1G 91 1ga starter relay clicks when trying to start the engine

[Nii]

Howdy y'all, so I've been running into this issue as of late, where my car will no longer crank.
For context, I've been working on getting my 1g started for the first time. It was cranking prior, but I got no spark. So I started the diagnosis process, and I ended up with something on the PTU side.

When I'd spin the CAS by hand with the key in the on position, the MPI relay would click inside the car, which I think that means its operating properly. So I continued down the line to the PTU, and I noticed that I wasn't getting a pulse from the ECU to the PTU. I Back probed Pins 54 and 55 and was getting a pulse. When I'd crank the engine on the PTU side, I’d get the 5-volt pulse to pin 2 the Y/R wire but no pulse to pin 1 the Y/B wire.

When I was lookin around, someone said that pins one and two were the pins responsible for getting that ECU signal, so I probed the rest of the PTU pins and saw that pin 6 was getting that 5-volt pulse. So I figured that they may have gotten swapped around or something, so I made individual quick disconnects for each wire and swapped them around. I tried cranking the car. Nothing happened, and it refused to crank. So I fugerd I burnt the starter motor and put a different one in, but again nothing.

When I turn the key to crank, both the MPI relay and the Starter relay click. From what I heard on the 1ga manual cars, the starter relay is not suppose to click because if it clicks, that means that there is a short or something. So I put the pins back to where they were originally, and still I'm just getting a click.

Also, for more information, when I was diagnosing the no spark issue, I found that the coil pack pigtail was broken, so I repinned it. But I'm not sure 100% if the pins are in the correct order. This is all a mess and I've been trying to find solutions, but I'm not the best with wiring and I'm having no luck finding the correct form thread I need.

For more information, the CCS is disconnected. The main ground from the battery to the starter bolt is there as well. The ECU from last time I checked is working properly. The CEL turns off after 5 seconds. The battery has been on a tender and puts out the correct voltage. I've used a jump box to check in case something was wrong with the battery, and I still have the same issue.

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[steve]

Thanks for making the jump here from Facebook. It's really hard to do more than the most basic issues there.

So this is for your 91NT?
Is the second and third pictures your coil connector?

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On a 91-99 PTU there are 8 pins, #5 isn't connected so you have numbered then incorrectly. I can't see the wire colors back in the harness for the ones you cut but the ends still connected to the connector look right. Switching pins 1 and 7 would not be healthy for the ECU. It puts 12v from the coil to the driver on the ECU.

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1 Yellow/Black OC2 to Coil
2 Yellow/Red IC2 from ECU
3 Black GND
4 White TACH
5 NC
6 Black/White Switched 12v
7 Yellow IC1 from ECU
8 Yellow/Green OC1 to Coil

The Coil connector looks like the wire are in the right place. When you look at the diagram you are looking into the connector on the coil. the same as looking at the back side of the harness where the wires come out.

Based on what you wrote first when you would spin the CAS by hand with the key in the on position, the MPI relay would click inside the car, which I think that means its operating properly. That indicated that the ECU was seeing CAS pulses and turned the fuel pump on. There are two relays inside the MPI case. The first is used to turn the power on to the ECU and most of the engine bay, the second is for the fuel pump.

You saw that you weren't getting a pulse from the ECU to the PTU. You back probed Pins 54 and 55 and was getting a pulse but when you would crank the engine on the PTU side, you'd get the 5-volt pulse to pin 2 the Y/R wire but no pulse to pin 1 the Y/B wire.

You should have seen 12v on pin 1 (Yellow/Black) and on pins 6 and 8. The PTU doesn't provide power to the coils it provides the ground to complete the circuit for current to flow through the coil. The PTU and the coils both get their power from the Ignition Switch not from the MPI relay but so does the CEL so if the light is turning on you should have power on both the MPI and IGNITION circuits. Did you check for power to the coils?

Getting the starter to crank is isolated from all this except for the ignition switch but it's a different set of contacts for the START signal than the one powering the IGNITION circuit. With your car being a NT I wouldn't expect it to have the factory theft protection circuit but does it have any aftermarket alarm or remote start added?

Without factory theft the circuit is really simple.

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The ignition switch provides 12v with it's in the START position to the Black/Yellow wire that runs to the Starter relay. Normally that relay is closed on a manual car and opens, disconnecting the signal, if the CSS isn't pushed in since it also in normally closed providing a path to ground for the coil in the starter relay. So with the clutch pushed in or the CSS disconnected the starter relay should be silent since it doesn't have to do anything and the signal from the Ignition switch should show up at the starter solenoid to cause the starter to crank the engine.

 

[Nii]

Thank you so much Steve for the wisdom! Yes the second and third pictures are for my coil pack. Yes this is for my N/T I've converted it over to a turbo car. The engine harness was swapped to a turbo harness. But the under dash harness and cluster are still the N/T variant. There are no aftermarket theft systems or remote start systems installed in the car from my knowledge. I did check for power to the coils but found that the wires were broken so I repinned and put the coil pigtail together. Prior I do remember getting voltage to the b/w wire that goes to the coils but couldn't verify the other two since the pigtail had two broken wires. I can definitely check for pulses if I can get the starter to crank over the engine again! And I can get you better photos of the ptu wires. The B/Y wire should get 12v but when I probed it I got nothing would that indicate there's a break in the line somewhere? And I'd also get 5 volt pulses on the sold yellow wire.

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[Nii]

So my 1g is still having a no crank issue when I turn the key to start it.

I noticed the starter relay is clicking when I do try to start it and I'm not sure why. It use to crank perfectly fine but now it refuses. I had an issue where it would spark every time I cranked the engine and I'm not sure if that's connected to the issue or not. The CSS is disconnected and there is no aftermarket Anti theft systems in the car.

This is the video of me trying to crank

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This is when it use to crank I'd get sparks from the starter

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[dwb]

Is the clutch safety switch still hooked up?
Sounds a lot like the issue I had, turned out to be the starter: https://www.dsmtuners.com/threads/1g-intermittent-starter-issue.544123/#post-153891021

 

[Nii]

No the CSS isn't connected

 

[steve]

If you listen closely the MPI relay should when you first turn the key to the RUN position at the same time as you see the CEL turn on. It should also click off after about 10 seconds when you turn the key off. Check to make sure that part is acting normally.

Secondly, because the fuel pump side has two inputs it get triggered first when you try to crank the car and then once the CAS starts pulsing the ECU also activates it's input and keeps the pump running while the engine is spinning.

Wife just walked in and reminded me I we have a date, I'll post more and finish my thoughts later.

 

[Nii]

Thank you Steve your always a legend I got the ptu all sorted out from my last post now I'm just needing to get this thing to start!

 

[steve]

So what I was trying to say was the MPI clicking might be normal behavior.

Sounds like it's time to get out the multimeter and start measuring where you're getting starting voltage and where it stops. As I've mentioned the starter relay shouldn't be activating normally and if it does it will keep the signal from reaching the starter solenoid. Probing the voltages a the relay will tell you what's going on. You should only have 12v and pins 2 and 4 when the ignition switch is in the START position and also at pin 3 going to the starter. If you don't see 12v at pin 3 then either the relay is bad or somehow you're grounding pin 1 causing the relay to activating.

Are you sure it's the CSS you've disconnected and not the other clutch switch?

 

[Nii]

I didn't know there were to switches and ill take a look but I was able to crank the car without stepping on the clutch. With that being said should I back probe the relay or am i good to unplug it and just probe the pins themselves. When i get home I'll probably unplug the relay and do it that way but just in case i wanted to ask.

 

[steve]

I didn't know there were to switches and ill take a look but I was able to crank the car without stepping on the clutch. With that being said should I back probe the relay or am i good to unplug it and just probe the pins themselves. When i get home I'll probably unplug the relay and do it that way but just in case i wanted to ask.

That would seem to check that you got the right switch before.

Pulling the relay and checking the pins will tell you the first part (that you have power to the relay) but not tell you if the relay is passing the signal or being triggered.

With it disconnected you'll want to measure the resistance to ground of pin 1. That's the wire that runs to the CSS and from the CSS to ground. When it's grounded, the relay coil is grounded and it activates the relay.

So you'll still need to back probe or measure at the starter to see if you're getting 12v to the solenoid.
To test the starter, you can buy one of those remote starter switch or just take a wire and short the solenoid to the B+ terminal that runs to the battery. That will tell you if the starter is the problem.

https://www.harborfreight.com/1224v-remote-starter-switch-70597.html

Amazon.com

 

[steve]

Hey Steve I think I was responding to your post on the DSM tuners website I just wanted to message ya to verify a quick question!

I did some probing and I'm getting 9 volts to the starter solenoid on that little spade connector. On the other pigtail side of that part of the harness I'm getting 12 volts to both y/b wires. I'm getting proper voltage too everywhere that I was supposed to get voltage to. When I did an ohms check to pin 1 I was getting 0.19 ohm and no volts to pin 1.

Do you think it's my relay that's gone bad? Or maybe since I'm getting 9v instead of 12v to the spade that there is a break in the wire? And the 12 volts only happens when cranking.

9 volts to the starter solenoid when?

What Yellow/Black wires? There are Black/Yellow going to the starter relay and from it to the starter. Are those the ones you mean? Which pin #s?

If you are seeing 0.19 ohms on pin 1 of the starter relay to ground that means somehow you have continuity to ground for the relay coil and when power is applied to pin 2 the relay is going to activate breaking the connection to the solenoid which will keep the starter from spinning.

Since the power going to pins 2 and 4 or the starter relay comes from the ignition switch when it's in the START position and no other time you should see any voltage on any of the pins except then and at that time is things are correct you'll have battery voltage at pins all the pins.

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All this information is implicit from the little diagram. If you think about it like water flowing from the top to bottom from two places, the battery to the starter and from the ignition switch in the START position. First it hits the starter relay where is splits in two. One side goes through the switch in the relay and the other side through coil in the relay. Since the switch is shown as normally connected to the output (Normally Closed) it continues through a few connectors before reaching the starter solenoid terminal and into the starter where it goes through the coils inside activating the switch in the starter that is shown as Normally Open, so when current flows in the solenoid the switch closed and the battery is connected to the starter motor.

Going back to the other side of the starter relay power get to the top part of the coil again when the ignition switch in the START position and normally passes through to the CSS and to ground since the CSS switch is Normally Closed making the connection to ground. Because current is flowing through the starter relay coil the relay activates and the switch inside goes from Normally Closed to open breaking the path to the starter solenoid. If you push in (or disconnect the CSS) the clutch the CSS opens and no current can flow in the starter relay coil so it doesn't activate and it's switch stays closed so power can reach the starter solenoid.

I hope I'm not being insulting, I don't know your comfort with electrical things but it seem like a more basic discussion might help.

Also note I don't waste time discussing on FB because anything useful disappears and nobody can benefit from it later. It took about an hour to put this post together so I would like to make it as useful as possible.

 

[Nii]

Thank you! Your not insulting at all electrical is not my strong suit but I'm willing to learn. I have a basic understanding of some things and others not so much. I'm self taught on everything when it comes to cars and dsms so I will have pot holes if knowledge I don't have any degrees in engineering or automotive work or whatever haha! So I'm doing my best with what I've got I truly appreciate you taking the time to help me and I hope to keep gathering more knowledge!

I also didn't answer your question sorry I get 9 volts when cranking to the spade connector. The black/yellow wires in question are the two wires that become 1 going to the spade connector on the starter motor.

It looks to be pigtail a-10 and pins 2 and 4 that are the two black and yellow wires that I'm referencing but I may be reading the diagram incorrectly

 

[Nii]

My starter relay no longer clicks but this black relay next to the two 15amp fuses clicks now. The MPI relay also continues to click. Would this relay be the reason it will no longer crank?

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[Nii]

I pulled what I think is the anti theft relay and now another relay in my engine bay is clicking but again the starter relay is not clicking. I also found 3 wires by the fuse box that were cut so I repaired them but again no luck with no crank

 

[Nii]

Had my wife crank the car the relay that is clicking in the engine bay is the alternator relay. Could that cause the no crank issue?