Mike94

I recently got a 97 Honda civic. befor I got the car it had a engine swap from a sohc to a DOHC b16a. Anytime I pull any extra power for the motor while idling like turning on headlights or pushing in the brakes or turning up the radio. it will idle down and most the time the car will stall. I have almost replace all the sensors and nothing I do to it makes any difference. I have recently discovered that the previous owners may not have swapped the ECU to a dohc ecu. How would I go about upgrading my ecu or chip. or whatever I need to do there to make it work for a dohc engine

Mike94

Anyone got any advice or know what I should do nothing I do make any difference

BlackJack_DC2

I believe you need to adjust the throttle body i remember warming the car up to operating temps, unplug the iacv, turn on all lights, radio, hazards, wipers and stuff while iacv is unplugged then adjusting the screw on the thrttle body until it idles around 550 rpms. I'm not 100% on this solution but just trying to throw out a solution for ya.

Mike94

Thanks blackjack I'll give that a shot because I just replaced my iacv yesterday

Mike94

I will update with results soon

Mike94

Wait one more question for you blackjack if the car won't stay running while I'm pulling all that power how am I supposed to adjust the throttle body to idle at the right rpms if it won't stay running

BlackJack_DC2

hmmm there might be another issue to look into but don't give up ! Do you still have your old iacv? give it a try i bought an iacv off of amazon and it was crap. Car wouldnt stay on after cold starting, so i would double check that iacv

Mike94

Iv had to adjust it to idle at 1500 rpms just so it won't stall when I use my lights and heat at the same time while idling. So if I idle it down to much it won't stay running when I pull extra power. What you suggested made since. I just cant ajust it to idle at 550 while I have all that on because it will stall. I believe the calibration in the ecu is off because it for a sohc engine and I'm running a DOHC and the ecu isn't telling the engine to produce the proper power to operate properly while pulling extra power from the engine if that made any sense lol

BlackJack_DC2

yeah i hear ya what ecu are you running? possibility the ecu is bad too as for the type of ecu, for example im running a p28(originally from a civic) on my gsr so i would imagine it should work.

Mike94

I just dont know how to go about making the proper upgrades to the ecu if that is my problem

Mike94

And I'm not exactly sur . All it says on the cover is
1998
Sohc ( obd2)
Single-cam
vtec p2p

Mrevann

take a picture of the ECU

JRCivic1

OP, just STOP. Before you "adjust" anything, you should make sure that you have the appropriate ECU to run your engine first. Who cares what it says on the cover... that is written by some jack *** that sold you the car. The factory part number is 37820-XXX-XXX where the middle three digits are the program type and the last three digits are the version number/transmission type. So before you make things harder on yourself, please post the ECU part number here so that we can assess what you have and then what you need. Then, once you get that ECU, or it's earlier equivalent, you plug it in and see what happens. If you still have idle related problems, then and only then should you start adjusting on stuff.

IF what you have is a 37820-P2P-XXX, that is a factory SOHC Vtec ECU, which means that you have a computer that is designed to run a 127 flywheel HP SOHC engine and you are trying to use it to properly control a 160 flywheel HP DOHC engine. You KNOW this isn't right... so why on earth would you try to make mechanical adjustments around this fact "HOPING" that everything works out fine ? That ECU cannot be programmed/modified to run your B16A... it is just wrong. You need to decide what alternative you wish to install to make things right.

Mike94

Mike94

So what would be the proper ecu to use

chrysler kid

You should call the honda dealer to see what ecu to use

If your car has been modified you need to take it to a mechanic for a proper diagnostic

We are not able to tell you why your car is having problems if you have no idea what car or motor or ecu you have.

Your problem could be anything. Your engine is not original, you could have a bad power wire to the ecu. The car has hundreds of wires which could have been damaged due to the modifications

Take it to a mechanic

JRCivic1

If you have a stock B16A engine, the ECU that would be the closest in programming to run it would be from the '96-97 Del Sol VTEC. The factory part number is 37820-P30-A02.

Mike94

I have found out the motor came out of a 93 delsol and the ecu came out of a car with a d16y8.

Mike94

It was a 93 delsol si-r swap the motor and tranny came out of the 93 delsol

Mike94

I may have been wrong it was a 94 that came with the b16a3 and the ecu was 37820-p28-ao3 is that the one I need or should i go with the p30

chrysler kid

Why do you think you need a new ecu? Did you test the old one? Or are you just guessing

Mike94

It got a 37820-p2p-a23 and iv changed put other parts and nothing I do solves the issue and multiple mechanics and ppl on this forum have told me that the ecu that's in the car isn't compatible with the motor that's in the car and everywhere I look ppl running the b16a are using either the 37820-p28 or the 37820-p30.

Mike94

But all that aside everyone is telling em the ecu that's in the car isn't compatible. and that I should stop changing parts until I put in a more compatible ecu and then go from there. All I need to know really is what ecu is compatible with the b16a and si-r tranny. Because from what everyone is telling me the ecu that's in the car is not

Mike94

So far everyone I ask has said it is not

chrysler kid

Ok I get that. But it sounds like your alternator and charging system is having problems because of a bad or missing ground connection. The ecu doesnt have anything to do with your lights flickering and engine bogging when you turn them on. The headlights are not controlled by the ecu they are an independent electrical system which has no relationship to the motor besides the motor reacting to rhe alternator causing extra drag on the system

The ecu has no relationship to your electrical problems. I suggest examining ground connections in the engine bay. There should be atleast 4 of them

p30 ecu to do it correct for obd2 readings and emissions

https://honda-tech.com/forums/honda-...-help-1432541/


Here's an example of running a sohc ecu and not having random non related electrical issues
https://honda-tech.com/forums/honda-...6-swap-859878/