lastchance

thanks man, i have a line on a few but will let you know. in turbo wagon news... i tested the CTS for resistance while cold, also while warm, again after driving around the block - i found that it didn't change (stayed low, around 30-42 ohms, no hundreds or thousands, just 30-42), i was testing by putting one lead to battery - and the other backprobing the CTS pigtail/harness. what does that mean, having really low resistance across the CTS, rather than changing or variable at higher resistance?

i was suspecting some issues with the air flow meter, checked resistance on each of the five pins in accordance with the ECU pinout - everything checks out there, i'm getting good at this! hahahaaha i checked resistance on the CTS, it's fine but i forgot to check while running. i noticed the back/bottom of the plug was cracked/missing so some grime/dirt got up in there - most likely the cause for a dirt connection. didn't see any corrosion but made sure to clean up the plug and business end of the CTS as best i could. i'll do the resistance check on the CTS tomorrow to see what it's at cold and warm, like naru mentioned. both of the ECMs i have share the same part number, i double checked today... so it's still super strange that the car won't start/run with the other ECM.

upon inspection i noticed the CTS had been replaced at one time or another with a newer looking plug-type jobby, the pigtail was spliced into the original wiring... this is what it looks like: http://images.whisystems.com/smartpages/partinfo_resize/B62/36413.jpg is that what the factory CTS looks like for an ea81t? near the CTS i noticed the single prong for the gauge, it looks like this, right? https://www.rockauto.com/getimage/getimage.php?imageurl=http%3A%2F%2Fwww.rockauto.com%2Finfo%2FSMP%2FTS61_PRIMARY.jpg&imagekey=40559-0&width=450

got it, thanks man. the CTS is the single prong on the left of the engine, near/on the thermostat housing, right? the AAV is the connector that plugs right into the top of housing, but the CTS is different and NOT on the radiator like some confuse it to be. haha!

i'll work on it when i get home... checking the resistance on the CTS should be done ??? i got the ECS light for the coolant temp sensor and atmospheric pressure sensor, i see on the pinout you posted position #3 is the "coolant thermosensor", is that different than the coolant temp sensor? if it's the same i can put one lead on this pin and the other on the plug for the CTS itself to check (accurately) for resistance, right?

this is how i was testing, just as you mentioned with - One lead on the unplugged ECU harness and the other on battery negative i'll check for resistance the way you mentioned (at least to test the AAV, etc.) i'm worried this ECM came from an 83 model car, thus giving me the non-start issue and smell of flooding. i'll check with the guy i'm borrowing it from to see if he knows.

the part numbers are the same, i verified before i had him send the ecm. don't know if the new one is bad, the car was definitely dumping fuel/flooding. :/

the ECM came from an established/trusted member but i'll ask him to make sure he knows it came from a running car. i got codes 11, 12 (of course, i know the gig with these two) and also 33, 41 (coolant temp sensor and atmospheric pressure sensor or circuit) when testing for resistance on the ECM plugs i was getting the following: could that fuel pump relay with high(ish) resistance be similar to what you mentioned? the "altitude signal" that showed high resistance, is that the same as the ECM trouble code for atmospheric pressure sensor? thanks again for your help.

a strange turn of events... got an ECM in the mail today, plugged it in and while it'll give me trouble codes (are these stored from the last car the ECM was in?) the car won't start, it just cranks but doesn't turn over. to make sure i hadn't messed something up in the wiring while down there i plugged in the old ECM and the car starts right up, no problems (except the trouble light stays on). WTH?

i saw your hatch in lyons last month, knew it was someone from the usmb.

i worked on uninstalling the alarm that's been in the car for over 10 years, cleaned up the ignition wiring, tightened up some other areas, fixed the hack job AFM wiring, retested and am showing much, much, much lower resistance across the coordinating circuits. i should have the ECM on monday to throw in there, we'll see if that fixes the o2 trouble code light, otherwise i'll be slogging through these other continuity issues. on a side note - i started the car after a few hours of cleaning up the wiring and the car ran perfect. haha, weird.

exactly. this makes me much more confident.

preliminary findings: 15 pin plug - high resistance on 23 and 29 (AAV and user warning lamp ECS) 18.4 ohms and 7.6 ohms 20 pin plug - high resistance on 18 and 19 (altitude signal and fuel pump relay) 70 ohms (YIKES) and 6.5 ohms all the other pins were showing 0.4 ohms or lower, most at 0.2 or 0.3, that's normal, right?

thanks naru!!! i'm working these wiring issues out right now, i noticed my ignition switch wiring was all hacked up from an alarm install by a friend of a friend - sorting that too. i also noticed the air flow meter connector was hacked up and showing crazy high resistance so i'm working that out too. getting somewhere!!!

oh, bummer! i'll be sure to get that thing clean, it's something easy i can do while i'm diagnosing these wiring issues. thanks!

oh, i guess i should note that on the ECM plug towards the front (the one with the female plug, male ends are on the ecm) i was getting a reading of 70.0+ ohms of resistance on the black/red wire (top row, 8th from left) - grounding issue, i assume. the other plug, closer to the driver, had two pins with poor continuity - 2nd row, far right (18.4 ohms) and the bottom row, third from left - 7.6 ohms.

well, i poked and prodded every connector i could find for continuity, definitely found some trouble spots in both ECU plugs plus on the red 9 pin check connector. i also noticed 2 big translucent yellow plugs way back up against the firewall that i poked around in, found an issue or two there, also. my problem now is figuring out what to do, i have the '83 FSM but not the one that covers the ea81t, so i've got all this continuity data but no pinout to link it up with. bummer. i didn't check for voltage but will in the morning, it was getting dark.

got it man, thanks for the clarification. i'm all over it this afternoon.

awesome man, thanks a ton. i'll report back.

thanks for the info, i appreciate it. for ohms: you mentioned - that's what you're referencing here, right? one lead to battery negative and the other probing each pin, most notably the ones you mentioned above? for volts: you said - backprobing? is that checking power to the pins with the plug plugged into the ECU, on the "out" side of the plug? checking voltage at the "check connector ground pin", do you mean the green "T" connector or something else? thanks again, man, i really appreciate you being patient/awesome.

thanks for the reply, home electrical is my thing but car electrical seems so much more confusing. i have a multimeter and know how to use it, understand electrical theory but struggle when i'm poking and prodding around under the hood. another member mentioned checking the plugs at the ecu/ecm, how would that be done? car running or not? ohms or volts? thanks! that's what i've been thinking and the reason i'm hunting down a backup ecm to test. i cracked the case a few weeks ago and checked out the connections, everything looked fine but who knows?

perfect, that sounds good man, i appreciate it.

nope. everything looks fine (ground cable to engine, cables to starter, etc.) there. i wonder if it's time that i suck it up and buy a new ECU/ECM. does anyone have one they'd let me borrow? i'll pay for shipping if someone wants to send me one to test in my car.

got it... i had starter issues for a while, then upgraded to a bosch (new) starter and bigger cables, fixed the problem with starting but seemed to start this ECM trouble light issue. hmmmmmmmmmm.......

ttt, pls help.