Car running lean - Very strange scenario - experts only
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Car running lean - Very strange scenario - experts only
Hey guys. Here's the deal. Car is running a Type R motor. Air/Fuel is perfect up until the car reaches full warm. Once this happens, the car begins to run lean. It fluctuates between 14.5 and 17.0 during normal driving. No hard acceleration or anything. This is with the A/C off. If I turn the A/C on, those numbers jump by about .5 across the board. Also, during this, the factory temperature gauge bounces around from middle to cold. It actually moves with the rpm's sometimes. Like a tach would.
Do any of you have any suggestions?
Do any of you have any suggestions?
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Re: Car running lean - Very strange scenario - experts only
Yes. Was dyno tuned by a local shop using my Hondata S300. It was tuned last summer and ran fine, with no problems like this. This has just started in the past month or so.
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Re: Car running lean - Very strange scenario - experts only
Recently my wideband exhibited similar behavior. It turns out one of the zip ties I used to secure it in the engine bay broke and the wiring found itself being worn away against the power steering pulley.
If it's not a wiring issue I'm going to have to go with your tune. Tuned cars run differently in hot and cold weather.
If it's not a wiring issue I'm going to have to go with your tune. Tuned cars run differently in hot and cold weather.
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Re: Car running lean - Very strange scenario - experts only
Engine temperature plays a big role in how the fuel trim is determined by the ECU. Your fluctuating coolant temperature indicates a bad thermostat and/or air trapped in the cooling system. Start by replacing the thermostat and bleeding the cooling system.
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Re: Car running lean - Very strange scenario - experts only
As for the gauge bouncing I am thinking the sending unit can be bad. That is right next to to the ECT sensor, the sending unit is 1 wire.
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Re: Car running lean - Very strange scenario - experts only
@Wrona.........really dude? I'm pretty sure we all know that there are multiple types of Type R motors, however, that is not relevant in this matter.
Last edited by Former User; 02-07-2012 at 11:54 AM. Reason: Post clean up. Keep the discussions civil and focused on tech..
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Re: Car running lean - Very strange scenario - experts only
Also, for clarification......the temp gauge will sit right around half when the car is warm, and then as i accelerate, it lowers down to cold, then jumps back to middle between shifts. Then starts again as I accelerate in the next gear.
#14
Re: Car running lean - Very strange scenario - experts only
Top off the radiator and reservoir with coolant and then bleed the cooling system (as detailed in your Type R service manual).
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Re: Car running lean - Very strange scenario - experts only
Update: All of the cooling system components and sensors seem to be functioning properly. However, a friend told me how to "burp" the coolant/radiator. I did have an excessive amount of bubbles come out of the radiator. I let it run for about 40 minutes, and finally shut it down. There were still bubbles coming up. Drove it that night, but it was so cold out, that the car never reached temperature. (Go figure). Should be a little warmer later this week. I'll report back then.
#16
Re: Car running lean - Very strange scenario - experts only
With it cooling off when you accelerate thinking you are building more pressure in coolant system that is making the thermostat open early and when you are at idle it holds its self closed would replace the thermostat, and if it didn't reach operating temp when it is cold out side the thermostat is bad as well it is to stay closed until you reach operating temp if it isn't reached it is opening too soon
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Re: Car running lean - Very strange scenario - experts only
So cold out the car never reached temp? I've driven my Civic in -10F before, and it'll still get up to temp. Did you change anything in the cooling system? Have you tried replacing the thermostat, like three people already said?
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Re: Car running lean - Very strange scenario - experts only
Sounds like thermostat to me but if you want to check the sending unit
http://www.autozone.com/autozone/rep...00c1528008bb85
What are you looking at to gauge the af ratio?
http://www.autozone.com/autozone/rep...00c1528008bb85
What are you looking at to gauge the af ratio?
#21
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Re: Car running lean - Very strange scenario - experts only
If you drove around outside in cold weather and the engine never warmed up, it sounds like your thermostat is stuck open. I've driven around in sub-zero temps and the engine always warms up, the only times it hasn't was when my thermostat failed open.
Not to beat a dead horse here, but I'd like to know what "Type R" motor you have... B18C5? B16B? K20A2? K20Z4? It's a nebulous term that can apply to multiple generations of motors, and depending on how difficult the swap was you could have a swap-related problem masquerading as a normal engine problem. Telling everyone exactly what engine you have lets them rule things out.
Not to beat a dead horse here, but I'd like to know what "Type R" motor you have... B18C5? B16B? K20A2? K20Z4? It's a nebulous term that can apply to multiple generations of motors, and depending on how difficult the swap was you could have a swap-related problem masquerading as a normal engine problem. Telling everyone exactly what engine you have lets them rule things out.
Last edited by MonkeyBoy668; 02-13-2012 at 11:15 AM.
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Re: Car running lean - Very strange scenario - experts only
Sorry, let me clarify what I meant. The car would reach temperature at a red light and such, but then as I started to move (less than a 1/4 mile down the road), it would begin cooling off again, and therefore not be at the temperature that the problem occurs.
As for replacing the thermostat....I replaced it with a Spoon thermostat not quite 2 years ago. Besides that, I did check it when I was burping the system, and it was functioning properly.
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Re: Car running lean - Very strange scenario - experts only
I thought that about the temp gauge, except that it ONLY occurs when the car reaches full operating temperature. If it was a ground issue, I would think that it would happen all the time, or at various temperatures.