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Discussion Starter #1
I am trying to limp a car home about 30 miles that is throwing these CELs, and wont rev past 2500RPMs or so, it is acting like it is bouncing off a rev limiter. I will fix all of them eventually, but right now I need to know which one is causing the car to be undrivable.

Tuned P28 ECU + B18C1 + engine harness that worked fine before in another car.

Unknown body harness (but seems ok) Unknown filter, new fuel pump.

Any ideas? Id REALLY like to drive this home today.
 

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Codes are for

6=ect

14=iat

21=vtec

22=vtec

41=O2 heater.

The ect,iat and O2 codes could be your problem. Might be from a broken wire in the harness or even the wrong plug was plugged into the sensor.make sure the chip is pressed in all the way.
 

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Discussion Starter #3
Yea sorry, I didnt mention that I know what all the codes are, I just dont understad which one is causing the main issue. I drove my other CRX for almost a year with this ECU without an O2 sensor hooked up, so I cant imagine that is the issue.

As far as the other go, maybe I have a goofy ground wire somewhere, I made sure all the connections were tight but I might have a broken wire, because the IACV (which is code 14) and ECT are definately hooked up, so I dont know why they are throwing codes.

The vtec and O2 are definately noot hooked up, but as I said I have driven on the same ECU without those connected.

The engine is also slow to respond to throttle right off idle, when you hit the gas it immediately tries to fall on its face before shooting up to 2500RPMs and then bouncing off the rev limit.
 

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Do you have the map and tps plugs right? All so is timing right? Did the motor run good before this problem?

Easy way to tell if you have the right plug plugged into the map sensor is check to see if it has a green/white wire in the plug.

The iacv plug should have a yellow/black wire and a blue/yellow wire.

The ect code could be from a broken wire near the plug end as oil gets on it and causes it to brake. Might be a little hard to see the brake tho.

Stupid but is the firing order right?
 

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Discussion Starter #5
This is a 88 crx HF engine harness, both the tps and the map have a green/whte wire.
 

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Discussion Starter #6
The engine ran great before, timing might not be dead on but is at least pretty close, firing order is good.
 

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This is a 88 crx HF engine harness, both the tps and the map have a green/whte wire.
Oh isn't the map wiring part of the cabin harness and not on the engine harness in that chassis?

How was the obd1 conversion done?
 

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Map sensor wire colors are white,yellow/red and green/white

Tps sensor wire colors are red/blue,yellow/white and green/white.
 

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Discussion Starter #9
I did the conversion myself, I was very careful about it, but am wondering if I was supposed to connect more of these green wires together though, I seem to have a lot of them left over.

I have 5 green wires that are unattached, 2 grn/blk, 2 grn, 1 grn/yellow
 

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Discussion Starter #10
Obd0 B plug wires not hooked up:
B2 B7 B9 B11 B17 B20

None of those are currently going to anything, there is also a spare grn/blk wire that isnt going anywhere.
 

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Discussion Starter #11
Ok, I switched around the IAT and the IACV plugs because the colors you gave me didnt match the way I had them, and I squeezed the ECT plug under the dizzy a bit.

Now I am throwing:
7 (TPS)
10 (IAT)
14 (IACV)

21 VTEC
22 VTEC
41 O2 SENSOR HEATER

Also the car will start and idle just fine until it warms up a bit, then it dies and you CANT restart it until it cools down.

What are the odds this is a sensor ground issue?
 

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Ok, I switched around the IAT and the IACV plugs because the colors you gave me didnt match the way I had them, and I squeezed the ECT plug under the dizzy a bit.

Now I am throwing:
7 (TPS)
10 (IAT)
14 (IACV)

21 VTEC
22 VTEC
41 O2 SENSOR HEATER

Also the car will start and idle just fine until it warms up a bit, then it dies and you CANT restart it until it cools down.

What are the odds this is a sensor ground issue?
The tps and iat Share the same sensor ground wire to ecu. For the O2 code your using a 4 wire O2 sensor right? The O2 sensor all so has a sensor ground wire that shares with the tps and iat even ect.

O2 wiring for obd1

White = d14 signal

Green/black =d21 sensor ground

Orange/black= a6 heater ground

Yellow/black = 12 volts switched source heater power.
 

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Discussion Starter #13
The O2 sensor isnt even hooked up right now. Is it possible that having the O2 sensor ground disconnected is causing the IACV and IAT codes?
 

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The O2 sensor isnt even hooked up right now. Is it possible that having the O2 sensor ground disconnected is causing the IACV and IAT codes?
Oh yea forgot you said that you don't have to O2 hooked up. It being disconnected isn't causing your issue with the other codes. There's something else causing the issues.
 

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Discussion Starter #15
Well, I gave up on it for tonight, im gonna try with a stock p06 ECU tomorrow and see if it has the same problem, or if it at least give me a better idea whats going on.
 

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Discussion Starter #16
Isnt the OBD1 "limp home mode" rev limit around 3500 rpms? Because I still dont get why I am hitting a 2500 rpm limiter....

I wonder if this ECU has some sort of launch control? But 2500 still seems really low....
 

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Okay. Stupid question time. You said you had this ECU in another car and it ran fine.

What engine is in the other car? Did you remap the ECU for the current engine? Could that be another part of the problem ... could it be throwing the codes because it is expecting different values based on the current tune/map? How's the distributor?
 

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Discussion Starter #18 (Edited)
The engine and ECU are matched. I took them both out of a different car that ran like a top along with the engine harness and full exhaust.

I am really wondering if it has a 2 stage limiter..... I honestly dont know if it did or not, the other car had such terrible tires I never had any reason to rev it up when it wasnt moving.

Guess it could be the dizzy, but it feels fine and isnt throwing any codes for it, if nothing else works tomorrow I will trade out dizzys with the one from my b18a1.
 

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Discussion Starter #19
Well its not a limiter, and its not ECU specific, it does the same thing when moving and it runs even worse on a stock p06 ecu.

I am going to trade out the dizzy, and if that doesnt work I will trade out the fuel filter, if neither of those work I am out of ideas.....

At this point I am honestly tempted to disconnect eveything but the MAP and dizzy to see if I can get it into limp mode, if it would rev to 3500 I could drive the damn thing home!
 

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To me it's sounds like it's something with the harness. Oh now that I thinking of it what chassis is the car and what is the engine harness from?
 
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