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Idiot light on at idle

Old June 23rd, 2019, 08:55 PM
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Idiot light on at idle

Ok. So I took my car out for a cruise today it was hot out, 80 or so. I got on it a few time to open up 4 barrels (it acts like itís out of gas when they open) any way got home and went to bank into the barn and the oil light was flickering and came on but if I give it 1-200 rpm itís off, oil looked kinda thin only about 65 miles on the oil did smell a little like gas but still on full mark. Any ideas?. It has straight 30 in it. Iíve read 15w40 ? Thanks guys
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Old June 23rd, 2019, 09:01 PM
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The only time I had gas smell in the oil was when the fuel pump diaphragm ruptured
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Old June 23rd, 2019, 09:07 PM
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Originally Posted by Fun71 View Post
The only time I had gas smell in the oil was when the fuel pump diaphragm ruptured
Will it still pump fuel with it ruptured? Have no problem cruising or starting
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Old June 23rd, 2019, 09:22 PM
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I suppose so as I was able to back out of the garage and idle in the driveway with the engine running. The trail of liquid down the driveway and the gasoline pouring out the weep hole in the fuel pump were indicators that something was awry.
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Old June 23rd, 2019, 09:24 PM
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Is your oil level above full on the dipstick?
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Old June 23rd, 2019, 09:33 PM
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Originally Posted by oldcutlass View Post
Is your oil level above full on the dipstick?
No right at full
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Old June 24th, 2019, 07:40 AM
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I think you are describing two different issues. The stumble when the 4 bbl opens is probably or at least could be a bad accelerator pump. The thin oil on the dipstick and the smell of fuel sounds like a bad fuel pump. They (fuel pump)may or may not show leaky fuel on the out side and still be bad and run.... Just my thoughts ...Tedd
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Old June 24th, 2019, 10:05 AM
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Check the fuel pump for sure. Connect a good oil pressure gauge up to the block to see what it is actually reading. Shouldn't be guessing at oil psi.
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Old June 24th, 2019, 10:11 AM
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Originally Posted by droldsmorland View Post
Check the fuel pump for sure. Connect a good oil pressure gauge up to the block to see what it is actually reading. Shouldn't be guessing at oil psi.
How do I check the pump if no visible Signs of leaking?
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Old June 24th, 2019, 10:12 AM
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Connect an external oil pressure gauge to measure the oil pressure. Take the car for a long drive, use some zip strips or tape to hold the gauge to the windshield while you drive, and to hold the oil line out of the way of moving parts. The oil light comes on around 5-7 psi. If the engine has more pressure than that, replace the sender. If not, either you have engine problems, oil contamination (gas,coolant,etc) or the wrong weight oil.

If the fuel pump pump diagram was leaking enough fuel to thin out the oil, the oil level on the dipstick would be slowly going up. If in doubt, replace the pump, change the oil. Far cheaper than engine repairs or replacement.
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Old June 24th, 2019, 10:16 AM
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Originally Posted by Jeff99 View Post
How do I check the pump if no visible Signs of leaking?
You will be "making oil". But I'd follow what Matt said. Replace the oil and the fuel pump. Verify oil pressure before road testing.
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Old June 24th, 2019, 10:44 AM
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If your fuel pump diaphragm is cracked and leaking enough fuel to back up into the engine, it should also be coming out the weep/vent of the upper portion of the pump housing. So, leave your car over night. The next morning, pop the hood and look at the top and sides of the fuel pump. Feel it with your finger. Is it wet? The answer is no, but this is an exercise so you know the difference.

Now, take your car for a drive and then park it. Pop the hood and observe the top and sides of the fuel pump. Feel it. Is it wet? If yes, your fuel pump diaphragm has cracked. Modern gas (10-15% ethanol) is hell on classic cars.

Note that you should also have a strong gas smell for thirty minutes or so until the excess evaporates and the engine cools. This is especially noticeable if you park your car in a garage.
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Old June 24th, 2019, 01:44 PM
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Originally Posted by Jeff99 View Post
it was hot out, 80 or so.
I love this definition of "hot." That's a cool summer afternoon here.
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Old June 24th, 2019, 02:09 PM
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Originally Posted by jaunty75 View Post
I love this definition of "hot." That's a cool summer afternoon here.
Thatís hot lately in mi. Lol
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Old June 24th, 2019, 03:18 PM
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Originally Posted by jaunty75 View Post
I love this definition of "hot." That's a cool summer afternoon here.
Yeah, it's all relative. We had a cool front come in over the weekend - the temperature dropped down to 100ļF.
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Old June 24th, 2019, 08:27 PM
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Why are you running straight 30 weight oil?
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Old June 24th, 2019, 10:24 PM
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Originally Posted by classicmuscle.442 View Post
Why are you running straight 30 weight oil?
Service manual says 30 weight was fine and I had a gallon given with the car
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Old June 25th, 2019, 05:32 AM
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Takes longer to get heavy oil into bearings on start up.
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Old June 25th, 2019, 09:34 AM
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Agreed dont use straight weight oil. 10/40 or 15/40.

Always run ethanol free in any carbureted machine.

80*F with RH of 80% and a dew point of 70* IS HOT...Humid tropical hot. Like step out of the shower and step right back in. Different from oven dry hot. 120*F is hot dry or not!
Big difference from you lucky southwest desert dawgs. A 110*F Phoenix day with 20% RH feels like an 85*F humid New York day, with the exception of the moisture-wicking capability of the dead humid air. Hate humidity. Give me desert dry heat any day!
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Old June 25th, 2019, 10:02 AM
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I might have a different view on 30wt oil because I think that's fine. I don't think you can gain a thing by changing to a multigrade oil. Or even a simple oil change.

I won't comment on whats hot or not.

I don't think any one brought up a possible reason and solution as to why the oil light flickers at idle. My theory is the oil pump pick up is probably somewhat clogged from bits of plastic broke off from the factory timing chain. I like the idea of installing a pressure gauge and confirming the pressure. This is common in older high mileage Oldsmobiles. But I'm afraid dropping the pan and cleaning out the bits would be the solution...and of course installing a new timing chain.

Now, I think the engine is going to fine for the time being, but this should be put on your to do list.
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Old June 25th, 2019, 10:20 AM
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Thanks for the replies, will I get piece of plastic in the oil when o change it to confirm that is possibly it?
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Old June 25th, 2019, 10:54 AM
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Originally Posted by Jeff99 View Post
Thanks for the replies, will I get piece of plastic in the oil when o change it to confirm that is possibly it?
Its possible, though I doubt it.
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Old June 25th, 2019, 04:18 PM
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Yes, good point Don.
Again for the OP see post #11....check the PSI.
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Old July 13th, 2019, 02:08 PM
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So got a gauge on and it has plenty of oil pressure. Light is on almost all the time now. There is no play between moving the crank and the distributer So donít think that nylon teeth are gone, guess itís the sender

Idling hot

Revving at 3000 rpm
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Old July 13th, 2019, 02:17 PM
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If you have oil pressure completely warmed and the light stays on its the sender.
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Old July 13th, 2019, 03:25 PM
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That's a relief. A $10 oil pressure sender is preferable to low oil pressure.
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