eec power relay July 26, 2018, 04:29:43 PM i have a bad eec power relay in my situation i converted an originally equipped 3.8L 1987 coug fully to a 5.0L MAF car.Interior is empty for now.i turned my key forward in order to test that i hear my fuel pump.... Nothing... but i did hear an audible "pop"i checked all fuses and they are good.i isolate down to the fact i have two hot legs arriving into the eec power relay.the ground on the control or coil side has continuity to chassis.the relay will not energize while its plugged in.i remove the relay and manually power it up... it does not i inspect the circuit board and see nothing odd.on the circuit board i find the two pads where the coil ties in at.i add the correct polarity dc power there and the relay clicks.oddly the problem is from the connector up to the coil.. and that area is kinda burred.since i heard a pop,,,, and can easily risk blowing up a new relay,, i have an idea....extract the wires from the relay socket.install a resetable circuit breaker fuse across the trigger/ control/ coil wires.install a resetable circuit breaker fuse across the contacts side of the relayturn key forward and if all is well my breakers stay closed and the fuel pump relay can now do its thing to power up the pump......thoughts on this???????????????i need a new eec relay if anyone has one.here is a pic of my eec relay mod where i relocated it prior to it failing. Quote Selected
eec power relay Reply #1 – July 27, 2018, 02:58:14 PM I am guessing that EEC power relay is from the original 3.8L.The circuit attached to it makes it have a 5-10 second delayed drop out.This gives the EEC time, after the key is turned off, to move the ISC motor plunger to the fast idle position.This sets it up for the next start.I suspect the cable harness you are now using has the voltage polarity wrong for this type of relay.On a common standard relay the polarity doesn't matter.My 84 shop manual volume HC Emissions Diagnosis, Engine/ElectronicsSection 3 Emission Related Components, Relay Assembly EEC (Power)Lists the EEC Power relay P/Ns and the what is connected to each socket pin number.It shows the time delay relay only used on engines that use the ISC motor.My manual pre-dates the SEFI engines. So I suggest you check in your 87 shop manual. Quote Selected
eec power relay Reply #2 – July 28, 2018, 11:41:34 AM Great information!,, i would not have known to even know to think of that angle.im not clear though because it seems even non cfi engines needed a time delay to trigger the fuel pump when the key is at the run position.updatewhile i waited on napa to get my "special relay in", i tested as follows.with an empty eec relay socket......i made up a jumper with an inline reset-able 10A circuit breaker and an 1157 light bulb which i then jumped across the trigger (small) terminals of my connector.I turn the key forward and the light bulb came on and stayed on and the breaker did not trip.this told me that there is likely no fault on the two wires that trigger my relay coil.i included a separate jumper with inline breaker to bridge across the "contacts" side of my eec relay connector.when hooked up, i heard my fuel pump relay click and my fuel pump ran for about 1 second then auto shuts off.with both sides of my relay socket tested i figured it simply may just be the fact i had an old eec relay that went kaput.I move on...........original relay was from the 3.8L 1987 CFI that did have an ISC motor controller.when i went to key on, i heard a pop then later found that something is nearly open across the relay "COIL" or trigger terminals.i took the cover off and was able to read the coil thats soldered to the circuit board itself and it has a proper resistance of 63ohms, yet at the two small terminals the coil reads 4.5MG ohms.i get a new relay from napa and install it after poping its cover off to verify it had a circuit board and parts.I measured the resistance of the contacts of the coil/trigger side and it was around 70ohms.i just now turned the key forward and there was no audible click heard nor did the fuel pump come on , nor did the fuel pump relay click.there was no pop noise like something blew up either.i removed the napa new relay and try to trigger it manually from the car battery and it does not click like it did before.I tested this relay the same way before i installed it and it did click so putting it into my car makes it self destruct.there are no signs of a burn or bad things happening to the relay, its just done.so i have two separate relays which end up becoming broken simply by plugging them into my car.if i manually and safely jumper across this relay connector everything works fine so my oldest son talked me into installing a regular non time delay relay.with this generic relay installed, i turn the key forward and everything works.i have failed to mention that on my eec rear connector i have the Tweecer chip installed. it takes over and replaces any factory programming using the eec pcb as a passive pass through communications path only.I did not remove the tweecer to see if having it plugged in would be the root cause of the time delay relays self destructing.thoughts.....??????????? cause im kinda lost at this time even though it appears i have a work around with a generic relay.... or do i? as in will a generic relay perform the functions needed??? Quote Selected
eec power relay Reply #3 – July 28, 2018, 11:49:11 AM what i think i need to understand is ..........are all 5.0L 86-88 equpped with a non time delay eec power relay? Quote Selected
eec power relay Reply #4 – July 28, 2018, 02:51:29 PM As far as I can tell from my 84 shop manual, only the 3.8L in our family of cars has the delay relay.But as I stated, my manual pre-dates SEFI engines. That's why I suggested you reference your shop manual.OK after studying the 87 EVTM I see that ckt 16 R/LG (hot in start and run) only goes to the 3.8L EEC. 3.8L EEC pin 5.The 5.0L EEC doesn't use pin 5.So the 3.8L EEC gets a heads-up that the key has been turned off. It then has 5-10 seconds to do its shut down routine before the power relay drops.I guess that's a round about way of saying you only need a standard relay.The fuel pump is turned off by a timer in the EEC.With the key on and the EEC detects the engine is not running for 1-2 seconds, it turns the pump off. What everyone calls priming.This is a safety thing. In case the reason the engine is not running is because it wrapped around a tree.This makes an EEC controlled pump work just like a mechanical pump. If the engine stops, the pump stops. Quote Selected
eec power relay Reply #5 – July 28, 2018, 03:01:56 PM pic from my shop manual Volume HC: Quote Selected
eec power relay Reply #6 – July 29, 2018, 06:06:19 AM will do,, checking shop manuals now Quote Selected
eec power relay Reply #7 – July 29, 2018, 11:28:50 AM I was going to scan my pages as well.my emissions manual is very hard to navigate,I started of with test points for no start and found the eec power relay but not the tables.i flipped pages and finally found the generic pn which stayed the same in the 87docs.what your two pages and my two pages boil down to is that if the vehicle had CFI,, that is the only instance i see as well where the eec had a time delay relay.that being said,, i ordered my relay from napa for a 5.0L 1987 cougar.they sold me a time delay relay,, same for what is coming to me on rock auto as well....Aparently all the box stores are wrong because we require a "POWER" relay for non CFI applications.on CFI it would be a "power time delay" relay.so.... i looked at my 20th and the relay itself is a small one, not this big tall one i had from the original OEM build which was time delay... being my car used to be a 3.8L.if this is my only hiccup ,, ill be amazed.planning to start up here in a bit. Quote Selected
eec power relay Reply #8 – July 29, 2018, 03:43:34 PM Do you have keyed power or ground on the center terminal of the three in a row?Do you have a picture of the terminal lay-out from the 87 Shop Manual? Quote Selected
eec power relay Reply #9 – July 29, 2018, 04:57:13 PM correct, i see the evtm's stating the 3.8L cfi EEC relay is wired the same but................here in my emissions page, it clearly states your earlier comment of my having the trigger / coil side of the relay reverse polarity- which is likely correct.I have my original 3.8L connector. if the emissions book is right and the evtm is wrong, i will see it.i wonder if my emissions book came "after" the evtem because my 87 emissioins book says "REVISED" on the cover. Quote Selected
eec power relay Reply #10 – July 29, 2018, 04:59:00 PM either way, i am not really sure how i could have noticed this issue, and it could have been a much bigger problem. Quote Selected
eec power relay Reply #11 – July 29, 2018, 05:01:19 PM of all the electronics i have ded over the years, i found i have 7 eec "POWER" relays. I have no time delay relays to my knowlege but there may be and i dont know it. Quote Selected
eec power relay Reply #12 – July 31, 2018, 09:21:49 AM I received my rock auto relay which is a "standard motor products" relay.it is also incorrect.All box stores are wrong, I am speaking with Standard to fix the problem.basically as mentioned earlier ,, the only instance you need a EEC time delay relay is if you have an electronic carb or CFI.all other applications require a "power relay" , or a common off the shelf simple coil and contacts relay.A time delay part description will have "electronic" within the description of the relay.if you have a 5.0L SEFI engine , all box stores and on line stores will provide you with the wrong part. Quote Selected
eec power relay Reply #13 – July 31, 2018, 10:29:15 AM standard just called me back and they finalized confirmation of the incorrect part.what the guy said was this relay is in big trouble because it seems to have SSDG applications that are incorrect.i asked him what SSDG is...........he clarified- SSDG (same shiznit different grill)problem is they dont get feedback from thier direct customers , so they dont know there is a problem.on that note, all the brick and mortar stores dont have process in place to intake customer feedback on a part either..... so it seems like this is where i have identified a business opportunity for someone. Call it E-verify if you will. when you buy a part, any company interested in standing out in an age of huge competition, knowing that care is taken to provide correct products stands out. I just looked up my car on advance auto parts ,,, there are a boat ton of parts that claim to be an 'exact fit" for my car. Example,, they show a wire harness headlamp connector for sale, its a three pr0ng slip on plug,, supposed to fit the headlamps on an 87 merc coug 5.0L engine. we know they are wrong,,, but is the box store interested in learning where thay are wrong is the important point.it looks like the correct number will end up being RY71,he pulled up the spec sheet on the RY111 and the RY71 side by side and will correct. Quote Selected