SPONSORED LINKS

Rough Idle, now Check Engine light on?

Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
Brian knows his stuff. I tend to do the reset with a tool mainly so I don't need to mess around driving it to reset the monitors. However you have that "luxury" being you are the owner. You can use a resistor or just connect the cables, both work.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
+1
Tuesday, January 24th, 2023 AT 6:58 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
Updating -

Only shortish trips lately. 45 minutes, an hour tops. So, no B12 in the tank just yet. Possibly next week, I have a jaunt planned.

However, either my OBD2 scanner is lying to me, or I am consistently seeing 0 misfire count. So that seems pretty good!

Also consistently seeing top temperature of about 175, even after nearly an hour warmup drive, even in weather that's not bitter cold, 40s to 50s. Keeping an eye on that - seems too cool?

Overall, much better. And using this process as an excuse to lead foot it whenever traffic opens up in front of me.
Was this
answer
helpful?
Yes
No
Sunday, February 5th, 2023 AT 3:18 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
175 would be running lower than it should. I would expect 190-200 if things are correct. Possibly grab a non-contact thermometer and take some readings with that. Possible that someone put a lower temperature thermostat in it.
Was this
answer
helpful?
Yes
No
+1
Sunday, February 5th, 2023 AT 5:44 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
I hear you on the temperature.

Is it possible that B-12 would have a nearly immediate effect? I drove about an hour to an airport drop off, on the way back dumped in a can of B-12 and filled up my fully warmed up car. Within about two miles of 25 MPH driving, I noticed clearly smoother idling.
Am I crazy?
Was this
answer
helpful?
Yes
No
Monday, February 6th, 2023 AT 3:33 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
Yeah, it can act that fast. It's one of the reasons why I keep it in stock by the case. I've seen it turn an oil burner into a clean running engine after a couple cans. I generally like to dump a can in our vehicles every 6 months or so. Watch your oil for changes, if you have a lot of carbon or sludge in the rings you can see the oil get dark as it get's cleaned away, then change the oil and filter.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
+1
Monday, February 6th, 2023 AT 4:22 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
That's astonishing, truly. I was noticing maybe 10% of the vibration I felt before, and that only intermittently. Most of the ride home, idle felt smoother than I can ever recall. Great suggestion, thank you. And I'll keep an eye on the oil per your experience.

I mean, it *did* cost me a whopping $4 a can, so not perfect, but I'll take the hit. ;)
Was this
answer
helpful?
Yes
No
Monday, February 6th, 2023 AT 4:33 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
Down the bottom of the tank with B-12 in it. I did some "spirited" highway driving and some very hilly winding roads, mixed with my usual short hops. Rough idle back somewhat, still happening intermittently, and the low temperatures still in evidence. No misfiring, still. So, more diagnosis, I guess. Next stop, laser thermometer then? What's my procedure? Thanks again, as always.
Was this
answer
helpful?
Yes
No
Monday, February 20th, 2023 AT 2:35 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
Still running cold, replace the thermostat with an OE spec part. See if getting it up to temperature stops adding extra fuel to the cold running engine.
Was this
answer
helpful?
Yes
No
Monday, February 20th, 2023 AT 3:00 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
It looks to me like the thermostat replacement will also mean a coolant drain/refill process too?
Was this
answer
helpful?
Yes
No
Friday, February 24th, 2023 AT 9:32 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
Yes, drain replace the thermostat housing and thermostat and refill. You need to burp that engine to get the coolant full. There is a bleeder on the water outlet. Loosen it, fill the reservoir to the max level. Once you see coolant at the bleeder tighten it. Now start the engine and get it up to temperature, check the coolant level in the bottle. Shut it off and let the engine cool. Be sure the coolant stays above the full cold level.
Was this
answer
helpful?
Yes
No
Saturday, February 25th, 2023 AT 1:36 AM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
Would it make sense to flush it fully at this point and do the switch from Original Weird Expensive Green to New Normal Gold? I've been considering that move because the green is harder to find and seems kind of obsolete. At least, Ford has moved on so maybe I should too?

Could I hose it through the thermostat hole as well and really get a power flush - make an opportunity out of it?
Was this
answer
helpful?
Yes
No
Saturday, February 25th, 2023 AT 6:56 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
Now would be the time to do it. I made a tool years ago to flush systems through the upper rad hose. Used a kong dog toy with a hole through it to fill the hose and let me put the water line in. These days they have similar tools as loaner tools in the parts store. Flush it out and change out the thermostat and its housing and then fill it with the gold. I usually buy the concentrated and mix it with distilled water and save some money. I would also check things like the heater hoses, water pump and such over real good before you start, anything looks odd, you could replace it at the same time.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
+1
Saturday, February 25th, 2023 AT 12:19 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
Okay. Realistically - this is all going to have to wait till it warms up around here a bit. Not a job for this bitter cold weather, I think. I'll suffer rough idling in silence for a month or so, until my hose bib doesn't freeze over at least. I have my marching orders, thank you. I had been kind of dubious about the green coolant for a while. I know it's not a big deal, but I'd rather have something I can be confident I can source to top up, and not pay through the nose for. I will probably be doing the gold concentrate & distilled water, too - NY water is very safe health-wise but it's fluoridated and a bit hard and I don't want it in my radiator. So, I think I'll want to send some distilled water through as a final step in the flush, maybe one 5-gallon jug or so.
Was this
answer
helpful?
Yes
No
Saturday, February 25th, 2023 AT 5:49 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
NY water where I am isn't something I'd ever put in a cooling system, far too many minerals in it here in mid-state.
Was this
answer
helpful?
Yes
No
+1
Saturday, February 25th, 2023 AT 7:53 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
Would you flush with it, and then do some more with distilled after? Does my plan sound realistic? I'm thinking the pressure from a hose to get things pushed out, then the clean water to replace the tap water. Otherwise, I guess I'd need something to pump distilled water through the system at some higher pressure than just pouring it? Is that the "real" shop method? The DIY stuff I've seen (FordTechMakaluco has a good video) shows using a hose to flush with and doesn't address water quality as far as I remember.

I feel like I must be overthinking this?
Was this
answer
helpful?
Yes
No
Saturday, February 25th, 2023 AT 8:07 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
You can flush it with tap water, but then fill it with distilled unless you know it isn't hard water. What I generally do is to flush the system with tap water, then I have a rig I put together with an air connection to blow out most of the rest. Then I use a bucket and distilled water with a small pump to flush with distilled. Then fill the system. That is on my own vehicles. For customer cars I have a flush machine that just uses coolant and a filter system.
Was this
answer
helpful?
Yes
No
+1
Saturday, February 25th, 2023 AT 9:24 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
I let the car idle for about a half hour yesterday. The upper radiator hose started ice cold, and after a few minutes was only barely warm. By the end of the half hour, coolant temperature was reading 172 on the OBD2, and the upper hose was still just slightly warm, no real change.

Does this info mean anything?
Was this
answer
helpful?
Yes
No
Friday, March 3rd, 2023 AT 8:19 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
Yep, thermostat is letting coolant flow when it shouldn't. Basically, the engine can't warm up because the coolant is constantly taking the heat away, the thermostat however should block that flow until it gets much warmer.
Was this
answer
helpful?
Yes
No
+1
Saturday, March 4th, 2023 AT 12:44 PM
Tiny
TUBEGEEK
  • MEMBER
  • 37 POSTS
Okay. So, next steps are clear - replace thermostat, flush coolant and convert to gold.

This is related to my rough idle, then? Can't get the engine hot enough to get the valves clean?

And another Am I crazy? Question: is it possible for a full tank of gas to behave differently from a partial tank? Seems like the idle behaves better right after a fill up. (The immediately smooth idle with the Berryman's was after a fill up, and I noticed this again on the next fill-up which was without the Berryman's.)

I'm just full of questions!
Was this
answer
helpful?
Yes
No
Sunday, March 5th, 2023 AT 9:03 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,451 POSTS
The lower engine temperature will tell the ECU that the engine needs more fuel because it's running cold, works like a choke on old engines. The side effects can be rough idle, bad fuel mileage, poor interior heat and others depending on the way the ECU is programmed. As for the idle changing with a full tank of fuel, that could be something related to a bad pump or cracked fuel pump feed line. Only a few ways to verify if it's one of those, pull the pump and inspect it or disconnect the front fuel line and run the fuel into a clear container and see if it has air in it. Another would be to test the fuel pressure with the tank low and again with it full. I would get the coolant issue taken care of and then see what it does from there.
Was this
answer
helpful?
Yes
No
+1
Monday, March 6th, 2023 AT 10:21 AM

Please login or register to post a reply.

Related Check Engine Light Content

How to Read Codes
VIDEO
How to Read Codes
Instructional repair video
Check Engine Light
GUIDE
Check Engine Light
Why is my check engine or service engine soon turned on? In this guide we talk about what this is associated with this notorious light, what it is used for and what you...
VIEW MORE

Sponsored links