1G Fresh rebuilt 94 2.0 non turbo dies when throttle applied

[Cooper8005]

Rebuilt a 94 non turbo 2.0. I replaced fuel filter, injectors, plugs/wires, vacuum lines, aftermarket air intake (since it didnt come with one), aftermarket temp gauge, oil pressure and tach since no gauge cluster. Cannot get it to run once as throttle is applied, it dies out.

Does anyone have any ideas what could be causing this issue? Or where to start.

I have checked for vacuum leaks and haven't found any, getting plenty of fuel, tired taking the IAC connector off to see if it would run better (it didnt change) and checked power coming to it, which it does.

 

[steve]

What ECU and MAF are you running?

 

[Cooper8005]

Pretty sure this is my problem. I was getting no power to my tps and checked the computer and wasn’t getting a signal so opened the computer and found this.

Question is can a switch to a federal computer without having to change any components since this one is a California emission computer.

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[steve]

The major difference between the two is the EGR system.

IC105 is for ISC coils B1 (ECU Pin 67) and B2 (ECU Pin 68), at some point you had a shorted ISC in your TB and if it's still there it will blow any new ECU to connect and turn on.

 

[Cooper8005]

So is this wire I got circled supposed to be the ground wire for the isc?? This is a race car so a lot of stuff isn’t connected and if there is a short in the isc do I need to get a new one as well or could it just be that there was moisture in the ecu? It sat for six years under a tarp before I brought it back from the dead.

The major difference between the two is the EGR system.

IC105 is for ISC coils B1 (ECU Pin 67) and B2 (ECU Pin 68), at some point you had a shorted ISC in your TB and if it's still there it will blow any new ECU to connect and turn on.

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[steve]

I can't tell what that wire is. It might be the Idle Position Switch connector which is missing from your Throttle Body.

It should go where I circled in green.

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The IPS has three purposes, first it is the throttle stop, keeping the butterfly from closing too far and biting into the TB bore. Second, it sets the position of the butterfly when the throttle is closed which controls the baseline air bypass. Third, the IPS tells the ECU that the throttle is closed (or open) which the ECU uses to perform idle speed control, dashpot emulation, or decel fuel cut.

The Idle Speed Control stepper sits below the TB bore and the ECU uses it to control the idle speed under various engine loads, to provide additional air during starting, and as the dashpot when the throttle closes.

In this image of a 1G NA TB the ISC is an original brown connector/metal body version that are known to have coils that short. It should be replaced in any case with a black plastic late modem ISC. You can also see the IPS.

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[steve]

You might want to post more pictures of the engine bay so we can see what else is going on.

It's possible that the ISC was shorted from moisture but it's also likely it had been like that for awhile.

 

[Cooper8005]

I bought a new ISC like you suggested since I had the brown one and I got a computer on its way as well. Went with the same one I had in it.

I will take a picture of it when I get home from work, but there is a lot missing since this is a dirt track car. I do have a video of when it was idling trying to apply throttle which I can send but that is when I noticed I wasnt getting any power to my TPS and everything I read pointed to the ECU, so I popped the cover off the ECU and noticed the fried board.

 

[steve]

If you had mentioned it was a race car to start with I would have suggested the Federal ECU. The California ECU is likely going to have an issue with no EGR and may be stuck in limp mode because of it. The MD166255 is also the most common DSM ECU made.

 

[Cooper8005]

I haven't done anything with the EGR, the system is still all in tack. I just went with I had since I am getting close to the wire and already went over budget on it.

If it will save me a heartache later I may go with the federal.

I do got a question though. With this not being hooked up is it going to cause me issues or do I need to replace the the plug? I already have an aftermarket water temp gauge, but I think I read somewhere that if that is not plugged in I could have issues, but I maybe wrong. I have read a lot of things lately and was starting to get lost.

I am super green with four cylinders, but I am trying to learn and understand them vs just taking them to a shop and glad I found this site since it has helped me a lot on things so far. I know more about old school cars/trucks with carburetor engines and less electronics since electrical is not my strongest suit.

I appreciate all the help you have been giving me, so thank you very much.

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[steve]

That one should be for the AC, which I assume is gone.
There are two other temp sensors on a 1G thermostat housing. The Gauge warning light is a single connector and the ECU Coolant Temp Sensor is the lowest one and it's the important one.

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[Cooper8005]

Prefect, Five is hooked up and does not appear to be damaged. Number four is where I put my aftermarket gauge sensor, so I am glad I did that right.
Thanks for summing that up for me.

Will not have the computer until the 31st and with all your help, I will have the IPS installed and the ISC replaced before hand. Hopefully I dont run into any other random electrical issues and this thing will be good to go.