For the past couple weeks the engine in my 88 Prelude Si has been acting strange. After the car is fully warmed up, the car intermittently (sp?) stumbles and has no throttle response. I have replaced the plugs, wires, coil (I have an MSD 6A and blaster 2 coil), cap/rotor, fuel filter, compression is good, crank/TDC sensors are within resistance specs, air/fuel gauge reads normal,and the spark plugs read normal.

I suspect it's the ignition module because of the occurance after the engine is hot, but has anyone ever had one go bad on a 3g? It's seems odd because it doesn't soak up as much heat because it's mounted on the shock tower, and I thought that if it did go bad, the car wouldn't run at all. Any other things to check?

TIA,
Greg

 

Have you checked that your cam timing is bang-on? How about your ignition timing? Just somethin' to think about .

 

yep, cam timing is right on, as is the ignition timing. That was my first thought. Someone said it may be a dirty EGR. Any other ideas?

Greg

 

Even though your A/F ratio is reading normal, is it quite up to speed? A faulty O2 sensor will still read stoich, it'll just respond to changes more sluggishly, causing stumbling idle, bad gas mileage, poor throttle response...

P.S. Have you tested your PCV valve yet?


[Modified by raeneshadow, 11:47 PM 6/27/2001]

 

yeah, the pcv is good. I have the A/F meter attached to the secondary O2 (on the 3g ludes, there are two on the manifold). I have a brand new O2 that I haven't gotten around to putting in. Is the O2 that big of a reference for the PGM-FI?

Thanks man,
Greg

 

The O2 sensor is like THE main reference for electronic fuel injection . It controls idle air mixture and part-throttle air mixture, but it's completely irrelevant under WOT. So if it never stumbles or anything under WOT, you might have a solution .

 

I think you're right on, as I got a check engine light today; secondary O2. I guess it's the O2 itself, I thought my A/F meter was altering the input signal because it's homemade and may draw more current than an autometer, but the O2 input to that is on a switch. O2 it is, and lucky for me I have a brand new one lying around.

Thanks bro,
Greg

 

Funny how the ECU takes so long to notice the O2 signal is crappy, huh? Oh well, c'est la vie. Glad I could be of assistance .