Community Forums

gatorcq · 01-05-2019, 07:25 PM

When the engine is started with cold coolant, the engine will operate in “Cold Mode”.The engine will operate with reduced performance until the coolant temperature has warmed.The Caterpillar electronic service tool software will indicate when the engine is operating in Cold Mode.The C7 engine will operate in Cold Mode below 64 Deg C.

GBDTN · 01-05-2019, 08:52 PM

Come to think of it. This happened after cleaning the radiator, changing the coolant and transmission fluid ad service all filters....hmmmm? It does run cooler

CountryB · 01-06-2019, 06:03 AM

use the ScanGauge to see exactly what temp is being reported to the ECM. Make sure it is correct (i.e. if the actual temp is 160 degrees and the ScanGauge shows 140 degrees, that would indicate a faulty temperature sender unit or wire-resistance issue (note that the dash gauge does not use the same temp sensor as the engine ECM uses, so you can compare the two but usually the dash gauge is more inaccurate so that test doesn't help much). The difficult part is knowing what the actual temp actually is.

In the automotive performance world some of the "tuner chips" will falsely report lower coolant temp to the car's ECM. This is so the car will think its in cold start mode or in open loop to provide more fuel for increased performance.
So - you could do the reverse, and add a resistor parallel to ground with the temp sensor to make the ECM think the engine is warmer. If the performance returns you will know it is a ECM-temperature programming issue.

The easiest way would be to buy a new ECM temperature sender unit - then you know for sure that is not the cause of the problem (or the problem is fixed).

Tizbad · 01-12-2019, 08:45 PM

Quote:

Originally Posted by gatorcq

When the engine is started with cold coolant, the engine will operate in “Cold Mode”.The engine will operate with reduced performance until the coolant temperature has warmed.The Caterpillar electronic service tool software will indicate when the engine is operating in Cold Mode.The C7 engine will operate in Cold Mode below 64 Deg C.

Actually, the software for cold mode is also looking at ambient air temp and compares that to the coolant temp. 64' is not a rock solid number since ambient temps. apply. Due to this, the intake and coolant sensors need to be reading appropriately for cold mode to operate correctly.

discovery39s · 01-21-2019, 04:18 PM

Just a thought relative to the low cost of components. Why couldn't a person unplug the air and coolant temp sensor(s), plug in a spare set that is pre-heated on hot water to see IF it is a sensor issue. Much cheaper test then a repair shop cost to hunt and peck for 150.00/hr. If she takes right off then it sounds like one or the other. Process of elimination.
IAP sensor is out. No affect by temperature, only pressure.
Good luck

rrtribble · 01-21-2019, 05:27 PM

Steve,

Looks like Wagner has the Cat service locked up in your area and they have a good reputation from what I saw. Recommend you talk the Service Manager informing him of the problem you are experiencing and see what he advises. If it doesn't start with diagnostics go to another Wagner or even out of the area. Could be as simple as a corroded coupling, sensor or computer setting.

My C7 starts and I'm able to hit the road within 3 to 5 minutes. I hate long idling diesels, especially next to me in the campground.

Good luck - Richard

Mike and Pat · 04-15-2019, 11:17 AM

While I was having my number 6 injector replaced at Holt CAT in Edinburg, TX I had them replace my Air inlet temp sensor. Now I don't have to wait for the engine temp to get up to 160 before I can move. I can take off in just a few minutes of warm up. After 8 years it is nice to have it back to normal.

FIRE UP · 04-18-2019, 11:11 PM

Quote:

Originally Posted by Mike and Pat

While I was having my number 6 injector replaced at Holt CAT in Edinburg, TX I had them replace my Air inlet temp sensor. Now I don't have to wait for the engine temp to get up to 160 before I can move. I can take off in just a few minutes of warm up. After 8 years it is nice to have it back to normal.

Man,
If I had to wait for our C-7 to get to 160 before I could take off with it, I'd be waiting for hours. I fire ours up and, even if it's dead cold outside, I can put it in D and take right off to 65 mph. I don't do that very often. The reason is, is because we're in campgrounds that are maybe big enough that it takes some driving around in them even before we turn out of them and onto a main street. And even then, I'm quite often, on a 25-45 mph city/county street/road that won't allow for higher speeds 'till we hit a freeway. But, the point is, our C-7 doesn't care if it's 35 outside or, 105 outside when I fire it up. It just goes.
Scott