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1G 93 laser no start please help!

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Sean92plt

Probationary Member
6
0
Feb 16, 2018
Chadron, Nebraska
I have a 93 Plymouth laser rs auto fwd nt. I bought a 92 turbo manual fwd parts car (every except the motor). I purchased a used 6bolt engine from a 90 eagle talon, so I did the 5 speed swap, and swapped on the 92 intake to match the wiring harness, ecu, and cas. I used the cas off of the 93 nt. I had the car running for a whole day. But I have no check engine light and no signal to my factory boost gauge. The next day I came outside I had no start and no injector pulse but I had spark. Nothing on my dash indicates that my ecu is booting up. I tested my pins in my ecu connectors and this is what I found. Pin 102,103, and 107 all have power, I have spark in all 4 cylinders(tested via spare spark plug). I have injectors pulse, and I also installed my cas while in tdc and alined the notches on the cas to the proper position. My room fuse isn't blown and also has power. I have compression in all 4 cylinders. The only thing that's not intalled is the downpipe. But I believe that the nt part of the interior harness may have something to do with me not having a cel or a boost signal. There's 2 plugs in my dash behind my ecu where the engine harness connects to the interior harness. But the car was a auto and that's what the other connectors are for because a auto the room signal goes to the tcu and as far as I know that connector isn't connected to anything. Could this be why my engine won't start because there's no memory? I've searched for a 92 connector for the engine harness but I cant find one anywhere. Could someone verify some of these thought it tell me otherwise? Thanks
 
As far as the wiring goes, there's nothing there that should affect the CEL. The boost gauge is likely, especially if you didn’t swap the dash harness as well. Fortunately for the CEL, you can check it at the ECU itself rather than relying on the light. This will tell you for sure whether the ECU is powering up and, if so, whether it is healthy. See: 1G basic ECU MPI circuit function

Did you check the engine coolant temperature sensor and the wiring running to it? You've also said you're getting the injectors pulsing, have you verified you actually have fuel spraying, i.e., the pump is working?
 
Yes I rewired my fuel pump with a relay and a switch and placed it in place of my power economy button. I pulled the fuel rail out and spun the cas to verify it was spraying fuel. And I didn't actually test the wires for the coolant sensor but I checked my sensor for resistance. I read this it says -
The ECU receives backup power on pin 103 from Junction Box fuse #19 (room) in the drivers footwell fusebox. This is used to maintain the RAM in the ECU's CPU and allow the ECU to power itself up.
But it was a auto before and it says that pin 103 of the tcu goes inside junction box(fuse#19) so if I don't have my tcu connector hooked up to my wiring harness I'm not getting power from my fuse? But I have power on 103 on my ecu.
 
I've already explained in the first part of my post that I have compression, spark in all 4 cylinders (verified with spare spark plug) my fuel pump was rewired with a relay. I have injector pulse and they are spraying. My cas is installed correctly. I had the car running at one point tho. Im starting to believe that my fpr is bad, or the room fuse #19 isn't powering my ram for the ecu or something close to that nature. Considering that Its a nt auto car the plug that goes to the tcu is just hanging it holds power to room fuse #19 for the ram memory. But I have power at pin 103 so I don't understand where the power is coming from. If anyone has experience in auto to manual swap and nt to turbo swaps please chime in
 
The fact that you had the car running at one point tends to suggest it is not a problem with the wiring. As far as I can see in the diagrams, back up battery power to both the ECU (pin 103) and TCU (pin 10) on the auto harness come from that room fuse #19, but they are not daisy-chained together.

Now having swapped the turbo M/T control harness into the car and not swapping the body wiring harness (leaving it A/T), you have not said how you mated the two together. The M/T harness would have the back up battery power coming through pin 5 to ECU pin 103 rather than the A/T harness would at pin 7 for, again, the ECU and TCU. So how did you make the connection at this junction where the M/T harness would have had a 14-pin connector and the A/T harness had an 18-pin connector?
 
I didn't connect my dash harness and my engine harness at all because I was told I didn't have to swap it with the manual I was told just to leave it alone. Which is why I'm trying to bring it up but do you think this harness is what hold my cel, and boost gauge signal wire? Could I just get 14pin manual connector for the dash harness and swap connectors with pinouts tools?
 
Just to knock it off your worry list. The tcu does not matter as far as the car starting/ running/ driving.
As far as the boost gauge and tach, I just noticed ur using a 90 ecu in a 91+.I know your using a different wiring harness. So I'll mention swapping pins 6 and 14.since your using that wiring harness I doubt ull have to add a wire for the maf, but I'll mention it for the hell of it too.
 
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My tach moves when I crank it over and I did swap those pins before I installed the 90s ecu. But I failed to mention that the car only ran with the 92 ecu which I'm sending off to get repaired. But it still doesn't explain why I don't have boost signal or cel on my gauge. I'm just gonna wait for the results on my ecu that's been sent to be repaired and tested (leaky caps).
 
Which is why I'm trying to bring it up but do you think this harness is what hold my cel, and boost gauge signal wire? Could I just get 14pin manual connector for the dash harness and swap connectors with pinouts tools?
Both the CEL and boost gauge signals run through that junction, so yes. But like I said, if you didn't swap the dash harness, it won't matter for the boost gauge signal.

Yes, you should be able to get the 14-pin manual connector for the body harness side or the 18-pin automatic connector for the engine control harness side. Either way, you have a little weeding through the details to make it all go together the way it ought to go. A rough list of the pin-outs are available in the links here: The 1990 Engine Control Wiring Harness.

But I failed to mention that the car only ran with the 92 ecu which I'm sending off to get repaired.

Hold the phone... the rest of everything else here is irrelevant if you have not verified in any way that the '90 ECU is good. Until you get the '92 ECU back or can confirm for us that the '90 ECU is good, we're all wasting our time with anything else here.
 
I don't know if it's related to my no start problem but I guess il work on that 14 pin connector and wait for my ecu to come back in the mail. It would probably be easier to get the 18 pin connector for the engine harness side to connect to the body harness side considering there's wires that won't be connected and don't want to just leave them hanging. Am I just trying to emulate the auto dash to the pinouts for the ecu? Do you have any suggestions to weeding through these diagrams and adapting watch pin to its connector?
 
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