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Old 05-13-2018, 11:54 AM   #1
bmdubya1198
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Default No Pulse to Injectors, Has Spark

I ended up replacing the EZK module in my '88 Turbo, and I finally have spark and the fuel pump engages when it's supposed to. The only thing keeping my car from starting at this point are the injectors. For some reason, the ECU isn't grounding them.
The injectors have power when checked between the terminals and a ground.

What can be preventing the injectors from getting a pulse? It's not the power stage, ballast resistor, or radio suppression relay. I already changed the power stage (plus if it was bad, it would not get spark) and the other two being bad would most likely prevent them from getting constant power.
I also bypassed the boost over pressure switch, so that's not the problem.

There is continuity between the injector connector and pin 13 on the ECU.
I have also changed the LH ECU, but I guess it is a possibility that it's another bad one (assuming my original ECU is bad?).
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Old 05-13-2018, 12:16 PM   #2
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I assume you've got the proper resistance injectors?
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Old 05-13-2018, 12:32 PM   #3
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I assume you've got the proper resistance injectors?
Yes, they are original green tops.
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Old 05-13-2018, 12:36 PM   #4
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Have you checked the pulse with a node light? This is a lh 22 or 24 car?
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Old 05-13-2018, 01:10 PM   #5
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LH 2.2. I haven’t used a noid light, I’ve been using a test light between the connector terminals.
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Old 05-14-2018, 08:24 PM   #6
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Any ideas here? Do I just have two bad ECUs?
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Old 05-14-2018, 08:41 PM   #7
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You've tried the boost pressure over pressure switch. How good are the connections at the radio suppression relay?
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Old 05-15-2018, 10:46 AM   #8
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No pulse/weak pulse to injectors can be caused by bad CPS, RSR, corroded resistor pack, bad ecu, and some other things. Does the vehicle start on starting fluid?

If you are certain your injector grounds are clean, you should remove the connector for the resistor pack and file the spades clean down to bare metal. Being corroded caused a no start on my 940t. Do you feel the RSR click in KP2? You can bypass the relay temporarily by removing it and jumping the 12v wire (should be red) to whatever wire gives power to the injectors. I believe it’s striped. You’ll have to look at a wiring diagram though.

As lummert mentioned, RSR connections can be gross. When I looked at them on the 740 the plastic was so old and rotted that it was booger consistency. I ended up cutting the harness and splicing in a Bosch style 4 post relay. All good now.
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Old 05-15-2018, 11:17 AM   #9
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Originally Posted by PromiseRing View Post
No pulse/weak pulse to injectors can be caused by bad CPS, RSR, corroded resistor pack, bad ecu, and some other things. Does the vehicle start on starting fluid?

If you are certain your injector grounds are clean, you should remove the connector for the resistor pack and file the spades clean down to bare metal. Being corroded caused a no start on my 940t. Do you feel the RSR click in KP2? You can bypass the relay temporarily by removing it and jumping the 12v wire (should be red) to whatever wire gives power to the injectors. I believe itís striped. Youíll have to look at a wiring diagram though.

As lummert mentioned, RSR connections can be gross. When I looked at them on the 740 the plastic was so old and rotted that it was booger consistency. I ended up cutting the harness and splicing in a Bosch style 4 post relay. All good now.
No CPS on a 2.2 car, just hall effect in the dizzy. Since he has spark, that rules out the hall effect.

OP is right, in that the RSR /should/ prevent power from getting to the injectors if it fails, but if he's got a spare, it takes 10 seconds to swap. I'd suspect the fuel pump relay before the ECU or wiring, since 88 has the decent wiring, and the fuel pump relay controls both the pumps and the injection.

A noid light will be your best friend on injection diagnosis, though.
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Old 05-15-2018, 11:27 AM   #10
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Quote:
Originally Posted by darksider415 View Post
No CPS on a 2.2 car, just hall effect in the dizzy. Since he has spark, that rules out the hall effect.

OP is right, in that the RSR /should/ prevent power from getting to the injectors if it fails, but if he's got a spare, it takes 10 seconds to swap. I'd suspect the fuel pump relay before the ECU or wiring, since 88 has the decent wiring, and the fuel pump relay controls both the pumps and the injection.

A noid light will be your best friend on injection diagnosis, though.
is the RSR the same as the A/C fan relay on those cars? may be an easy way to test it.
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Old 05-15-2018, 11:45 AM   #11
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is the RSR the same as the A/C fan relay on those cars? may be an easy way to test it.
Yes.
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Old 05-15-2018, 01:37 PM   #12
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Originally Posted by lummert View Post
You've tried the boost pressure over pressure switch. How good are the connections at the radio suppression relay?
The connections are good at the RSR. I just soldered some sh***y looking splice connectors and cleaned them up, but still no difference.
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Originally Posted by PromiseRing View Post
No pulse/weak pulse to injectors can be caused by bad CPS, RSR, corroded resistor pack, bad ecu, and some other things. Does the vehicle start on starting fluid?

If you are certain your injector grounds are clean, you should remove the connector for the resistor pack and file the spades clean down to bare metal. Being corroded caused a no start on my 940t. Do you feel the RSR click in KP2? You can bypass the relay temporarily by removing it and jumping the 12v wire (should be red) to whatever wire gives power to the injectors. I believe itís striped. Youíll have to look at a wiring diagram though.

As lummert mentioned, RSR connections can be gross. When I looked at them on the 740 the plastic was so old and rotted that it was booger consistency. I ended up cutting the harness and splicing in a Bosch style 4 post relay. All good now.
Last I checked, it ran on starting fluid. But not since I replaced the EZK module, but I haven't exactly tried either.
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Originally Posted by darksider415 View Post
No CPS on a 2.2 car, just hall effect in the dizzy. Since he has spark, that rules out the hall effect.

OP is right, in that the RSR /should/ prevent power from getting to the injectors if it fails, but if he's got a spare, it takes 10 seconds to swap. I'd suspect the fuel pump relay before the ECU or wiring, since 88 has the decent wiring, and the fuel pump relay controls both the pumps and the injection.

A noid light will be your best friend on injection diagnosis, though.
Yes, already replaced the hall sensor. The fuel pump relay is kicking on when it should. The injector side clicks on with the key on and stays until I turn the key off, and the pump side clicks on while cranking and holds until shortly after. And it sounds like it's clicking on and off while cranking... is that normal behavior?

I'll have to pick up a set of noid lights today just to be sure. No point in fiddling with the test light anymore.
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Old 05-15-2018, 01:46 PM   #13
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Oops I missed the part where you said 88 no CPS. I would definitely check the resistor pack for corrosion more closely.
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Old 05-15-2018, 02:29 PM   #14
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Labscope.
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Old 05-15-2018, 11:09 PM   #15
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Picked up a set of noid lights earlier this afternoon and tested the injector connectors again. The injectors are definitely not getting a pulse signal.
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Old 05-15-2018, 11:50 PM   #16
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Originally Posted by bmdubya1198 View Post
Picked up a set of noid lights earlier this afternoon and tested the injector connectors again. The injectors are definitely not getting a pulse signal.


RSR
Ballast resistor pack connector
Injector grounds

Do you 100% have spark? Did you try starting fluid again?
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Old 05-16-2018, 12:02 AM   #17
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I will check those things tomorrow. Where are the injectors grounded other than through the ECU? The ECU grounds are all good as well.
I’m 100% sure I have spark. My spark tester shows a signal. I have yet to try the starting flud again because it’s a bit of a pain doing that without help. I’ll give that another try tomorrow as well.
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Old 05-16-2018, 03:25 AM   #18
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The 2 10mm bolts on the intake manifold are your injector grounds.
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Old 05-16-2018, 09:40 AM   #19
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And that should show ground at any point? I thought that the injectors were NOT supposed to be grounded unless the ECU was doing so?
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Old 05-16-2018, 09:41 AM   #20
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Those are not injector grounds.
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Old 05-16-2018, 10:57 AM   #21
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Those are not injector grounds.
That's what I thought. I remember you or someone else saying that in one of my other threads.
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Old 05-16-2018, 01:04 PM   #22
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Pretty sure without the grounds being clean and tight the car won’t run. Are they the grounds for the ecu?
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Old 05-16-2018, 02:26 PM   #23
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Pretty sure without the grounds being clean and tight the car wonít run. Are they the grounds for the ecu?
From what I understand they are the grounds for the ECU, and they are all clean and tight.

I tested the ballast resistor, about 12.6 ohms between each of the terminals. Proper spec from what I understand.
As I've said before, RSR clicks on as it's supposed to. Whatever this issue is is coming from the ground side of the injectors, not the power side. They have sufficient power.
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Old 05-16-2018, 02:46 PM   #24
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if those grounds arenít clean, the ecu isnít grounded, which means the injectors canít be grounded. My statement remains then, they are also injector grounds.

Did you try starting fluid yet?

And just because the RSR clicks doesnít mean 100% forsure that the injectors are receiving full current. You could bypass the relay just for safe measure. Run 12v directly from the battery to the output wire of the relay (look at a diagram).
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Old 05-16-2018, 06:50 PM   #25
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Good enough!
Haven't tried the starting fluid, been on and off raining all day and never got the chance to do that. But I still see no reason why it wouldn't run on it.
I will try the bypass tomorrow.
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