Need Help With Engine Temp

[Rearanger]

Thanks JP02XLT. Good to know I'm not alone. NAPA doesn't make any of their own stuff. Last stat from them was Stant "SuperStat" but with NAPA part #.

Yes, it's coming down to trying several stats to get one that will work. I'll test ECT first to make sure the info to computer is correct, then replace stat if necessary. Also looking at fuel trim with the scan gauge, looks like maybe cooler operating temps is not the cause of my extra fuel consumption.

Been emailing Stant, not much help only to say it's not a stat problem. Looked at Wahler stats, (German) but they don't make a 54mm one for Ranger.

 

[det107]

Try blocking off part of the rad with a cardboard box. If the temp comes up and MPG goes back up you may be on to something.

I have never seen this trick done on a Ranger. Just make sure all eyes ore on gauge to prevent accidental overheating-

 

[det107]

Partially blocked the rad today, no change in stat operation

Actually try blocking the whole radiator as a last resort.
What I do is:
Partially block the rad on 1st attempt (small piece in center)
2nd time is to block rad except for the inlet & outlet areas
If no change....Then block the whole rad-

Again, check to prevent overheating

 

[JP02XLT]

Rearanger, can you data log your O2's to check how many times they change say per 10-15 seconds?, You would be surprised how fast they fall off and become slow and can really crush fuel mileage. Also the increase of winter blend (ethanol) can really cut mileage especially on a FFV, Fords ridiculous method of guessing at what the vehicle needs for fuel input is just stupid on the newer FFV vehicles. Their adaptive strategy works partly on how many fill-ups you make along with other wild guesses as to what the tune should be. Someone needs their butt kicked over that BS programming.

I knew Napa did not make their own line of parts but, generally its not 2nd or 3rd run items as in some other cases and I like the fact that all I needed was a 54mm stat, and I had plenty of choices on temps, I really did not care about the fail safe option, I just wanted the temp where I needed for tuning with the SC.

On the Scangauge how old is yours? I had an original and sent it back for upgrades here recently and now have issues with it connecting, it will report the last known data & just freeze, mine has the hp, 1/4 mile and other new functions but the non connection issue is a real pain.

JP02XLT

 

[Rearanger]

Rearanger, can you data log your O2's to check how many times they change say per 10-15 seconds?, You would be surprised how fast they fall off and become slow and can really crush fuel mileage.

O2s were replaced several months ago when I noticed mileage dropping off in gradual decline - did not improve mpg.

I just have a dash mounted scan type gauge (no logging) with refresh data originally defaulted to every second. Too fast for me to comprehend so I slowed it down to every two seconds - much better. O2s were changing every second - or more.

Also the increase of winter blend (ethanol) can really cut mileage

Here in NC I never noticed any change in winter mileage since owning the truck from 2003. My mileage data goes back that far. We always have about 10% corn.

I had plenty of choices on temps

Could I get a 54mm 200F?

On the Scangauge how old is yours?

Mine is an Ultra-Gauge, about $80 with what seems like all of Scan Gauge's features. I just purchased it and am playing with getting and understanding the data. I got it mainly for engine temp for now, but it'll give all the data you really didn't have to know LOL.

Looking at TOAD (AU) software for something I can graph on a laptop so that the data is more understandable. Truck is 10+ years old now so I figured I'd need the LTFTs, STFTs, O2s etc code reader ability soon. Other vehicles are OBDI

Tomorrow is ECT test day (65F here in NC ). I'll post results.

 

[Rearanger]

OK, did resistance/temp test on ECT sensor. As accurate as I could do. I have an induction heater that can digitally increase temps every 5 degrees. Used that with probe thermometer immersed and sensor off the bottom in a drilled PVC pipe for support and to isolate it from pot bottom. Kept water stirred so temp was even throughout.

Went with Ford spec temps in FSM that had corresponding ohm readings. The higher the resistance the lower the temp reading.

Ford says actual can vary by 15%, but did not say 15% high and 15% low (30% variance) or 7.5% high to 7.5% low (15% variance) - there is a huge difference.

My resistance readings were all higher than midrange spec which would show a lower temp on the scan gauge than actual water temp. But I was within 5% high on all temps except for the 194F reading. That resistance was 12% higher than midrange. My actual ohm reading at 194F was 3.14, spec is 2.8. So my stat may be keeping coolant at 195F but showing 185.

The volt curve in the manual is bare bones and not a straight line but a shallow curve, so extrapolation without a detailed temp/resistance curve is difficult.

Looks like Ford never meant this to be exact, just within grenade distance.

Would be good to have a way to measure actual coolant with thermometer. My infrared temp gun only gets close. Using an aftermarket heat gauge that can be bench tested before installation would be a better way to keep track of engine temps.

The factory heat gauge doesn't show 10-20 degree differences.

 

[Rearanger]

Doing some research into fuel trims since I have a scanning gauge and my possible cause for reduced gas mileage, other than engine temp measured by ECT sensor.

There is a "start enrichment" of the first second of engine rotation based on engine temp. Then there is an "after start enrichment" of the first 20 seconds of engine rotation proportional to engine temp. After the time out of the other enrichment stages there is "warm up enrichment" based on engine temp up to 140F after which the enrichment due to engine temp ceases.

Looking at this fuel trim information tells me why the ECT sensor accuracy is not that important since after 140F (or thereabouts) the ECT sensor adds nothing to additional fuel metering. So I have to conclude that I need to look for another cause of my reduced mpg.

If anyone can add to this that would be great.

 

[JP02XLT]

Your correct on the enrichment adjustment periods, but if the ECU goes into closed loop the O2's will correct the mixture based on their signal input as well.

How much mileage drop have you seen?

I know my truck looses 2-3+ mpg in the winter months, we see more winter blend fuels and I let it warm up before I take off.

Have you ever done an oil analysis? Extreme cold causes many clearance issues on engines, doubt that is your case, just wandering if you ever see any changes in your oil from Summer to Winter.

Since you have the ScanGage tool, see how quickly your getting into closed loop and what your STFT are at that time, just curious as to what your seeing on your truck & if the ECU is having to make large adjustments.

I am sure you have monitored your instant fuel mileage with the ScanGage, these 3.0's are so bad about spending the majority of the time sucking fuel, for apparently no good reason, even under light acceleration the instant mileage is awe-full compared to other vehicles I have had my Scangage on. Not sure if the fuel map is that poor or the ECU has that little of a scale for control. I had my ScanGage on my Fathers Jaguar, it has a 4.2L V8, 11to1 compression ratio and the ECU is changing the injector pulse about 5-6 times per second, it is really an amazing piece of work. The ECU will change the fuel & timing curves to adapt to 87 octane with only minimal performance loss over the suggested 93 octane. But I will tell you it is very quick to report a problem with an O2 or plug, unlike our Ranger ECU's. My O2's were almost dead as far as changing and it never lit up the SES light or set a code, I think as long as they were plugged in, it was happy.

Shoot me back some symptoms & I will try to help you all I can.

JP02XLT

 

[Rearanger]

JP02XLT,

My mpg drop has been about 1-2. Here in winter NC I've never noticed much if any of a drop. Previous 4 tanks in a row went to low 18's with last tank to mid 17, a number I've never seen since truck was in break-in period. This is definitely out of norm.

I've done several oil analysis. In fact I just sent a sample in on Monday as I suspect now that I have leaking injectors and I want to see if fuel in oil. Fuel pressure check showed normal pressure but pressure leaked down quite quickly after shut down.

My idle fuel trims are both banks about -7.5. Bank 1 runs about double bank 2 in positive trims but within the 10% allowance. The idle also has been a little rough(er) than usual. New wires, plugs, cam sensor, O2s new several months ago and scanner info shows them to be OK. Compression done a few months ago was as good as several years ago. May do another this weekend.

I haven't set up my fuel usage yet on this scanner. I'd have to enter in multiple fuel fills info and then wait while scanner got better at mpg estimates. Doing it by the tank is fine for now.

I'll wait for oil analysis to see what next step is going to be.

 

[JP02XLT]

When you say Idle fuel trims, is that your short term fuel trims? at -7.5 in closed loop something is telling it to pull a bit of fuel from the mix, Have you checked the fuel dampner on the rail for any gas in it.

If you were closer I could check your injectors for you, I built a neat fuel injector tester from an old fuel rail, 12v laptop supply and some fittings to get air pressure to the rail, and a glass jar to catch the fuel being sprayed, it works real well, easy to add injector cleaner to the rail then cycle injector, It has a simple home built timing circuit so you can precisely measure flow over a given on cycle time, at any pressure you like.

Let me know on the fuel trims

JP

 

[Rearanger]

-7.5 is LTFT at idle, meaning rich mixture so computer shortens injector open time to compensate. Yes, I pulled fuel dampener vac line, no fuel.

Thanks for the help, but if I'm going to pull injectors for test I'd just prefer to send them out to be flow tested, cleaned and new o-rings - which may happen yet.

On another vehicle I found fuel in oil and sent injectors out and that solved problem. Other alternative is to buy already re-built injectors for about $8 more than the cleaning service - and not have the one week wait time.

 

[JP02XLT]

can you see your short term fuel trims, generally a better indicator of whats happening within a 15 second window, Ltft in the negative can be due to several conditions where the ECU has adjusted for driving conditions, load, rpm etc.

I checked on mine today, STFT's were in -1 to +1 range, LTFT were in the 3's, just for your reference

JP02XLT

 

[Rearanger]

STFTs are a little hard to follow as they jump around. Would be better with graphing software. Looking into that this week.

My LTFTs are steady negative on idle - no jumping around. I imagine leaking injectors have a higher influence when air flow is small and less and less as air flow increases - hence my LTFTs go into positive range off idle.

What are your LTFTs at idle?

 

[JP02XLT]

I will check for you tomorrow, are you in open or closed loop on idle? it should go into open loop on idle, but almost immediately go into closed loop with almost any throttle input

JP02XLT

 

[Rearanger]

Open loop on idle??? Why would that be? Pretty sure it's closed loop all the time once heated but really haven't paid close attention. I'll check closer tomorrow. Are you saying that every time the engine's on idle it'll switch immediately to open loop?

Isn't it in closed loop once O2 sensors get to full operating temp?