B20B Issues

Roadjack

New Member
I have recently purchased a '98 Civic DX Coupe with a B20B. The motor ran like crap and knocked. I didn't want any compatibility issues with a different swap so I just bought another B20B and swapped it in. I hooked everything back the way it was before. It ran like crap still but no knock. Cold start, it takes a few seconds of cranking and starts then dies. Repeat 4-5 times. Terrible idle. Press gas any other way than a *snap* over and over, it dies. When it warms up, it runs a little stronger, not better. I can open the throttle a little longer and it won't die as fast. I get it to this point to start diagnosing things. Seems to be starved of fuel to me.

Fuel pressure after the filter is 40psi. Regulator appears to be working. 2 different TPSs. 2 different MAPs. Checked vacuum routing with alldata. The EVAP system was disabled prior to my ownership. I left it disabled because it shouldn't be affecting the idle or throttle. Spray starting fluid on the filter while opening throttle and it runs perfectly.

I'm convinced it's an ECU issue. My ECU is denshigiken 37820-p08-902. A google search of this number tells me its off of a '92-95 civic D15 auto. If it is my ECU, should I replace mine with the same model? Or should I go with a different ECU? If different, what modifications do I require to make it work with my current setup?

Thanks guys.
 

civteck

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If its a p08 from a obd1 and you have a obd2 car you should have a jumper harness installed, or a complete harness transfer, any cel's? But before all that you said you spray starter fluid on the filter and it runs good? Sounds like you have an answer there.. put a pair of needle nose vice grips on the return line after the regulator to boost fuel pressure, any diff? Gonna need to do some more digging and give more info here but a good start..

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Roadjack

New Member
I have some sort of harness transfer (I would assume). It's a harness of red wires that connects to the ECU and then the car's harness connects to that. I have a CEL but cant get a scanner to read anything from it. I've tried CRVs, and various Civics and I still get a No Communication error. (Snap-On MODIS). I'll have to try pinching the return line tomorrow morning when I get to work. Will update.
What else do you suggest I check before jumping to replacing the ECU?
 

civteck

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Registered VIP
The obd1 ecu will not read codes from the obd2 port, theres a plug under the pass side dash that has to be jumped and the cel will blink the code numbers, that being sait thats for an obd1 car, someone here hooefully will chime in as i only have built and own a 93EG6 so i know some obd2 stuff but not all. Atleast now we know the body harness is not hacked and you have a jumper harness.. report back after you do the fuel press test with vicegrips hopefully by then someone else will know more about the obd1-obd2 tricks.

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Roadjack

New Member
Clamping the return line drastically improves the idle and rev. Its idling at about 1500 now. And it sounds like its misfiring. I think it may still need an ECU. But idk what to get or how to make it work.

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Roadjack

New Member
Took clamp off and its running so much better for whatever reason. New plugs. Wires and a full tank of gas shortly.
 

Roadjack

New Member
New plugs and wires. Idles crappy again after you let it cool and start it with no clamp.

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Roadjack

New Member
I found the connector. I'm a little surprised that I even had it.
In getting 2 codes repeating:
!.........
!!.
I assume 19 and 21.
I don't have VTEC or A/T


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civteck

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What does the fuel pressure go to when you have it clamped? Unclamped? I have seen oem regulators go bad, do you have the one off the other motor? I had a similar problem on my b18b1 swap in my 88 accord, the banjo bolt at the rail from the filter was wrong and would starve the fuel rail but pressure showed good cause it was after the gauge. Pull the return line off the regulator put it in a water bottle and see how much fuel comes out upon key on no start then at idle.

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civteck

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Just watched the vid, sounds like a dead cyl or firing order, did you ever do a compressiin test?

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Roadjack

New Member
I didn't test the pressure with it clamped. The tester fitting was spliced inline between the filter and the rail. So the rail was still getting pressure while I was testing. I'm starting to think the regulator is bad. The intake off the new motor is a high crv intake so I had to use the old one. The 2 fuel rails and regulators are different and not interchangable.
Ill have to test the pressure clamped and try the bottle tomorrow at work. Where did you find a bigger banjo bolt?

She's running beautifully with the new plugs, wires and return clamped.

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civteck

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I drilled out the hole in the center mine would run fine till 2500rpm or so then starve, the pressure gauge never told me anything bad cause it always seeing correct pressure but the rail was low thats why im curious to know what comes out of the regulator

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Roadjack

New Member
That reverts to some of my original questions.

I'm convinced it's an ECU issue. My ECU is denshigiken 37820-p08-902. A google search of this number tells me its off of a '92-95 civic D15 auto. If it is my ECU, should I replace mine with the same model? Or should I go with a different ECU? If different, what modifications do I require to make it work with my current setup?

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Roadjack

New Member
Guy was selling a 98 civic with a b20b for $1500. Couldnt start it at his house so i talked him down to $850. Towed it home and got it started. Engine knocks and runs like crap. Swapped the engine and now i have to work out the kinks.

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