My CEL came on last night, and i tried the Jumper between the STI and the SIG_RTN wire and it does a few tests (fan and Fuel pump) then the light just stays on. It never gives me a code. I even tried it with a Analog Multimeter, i get 1 sweep and thats it. I think though i may have found the problem. When warm the car starts real rough and doesnt want to idle, but i noticed that the cooling fan kicks on instantly, so this led me to beleve the Engine coolant temp sensor is bad, i unhooked the sensor and attemped to check Ohms across it and i cant get a reading on it. The car was warmed up to ~130, not hot enough for the fan, but shouldnt this be hot enough to get a reading off the sensor? Is my ECT sensor bad? Anything else i should check? Why cant i pull codes?
Its a mustang LX with a 88tc motor and an 8ua.
Thanks.
Dr.
--1973 Mg Midget--
--1992 Mustang LX 2.3T--
88TC Swap, LA3, T5, volvo IC, Bailey BOV, .63 T3.
--2019 Flex Limited Ecoboost--
What exactly do you mean by "cant get an ohm reading on the ECT"? It reads infinite? If so, it is bad, but that should not turn on the fan, as the ECT is telling the PCM the coolant is very cold.
If the O2 ground wire at the turbo inlet connected? If it isnt, EEC will not output codes.
No codes outputted and cooling fan on all the time could mean a bad EEC. Got a spare to try?
Jeff Korn
86 Tbird 5.0 - lots of mods / 88 Turbo Coupe - lots of mods / 05 Taurus Duratec / 04 Taurus Duratec (wifes) / 02 Grand Prix GT
Ok, i replaced the ECT, and it still is showing Check engine.. I found my multimeter batterys were low, and now it is reading both the old, and new Sensors, so i dont think thats its. The fan is still running constantly. The car runs great once you get it started, it will boost and drive like normal until you try to make it idle or start. I Do have a spare Computer, but im not sure if its any good, its kinda beat up looking. The 8uA thats in there does have a "remanufactored" sticker on it, so its possible it went bad again..
Dr.
--1973 Mg Midget--
--1992 Mustang LX 2.3T--
88TC Swap, LA3, T5, volvo IC, Bailey BOV, .63 T3.
--2019 Flex Limited Ecoboost--
well i just swapped my 8ua for the spare LA2 i had and the only thing that has changed is now the light flashes instead of staying on constantly. The fan still runs when the engine is started (cold) and when jumpering to check codes it just does the fan and fuel pump check, then the light stays on. is there something i need to do to get the test to proceed? It flashes off and then back on when i push the brake on and off.
Dr.
--1973 Mg Midget--
--1992 Mustang LX 2.3T--
88TC Swap, LA3, T5, volvo IC, Bailey BOV, .63 T3.
--2019 Flex Limited Ecoboost--
i just checked my 5v reference and it seems fine, anyone have any suggestions of other things to check??? I cant get this thing to tell me what is wrong.
Dr.
--1973 Mg Midget--
--1992 Mustang LX 2.3T--
88TC Swap, LA3, T5, volvo IC, Bailey BOV, .63 T3.
--2019 Flex Limited Ecoboost--
Is the fan supposed to turn on when the A/C is on? If so, there may be a fault in your A/C wiring or switch.
84 SVO RR cam, big valves + ported lower&head, custom upper, blow-thru VAM, Volvo IC, T3/T4, 3" from DP back, walbro, LA3 & injtrs. 15s in the 1/4
Ok, i took the car over to my mechanic friend and hooked it up to his code machine, I got tons of codes.. KOEO 22, 81, & 83 and the KOER codes are 21, 22, 23, 24, 25, 34, & 76. I drove the car all over town today and it runs fine, boosts just like it always has. Still fast, the only thing that has changed is the CEL is on, the car doesnt want to start when hot, and the Fan runs ALL the time. What i have dones so far is swap vams, Computers, swap ECT sensors, and swapped the TFI module. None of that made any difference. When the 8UA is installed the CEL light stays on, with the LA2 installed the light flashes.. Anyone have any ideas to try next? this thing is starting to get on my nerves..
Dr.
--1973 Mg Midget--
--1992 Mustang LX 2.3T--
88TC Swap, LA3, T5, volvo IC, Bailey BOV, .63 T3.
--2019 Flex Limited Ecoboost--
I can't speak to the fan running all the time, unless the EEC is going into limp-home mode - but, the 8UA is for an A4LD-equipped Bird. I can't remember if it just controls lockup (pin 53) - or, whether it also controls the 3-4 shift (pin 34). But, either way, it might be turning on the CEL because it's detecting an open in one or both of those circuits. If that's the case, then you may need to put a resistor in series with that/those circuit(s) and 12V (VPWR), in order to fool the EEC. Jeff K? :dunno:
C'ya - RAY
Placerville, California
(former) '78 2.3T Courier w/blow-thru Autolite 2bbl carb ~ (current) '87 2.3T Ranger w/PiMP’d EFI
i was wondering the same thing Ray, but i have driven the car for almost 6 months with this setup and i hasnt given me any problems till now, I also expected to find the BCS code spit out (since i dont even have it pinned in) but it didnt. I did swap to the LA2 though which is a manual computer and i still get codes. (in fact all the codes listed came from the LA2) I wonder though if i set the machine up right. The computer asked for the Engine Vin code, and since the mustang vin doesnt match the Donor TC's vin i just did a quick search and came up with Engine code "T" is this correct? The engine and computer were from an 88 TC.
Dr.
--1973 Mg Midget--
--1992 Mustang LX 2.3T--
88TC Swap, LA3, T5, volvo IC, Bailey BOV, .63 T3.
--2019 Flex Limited Ecoboost--
Since it was running OK for so long and then just suddenly started acting up, I would check all yer EEC's grounds, if I were you. Especially the one that's in close proximity of the ECU and bolts to the sheetmetal (comes right out of the EEC harness).
The main EEC grounds are pins 20, 40 & 60 - they should all have extremely-low resistance to ground when checked at the 60-pin EEC plug with an ohmmeter. Also, did you check the orange-wire O2 ground at the turbo inlet, as Jeff suggested earlier in this thread? :dunno:
C'ya - RAY
Placerville, California
(former) '78 2.3T Courier w/blow-thru Autolite 2bbl carb ~ (current) '87 2.3T Ranger w/PiMP’d EFI
