Correlation bet. new oil/ techron and worse cold start

holtjv · 02-14-2007, 07:25 AM

I've read a lot of oil threads and I think one post which claimed that syn oil is better for cold starts than dino. And another which said that techron can contaminate oil.

So here's the story:

My cold start has always been interesting--idle drops precariously low, but never dies--revs back up to a consistent cold start idle (1200-1500). Intra-day cold start was never an issue.

The weather in austin has gotten warmer in the past month.

I changed the oil from a synthetic to dino, although the syn was 6 months old and had been topped exclusively with dino.

Very shortly after I changed the oil I added a bottle of techron--probably didn't drive it 50 miles, but at least 30 hard miles.

Now, my overnight cold start dies each time--the next turn works as it had before the oil/techron. Intra day starts occasionally die but always drop precariously down.

You think there's any correlation between either the new oil or techron and the worsening cold starts?

Thanks,

Jack

cnavarro · 02-14-2007, 11:03 AM

Even if techron did contaminate the oil, which I personally don't think has much more effect than similar fuel contamination of oil (or lead back in the day), I don't think it would cause your engine to die after a cold start.

Could the thicker viscosity make the engine harder to turn over, requiring more hp to idle due to frictional loss, maybe, but I think that's a long stretch IMHO.

Maybe the technron broke some deposits off and is causing a valve to stick, affecting idle? Again, a long shot. Just throwing out ideas.

cak · 02-14-2007, 11:15 AM

This sounds exactly like the way my 73.5 with stock CIS cold starts. I am learning to catch that initial drop off before the engine stalls - usually by pushing the hand throttle down a bit after it catches (throttle must be up fully to engage the microswitch).

I suspect it's temperature related, and that your "ideal" starting mixture has changed.

holtjv · 02-14-2007, 12:50 PM

The techron and/or oil correlation definitely seem like long shots--I just don't believe in coincidences.

I'm thinking about changing to mobil1 oil after having read the excellent oil additive thread--maybe I'll do that this weekend and see if there's a difference.

As to adding some throttle--immediate backfire if I do that and the popoff pops. I have thought about adding some throttle prior to starting---JH

Steve 82SC · 02-14-2007, 01:02 PM

I've used Techron and can smell it on the dipstick. I make it a habit to add the Techron to an empty tank and fill it with 10 gallons. After I run that tank out, I do my oil change.

Steve

cak · 02-14-2007, 01:13 PM

Quote:

As to adding some throttle--immediate backfire if I do that and the popoff pops.

Well, every car is different. I don't really know how the later CIS cars do when starting; mine is the only one I've experienced.

One thing I was told when I bought the car was to let the fuel pump run for about 30 seconds before trying to start, to avoid backfires. My car doesn't (yet) have a popoff. This technique seems to work (avoiding backfires) ... but I don't have a comparison, because I always do it that way.

Loaded · 02-14-2007, 01:44 PM

keep running techron it will go away usually. happened to my car. Carbon and varnish etc loose up. Keep using it and it will make it right. Techron rocks.

DanielDudley · 02-14-2007, 03:02 PM

When you put techron in you need to go for a long drive. I like to put in a strong solution, drive it home and let it sit overnight. Then I like to fill up and run the P out of it.