Bad ECT sensor causing this problem or what???

Mustang5L5 said:

Ah…I defaulted to a fox car in my thinking and didn’t thinkSN95 with regards to fan control.

Sure it’s not the tune? Is this a sudden change?

Click to expand...

It's a sudden change and no not the tune.

Mustang5L5 said:

Ah…I defaulted to a fox car in my thinking and didn’t thinkSN95 with regards to fan control.

Sure it’s not the tune? Is this a sudden change?

Click to expand...

I'm pretty sure it was not doing this the many times I've driven it since the tune late January LOL

Mustang5L5 said:

Ah…I defaulted to a fox car in my thinking and didn’t thinkSN95 with regards to fan control.

Sure it’s not the tune? Is this a sudden change?

Click to expand...

So I pulled the codes and key on engine off I got 511 which is eec processor ROM test failed, 117 ECT sensor circuit grounded, and 564. There is no 564 in my Chilton manual so if I recall correctly when I googled what that is I have to double check but it didn't seem like anything significant in regards to what the car is doing.

With the key on engine running I got a 998 which is a hard fought present and the 117 and there was another code but I did that test two more times and after it read the 998 and 117 when it started the third code the car cut off.

I went ahead and swapped out the ECM with the one out of the 94 cobra and started the car up and the fan is still coming right on. So with that cold 117 ECT sensor circuit grounded I may just go ahead and buy another sensor anyway even though they all had similar readings and even the one I tried in AutoZone earlier today. If it's possible the sensor is bad then worst cases I will have a new one lying around instead of the other used ones but I hope I don't have an actual ground somewhere in the wiring system from the PCM to the ECT....

564- fan control circuit failure
998 - operating in failure mode

You know you have some kind of fan issue so that explains that code. The 998 is most likely set due to 117 code. I have seen several threads where bare wires at or close to the ECT.

AeroCoupe said:

564- fan control circuit failure
998 - operating in failure mode

You know you have some kind of fan issue so that explains that code. The 998 is most likely set due to 117 code. I have seen several threads where bare wires at or close to the ECT.

Click to expand...

what did they do to fix the bare wire issue? I know when I did the engine a few years ago I found the wires to the Ect plug one I believe just one was frayed so I taped it up good so it wouldn't touch the other eventually. I believe just some sheathing was broken but the wire was still intact. I played around with it today with the car running to see if there was a change in anythign or the fan turning off, ect but nothing. I really don't think that wire is an issue but still a little concerned.

Just get a new ECT pigtail. Several places sell them including parts stores.

AeroCoupe said:

Just get a new ECT pigtail. Several places sell them including parts stores.

Click to expand...

do you think it's likely where I taped is the culprit and not anywhere along the wiring in the harness itself? (those same wires by the way)

Not there so hard to know. Get a DVM and see if any of the pins in the connector are shorted to each other.

AeroCoupe said:

Not there so hard to know. Get a DVM and see if any of the pins in the connector are shorted to each other.

Click to expand...

how do I test that, ohm it out? On what setting? I'm not that familiar with a lot of the settings and such other than following a chart and such lol......

I do have actually a used pigtail that I splice in on the other car the one that got hit years ago and the harness is still good. I can definitely remove that and splice that in ( temp) to see if that solves the issue as well....

Mustang5L5 said:

Either resistance (ohms) or you can use continuity. Continuity will beep if the wires are part of the same circuit (shorted together)

Ohms is the horseshow and continuity looks like a speaker emitting sound. (yellow icon circles below)

Click to expand...

Gotcha

Update -
Ended up being the ECT connector. Once I started peeling the tape back I got 5 volts. Swapped to actually a used connector from my other car that looked damn good and good to go now. Through the process I learned how to pin and check a good bit of things

Mustang5L5 said:

Wait Til the car is cold. Then just look at your outdoor temp. If it's 80 degrees, then look at the resistance values for 80 or as close to whatever temp you are at.

For the ect, you are measuring resistance. Unplug the plug and measure resistance on sensor across the two plugs.


Sensors are cheap. Rockauto has a number (including motor raft) for about $20




Sent from my iPhone using Tapatalk

Click to expand...

Moto raft lol

Mustang5L5 said:

Nice work!

Click to expand...

Now just gotta figure this out smgdh-‍


man I'm so perplexed and just you know I'm trying to figure out some things before I go and get the tune check and changed. I've tried a lot of things recently and tomorrow I may even unplug the chip to see if that will solve the issue I am having of and it's not a startup issue idling crazy or anything like that when cold or nothing like that my issue is just in the summertime and the car gets up to about 190°, after I shut the car off when I go to start it back it will start fine even though in extreme hot weather it will sound sort of like it it doesn't crank up as strong as it normally does, but it will kind of sort of sound like it's too much fuel at the startup or something almost like a flooding situation but it will start up fine all the time.

It will idle fine for about 20 seconds and depending on how hot the weather is it will sometimes it will you can see the RPMs going to go up just a little bit you'll come right back down to the same spot and idle for a little bit more and then eventually it will just cut off. If I tap the gas it will auto up the RPMs will go up of course and it will idle another well it will go up and then come back down to the original RPMs and then after that a few seconds that maybe 5 seconds or so it will cut off unless I play with the gas and until I get going it will do that. Once I start to drive off and if I can continue driving for up to some speeds up to about maybe 40 45 50 for a good minute or so it will be fine it won't do it again until I cut the car off again.

Everything checks out the TPS I've checked the range of the TPS it has a nice steady smooth flow from one volt to 5, tried a new idle air valve, fuel filter is new, a used distributor off my other car, used TFI module, a new ECT sensor, now I did fix the ECT connector since I had the tune actually rechecked in January and so I remember him saying something about the car was warm you knew the car was warm it's been running for a while but it was showing that it was still cold or something like that. So I'm hoping that's all it is is he needs to change the has someone said earlier in this post the startup fuel tables so I'm going to make sure I have a note of that for him so that he can have something to go by as in playing with and trying. I'm going to get there early that morning and I'm not leaving Columbia which is 2 hours away they close at 5:00 but if I have to stay all day trying and I'm sure he'll have different vehicles he'll be working on, but he'll just have to play with it all day if he has to to figure this damn thing out because it's a shame man it's it's been the same thing on the other car when the engine was in there and I'm sure I have a whole lot more things corrected and fixed and tried and checked this time around on this engine that is just perplexing man to still be doing the same damn thing pretty much. Does not do it in any other weather by the way I mean winter time spring fall the car does not have this issue. And the thing drives too strong and too good it does not have any kind of idle issues even in the summertime other than when I cut it off and start it back up. If startup fuel tables need tweaking would that be an issue only in summer though????

The injectors that I have are 20 something years old and they were used when I got them the 24 pounders in so I was even going to order some 36s because I'm going to do a 331 at some point either for this car or for the 95 and worst case is after he makes some changes and it still doesn't fix anything I may just go ahead before I leave there put those injectors in and let him go ahead and make the changes and see if it's a leaky injector. But if it's a leaky injector why isn't it doing it at any other time of the year or anything like that and they're definitely isn't any signs of any leaking you know any injector leaking on top of the intake or anything like that and also the fuel pressure it is holding a good fuel pressure very well and no smell of fumes in the vacuum line when I pull off regulator.

I will also take all of the things that I just bought even though I'm going to take them back to AutoZone but I'm going to take them anyway just in case he wants to try one of those on during the process of anything else that needs to be checked or tried the TFI module, the IAC, the ECT, and the distributor.

Change the fuel filter recently as well because I did not change it when I did the engine in 2021 when I put it in still no change and I'm sure if it was a fuel pump situation the car would act up and other normal regular situation as well. Should not be vapor locking from what I've read with newer cars and the fuel pumps PSI it should not be a situation where it's vapor locking even though the symptoms sound like you know yeah that could be a situation where the fuel is too hot or something like that but definitely should not be that.

Have you check for codes? Have you checked the fuel pressure? Any fuel in the vacuum line on the fuel pressure regulator? I will tell you that running injectors that long and buying them used all adds up to needing to get them cleaned. I bought 24 lb/hr units from a buddy and ran them for a few years and before I got the car tuned I had them cleaned. They were flowing about 22 lb/hr when he checked them and the spray patterns were marginal. After the sonic cleaning, new filters, and new pintle caps they flowed 24 lb/hr and the spray pattern was greatly improved. Same thing on the 42 lb/hr units I bought from the same friend years later due to running out of fuel on the dyno and plugged them in and they worked great. Years later and tuning the 331 we had to turn the fuel pressure up to get good AFR past 6,000 rpm. Reworked the fuel system and again had the injectors cleaned. They flowed 41 lb/hr and the spray pattern was again marginal. Sonic cleaned them after removing the filters and they were filthy. New filters and new pintle caps and they flowed 45 lb/hr and the spray pattern was really good. These were off a Ford Lightning so factory injectors.

So with all of that I would pull codes, check fuel pressure & the FPR vacuum line, and I would strongly suggest you either clean or replace the injectors. Typically cleaning the injectors, replacing the filters, replacing the pintle caps, and putting new o-rings on is in the $125 range or it is here in the Tulsa, OK area.

AeroCoupe said:

Have you check for codes? Have you checked the fuel pressure? Any fuel in the vacuum line on the fuel pressure regulator? I will tell you that running injectors that long and buying them used all adds up to needing to get them cleaned. I bought 24 lb/hr units from a buddy and ran them for a few years and before I got the car tuned I had them cleaned. They were flowing about 22 lb/hr when he checked them and the spray patterns were marginal. After the sonic cleaning, new filters, and new pintle caps they flowed 24 lb/hr and the spray pattern was greatly improved. Same thing on the 42 lb/hr units I bought from the same friend years later due to running out of fuel on the dyno and plugged them in and they worked great. Years later and tuning the 331 we had to turn the fuel pressure up to get good AFR past 6,000 rpm. Reworked the fuel system and again had the injectors cleaned. They flowed 41 lb/hr and the spray pattern was again marginal. Sonic cleaned them after removing the filters and they were filthy. New filters and new pintle caps and they flowed 45 lb/hr and the spray pattern was really good. These were off a Ford Lightning so factory injectors.

So with all of that I would pull codes, check fuel pressure & the FPR vacuum line, and I would strongly suggest you either clean or replace the injectors. Typically cleaning the injectors, replacing the filters, replacing the pintle caps, and putting new o-rings on is in the $125 range or it is here in the Tulsa, OK area.

Click to expand...

the last time I did a Koeo and koer test some months ago after I actally came back from the tuner in Jan for him to see if he could get more out of my combo since changing a few things from the last setup on the other car, I got codes :

copied and pasted from March 18th:
So I pulled the codes and key on engine off I got 511 which is eec processor ROM test failed, 117 ECT sensor circuit grounded, and 564. There is no 564 in my Chilton manual so if I recall correctly when I googled what that is I have to double check but it didn't seem like anything significant in regards to what the car is doing.

With the key on engine running I got a 998 which is a hard fought present and the 117 and there was another code but I did that test two more times and after it read the 998 and 117 when it started the third code the car cut off.

I did fix the ect sensor harness and the othe stuff were related to it so and that fixed my fan coming on initially situation. The fuel pressure is good and I do have an aftermarket regulator with a gauge on the rail. No fuel smell in the vacuum line. The tuner did not mention anything about fuel being an issue when I was there in January and so I'd like to feel like they might be an issue, but is it causing my ONLY issue with this car and that is what I explained as in summer time only and when I cut the car off and re start it? Why would it not act up year round?

Here's what I asked a guy over on SN95 forum about injectors, well it's what I said in my plans on taking parts including new injectors when I go back to the tuner. I'm hoping it's just some adjustments in the hot start fuel tables that will fix the issue. I think 39's or 42's for my intended 331 will be sufficient by the way, NA and expecting somewhere about 350-375 rwhp is really all I'd want and need out of it.

So yeah I've checked and tried everything, change some parts though some were used from my other car(s). Ohmed things, chedcked voltage, smoke test using cigar method, ect ect. I will actually take some parts with me when I go back to the tuner in case we need to try another part. I'm hoping it's in the hot start fuel tables that need to be tweaked. I did fix a bad Ect sensor connector harness since I was there in January actually for him to try and see if he could get more out of the changed combo since he tuned my setup years ago with shorties vs LT's and a few other things from my wrecked 95. I was thinking of just getting new injectors as well in case it's a leaky injector that's only acting up in summer and under the situations I named earlier. There is no leaking up top or the smell of fuel anywhere, including the aftermarket fp regulator's vacuum hose. But since I'll need a meter calibrated for the injectors I might not make that move right now. I could see getting the injectors if it was plug and play and could work with my Pro M calibrated for 24's.

(O) = Key On Engine Off test
(R) = Key On Engine Running test
(M) = Memory code

117 - (O,M) ECT sensor is/was low or grounded – ECT
511 - (O) No power to PCM pin 1 or bad PCM (processor)
564 - (O) Fan Control (FC) circuit failure – A/C and Fan Circuits

So have you checked fuel pressure and checked for fuel in the FPR vacuum line?

AeroCoupe said:

(O) = Key On Engine Off test
(R) = Key On Engine Running test
(M) = Memory code

117 - (O,M) ECT sensor is/was low or grounded – ECT
511 - (O) No power to PCM pin 1 or bad PCM (processor)
564 - (O) Fan Control (FC) circuit failure – A/C and Fan Circuits

So have you checked fuel pressure and checked for fuel in the FPR vacuum line?

Click to expand...

I know that was a lot to read LOL but I did answer but I did in fact check the fuel pressure the fuel pressure was good and I mentioned what I have as far as fuel parts aftermarket regulator fuel gauge. Everything is checking out fine and there is no smell in the vacuum line when I pull it off of the regulator. The tuner did not mention any issue of any fuel problem as well or had to make any adjustments to fuel pressure. And what I did with the ECT connector fixed the issue issue at hand at that time with the fan coming on and the ECT since they're grounded as to the codes to

AeroCoupe said:

(O) = Key On Engine Off test
(R) = Key On Engine Running test
(M) = Memory code

117 - (O,M) ECT sensor is/was low or grounded – ECT
511 - (O) No power to PCM pin 1 or bad PCM (processor)
564 - (O) Fan Control (FC) circuit failure – A/C and Fan Circuits

So have you checked fuel pressure and checked for fuel in the FPR vacuum line?

Click to expand...

The fuel pressure is holding nice and steady as well when I switch the car off

So have you cleared the ECU and driven the car around? That will allow any old issues to be removed and any new ones to populate.

The OBD-I’s are first in first out so you have to fix what they show, clear the ECU, drive the car and then pull codes. Rinse and repeat until all codes are cleared that can be cleared i.e. any deleted smog equipment codes.