Jack Panting

Hello,

I have a civic ej 1.4 2000.
I have put in a b16a jdm engine with p30 ecu using a obd2b harness with a obd2b to obd1 jump lead .
Car runs fine for 10 minutes of driving then throws the checkengine light on and does a surging idle. 750-1800rpm
These are the codes that have flashed

1 O2A - Oxygen sensor #1
10 IAT - intake air temperature sensor
20 Electrical load detector
23 Knock sensor


i have checked these sensor with a volt meter all are running 5-6 volts which i pressume as fine?

I have replaced oxygen sensor becuase someone had mig welded the last one in to the manifold.
I know about the ELD code and that doesnt make any problems.

Can anyone shed some light on to my problem.

Thanks Jack

nuginu

Well, for one Knock Sensor shouldn't Give out 5v unless you have a terrible problem. I'm pretty sure it is a piezoelectric sensor, which is essentialy a Mic from what I understand. I did some digging in the forums and came across this chart. Left hand numbers being RPM and the right being the output voltage. To test this you'd have to use the block as a ground, and the one pin in the sensor as your positive lead.
0 0.01953125
800 0.01953125
1600 0.01953125
2400 0.05859375
3200 0.29296875
4000 0.7421875
4800 1.23046875
5600 1.71875
6400 2.2265625
7200 2.71484375
8000 3.22265625
8800 3.7109375
9600 4.140625
10400 4.609375
11200 4.98046875
12000 4.98046875
12800 4.98046875

None of these sensors should give you this surging idle though. I'd be thinking maybe something to do with your IAC. I'm not 100% sure if you have to do the 3 to 2 wire IAC change in your case, but I had to do it and it made my car run awesome.
Here is a link to the forum post regarding this. https://honda-tech.com/forums/honda-...-vtec-2987229/
Do all the wiring, and then double check it again. I ran into all kinds of issues during my swap (B16A2 into 2000 ek OBD2B)

Also, Check you have the IAT plugged into the right spot. I had two identical plugs in my harness that would both fit into the IAT.
Electrical load detection probably has something to do with the alternator wiring to the ECU. Not sure on that one.

Sorry if my information isen't 100% accurate, I'm only out here trying to help fellow members.

mk378

Plugged in to the wrong plugs is quite possible. Trace the wires all the way from the sensor plug to the ECU pins to be sure it is wired properly. Concentrate on the IAT first, that one is important for proper running.

tony_2018

knock should only have 1 wire running to it that is shielded

Jack Panting

Thanks guys

Update

Changed lambda sensor because i'd put a d series one in.
Did nothing, still putting same codes on.
Hose looked mushed on the map sensor chopped it and put new hose on. Did nothing

I changed my iat plug on the loom to a obd 1 plug because the b16a has them on the inlet, white plug, instead of the one on the intake tube like obd 2 engines.

Did all of this then unplugged ecu to reset it but did no difference

Out of ideas again

Any more ideas please
Thanks Jack

nuginu

Did you check the Idle air Control?

Jack Panting

Check as in with a volt meter? Yes running 5-6 volts which is correct i think?

mk378

Unplug the ECU (always disconnect battery before unplugging ECU) and measure the resistance of the IAT sensor circuit from the ECU harness pins. It should be the same as measured at the sensor. Then unplug the sensor and confirm it goes to open circuit.

The IAT and several other sensors get power from the 5 volt sensor supply which is provided by the ECU, it should be very close to 5.0 volts to ground. The other wire of the sensor varies with the sensor reading but it is less than 5 volts.

muellersfan

You need to clear all of the CEL codes.

Among the codes, the knock sensor code is most likely to cause running problems. Is it connected? Is the KS broken?

Also clean the IACV, and as mentioned you could have some swapped sensor connectors.