85 Problems, Thermostat?
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From: Custer, WI
85 Problems, Thermostat?
1985 vette. Mostly stock except cut lid w/ k&n and bypassed tb.
When driving the car to stevens point, (15 miles from where i live) the car didn't even reach 195 degrees today. The thermostat is stock. Sometimes the car will get up to 195 and maintain it, but other times it sits around 180-190. What would cause this? thermostat stuck open? Would this also cause the car to run bad when its cold?
When driving the car to stevens point, (15 miles from where i live) the car didn't even reach 195 degrees today. The thermostat is stock. Sometimes the car will get up to 195 and maintain it, but other times it sits around 180-190. What would cause this? thermostat stuck open? Would this also cause the car to run bad when its cold?
Drifting
Joined: May 2006
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From: Chewelah Wa
That is exactly where my 85 runs by design. It runs way better at these temps than when it was overheating all the time. In my opinion.,195 is perfect. If you think you need to run hotter, I would start with the thermostat.
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From: Custer, WI
I don't want it to run hotter, i'm just wondering what would cause this? The car runs like absolute **** when its cold, and i'm trying to figure out why lol.
I get some bucking between 800-1500 rpm when under 50 mph too. The bucking only occurs when the throttle is held steady, not while accelerating.
It runs really rich, I can smell gas when it starts up.
I get some bucking between 800-1500 rpm when under 50 mph too. The bucking only occurs when the throttle is held steady, not while accelerating.
It runs really rich, I can smell gas when it starts up.
Last edited by Pwnage1337; May 19, 2009 at 08:21 PM.
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Sounds like a tuneup issue to me: timing, plugs/wires/cap/rotor, maybe fuel filter needs replacing. Could also be sticking in open loop (O2 sensor), but even if the stat is open you should be well into closed loop at those temps.
Not related to your thermostat from what you say.
I assume there are no codes set when its cold. Usually they are quite jumpy on the throttle when cold and run well, but rich in open loop.
Not related to your thermostat from what you say.
I assume there are no codes set when its cold. Usually they are quite jumpy on the throttle when cold and run well, but rich in open loop.
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St. Jude Donor '10-'11
Cold start injector possibly? No way that has anything to do with a thermostat. Stock thermostat is 195. I went to a 160* then back to 195* and tomorrow I am putting in a 180*. I don't know what your weather climbate is there but if it's hot, 160, if not, 180*.
Definatley sounds like a tune up issue though. Are your spark plug wires burned anywhere? Can you pull a plug to see if it's fouled?
Definatley sounds like a tune up issue though. Are your spark plug wires burned anywhere? Can you pull a plug to see if it's fouled?
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From: Custer, WI
Sounds like a tuneup issue to me: timing, plugs/wires/cap/rotor, maybe fuel filter needs replacing. Could also be sticking in open loop (O2 sensor), but even if the stat is open you should be well into closed loop at those temps.
Not related to your thermostat from what you say.
I assume there are no codes set when its cold. Usually they are quite jumpy on the throttle when cold and run well, but rich in open loop.
Not related to your thermostat from what you say.
I assume there are no codes set when its cold. Usually they are quite jumpy on the throttle when cold and run well, but rich in open loop.
new cap & rotor & Accel SuperCoil
plugs & wires
fuel filter & 02 sensor.
I put all of this on it about a month after i owned it
timing set @ 6 degrees BTDC
it has a new TPS, MAF, IAC.
If you block off the cold start injector, does the car have to have an ECM flash or something?
I've been experiencing problems with the car eating MAFs, and i think maybe the richness of the motor is damaging them.
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St. Jude Donor '10-'11
Sounds like a tuneup issue to me: timing, plugs/wires/cap/rotor, maybe fuel filter needs replacing. Could also be sticking in open loop (O2 sensor), but even if the stat is open you should be well into closed loop at those temps.
Not related to your thermostat from what you say.
I assume there are no codes set when its cold. Usually they are quite jumpy on the throttle when cold and run well, but rich in open loop.
Not related to your thermostat from what you say.
I assume there are no codes set when its cold. Usually they are quite jumpy on the throttle when cold and run well, but rich in open loop.
Most people forget about this, and its the easiest thing you can do, the base timing is 6* BTDC and you can set it to 8-10* without issues. This can get you .1-.2 gain in the 1/4mi by itself.
Thats not to much timing.
I qouted that Timing paragraph from vaders site. Notice he said the base timing is 6*.
Don't mess with timing unless you have a timing light and know what your doing. Are you SURE the timing is set correctly? You can get the CSI(Cold Start Injector) removed from your chip. That way you can use aftermarket intakes as well.
Last edited by M.J.L.; May 20, 2009 at 01:01 PM.
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From: Custer, WI
Timing Changes
Most people forget about this, and its the easiest thing you can do, the base timing is 6* BTDC and you can set it to 8-10* without issues. This can get you .1-.2 gain in the 1/4mi by itself.
Thats not to much timing.
I qouted that Timing paragraph from vaders site. Notice he said the base timing is 6*.
Don't mess with timing unless you have a timing light and know what your doing. Are you SURE the timing is set correctly? You can get the CSI(Cold Start Injector) removed from your chip. That way you can use aftermarket intakes as well.
Most people forget about this, and its the easiest thing you can do, the base timing is 6* BTDC and you can set it to 8-10* without issues. This can get you .1-.2 gain in the 1/4mi by itself.
Thats not to much timing.
I qouted that Timing paragraph from vaders site. Notice he said the base timing is 6*.
Don't mess with timing unless you have a timing light and know what your doing. Are you SURE the timing is set correctly? You can get the CSI(Cold Start Injector) removed from your chip. That way you can use aftermarket intakes as well.
I have a timing light, and i know how to read the timing on the harmy balancer. How hard is it to get the CSI removed from the chip? I would have to get a custom tune wouldn't i? I checked all the injectors hot and cold, they are 17 cold and 16 hot.
I pulled all of the spark plugs about a week ago, and they all looked OK.
could this be a slipped balancer thats giving me false timing readings? How can i tell if its slipped?
I don't have a lot of experience with timing engines, but it was a very basic procedure.
Should i try to time it "by ear"?
Last edited by Pwnage1337; May 20, 2009 at 03:33 PM.
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From: Custer, WI
I don't have a FSM yet, but my Haynes manual says 6 degrees also. I think when i got the car, the timing was at 2 degrees BTDC; i can't remember for sure.
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6* is the correct timing. I run 8*. When my balancer went bad, you had to really hold the timing light on it and watch it to notice what was happening. Do be sure to correct the timing properly with the EST wire disconnected.
Your symptoms are also consistent with a bad MAF sensor, it'll trip into limp home mode and run like dogsh**. Since you said you had no codes, I didnt mention it, as usually it'll set one if its that bad....though like the O2, not every time. The richness is a symptom of that, not the cause of the MAF failure.
The next thing I would do is connect a fuel pressure gauge to the rail, and watch and report here what happens with the car on and then off.
Your symptoms are also consistent with a bad MAF sensor, it'll trip into limp home mode and run like dogsh**. Since you said you had no codes, I didnt mention it, as usually it'll set one if its that bad....though like the O2, not every time. The richness is a symptom of that, not the cause of the MAF failure.
The next thing I would do is connect a fuel pressure gauge to the rail, and watch and report here what happens with the car on and then off.
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From: Holden, MO
Cruise-In IX Veteran
Believe it or not you could have gotten a bad O2 sensor even though it is new. Mine was bad and didn't throw a code. It just wouldn't react fast enough. Just something to think about.
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St. Jude Donor '10-'11
Damn Robertshaw mexican made stuff.It just occurred to me, why don't you unplug the maf sensor and see if it runs any better. That way you will know if it's another bad maf. If it runs better, get a new maf.