So my 1993 Del Sol has a JDM D15B swap in it, car ran fine for a wile until the transmission was dropped. I had the transmission dropped and worked on because the main shaft bearing was completely shot. Long story short, since then the car has been running rich, sounds like it's getting a lot of gas. Stomp on the gas and it doesn't get up and go like it should. The idle goes up to 1500 when the car is cold and then started. It works it's way down to a normal idle but when I turn the AC on it gets very low like it's gonna stall out. I thought it was gonna be the o2 sensor, NOPE... Bought a brand new Denso 4 wire o2 sensor. It runs a little better, only real change is that it started to back fire a little bit.

D15B
S20 Trans
Decently new spark plugs
stock exhaust
new 02 sensr
new cluth/flywheel

Throw some idea's of what it can be. I'm thinking the mapping sensor or the TPS. It's driving me crazy because the car use to run so well when I first got it. Idk if the shop that had the car might of fucked it up wile they were taking the transmission out or what.

Help is mucho appreciated.

 

does the car have any check engine lights? It is possible that the wiring for the O2 was damaged during the work.

 

No way the wiring on the o2 is bad, simple install. Check engine comes on after driving a little bit, but when you turn car off and back on it's gone. I still haven't managed to get the damn plug to check the code out of the boot its in. Low MPG, smells like gas behind me. Thinking exhaust leak or possibly another sensor being bad.

 

Well you need to check the CEL.

 

So today I found out that it doesn't only mess the idle up turning the AC on... Turn the heat, AC or headlights on and the idle will get low.

.... CEL is least of my worries atm cause to even get the plug out of the boot it's in, I'm prob gonna have to unscrew the ECU from the floor and take it out so I don't rip the wires apart.

 

Uh the CEL is NOT the least of your worries. It's trying to warn you and give you EXTREMELY important information. Unless the Del Sol is that different the connector you need should be just hanging there or stuffed behind the ECU. All you need is a paperclip. No special tools need to pull codes. When CEL comes on, pull over, do not shut off the car, and count the flashes. My wife can do it in less than 5 minutes.

And if I were would I'd start checking your charging system, mainly the alternator and the belts. The only thing in common with all those systems is the charging system.

 

Someone was saying it might be the alternator today. Seems like when I cut more **** on the worse the idle gets. Gonna try the IACV and check the alternator.