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Discussion Starter · #21 ·
Just to confirm (despite the title of this thread) currently the vehicle is a 1990 Tracker, all stock, and nothing from any other vehicle, correct??
I believe that the distributor should hold vacuum for about 30 seconds, if the diaphragm is ok. It doesn’t??
Yes... Vehicle is a 1990 with no mods or parts from other vehicles. The distributor holds no vacuum, removing the hose does nothing as it is basically a vacuum leak at this point. I tested using a tee on the distributor line connected to a vacuum gauge... The gauge did not register any vacuum, when I removed the tee and connected the gauge to the vacuum port on the driver side of the throttle body I got 5 in/hg at idle and 14 hg under light acceleration... I believe this is fine since that's a ported vacuum port. This is how I deducted the diaphragm is busted.

How do I remove this diaphragm? I tried removing a screw holding it but it didn't come out all the way, like something else is holding it besides the screw...

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Discussion Starter · #22 ·
For those following this thread, I am sorry to report the car failed to start this morning :(
I'm very sad about it, I thought I had nailed it... I do not have power at the injector nor a negative pulse, my logic probe gives me a solid ground on the injector and no power. The ECU power on, CEL light gives me a 12, I do have spark I tested that, and fed 12 volts to the injector in short bursts using an adjustable power source I have, car wanted to start when I fired the injector since there was fuel there from when the injector fired, but I get no power from the ECU...
I visually inspected the ECU, retested the caps, retested all connections, everything checks out... I am out of ideas and ready to take the ECU to a specialist...
Feel defeated, my glory was short lived, If anybody has any ideas, I'm all ears...
 

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99 Tracker, 5 door, 2L, 4x4
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Feel defeated, my glory was short lived, If anybody has any ideas, I'm all ears...
The monitors on this forum hold any guessing and non professional diagnostics as not approved.. so you are defeated..
 

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Discussion Starter · #24 ·
The monitors on this forum hold any guessing and non professional diagnostics as not approved.. so you are defeated..
Not sure what you mean sir.

My apologies if I missed the joke... Would you be able to provide some relevant information about the ECU which will allow me to perform further troubleshooting?

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I’m not quite following. You’re advising you’re getting no power from the ECU....where? Are you saying that a noid test has failed? I don’t know if your adjustable power source would pulse the injector as quickly as the computer would, nor does that indicate, of course, that the computer is doing this on its own.
When you changed the caps, did you clean the board (top and underneath??) and check for continuity?
And what about your issue with the distributor not holding vacuum?
The ECU provides power to the injector via the red wire going to it. Did you check for continuity on that circuit? If you have a short on that circuit, it will blow the injector driver in the ECU. If you look at your photo, you’ll see a vertical plate, where there are 4 screws attached to it (look at the bottom of the photo that you have above). The drivers are there, normally listed as Q1 or Q101 (or 101-104 for the 16v).
What happened to the distributor that holds no vacuum? What was the result of your fuel pressure test?

You advise that you have spark...so your engine should run when you spray starter fluid into the intake. Does it?
 

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Discussion Starter · #26 ·
I will answer all your questions :)
I’m not quite following. You’re advising you’re getting no power from the ECU....where?
The red wire at the injector connector

Are you saying that a noid test has failed?
Yes it has, I have a solid ground on the connector on the ground cable and no power at the red wire, my test light did not blink

I don’t know if your adjustable power source would pulse the injector as quickly as the computer would, nor does that indicate, of course, that the computer is doing this on its own.
You're right on both accounts, the purpose of pulsing the injector using a adjustable power source was to confirm it was in good working order, which it is, injector works, the ECU is not firing it

When you changed the caps, did you clean the board (top and underneath??) and check for continuity?
Yes I did, on both accounts, and in fact it worked for two days, then failed again, I retested my capacitors and continuity again, everything was normal.

And what about your issue with the distributor not holding vacuum?
I discovered this just now, because when the ECU started working ( for the two days it worked fine ) I still felt acceleration was sluggish, so I checked the timing with a timing light and tested the vacuum on the distributor vacuum advance, then I found out it was bad, I just found out about this at this moment, but this is unrelated to the ECU problems.

The ECU provides power to the injector via the red wire going to it. Did you check for continuity on that circuit? If you have a short on that circuit, it will blow the injector driver in the ECU. If you look at your photo, you’ll see a vertical plate, where there are 4 screws attached to it (look at the bottom of the photo that you have above). The drivers are there, normally listed as Q1 or Q101 (or 101-104 for the 16v).
Yes, on both wires, they come to the ECU ports on the green connector at the far left, I used some alligator clips and a multimeter and both wires have continuity from the injector connector to the ECU connector. I see the drivers but I don't know what kind of transistors these are, or how to test them. I suspect this is next in the list of possible failure points, do you know how to test these?

What was the result of your fuel pressure test?
31 PSI

You advise that you have spark...so your engine should run when you spray starter fluid into the intake. Does it?
Yes it does, I have spark


Hope I answered all your questions.
Thanks for the help!
 

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A couple if simple answers first - factory spec on fuel pressure is 34-41 psi. If your procedure was correct, then your fuel pressure is a bit too low.

Regarding the noid test - have you performed it at the ECU connector itself. Have you confirmed that the resistance across the injector is 0.8-1.8 ohms? If you disconnect the connector at the ECU, and test for resistance on the connector itself (with the injector plugged in) do you get 0.8-1.8 ohms? When looking at the drivers, you should see damage, if they are the problem. When my drivers fried (because of a short in the red wire), the ECU circuit board around the Q101 driver was very noticeably burned.

A problem with injector drivers was one of the reasons I found this forum. You may wish to trawl through a couple of pages of this:
The red wire for your injector runs the Q101 driver (12v) (green ECU connector pin 8)
The yellow wire runs the Q02 (ground) (green ECU connector pin 17.
The transistors the run the injector drivers cannot be tested in circuit - they need to be removed from the board.
I see that the above link indicates two drivers for the injectors are 2SB1020. In the thread above, it was suggested that the D112 circuit on the ECU might be part of the problem, which is apparently 2DS1415. I don’t believe that I changed D112 during this repair. What we did do, however, was put a 5v inline fuse into the injector circuit, so that if the red wire fried again, it would take out the 5v fuse, rather than the injector drivers.
 

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The monitors on this forum hold any guessing and non professional diagnostics as not approved.. so you are defeated..
Yeah. Ya' gotta' watch those 'monitors'. They can be sneaky rascals. ;)

100918
 

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Discussion Starter · #29 ·
A couple if simple answers first - factory spec on fuel pressure is 34-41 psi. If your procedure was correct, then your fuel pressure is a bit too low.
I figured... the pump probably hasn't been replaced in a long time... I will look into a new pump once the car is operational again

Regarding the noid test - have you performed it at the ECU connector itself. Have you confirmed that the resistance across the injector is 0.8-1.8 ohms? If you disconnect the connector at the ECU, and test for resistance on the connector itself (with the injector plugged in) do you get 0.8-1.8 ohms?
No, I have not performed these tests... I did not test the resistance across the injector and my continuity test only covered from the connector at the ECU to the injector connector, I had practically zero resistance on this wiring. The car is now at my friend's place about 5 blocks from my place ( this is where it died last time ) Whenever I have a chance I will take a stroll and bring my multimeter to perform these tests and give you results.

When looking at the drivers, you should see damage, if they are the problem. When my drivers fried (because of a short in the red wire), the ECU circuit board around the Q101 driver was very noticeably burned.
No visible damage at all at the ECU, I pulled it out and it looked exactly the same as it did when it was working... I'm puzzled

A problem with injector drivers was one of the reasons I found this forum. You may wish to trawl through a couple of pages of this:
I will, tomorrow I'm taking the ECU to a local shop specializing in car electronics, still I am going to do the reading you suggested and will ask them to give me a detailed report on what failed, information may be important for other forum members.

Thank you Bex, your help is invaluable.
 

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Discussion Starter · #30 ·
ITS ALIVE!

I measured the injector resistance and it was within specs, with and without the connector plugged and measuring from the ECU connector... So I found a multimeter able to register micro farads and decided to measure my new caps... One of them was off... Lasted two days, very low quality China part.

I replaced it with another and it started right off!!

Now I have to order those caps from the US from a reputable brand... What I can find in the local market is very bad quality

So for now it's running but I don't know for how long... Hopefully it will last until I can import the good quality caps from the US.

Here's a picture of the engine and car




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Yep, many of us have learned to stay away from some of the stuff coming out of China. If you want a good US source for the caps, post #34 here:
 
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Discussion Starter · #32 ·
Here's what I ordered. One of the part numbers was not available so I replaced it with a Panasonic... I'm hoping it will do the job. My ECU uses a 10uF cap instead of the recommended 22uF, perhaps because it's an older model.

100950
 

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always replace like for like in uf rating, higher voltage is always fine. Panasonic caps aren't too bad, if you have a hot glue gun, a small blob where they meet the board once soldered in is always sensible so they don't vibrate and metal fatigue crack the leads.
 

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What is your ECU model number??
 

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Discussion Starter · #35 ·
Here is a picture of it, I believe the part number is on top? This is what they call a Golden ECU, when I replaced the caps, I found out one of the capacitors had a different micro-farad rating... I used what was originally in the ECU.

100961
 

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The model number of the ECU will be on a sticker on the case. It will be 33920-XXXXX. It’s the X’s that we need to know.
 
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