ST185 swap fuel/air ratio, Getting black smoke from my exhaust Options

[ManpreetS512]

Hey 6GC Members,

I hope you all are doing well.

My name is Manu and I am new to this site, so I apologize if this has been discussed else where and I couldn't find it. If there is already a thread, please point me to it and i'll look it over.

I have a 97 Celica GT with a JDM ST185 swap with JDM ECU. The engine is stock with no modifications thus far. This car was given to me as it sat in a garage for 10 years without ever running. Needless to say, I've gone through a lot of different issues starting with replacing fuel lines, gas tank, fuel pump, cold start injector, etc. to get the motor to crank up again.

The car did not have an exhaust since the previous owner didn't purchase one and mainly wanted to get the swap to run. When we got the motor to crank (finally), it was running really rich. So I took it to a muffler shop and had them add a catback exhaust from the downpipe back with turbo muffler and all 2.5" piping.

Now the car has black smoke coming from the exhaust when it cranks up, so I am assuming that the engine is still getting too much fuel. So friends of mine recommended that I may need a ECU tune but in order to do that I would have to purchase an expensive standalone ECU and then take it to a certified shop and have them tune it.

Before going down that route I wanted to post here to see if anyone has seen similar issues with their swap or this engine in particular? I was also wondering if anyone here knows if the O2 sensor on the downpipe is needed for the ECU to function properly? I ask because when the car was at the muffler shop, I saw the O2 sensor on the downpipe and it was not only rusted but the wire connected to it had been snipped clean - so that O2 sensor in not connected to the wiring harness at all. I also get no check engine light which is odd.

I'm thinking that the O2 sensor on the downpipe does need connection to wiring harness and someone may have snipped it to get the car running before since it had no exhaust. I am not an expert by any means and am learning as I go.

Please let me know if anyone can provide any advice.

Thanks,


Manu

[ManpreetS512]

Thank you for the responses.

I replaced the spark plugs last night and still have the same issue. I test drove it again a few times and on the 3rd or 4th start up, the cylinder had flooded again as well.

My next item to troubleshoot is the vacuum system. I’m going to see if I can locate all of the vacuum lines and replace myself. I have the JDM ST185 and from what I read this version doesn’t have an EGR. Can anyone confirm this? I think the US all Trac gt4 does have it though which is confusing to me. I cannot seem to find a manual specially for the JDM version nor can I locate the EGR valve or lines on my set up. I also don’t see a map sensor or place to plug one in either.

If anyone here has experience with their vacuum system and can provide any input or pointers, please let me know. I’ll try and post a pic of my setup as well so you all can see what I’m working with.