Ok I've searched and searched and haven't found a problem like this. I have a 90 civic converted to mpfi. I did the conversion years ago and I'm sure this has nothing to do with it. a few months ago I put in a d16y8. Needed a motor, couldn't find another a6 to replace it with. So the d16y8 is running off of obd0 everything, dist, Si ecu, even Si injectors. No vtec, wasn't worried about it. It runs fine EXCEPT when I'm on the highway trying to keep up at 80. It starts to miss pretty bad. I'm thinking it's ignition related. I've already ordered everything to swap to obd1 and a p28. I'm just wondering what would cause the miss at that time. It's running around 4-4500k on the tach when it does it. It doesn't seem to to it when I'm running through the lower gears at those rpm's though. The old a6 never did it and I didn't change any wires. Any thoughts?

 

i would say pull your dizzy apart n clean maybe replace coil n ignitor, not sure just a suggestion, you got a cat on it, maybe its getn clogged, try an injector cleaner

 

What exhaust manifold are you using? You can NOT run a 1-wire O2 sensor on a Y8 manifold that has the bung near the collector. Are you throwing any codes? That type of information is pretty useful...

 

Did you also set your ignition timing manually to the Y8's spec? I swapped a Y7 into my car but neglected to consider that the stock A6 ECU advances the timing too far and well I learned my lesson to put it simply.

 

The dist. Is about 7 months old, but I'm sure it couldn't hurt to take a look. No cat on it, came like that. I'm not positive about the exhaust manifold, but it has the u2 sensor in the original location for the dx motor, close to the head. I did set the timing to the y8. It's odd it doesn't seem to do it when I run through the gear, just when I'm trying to cruise.

 

i almost want to say vtec is trying to kick in from the oil pressure.

 

For some reason I was thinking the same thing. I wasn't sure if it was possible. I'm not exactly sure how to confirm that though

 

That is laughable at best...

Impossible. Also, VTEC is activated electronically and requires oil pressure to be a LEAST a certain PSI to activate. Oil pressure alone can't activate it. To add to this VTEC comes on much later than 4,500 RPMs...

 

That's what squashed that thought, the fact that it would act up before the vtec engagement point. Maybe my coil is dying out when it starts getting the rpm's up. And it is throwing one code for o2 sensor. I replaced it with a direct replacement and it still throws the cel. Seems to take awhile at times, but still throws it.

 

i just put a d15b7 in my 88 dpfi civic it runs but wont stay running what could the problem be

 

i have to throtle it to keep it running and when it is running it runs really ruff i got good spark,fuel, and timing is on

 

its also all obd1 dizzy everything was converted

 

Thanks for sharing, Bogger.

 

can you help me with my problem

 

i would say its fuel or ecu related. you can try adjusting the throttle cable maybe? also you should probably start a new thread or do some searching. people around here will kill you for taking their thread or asking questions.

 

i would have to say its a management issue seems like your ecu might be damaged or just showing its age, but if the dizzy was acting up with would be apparent at idle as for injectors yes as rpms get higher more gas is used and once you get to that level of open jet it could be spitting fuel thus flooding your chamber and you get a misfire, try replacing the injectors with some spare or a good fuel soak to clean um.....up to you