.




also for the sake of it I tested the blue wire on the main relay plug without the key and it read 12v

Last edited by mario4817; 11-29-11 at 04:51 PM.
Old 11-29-11, 04:51 PM
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There are two Orange connectors located side by side and very close to the passenger kick panel (above and to the right of the ECU position). One connector has 15 wires while the other has 13. The one w/13 wires has two Black/White wires. Check these for voltage w/key to on. This wire powers up the ECU. Focus on the bottom or lower side of the connector as the top is from the Front harness and the bottom part is the Emission harness and it is this part which is easier to access.
Old 11-29-11, 05:06 PM
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I know satch knows his stuff but could this be from the afm not being plugged in? Worth it tto check the plug I would assume right...
Old 11-29-11, 05:06 PM
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why is it hard to get to?
Old 11-29-11, 05:11 PM
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Originally Posted by matt87FC
I know satch knows his stuff but could this be from the afm not being plugged in? Worth it tto check the plug I would assume right...
If the AFM was shorting out the signal to the Vref voltage that would explain at least one of his problems, but it being disconnected would not in itself short out the Brown TPS wire which is supposed to get its signal from the Vref.
Old 11-29-11, 05:13 PM
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Not ahard to check t all. Front passenger side attached to the air box. Its roght there and has a rectangular plug going into it (if its connected that is)

True satch I was just throwing it out there since i seen that it hadnt been mentioned yet.
Old 11-29-11, 05:13 PM
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Originally Posted by mario4817
why is it hard to get to?
No, but the Orange connectors are a tight fit to work around. Just check the B/W wire(s) as suggested for now and see how that plays out.

And the 15 wire connector does'nt have any B/W wires.
Old 11-29-11, 05:14 PM
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Originally Posted by matt87FC
Not at all. Front passenger side attached to the air box. Its roght there and has a rectangular plug going into it (if its connected that is)
I believe he's referring to the ECU.
Old 11-29-11, 05:22 PM
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Originally Posted by satch
I believe he's referring to the ECU.
Ohh ok. Posts got a lil jumbled up there. Lol
Old 11-29-11, 05:55 PM
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Correct me if I am wrong but i am testing the lower orange clip, and am testing that black/white wire kinda to the right on the connector

Old 11-29-11, 06:52 PM
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Yeah, it's the one with two B/W wires on top and two coming out below. Both sides should have the same results as opposed to just one side.
Old 11-29-11, 10:53 PM
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In the last picture I posted the bottom side of the clip there are two different sets of black/white wires.... going from left to right it goes yellow, yellow/black, black/white, blue, and then another black and white... which black and white am i testing?
Old 11-29-11, 10:58 PM
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There are only two B/W wires on the Emission side of the connector and three on the Front harness side so check both B/W wires on the side that has only two B/W wires which would be the emission side.

And when you use the Red meter lead to check for voltage on the wire make sure the lead is stuck firmly and snug into the back of the plug and making contact with the wire clip inside the plug.
Old 11-29-11, 11:51 PM
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Never will I be a electrician lol, ok so I think i know the wires your talking about, on the bottom of the clip there is a set of fat black/white wires that have no voltage but they are kinda spread apart from each other

But there is another set of black/white wires that are right next to each other. tested one wire and it read 12v, tested he other and it read 1.3v was the most i got out of it

So with reading those I decided to follow it up the clip to two other black/white wires that were right next to each other and one read 12v and the other 1.3v was the most i got out of it.
Old 11-30-11, 12:05 AM
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Originally Posted by mario4817
Never will I be a electrician lol, ok so I think i know the wires your talking about, on the bottom of the clip there is a set of fat black/white wires that have no voltage but they are kinda spread apart from each other

But there is another set of black/white wires that are right next to each other. tested one wire and it read 12v, tested he other and it read 1.3v was the most i got out of it

So with reading those I decided to follow it up the clip to two other black/white wires that were right next to each other and one read 12v and the other 1.3v was the most i got out of it.
The wire that you tested at the Green check connector was B/W. It is this very same wire that you are testing in the Orange connector. As this wire approaches the Orange connector on the front side of the harness it splits into two B/W wires so both wires should have exactly the same results. The only possible explanation would be the joint where the two wires split is poor but if there is voltage on one wire that should be enough. Instead of removing the items to gain access to the ECU you can do something else in the meantime. In the pic provided there is a White plug behind the Orange connector that has 4 wires plugged into a Black sensor. Note the Brown wire. This is the very same Brown wire that you tested at the TPS. So w/key to on test for 5 volts on this Brown wire. Also, at the TPS test the Green/Red wire for voltage w/key to on.

EDIT: The two B/W wires in the Emission side of the Orange connector should be side by side and one should be next to the Brown/Yellow wire and the other next to the Yellow wire. And the B/W wire in the Emission side that you should not be testing is fed by a Black/Red wire from the front side of the Orange connector. So the two wires you focus on are fed by B/W wires from the front side of the connector and not another color.


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