1989 CRX Si
D15B1 on MPFI, using the cars original MPFI parts

Problem:
Car starts right up. after idling for a moment, it starts to lightly bog a bit. If you rev it at all it throws it into a constant bog up and down.

Ive searched this thoroughly, coming up with a multitude of possible causes but have had no luck yet so Im asking. These are the things I've checked:
-PCV Valve
-Ignitor
-Timing
-Spark Plugs and Wire

The alternator wire (B5 on ecu, white and yellow wire) was cut from the ECU. I put a new pin on it and stuck it in there, and to my knowledge it works, because when I start the car and let it run several times, the battery still maintains its charge. And this is a battery that'd been dead for months until I jumped it and its worked fine since, so I'd assume its being charged.

Sorry for going on and on, just want to give as much info as possible.

Thanks guys

 

Are you throwing any engine codes???

If not then I would first take a look at the condition of the plugs, wires, cap, and rotor...

Oxygen Sensor comes to mind b/c it controls some of the fuel mixture after startup...

My old wagon would always bog down b/c of oil getting onto the plugs...take a look at yours when you pull them to make sure they aren't oily b/c that will cause it to run rough...

 

Could it possibly be the fast idle control valve being stuck closed and making it hard to warm up with a low idle? Is the timing good?

 

Engine isnt throwing any codes

Timing is good

I think all the plugs are good and the o2 sensor should be good also, but I guess I'll swap it out since it takes 2 seconds

 

Update:
After driving the car, I found that it only bogs when idling, not while driving. I redid all the vacuum hoses properly and the problem remains.


I just wanna thank all the people of HT for not bothering to chime in with their 2 cents on either of my problems.
Remember how you couldnt help me next time you look at one of my write ups.

To the people who have tryed to help, thanks alot!

 

You have your idle speed set correct? Spark plug gap set correct? Air filter not clogged? leaking headgasket? just tryin to shoot some ideas...

 

It definetly sounds like you got a vaccum leak somewhere.