88TII: Strange no spark/no fuel issue
12-22-08, 02:15 PM
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88TII: Strange no spark/no fuel issue
So I just finished putting my first TII back together, and I'm all kinds of excited to hear it run. I bought the thing with a carbon-locked motor and all I know about it's history is that it was owned by a middle-aged mother of two teenagers and has sat since 2000. It turns over just fine, but won't run! Here's what I've observed so far:
The fuel pump runs. (I had a loose fuel connection, so I have the fuel on my garage floor to prove it.)
The plugs fire when the ignition is turned on and (sometimes several times) when it is turned off, but not while cranking. I can hear the main relay next to the trailing coil pack clicking whenever the plugs fire.
The Engine fuse in the footwell and the EGI fuses under the hood have power and continuity.
The two ring terms on the leading coil pack show battery voltage.
The solenoid rack shows battery voltage.
The CAS shows ~130ohms on both coils.
All 4 pins on the engine side of the CAS connector show ~9V with the VOMs (-) probe grounded.
The fuel injectors do not click when the CAS is turned by hand.
When I plug my homemade 2-LED checked into the diag plug next to the leading coil, but leds stay lit. They sloooowly dim after the ignition switch is turned off.
I've been searching the FSM and this forum for a few days now and I'm not really sure where to go next. Any input/ideas are greatly appreciated.
The fuel pump runs. (I had a loose fuel connection, so I have the fuel on my garage floor to prove it.)
The plugs fire when the ignition is turned on and (sometimes several times) when it is turned off, but not while cranking. I can hear the main relay next to the trailing coil pack clicking whenever the plugs fire.
The Engine fuse in the footwell and the EGI fuses under the hood have power and continuity.
The two ring terms on the leading coil pack show battery voltage.
The solenoid rack shows battery voltage.
The CAS shows ~130ohms on both coils.
All 4 pins on the engine side of the CAS connector show ~9V with the VOMs (-) probe grounded.
The fuel injectors do not click when the CAS is turned by hand.
When I plug my homemade 2-LED checked into the diag plug next to the leading coil, but leds stay lit. They sloooowly dim after the ignition switch is turned off.
I've been searching the FSM and this forum for a few days now and I'm not really sure where to go next. Any input/ideas are greatly appreciated.
12-22-08, 06:07 PM
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Care to elaborate? I don't suppose you're suggesting I rebuild my engine to cure an electrical issue are you?
Seriously. I've been tinkering with engines most of my life and I've never seen an ignition system do this before. What I'm looking for is advise on tracking down this and the other issues listed, which I believe to be related.
Originally Posted by farberio
What??
Your plugs fire when the engine doesn't turn over? Really?
Track down this problem and you will probably find your problem.
Your plugs fire when the engine doesn't turn over? Really?
Track down this problem and you will probably find your problem.
12-22-08, 06:57 PM
#5
yea the plugs firing when the motor is not spinning sounds like a major issue. the injectors not firing when you turn the CAS is also an issue, do you have a spare set of injectors? are you sure the injectors are not stuck open or closed? pull the rails with the injectors, keep the injectors secured in the rails and visually see if the injectors are firing.
12-22-08, 07:02 PM
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yea the plugs firing when the motor is not spinning sounds like a major issue. the injectors not firing when you turn the CAS is also an issue, do you have a spare set of injectors? are you sure the injectors are not stuck open or closed? pull the rails with the injectors, keep the injectors secured in the rails and visually see if the injectors are firing.
12-22-08, 07:08 PM
#7
I would check the signal wire to the coils when you are cranking vs when you are getting your mysterious sparking with a test light or DMM if you can.
Just to be sure, you aren't talking about weird sparking when you are turning the CAS by hand, because that would be normal.
A third thing to look at, on the leading coil pack there is three connections, a 12V Switched (Brown coil side/Black Yellow harness side), a Signal Wire (Pink coil side/??? Harness side) and a black wire that has a bullet connector. The black wire with the bullet connector should not be connected to anything, it is not a ground.
Just to be sure, you aren't talking about weird sparking when you are turning the CAS by hand, because that would be normal.
A third thing to look at, on the leading coil pack there is three connections, a 12V Switched (Brown coil side/Black Yellow harness side), a Signal Wire (Pink coil side/??? Harness side) and a black wire that has a bullet connector. The black wire with the bullet connector should not be connected to anything, it is not a ground.
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12-22-08, 07:57 PM
#8
If you can, try getting another ecu, or boorrowing one.
The cas sends signal to the ecu, from here the ecu sends a signal to the coil packs and the injectors.
Just to be safe, check the injectors.
Check the resistence, should be between 12-16ohms
Try and get a noid light and see if the ecu is sending a signal to the injector when you turn the CAS by hand, you can try a led light, it might work I did it before, but since there is no resistor in it, it might damage something. You can also try a test light on the Light green wires, and grounding the other end of the test light. If it lights up, you got a fuel signal.
The leading coil should have less then 1 ohm on the two connection.
I know you said you checked the CAS, but check it again.
Should be 110-210 ohms between G1 and G2, and also between NE2 and NE1
The cas sends signal to the ecu, from here the ecu sends a signal to the coil packs and the injectors.
Just to be safe, check the injectors.
Check the resistence, should be between 12-16ohms
Try and get a noid light and see if the ecu is sending a signal to the injector when you turn the CAS by hand, you can try a led light, it might work I did it before, but since there is no resistor in it, it might damage something. You can also try a test light on the Light green wires, and grounding the other end of the test light. If it lights up, you got a fuel signal.
The leading coil should have less then 1 ohm on the two connection.
I know you said you checked the CAS, but check it again.
Should be 110-210 ohms between G1 and G2, and also between NE2 and NE1
12-22-08, 10:20 PM
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The spark plugs should have sparked when the CAS bottom gear was spun by hand. Just pull one of the two wires in the Lead coil assy out, then lay it just at the hole in the coil. Spin the CAS. Spark should be seen.
I'd recommend going to the ECU and backprobing the wires and comparing your readings with the readings in the FSM, Fuel and Emissions section, Control Unit pages.
I'd go to the wires for the CAS output to the ECU and compare those first.
Main Relay should NOT click when the engine is turned over. That's a clue worth looking into.
It should stay latched once you put the key to ON or better. Something is amiss there. Going on/off would kill the power to the ECU/injectors/coils. It'd be coming and going as it clicked. Something is really wrong there. You might start there.
A quick work around to see if that is the problem, would be to pull the four wire plug off the Main Relay. Then jumper the wires together so it simulates a pulled in Main Relay. THEN if you go to start and the thing starts/runs/shows life.......then you can concentrate on why the Main Relay comes and goes. Ain't normal at all.
You'd jumper the B/G to the B/Y and then the B/W to the W/L. Just get a piece of old wire and cut off two pieces. Bare each end of the wires. Stick one in the B/G and its other end in the B/Y. The the other wire with one end in the B/W and the other end in the W/L. Start car....or try to. Jpg attached of series four wiring. I assume you have a series four car.
I'd recommend going to the ECU and backprobing the wires and comparing your readings with the readings in the FSM, Fuel and Emissions section, Control Unit pages.
I'd go to the wires for the CAS output to the ECU and compare those first.
Main Relay should NOT click when the engine is turned over. That's a clue worth looking into.
It should stay latched once you put the key to ON or better. Something is amiss there. Going on/off would kill the power to the ECU/injectors/coils. It'd be coming and going as it clicked. Something is really wrong there. You might start there.
A quick work around to see if that is the problem, would be to pull the four wire plug off the Main Relay. Then jumper the wires together so it simulates a pulled in Main Relay. THEN if you go to start and the thing starts/runs/shows life.......then you can concentrate on why the Main Relay comes and goes. Ain't normal at all.
You'd jumper the B/G to the B/Y and then the B/W to the W/L. Just get a piece of old wire and cut off two pieces. Bare each end of the wires. Stick one in the B/G and its other end in the B/Y. The the other wire with one end in the B/W and the other end in the W/L. Start car....or try to. Jpg attached of series four wiring. I assume you have a series four car.
Last edited by HAILERS; 12-22-08 at 10:29 PM.
12-23-08, 08:22 AM
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01-01-09, 01:56 PM
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Hailers: Thanks for the advice! I had really hoped one of the "big guns" would notice my thread and chime in. I greatly appreciate it.
To the other folks who have been kind enough to chime in: I will definitely be checking my injectors more closely once I figure out my power distribution problem.
I'm afraid my work got interrupted. My father-in-law, who was very gracious in letting me use his garage space for my project, decided he wanted to insulate and sheetrock the garage. I'm grateful for the extra warmth (working on the car at 10-15deg is kind of pushing it), but between that project and the inevitable Christmas family time I'm just now getting back into the car.
I had missed the ECU pinout specs in the FSM. I guess I saw the test methodology with the Mazda SST and skipped past. The ECU main relay was not clicking while the engine was turning over, but it did sound like it was clicking several times after the ignition switch was turned off. Now that I listen closer, I realize that's the "snap" of the spark plugs firing that I was hearing. They fire once when the ignition switch is turned on, not at all when the engine is turned over or the CAS is spun by hand (I also tested with just the wires, even though the plugs are new) and sometimes several times after the ignition switch is turned off.
Since I found time to get back into it, I have gone to the ECU and backprobed the 4 pins for the CAS. The FSM says they should show less than 1V with the ignition On. I get ~.6V with the ignition Off, and ~9.6V with the ignition On. I get the same values for all 4 pins. Then I checked pin 3I to the Main Relay and found that it shows 0V until I switch the ignition On, then it shows 12V and continues to show 12V after I switch the ignition Off. It stays hot until I disconnect the battery. My test LEDS on the diag plug are now staying lit until I disconnect the battery.
Because of the high voltages seen at the CAS pins, I suspect the ECU is toast. Unfortunately, I don't have another here for testing. Since I know I have a power distribution issue TO the ECU, I'm going to focus on the Main Relay and see why it doesn't switch off. Hopefully that will lead somewhere useful.
To the other folks who have been kind enough to chime in: I will definitely be checking my injectors more closely once I figure out my power distribution problem.
I'm afraid my work got interrupted. My father-in-law, who was very gracious in letting me use his garage space for my project, decided he wanted to insulate and sheetrock the garage. I'm grateful for the extra warmth (working on the car at 10-15deg is kind of pushing it), but between that project and the inevitable Christmas family time I'm just now getting back into the car.
I had missed the ECU pinout specs in the FSM. I guess I saw the test methodology with the Mazda SST and skipped past. The ECU main relay was not clicking while the engine was turning over, but it did sound like it was clicking several times after the ignition switch was turned off. Now that I listen closer, I realize that's the "snap" of the spark plugs firing that I was hearing. They fire once when the ignition switch is turned on, not at all when the engine is turned over or the CAS is spun by hand (I also tested with just the wires, even though the plugs are new) and sometimes several times after the ignition switch is turned off.
Since I found time to get back into it, I have gone to the ECU and backprobed the 4 pins for the CAS. The FSM says they should show less than 1V with the ignition On. I get ~.6V with the ignition Off, and ~9.6V with the ignition On. I get the same values for all 4 pins. Then I checked pin 3I to the Main Relay and found that it shows 0V until I switch the ignition On, then it shows 12V and continues to show 12V after I switch the ignition Off. It stays hot until I disconnect the battery. My test LEDS on the diag plug are now staying lit until I disconnect the battery.
Because of the high voltages seen at the CAS pins, I suspect the ECU is toast. Unfortunately, I don't have another here for testing. Since I know I have a power distribution issue TO the ECU, I'm going to focus on the Main Relay and see why it doesn't switch off. Hopefully that will lead somewhere useful.
01-01-09, 09:08 PM
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I was going to suggest you were reading the wires from the wrong side of the plug, but seeing as you mentioned 3I, and seem to have that right, you must be looking at the plugs from the Wire side of the plug reading from right to left in a up/down method.
I'd turn the key to ON, the go to the engine bay and pull the smaller plug of the two on the Main Relay. When you pull it off, you should hear it click. Then reinstall the same plug and listen/feel for it to click. Verifying it's being pulled in and relaxing when the plug is off it. Then you might just pull the other plug with four wires off. And while that plug is off, go look at 3I to see if the batt voltage went away. Should have. If it didn't, then some other thing is feeding 3I.
I don't know what to say about the CAS wires. Except pull the plug off and then see if there's any voltage on those wires in the plug. If there is ....then some thing other that the ECU is putting it there. That's sort of a must do type thing you need to do. Do it with the key On and the plugs on the Main Relay.
I'm not a big hitter. I just type while watching the TV. It's about the one hundreth time I've seen the battle of Midway. Task force 17..........Yorktown...........
I'd turn the key to ON, the go to the engine bay and pull the smaller plug of the two on the Main Relay. When you pull it off, you should hear it click. Then reinstall the same plug and listen/feel for it to click. Verifying it's being pulled in and relaxing when the plug is off it. Then you might just pull the other plug with four wires off. And while that plug is off, go look at 3I to see if the batt voltage went away. Should have. If it didn't, then some other thing is feeding 3I.
I don't know what to say about the CAS wires. Except pull the plug off and then see if there's any voltage on those wires in the plug. If there is ....then some thing other that the ECU is putting it there. That's sort of a must do type thing you need to do. Do it with the key On and the plugs on the Main Relay.
I'm not a big hitter. I just type while watching the TV. It's about the one hundreth time I've seen the battle of Midway. Task force 17..........Yorktown...........
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