So I posted about a month ago about an issue with the IRCM. So now I have had time to look over the car and to determine that the IRCM was bad, but then I have found another issue.
Upon further diagnosing I have come to the EEC to be another problem. I went to start the car after replacing the IRCM and it started right up, YAY!!! Then it happened, the same issues as before no fuel pump. On top of it there is no spark, no tps signal, no power to IRCM, no power to really any system.
So i began the long process of pulling wire looms apart to check and probe wires to find the problem... THE EEC. I traced all problems to this location. i probed the back of the EEC to find power going in but nothing coming out. the yellow always hot wire is the only wire with power to it. every other 49 or so wires are dead.
Before I go ahead and order the EEC, does anyone have any suggestions or another way to check and make sure that this is my problem. I really do want to order this and pay the hunderds of bucks if this is really not my problem that it is as simple as a fuse or a relay.
Please help.
Did you run your test with the key in run? With the key off, the only hot wire to the EEC is the KAM power. When you say no power to the IRCM, do you mean there is no power on the 3 heavy gauge yellow wires going to the IRCM? How have you been checking power circuits? With a DMM? If so, dont do it that way, use a test light to test power circuits, as a DMM will indicate system voltage even if there is high resistance in the circuit.
Jeff,
Yes I ran the test's with the key on, and the only power to the EEC was the yellow wire nothing else has power, and yes i am using a test light and mot DMM. I ran the fuel pump tests to see if there was a problem with the IRVM. but I was on step two I think and there was no voltage to the TPS and thats when I started checking the EEC and found what I said previous. so now i have my father which had the t bird previous sending me additional parts. any suggestions.
Next question: Does your CEL come on with the key in run? This assumes the CEL isnt burned out, etc. If not, the EEC isnt being powered up, which it sounds like it isnt. Check the VPWR (12V feed to EEC) at the IRCM, which should be hot in start and run. If CEL is burnt out, etc, check for 5V VREF at TPS connector to see if EEC is powered up.
Have you checked the 3 yellow wires at the IRCM for 12V hot at all times? These 3 yellows are on 2 different circuits / 2 different fuse links if I remember right. All 3 must have 12V hot at all times for the IRCM to do its job.
I am wondering if you have a partly blown / intermittant fuse link or links that supply power to the IRCM, coil, etc.
Thank you, yes i did check to see if the CEL turns on and the answer is no, i checked the bulb and replaced it just to make sure. still no CEL. i checked the TPS and it shows 0.5 volts between the orange and black. so i am assuming that it is the EEC. but i will check to make sure that the other wires going to the IRCM have power. and yes i had the DMM on 12v.
So let me understand this if the IRCM does not get power the EEC does not either. the IRCM supplies the power to the EEC. and is it possible to just replace the fuse linke with an inline fuse holder or just a plain wire?
I will check the three wires but if they do not have power then it is a fuse link, but if they do have power its the EEC that needs to be replaced?
The EEC gets its power from the IRCM via the EEC power relay inside the IRCM. The IRCM doesnt get power from the EEC. If the IRCM doesnt get power on all 3 heavy gauge yellow wires, it wont power up the EEC, fuel pump, etc.
I doubt the EEC is bad, it just isnt getting powered up. The IRCM has nothing to do with the ignition system at all. The coil, TFI (and the PIP via the TFI) are powered up directly via the ignition switch. I seem to remember there is a fuse link or 2 in that circuit also.
Fuse links protect major branch circuits. A bad one could be replaces with a bolt in type fuse, but I wouldnt use a blade type fuse that plugs into a socket. New fuse links can be bought at most parts stores. All a fuse link is is a section of wire 2 gauges thinner than the circuit is protecting with low melting point insulation so you can see it is blown / damaged by the melted / bubbled up insulation.
Dont worry about the .5V on the TPS connector. This is telling you the EEC isnt powered up. It doesnt read zero likely due to random very low currents feeding back thru some other circuits.... automotive electrical systems are very electrically noisy.
ok great i will start looking for the fuse links and see if i can get this all sorted thank you jeff for all the help. and thanks pete for the email. jeff its great being part of this forum and having guys like you to help out and give knowlegde to guys like me that know enought to do the work but not enough about this wonderful, headbanging against the wall car at times but driving it is worth the effort.
thanks again.
OK, So I went out today and checked the power to all three yelow wires and they all have power even traced them back to make sure they still have power and yet they do.
so I checked the inirtia switch and there is no power going to it, also still no CEL light on when key is turned on. I checked all that you said to check and now I am at a lose of what to do next or what system to check.
I have replaced the IRCM with a known good one and yet still nothing same with the EEC and still nothing. I am stuck, could the ignition switch have anything to do with it.
I converted over the old TEVES brake system to vacum boost could that have something to do with it. or could there be an issue with the relays that are under the vacum tree on the fire wall.
I need some help you guys have been great so far but i am lost now. other than stripping the car down and tracing every wire i dont know what else to do.
Wow, sure hope ya got a good deal on that lemon; ya never know what a previous owner has done to a car! L O freaking L - I gotta get going on my svo project, I'm probably gonna be in for the same thing - it's been sitting for 3-4 years now.