Civic 4d 97.
Turbo d16z6(new), comp.ratio 8.7.0
Obd1 p73 jdm crome,
Boost 10psi

Help to find problem
Car ran already 20k.
2 months ago noticed intermittent (periodical) failure like Power loss and EGT extreemly high. . I noticed those symptoms start after long traffic jams or just cruising. Or sometimes after several runs w wot and fast shifting. Then after I continue drive and increase speed slowly when the turbo spools the engine may go normal but sometimes not. AFR shows 11.7 at wot and 14.0 on idle .Zeitronix shows right data . Also sometimes when stop the car idle may jump and down from 1100rpm to 500. And then got stable.

I changed spark plugs and noticed oil in 3rd cylinder well. I cleaned up all the pcv system and found cloged pcv valve. Then i just threw it out. My pcv system: blackbox then hose goes to valvecover and with 3way fitting(engine block, valve cover, --》to oil catch). From oil catch the hose go to intake just before turbo. Fixed that but problem is still present.

I changed the ignitor, and it didnt help.,... please help. ! Any suggestions what system is faulty? Is it ignition coil? Or its IAT or ECT sensor? And why this happening when car gets hot? Can the sensors act wrong when hot? But then i should have the CEL code. But I dont have any faulty codes....

 

I had the ECT go bad in a non-boosted D16Z6 and I never got a cel but the car only ran normal when it was cold. After it warmed up it had poor performance, no throttle response, etc. Also the engine would not start after it was warmed up. The air fuel ratios will not adjust in a warmed up engine and I never got a cel for it. A new ECT for $26 made it run like a new car.

 

But mine can run. I can drive hour or two normally but then suddenly the problem appears. But if i turn off the engine and wait a bit like 15min. The engine will not get cold for that short time period. And after start it may be normal and run good.

 

Did you not read what he said? He basically said that an ECT could be the potential suspect of your poor performance.

Go test the ECT

 

Correct.

My car was a 93 del sol, so that sensor was over 20 years old when it failed.

Sensors can't last forever especially when they work thru heat cycles.

Under turbo conditions, forgetaboutit.

 

You should also look to upgrade from Crome. May not be the cause of your problem but it doesn't help the cause.

 

Ok. If the ECT faulty the afr should be different cause of different fuel value corrections by ecu. But O2 sensor shows same afr ratio. Or I am wrong?

 

So checked my temp sensor. According to service manual the resistance shoukd be 200-400 ohms. I shecked and it shows 240ohms. Alsotested the IAT, ok too. Can that be the Ignition coil?

 

you can check the resistance of the coil, if it was the coil I would really think you would be getting missfires

 

Or it may be crank or cam sensor in dizzy... I'll try to check resistance of dizzy sensors... and the coil.