Got an 88 Civic with a b18a1 OBD1 engine in it and ECU. Starts like a brick and engine light flashes and it keeps going into limp mode and I discovered when I unplug the coolant temperature sensor it runs just fine and revs out but just doesn't cold start and ik that sensor is important. what could this possibly be I'm baffled I checked all wires everything's connected where it's supposed to brand new sensor too

 

You can get engine codes by jumping the SCS connector and turning the key. The MIL will blink to convey the codes.

If it runs better with the temp sensor unplugged, have you let it warm up, leaving it unplugged? It might have a hard time cold starting since the ECU doesn't know its cold, but once its warm it should be fine.

Once the engine is warmed up, check the resistance between the 2 pins of the coolant sensor, it should be between 200-400 Ohm. That will tell you if the sensor itself is good.

 

........I did that it throws code 6 and 9 code 6 will go away if i plug it in but then it's in limp mode...if I warm the car up unplugged then plug it in still misfires for like 2 seconds then limp mode again......also without the temp sensor I've herd its sluggish and gets bad gass mileage....and cold the ohms were at 340 I think haven't tested it hot yet

 

Code 6 is the ECT sensor, code 9 is the CYP sensor. The car is going to have issues w/ CYP sensor being out of whack. I don't know why it runs better w/ a bad CYP signal and the ECT unplugged, but the CYP sensor is going to cause issues for sure.

This thread might be helpful: https://honda-tech.com/forums/honda-...ensor-2904710/

CYP sensor is in the distributor, it measures cylinder 1 position for fuel injection. Essentially check the sensor to make sure its good (measure resistance) and check the distributor wiring.

Best of luck

 

I cant get code 9 to go away different dissy and checked wiring many time I believe it right but no matter what I do it's the same check engine light flashes when started then shuts off comes back in what I believe limp mode aont pass 5k without it shuting
down

 

I had both those codes and went through 3 dizzys. On the third one (being a reman and not a new one from garbage zone) it right up but then I started getting code 8 (Tdc sensor in the dizzy) so I’ve been Messi g with the timing and I got it to where it runs good and strong, no more limp mode. But I still have the cel on so I think I’m really close but the timing is still off. Pretty common for new dizzys to be trash and not work for these cars 🤷🏻‍♂️

 

.....so if you had code 6 and 9 getting a working dissy fixed it (kinda)...I do t understand code 6 is coolant temp sensor hows that got to do with cyp and the dissy I tried was used

 

For me just changing the Coolant temp sensor solved that code right away. Then I just had 9 and kept messing with the riming and nothing was working so I went to a reman dizzy and it at least started for me but was in limp mode. Kept messing with the timing and then code 9 went away but I started getting 4 and 8. Kept messing with timing and was getting closer and 4 disappeared and so did limp mode but code 8 (tdc I have been living with for a while now. I try my hand one tooth at a time but nothing is getting to go away

 

.....I got a brand new sensor and I can get code 6 to go away I believe...but not code 9 and the limp....now what mine dose is when you start it it light flashes and it misfires at you...then light shuts off then comes on constantly and it runs great but has a panic attack when hits 4500rpm also dumps gass outa the exhaust way to rich

 

That’s what mine was doing. For me it was the timing being off. It’s still running rich but no more limp mode. I’m going after mind today and will see if I can get the light to turn off

 

that's a really odd problem we got...lol I'll mess with mine later and see what happens...possibly o2 sensor
?