Looks RICH to me

[JGee]

They have about 100 miles on them. Compression test cold 190,187,195,195,190,190
Thoughts?

[TobyB]

The internet makes the bottom one look tight.

They all look oily at the base for 100 miles, but #5 has an oil problem.

#1 looks really lean on the internet, and the flaking on the ground looks unhealthy.

All of them show the little balls that I associate with early signs of det.

#6 porcelain looks healthier than the rest.

BUT
I've never had plugs tell me much unless I did 3 laps flat,
and cut the ignition and coasted into the pits.
They often confused me, otherwise....

t

[JGee]

I will pull them again and check the gaps but I believe it's just bad photography.

I didn't have the opportunity to run and cut the ignition. So, I guess the pics. are pretty much useless anyway.

The car is running great, very smooth but will not pass SMOG . New Cat, O2, intake hoses, air filter, plugs, cap n rotor. I did put some 87 octane in because I heard it would burn faster and result in less HCs out the tailpipe. Maybe the source of the "balls".

I'll try and get a proper plug read done.


JH

[kronus]

that compression is way higher than any M20 I've seen. recent build? stroker? fancy pistons?

[JGee]

Yeah, I thought those numbers were high. No fancy nothing here! Old crusty bitch from '88. I checked compression back in 2012 and the numbers were all 5-15lbs. lower. Maybe something going on with the gauge after all it's probably for the sixties. I did use some "snake oil" stuff awhile back Rx something or other in the oil.

I did find a problem with the pick-up fuel pump in the tank. (Car is a 86 engine is 88) Couldn't get it to work in the car so I pulled it held it in a pan of gas and it's not picking up it's just pissing out a little hole near the bottom.



JH

[ForcedFirebird]

Check your throttle switch for idle contact, and coolant sensor needs to be ~300-340ohm at operating temp. Either of these can cause a rich idle.

Compression numbers are high. A fresh m20b25 .020" over does ~185psi. With a 272 cam, they are about 145-ish. Broken in and still healthy, they are 175 all day. Your gauge might be off, but they are consistent, so I wouldn't concern the actual numbers.

[JGee]

So, I went cheap and installed a Chevy Vega style pick up fuel pump. Napa sells a kit P/N B0255E. On the Napa website they state it is a "OEM equivalent" and a "direct fit". Nothing could be further from the truth and I defiantly don't recommend doing this but, it is working. No more intermittent noise from main pump. I figured it was just on it's way out.
Details here:https://www.r3vlimited.com/board/sho...d.php?t=215034

Remember this is the one year only '88 Seta engine swapped into a '86 chassis.

Looks like my temp sensor is out of spec. With the engine at temperature, I measure 208 ohms. I am not positive which sensor I should be running, the one in there now has a white connector. All parts suppliers I have researched say blue connector is correct. I am running a "154" ECU. Which is Motroninc 1.1 right?



Throttle switch is switching fine.

Fuel pressure is a bit funky. FPR marked 2.5bar on it. Measured system pressure is 42psi. (engine not running) Regulated pressure is 32psi. and goes to 42psi when the throttle is bliped. Bentley reads 36.3 +/- 0.7 system pressure and 33.4-39psi regulated. The return appears to be clear. I did pinch the return line momentarily and pressure went to 70psi before I let go.



JH

[TobyB]

That's a bit high for 2.5 bar (2.5x14.7 = 36.75) . Manifold pressure is
subtracted from it, so measure it with the vacuum line unhooked, and you'll probably
get 42 psi.

Dunno about temp sensor.

t

[JGee]

Gross polluter

I don't know. How is this possible? Everything I do just makes it worst.

Timeline:
Smog Check


Replaced:
idle control valve hose
Oil change
Plugs
Cap and Rotor
Vacum hose
Breather hose


Smog Check


Replaced:
Intake Boot
Cal. Converter
O2 sensor
Fuel pick-up pump
Fuel Pressure regulator
Temp sensor - Blue

Smog Check


Sent injectors out for rebuild:



Ha! Holly shit how was this car running so good. After I reinstalled the injectors, took it on a 200 mile drive and it never ran better. Very noticeably improvement above 3K RPM. Happier than a pig in shit, No way it could fail now. WRONG!

Smog Check


WTF


JH

[cscracker]

It was probably running too lean before, and now that you've replaced everything, it's running richer and producing higher numbers. If you're running premium gas, try running low octane for the emissions test. You can try reintroducing some unmetered air to make it run leaner, or mix some e85 or denatured alcohol with the gas to make it run cleaner, too.

[JGee]

It was probably running too lean before, and now that you've replaced everything, it's running richer and producing higher numbers. If you're running premium gas, try running low octane for the emissions test. You can try reintroducing some unmetered air to make it run leaner, or mix some e85 or denatured alcohol with the gas to make it run cleaner, too.

Thanks, I would prefer to have a properly running car but if I have to, I will.


I have heard conflicting reports. How critical is the smog test to oil beaning burnt by the engine? I have heard as long as it's not smoking but....






JH

[JGee]

I hate when people don't finish their problem threads!

So long story short, The head gasket was failing the whole time. I guessing artificially heating a sensor and making it run rich. Had the head rebuilt, replaced the gasket, installed a wide band to reset the AFM and it passed. Runs like a champ.




JH

[ADEN]

You didn't notice the high temp, I am wondering can we have a shot HG without milky oil , white smoke or high pressure cooling system????

[JGee]

The car was not running higher than normal temp, until I took it to a mechanic. The mechanic cranked the AFM leaner then he noticed it running hot. He changed the thermostat, no difference. He suggested the HG probably has a problem, $3K. I got the car back from him running hot, I could baby the car on the highway and the temp would go down. I adjusted the AFM rich till it was running a normal temp but you could smell the raw fuel out the tail pipe. Then one day I started leaving smoke screens behind the car. The HG finally failed, squirting oil onto the exhaust when the oil pressure was high enough.

So yeah, no milky oil ever, no water being forced out of anywhere, not enough smoke out the tail pipe to worry about. The car has always been tough to pass smog. It has always ran on the rich side but the car ran so well I never addressed it. I am a light user well under 5K a year.





JH

[ADEN]

The car was not running higher than normal temp, until I took it to a mechanic. The mechanic cranked the AFM leaner then he noticed it running hot. He changed the thermostat, no difference. He suggested the HG probably has a problem, $3K. I got the car back from him running hot, I could baby the car on the highway and the temp would go down. I adjusted the AFM rich till it was running a normal temp but you could smell the raw fuel out the tail pipe. Then one day I started leaving smoke screens behind the car. The HG finally failed, squirting oil onto the exhaust when the oil pressure was high enough.

So yeah, no milky oil ever, no water being forced out of anywhere, not enough smoke out the tail pipe to worry about. The car has always been tough to pass smog. It has always ran on the rich side but the car ran so well I never addressed it. I am a light user well under 5K a year.





JH

Looking at the picture it seems that your compression loss is due to your piston rings are worn look at the piston face, clean at the edges indicates ring sealing problem.make sure that rings are ok before assembling.