HELP Please!!!!! '98 4.0 SOV warm start issues

[hottrodk10]

ok.... thought I had posted 2 mos ago .... here goes again. 1998 explorer 4.0L sov engine, ran great until I changed the(stuck open) thermostat, Temp sending unit, & ECT in January. then started not wanting to stay running after its ran at temp and then shut off for 15-20 mins(starts, idles up then idles like a flooded out carb ). if you crank it right after shutting it off then it fires up and runs fine. if you wait it fires up and runs like a flooded carb(instant :thumbdwn: gas mileage too now) . New Fuel filter, Battery, CPS, MAS, new plugs, wires, Fuel pressure regulator, cleaned IAC.... changed second ECT just in case the new one was faulty. just realized that the sending unit Advanced sold me has 2 blades--my plug is a single... had one mechanic tell me everything checks out perfect, that my injectors are "dirty" & to run Seafoam thru(did). Another just told me that the double blade sensor with my single blade plug could be messing up the ECT talking to the computer????? The diagnostic did show that the actual engine temp and what the gauge showed is off with this sending unit? -- this is my only vehicle and I'm having to do the work on it(yes, I'm a girl ) -- any thoughts would be Greatly appreciated

 

[decipha]

your definitely going to need datalogging support in order to see what the ecu is seeing, changes are something its getting is out of wack

Do you have access to an obd2 scanner ?

 

[Stick4503]

The ECT will defiantly cause problems with fuel delivery. I would get the correct one and see if that helps.

 

[XLTrunner]

X2. Sounds very much like an ECT problem with the no start on warm engine. Defective (or, wrong) ECT sensor may tell the PCM to enrich the fuel as though it's a cold engine start. Would explain the symptoms of a flooded engine. Kind of surprised it's not throwing an engine code, though. What brand/part number sensor are you using?

 

[hottrodk10]

have had 2 different $10,000 scanners hooked up to it to no avail. the only thing the last one showed us was that the gauge isn't reading the engine temp correctly(because we could see the actual(?) engine temp)--this second mechanic says the problem is being caused by the incorrect gauge sending unit(2 blade unit, single wire plug??) which by all my research this only "talks" to the gauge, not the computer but??? on the other hand, when I changed all three of these(sending unit, ECT & thermostat) IS when I started having problems . according to the first mechanic the computer said everything was "perfect"-- he's the one that said my only problem was dirty injectors--which didn't make sense to me (wouldn't dirty injectors cause problems cold too??) --

 

[hottrodk10]

and as far as I know the ECT is the correct one, it's the one that talks to the gauge that is questionable

 

[XLTrunner]

Just got back from the local Pick-n-Pull and stopped to look at a '97 Explorer OHV. It had the single wire Temp sender orange plug as you describe...but, the factory original Sender itself was a 2-prong. The Sender has Ford Pt# F77F-10884-AA on it. If it were me, I'd start with double-checking that the one you installed is a direct cross-over to this Ford (Motorcraft) part. Still don't understand the correlation between the Sender and engine performance as I thought all it did was feed the coolant temp to the dash gauge. But, maybe somebody else has some insight on this and can educate us all.

If that doesn't solve the problem, I'd go back to double-checking the ECT Sensor part number you installed. The fact that your engine started acting up only after you replaced these items would lead me to believe it's related...and, not something like dirty fuel injectors. Did you touch or disturb anything else while in the process of replacing these items? All wiring connections in and around the area you worked in have been checked for secure fit?

 

[hottrodk10]

XLTRunner,
Hey, thanks for looking at the jy one for me
I'm with you on the sending unit not having anything to do with engine performance but I'm ready to pull my hair out over this so I just came in from changing it.... Again.... I didn't even think that the ECT could be the wrong one.... its a Carquest part? how would I make sure they're cross referencing the Ford part # on it? I've checked and double/triple checked all the connections everywhere that I can see on the engine because that was my first thought(that I had bumped something) -- the only thing that is messed up is the vacuum line that controls the "door" on the ac/heater.... you wouldn't happen to know just where the other end of That is?? ugh -- only code I'm popping points to a vacuum leak and thats the only line busted(again, mechanic said That's the cause of my vacuum code, which doesn't make sense to me either-- from what I can tell it has nothing to do with the engine? unless it connects behind the TB?)
I really appreciate your input

 

[XLTrunner]

I see Carquest sells BWD brand sensors/senders...and, I can't find anywhere on the net where BWD references any interchange with Motorcraft part numbers. I'm sure you're getting tired of spending money and time (must be getting pretty astute at changing those out by now) on these...but, I found a thread on this forum describing the exact symptoms you're having and it was the ECT sensor. If you just can't find any other source for the problem, you might consider doing both one more time using Motorcraft part numbers. Contact Ford to verify the exact ones you need and then buy them on Rockauto.com for a fraction of Ford's price. Rockauto will show a cross-reference to Ford's part number in their product info when looking up Motorcraft parts. At least you could eliminate those as the culprit...once and for all.

As for the A/C-Heat vacuum leak...I've not had the pleasure of digging into mine and thus, can't really share much info. Tried finding vacuum diagrams on this site...but, to no avail. Regardless...if the engine was working fine before and the vacuum line was broken or disconnected all along, then I don't feel it is relevant to the current engine performance. I'll investigate this for you though, as I'm always up for an adventure...lol!

 

[ranger7ltr]

I have a quick question...

Why not put the old temp gauge sending unit and the ECT sending units back in the intake? My 99 has 2 units as well; a gray body unit with 2 wire connector on the drivers side and a brown/orange body unit with one wire connector on the passenger side...

The 2 sending units are not the same and do not let anyone tell you that... It has been a while, like 6 years, since I replaced mine...In fact I bought them from either Rockauto or Autozone when I built a new engine and I have not looked back... They work as designed...

Did you replace yours because you were having problems with them or just to replace them with the thermostat?

And yes the wrong sender for the ECU will cause all kinds of drivability issues including poor fuel economy, running rich if at all, and low power if it does run...

 

[XLTrunner]

The Ford part number off the ECT sensor I removed from the '97 OHV Explorer is F5AF-12A648-AA...if that's any help.

PM me if you want to discuss the vacuum lines.