I am working on my 1990 base civic hatch, with DPFI D15B1.

I have a CEL, no codes, checked the grounds, all seems well. even disconnected the ECU grounds entirely and cleaned them and re-connected them.

car still runs, but struggles more than usual going uphill,

under 3000 RPM the exhaust splutters and pops a lot, (more frequently and louder, the more i push the gas),

fuel economy dropped from 29-32mpg to 23-25 mpg, and once warm, tends to want to idle 250 RPM or lower unless i pump the brake (engine revs up to 500 when i let go of the brake) or step on the gas.

 

Solid cell = ECU problem. 94

 

thats kinda what i was afraid of... lol working on getting together the parts for a MPFI swap, but im still missing some odds and ends. vancouver WA and Portland Oregon dont get very many MPFI OBD0 hondas in the junkyard, and id like to keep everything but the injectors OBD0.

i still need hoses, a TPS, and am looking for a D15B2 or D16A6 cam to go in my B2 head with the swap.

 

We have shitload of Civic at our PicknPull, [40 to be exact] from 86 and up.

What do you need maybe I can help, I am always going to PnP to get parts. 94

 

Just a shot in the dark....

You said you checked all ground. Specially, did you check the thermostat housing?

Try probing the ECU for the grounds. Aldo verify all the 12v at the ECU.
I recall a few people with solid ECU light because of a power wire issue.

Did you work on anything on the car right before this problem started?

 

only thing i did was upgrade my cluster lights, blinkers, and tail lights to LED. other than that it has been MONTHS since ive done anything to the car.

i checked the wires at the ecu, as well as the grounds to it. i pulled the wires off the thermostat, cleaned the terminals, bolt flange, and thermostat housing with a wire brush and 600 grit sand paper to be sure, and then bolted the wire back onto the thermostat housing. still have the CEL with no codes. still runs like crap.

as for the MPFI swap, i need a PCV grommet/tube that goes from the intake manifold to the breather, and a plug for the FITV, which i noticed today has the same type of plug as the purge solenoid, so i may just grab one of those from the junkyard since none of the SI cars ive seen with the FITV have had a wiring harness... problem i have had with the PCV grommet is that every single one of the HUNDREDS i have found, wont come out of the intake without breaking...