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Discussion Starter #1
Hey guys, you've been a great help on my last post so I thought I'd try again.

So I've got the typical black soot on the bumper (damn white car!) and I did some reading, which led me to think that the car isn't burning all of the fuel that is being injected. Note that the car has an AEM V2 intake and a 2.5 inch aftermarket exhaust. Newer O2's are on it, and a newer cat. Scan tool didn't turn up anything.

Today I noticed that my temp gauge never covers the 2nd little wavy line on the temp gauge, and I've never heard the fans come on. I'm able to drive the car to its normal operating temp (still looks low on the gauge whatever temp that really is) pop the hood and stick my hand on the upper radiator hose. I'm pretty sure I shouldn't really be able to do that and the fans should be turned on after I park it.

So I checked the fan fuses, and they're good, I ran power to the fans, and both spun so that's good. I grounded out the temp gauge sensor, and it went all the way to cold, so I think it's working. I haven't been able to check the ECT sensor that tells the ECU what temp the coolant is yet.

But long story short I think someone put a very cold thermostat in the car, so it won't get up to proper operating temp, thus causing the fans to not turn on, and the car to constantly run rich. Am I on the right track with this line of inquiry? Oh and what is the proper thermostat opening temp? I've sen 160-198 degree stats online and am not sure what OEM was.
 

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Hey guys, you've been a great help on my last post so I thought I'd try again.

So I've got the typical black soot on the bumper (damn white car!) and I did some reading, which led me to think that the car isn't burning all of the fuel that is being injected. Note that the car has an AEM V2 intake and a 2.5 inch aftermarket exhaust. Newer O2's are on it, and a newer cat. Scan tool didn't turn up anything.

Today I noticed that my temp gauge never covers the 2nd little wavy line on the temp gauge, and I've never heard the fans come on. I'm able to drive the car to its normal operating temp (still looks low on the gauge whatever temp that really is) pop the hood and stick my hand on the upper radiator hose. I'm pretty sure I shouldn't really be able to do that and the fans should be turned on after I park it.

So I checked the fan fuses, and they're good, I ran power to the fans, and both spun so that's good. I grounded out the temp gauge sensor, and it went all the way to cold, so I think it's working. I haven't been able to check the ECT sensor that tells the ECU what temp the coolant is yet.

But long story short I think someone put a very cold thermostat in the car, so it won't get up to proper operating temp, thus causing the fans to not turn on, and the car to constantly run rich. Am I on the right track with this line of inquiry? Oh and what is the proper thermostat opening temp? I've sen 160-198 degree stats online and am not sure what OEM was.
you need a new thermostat, different ones can open so far giving different tempetures, just get the factory recomended one
 

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Opinionated Bastard
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+1 for a new thermostat. A 180* unit should work fine in your case.

Sounds like the unit currently in your car is stuck open, which isn't allowing your engine to get up to operating temperature.
 

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Discussion Starter #4
Alright, thought I'd update this since I've done the work. I went ahead and replaced the thermostat, labeled Motorad and Germany...yeah probably not a Honda part, with a high quality Stant one, 78 degrees C the expensive one with the jiggle valve and the proper rubber tab thingies.

That petcock at the bottom of the rad was a b%&#^ to get out! I had to take off the splash guard (or whatever it's called) to fit my hand in there and even then it was tight.


What was surprising to me, was I tested the old thermostat in a pot of heated water and it opened at around 175 and fully opened by 180 or so, so it looked like it was working right? Then I tested the new thermostat, before installing it, to make sure it was operating properly before going through with the work. It opened right at the listed temp and was fully open by 190 or so. I also tested my Fan temp sensor the same way and it gave me continuity right at 208-212 degrees, I think it's working right then?

So after fixing a small hose leak and a weird idle problem (read up on why it happens when air gets in to the idle control thing-thanks PP!) the car runs great. It now heats up in minutes vs never, and the fans actually came on in the driveway when I was idling it.

Hopefully this will help some with the carbon problem.
 

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Opinionated Bastard
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I wouldn't completely bet on having less soot, H22's are infamous for burning rich from the factory, compounded by the fact that they like to burn oil.

The next step would be to check on the health of the motor and see if it's really tired. (Compression check, leak-down test, etc.) Worn rings are what causes the most chaos for us.
 

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I wouldn't completely bet on having less soot, H22's are infamous for burning rich from the factory, compounded by the fact that they like to burn oil.

The next step would be to check on the health of the motor and see if it's really tired. (Compression check, leak-down test, etc.) Worn rings are what causes the most chaos for us.
I don't want to jinx myself but both my 99' 5thgens didn't have mentioned issue too bad. No soot on rear bumper cover, just a little soot inside muffler tips. Both did have the notorious EGR issue with gunked up resin inside IM runner ports and EGR valve.
 
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