New member here, looking for some assistance

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New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 4:03 pm

hey guys, been working on getting my 1990 GT-FOUR running, its a 3RD gen swap, and im using a MSPNP2 (TS9092) and the original gen 2 harness, got everything back together now but the car is only running on cylinders 1 & 2, #3 / 4 are getting spark but no fuel, is this an issue with the ECU im using? 1990 JDM ecu pinout should be the same as 90-92 USDM ecu? is the reason im not getting fuel possibly because of the injector resistor pack going bad? how do i test the resistor pack? not sure what to do, its probably something simple but i really dont know anything about electrical stuff, i unplugged injector #4 and used a voltmeter and it gets 12volts but i dont know if it is being signalled to inject, i cranked the car for a while with the coil disconnected and plugs 3/4 were dry.
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 4:05 pm

also should mention did a compression test all 4 cylinders were around 155psi with only a few psi difference
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Re: New member here, looking for some assistance

Postby alltracman78 » Mon Oct 18, 2021 4:42 pm

Power goes from the fuse to the resistors to the injectors and grounds through the ECU.
So if you have power at the injectors the resistors are good.

You can try swapping with the 2 good injectors to make sure they're ok.
You can check the wiring by making sure there is 12v at the injector wires on the ECU connector. That's with key on and engine not running.

Who modified your harness?

If you don't know anything about wiring this isn't a good project for you IMO.

A couple of things.

The JDM wiring is slightly different for some of the emissions and body stuff. Just FYI.

90 - 91 are the same and 92 - 93 are the same. 91 and 92 are not (a lot of places mix this up because they confuse it with the MR2).

92 - 93 wiring is ALMOST identical to ST205 wiring. There's something like 5 wires different? Been a while. 90 - 91 is similar, but there are more differences.
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 5:01 pm

the ST185 harness im using is completely original other than the knock sensor plug i switched, i used the distributor cap from my 2nd gen engine as the plugs were different.

maybe i am in over my head a bit but i want to figure this out, im using a standalone ecu that has its own MAP sensor and i wired in an iat sensor to the ECU, the ecu is supposed to be plug and play for 90/91 3sgte
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Re: New member here, looking for some assistance

Postby alltracman78 » Mon Oct 18, 2021 5:08 pm

OK

IIRC the intake temp sensor is using the EGR wiring. You can just repin that. Might have a couple other issues. I can't remember right now.

Unplug the ECU connector that has the injector wires and check for 12 with the key on.

Where are you located?
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 5:29 pm

i am located in Atlantic Canada, i checked the injector wires on the ECU connector and they all have 12V,

beginning to feel that injector 3/4 are plugged, the engine was sitting for a while so there may be some debris that could have made its way into the fuel line :/

kinda makes sense as those are the first two injectors and dirt would have fell onto those before injector 2/1 if im getting 12v at the injector and 12v at the ECU it should be firing correct? if the injector was plugged would i still hear it clicking? my grounds should be good i checked and cleaned them all when i was putting the engine back together, main ECU ground is on the intake plenum, another ground by the alternator to body, ground from under coolant neck to body, two grounds from negative battery terminal one is connected to the trans, and the other by the strut tower
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Re: New member here, looking for some assistance

Postby alltracman78 » Mon Oct 18, 2021 6:47 pm

Easiest way to check if the injectors are ok is swap the 2 that are working with the 2 that aren't.

If you have 12v at the ECU plug either the injectors or the ECU is bad.

There's an old school tool called a noid light that you plug in instead of the injectors to see if they're being fired.
You can also use a test light to do this. Engine has to be cranking though.

If you mess with the injectors themselves make sure the seals are installed correctly. You can get a vacuum or fuel leak if they don't.
A vacuum leak on a MAP based system will give you a high idle.
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 7:03 pm

ECU is brand new so should be good, I could try my 2ND gen ecu to verify that the MSPNP2 is working. As for swapping the injectors I don't have the time to do it, I'm leaving for work and the car is going into storage for the next 6~ months, kinda unfortunate how the timing worked out as I was delayed getting everything back together, was hoping to get the car running good before i had to leave but seems like it's gonna have to wait untill the spring to be finished. I could probably get the injectors switched and verify that's the problem, but I'm not gonna have time or money to get them cleaned/replaced
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Re: New member here, looking for some assistance

Postby alltracman78 » Mon Oct 18, 2021 7:54 pm

Would be nice to know what the problem is before you go. Even if you can't fix it.
Will make it easier to get back to IMO.

And that way if something else crops up while it's sitting you'll know the 2 aren't related.

AFAIK the 2 ECUs aren't swappable without some modifications. Stock ECU is set up for gen II electronics. MSPNP2 is set up for a few differences. Plus you have a gen III engine.
So I don't think it's a simple as just removing the MSPNP2 and putting in the stock ECU. Things will act funny. Though the injectors should fire either way. I don't think the wiring moved. *I just went and checked the manuals. Injector wiring for all 3 is the same. Wanted to make sure I didn't give you bum scoop.*

Wouldn't be the first time a brand new part was bad. Especially aftermarket.
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 8:24 pm

Was thinking just trying the gen 2 ecu to see if it fires the injectors I know the car probably won't even fire up like that but it should be enough to see if it's squirting fuel, also the car fires no problem and idles even though it is running on 2cylinders, the reason I went with the MSPNP2 was so I could keep all the gen 2 stuff on the gen 3 engine, going with the OEM gen 3 ECU would have required me to either have another harness made or to modify and repin the original harness, i have looked at the 3RD gen swap threads and you would also need the 3rd gen ignitor and MAP sensor also people have issues with getting the AC to work and wiring for the WTA intercooler I decided to delete the AC and have a FMIC, so overall the MSPNP2 is a much cheaper alternative than using the gen 3 ecu and should work fine, as everything it needs to control the engine is the same on both gen2gen3
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 9:10 pm

alright so im pretty sure i was able to verify the ECU is properly signalling the injector, i took the plug off the injector and put the test light on the terminals and it flashes while im cranking the car over, so pretty much confirms the 2 injectors are bad/plugged. thanks a lot for the help i really appreciate it, unfortunately my time is up i'm leaving the day after tomorrow and i have a bunch of other stuff i need to do, so gonna have to wait till the spring. feeling fairly confident thats the problem anyways.

oh well i can spend the winter doing my research and maybe come spring i will have a better understanding of the car and its systems! have learned quite a bit in the last few weeks getting everything put back together but there is still tons for me to learn :)
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Re: New member here, looking for some assistance

Postby Oxygenz » Mon Oct 18, 2021 9:58 pm

here some pictures of the car figured you guys would enjoy
Attachments
ST185-4.jpg
ST185-2.jpg
ST185-1.jpg
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Re: New member here, looking for some assistance

Postby Oxygenz » Tue Oct 19, 2021 2:15 am

its probably worth mentioning that the car is heavily modified at this point.

the previous owner had made tons of modifications that i am trying to make sense of, things like car alarm and extensive sound system, battery relocation, the fuel pump resistor has been deleted and i only found that out because i had the resistor but not the secondary harness or wiring to plug it in, also some work around was deleted/modified from the main fuse box.

then i had all these little things too make the 3rd gen engine work, the coolant inlet doesn't match/has less ports for the cold start injector/AC temp switch, also the coolant lines are different for the turbo, knock sensor plugs are different, different vaccum ports on the intake, different distributor cap, but all of these are easy work arounds,

the main problems people have with the 3rd gen swap is in using the 205 ECU, you can make all the 185 electronics work on the 3rd gen engine if you can go standalone, im not using alot of the 185 electronics like the VSV and TVIS, EGR , cold start injector, A/C, 02 sensor etc, basically trying to make things as simple as i can as i dont need to worry about emissions or compliance with road safety, luckily i dont need to have my vehicle inspected to be able to register and drive it.

i know i have a long road ahead of me in figuring this car out but i plan to keep it and want to learn as much as i can.
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Re: New member here, looking for some assistance

Postby underscore » Tue Oct 19, 2021 5:13 pm

At least now you know what the issue is. As soon as you get back to the car you can send the injectors to be cleaned and be good to go.
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