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Something to note for those using the host car main/fuel pump relay (instead of the SVX main/fuel pump relay). This is for an EG33 into a 1999 Impreza 2.5RS.

Power for the IRIS valve, IACV, purge solenoid and EGR solenoid comes directly from the main relay and they are then grounded by the ECU. I missed this power wire since I removed the SVX main relay and had a consistent, but fluctuating idle (it would bounce from 1000-1500 RPM 95% of the time, but drove fine) and CEL codes 24, 34 and 35.

So, at plug B5/E1 (one of the large square plugs by the rear of the passenger head), Pin #8, there is a LR (blue with red stripe) wire. This splits to the 4 solenoids on the engine harness side, leave this alone. On the body harness side, take the blue w/ red stripe wire and give it 12V switched power. You can use the same source you use to power the injectors and coils (I used a power wire directly from the Impreza main relay, mirroring how the SVX was set up). If you need wiring diagrams, there are here.

Any questions, don't hesitate to ask.

cheers
 

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1995 Impreza
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Running Rich

Hello everyone, I've been lurking since I got my EG33 swapped GM6. I've learned tons from this thread so thank you!
I've run into a problem recently with the idle or AFR. I went for a test drive and after a few blocks it died and I couldn't keep it running. It will idle fine when cold, but after the warm up cycle or closed loop I think its called, it runs very rich until it cant run any longer. It almost seems like its not getting enough air.
After searching all over this thread and the SVX forums I cant find anyone with the same situation as me.

Here are things I've checked or replaced:
- Fuel pump (new 255 now)
- Fuel pump regulator
- Spark plugs (old ones were soaked with gas)
- Air box and MAF (MAF says Nissan, I think its a Z32)
- Downstream O2 sensors and wiring (both heat up normally)
- Throttle body (clean and moving freely)

The only things I can think of are IACV or upstream O2 sensor?
The car sat for about a year while everything was being stripped, fixed and replaced (minus the engine and ECU).
Is there something I'm missing here? I'm sorry if this has been covered before or already solved by someone. Any info or ideas would be great, thank you!
 

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Is the idle bouncing/fluctuating until it eventually stalls out? Just slowly bogs and dies? Erractic?

Does it drive normally other than idle?

Any CEL codes?

Are you tuned for the Z32 MAF? I don't know of any MAF that are a direct plug & play for the SVX. A 2.2L Legacy one will work for idle/low rpm/diagnostic purposes, but it's scaling is incorrect for the EG33.

cheers
 

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1995 Impreza
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Thank you for the quick reply! I had to start it up again and check it's idle behaviour before it dies.
It runs longer now, about 1-2 minutes before it goes into the rough idle. I got it to keep running in the rough idle for a little while and it is fluctuating.

As for the MAF, I have no idea about the tune. The previous owner said he had remapped it to run E85 and had put bigger injectors in. Not sure if that's true or not until I pull the injectors and look at them. Also he used a iwire harness merger.

For CEL I'm not sure how to check for any codes. I had read that OBD1 EG33s use a series of engine light blinks to indicate the code. However my dash lights aren't hooked up. I've seen some OBD1 readers but heard mixed info about them.

As for driving, it has ran smoothly in the past. It cuts out when not pressing gas occasionally.
After I ran into this issue it will not stay running even when in gear and throttle is applied.
 

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After reading my own post it makes me lean towards a stand alone ECU more and more with each odd issue I find haha.
 

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Baby❤Daddy
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you may want to contact iwire. i'm not aware of brian doing harness for the eg33. infact, last i talked to him he explictly said he would never do one. not to say he didn't, just might want to check up on it. it sounds to me like there could be some issues here in what the previous owner has told you versus reality. which can cause all of what you're experiencing.
 

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'MURRICA!
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Do me a favor, take a couple pictures. One of the engine bay, one of the ECU.

Something's fishy here. EG33's don't do E85. They don't do remaps. IWire has repeatedly said he wouldn't touch them because the wires are old/brittle and he can't guarantee the harness will be any good (and all of that is true).
 

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The person I bought the car from gave me all the info second hand form the swapper (who they had bought the car from). So I'm not sure what's true. When I was digging around the SVX forums I thought I read that you could only chip the EG33 and not remap it.
Sorry for all the ignorance on my own car, I'm new to EG33s and engine swap/harness merging.









 

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'MURRICA!
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ECUTune chip w/ the Z32 MAF (and probably purple-colored fuel injectors too). That extra wire coming off the ECU is for switching fuel maps.

That being said, I'd look into hooking up your CEL and finding the wires you need to connect together. Step 1 for troubleshooting is asking the ECU what it thinks is wrong!

Thanks for the photos, I'll reply more once I get home!
 

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Thanks, that makes a lot more sense now that you told me. I'll have some time this weekend to pop the dash out and try to hook the wiring up to get some codes.
 

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1995 Impreza
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ECUTune chip w/ the Z32 MAF (and probably purple-colored fuel injectors too). That extra wire coming off the ECU is for switching fuel maps.

That being said, I'd look into hooking up your CEL and finding the wires you need to connect together. Step 1 for troubleshooting is asking the ECU what it thinks is wrong!

Thanks for the photos, I'll reply more once I get home!
I hooked up the gauge cluster wiring and the only light I can get is the oil light. When I use the turn signals or headlights the heat gauge goes up and down haha. So I have some wiring gremlins I didn't know about.

Another odd thing, the two "u-check" plugs were already plugged in. As were the two diagnostic green plugs. I unplugged both and each separately and no change.
I was under the impression those should always be unplugged unless retrieving codes or running diagnostic checks.

I thought I read somewhere that the dash lights shouldn't be affected by an EG33 swap. Only the tach would be off. What I plugged in was the two main long plugs on the sides of the cluster and the small 4 pin right behind the tach.
If anyone knows what I'm doing wrong or if Im supposed to have some signal altering wiring done or Dakota digital box let me know. Thanks!
 

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The person I bought the car from gave me all the info second hand form the swapper (who they had bought the car from). So I'm not sure what's true. When I was digging around the SVX forums I thought I read that you could only chip the EG33 and not remap it.
Sorry for all the ignorance on my own car, I'm new to EG33s and engine swap/harness merging.









This is my old stuff. I'd be very interested in knowing where you got it from. I haven't seen any of it in about 5-6 years.
 

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This is my old stuff. I'd be very interested in knowing where you got it from. I haven't seen any of it in about 5-6 years.
Hi Jake,
I bought the car about 2 years ago from a guy in Eau Claire, WI. I don't remember his name, only that he had a big wing miata on RPF1's that looked rather track ready.

I know it was quite awhile ago since you saw this car, but do you remember any of the wiring that was done with those test plugs? Were they used to switch maps? Thanks for any information you can remember.
 

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The last I knew, about 4 owners and a slew of parts ruined/exchanged/etc later, the car was parted out. I now know who you bought it from, and I'm glad we're connecting the dots.
The wiring is mine, and was 100% when I had it. Iirc, I was asked to troubleshoot some part of it but refused based on the owner at the time.


The test connectors should not be connected. The tune changes based on a 12v power to that gold connector. The primary map is for pump gas, the secondary with 12v applied is e85. The ecutune maps are pretty terrible calibrations, to be honest. The injectors you have should be cleaned or replaced, and same for the z32 maf.
I would be highly suspicious of the engine's health. Have you tested compression and leak down?
 

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Thank you Jake. That info is really helpful! No compression test yet, although that's a good idea. I think I'll get it back onto the factory map and check/clean the injectors and MAF and go from there.
 
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