Junkyard ignition module for 7AFE, Looking for help determining part number equivalents Options

[Langing]

Hello my old friends!

I have finally got my 1994 ST 7AFE engine put back together and back into the engine bay. It started back up without much trouble, but the second start was very rough, one cylinder seemed not to be getting spark, then no more sounds of cylinders firing at all.

Proved that I had 4 spark plugs sparking, had good compression, fuel and air. Just no firing. As I was checking to prove the timing belt had not broken or stretched or skipped a gear, a miracle happened. When going to put the valve cover back on and went to apply seal packing to the places pointed to in the FSM, it became obvious that the two bolts holding the cap for the o-ring of the distributor shaft were loose!!

Turned out that that step simply is not written into the FSM, and I only did what the manual said to do. No torque down of those two bolts specified, I didn’t torque them down. The loose bolts lead to an oil leak around the distributor outlet from the cylinder head, which I tried to fix by stupidly wrapping teflon tape as “extra protection” against oil loss, not stopping to ask myself why the leak when the o-ring should have done that job. Guess it was the excitement of hearing her run, after more than two years being nothing more than parts.

From the evidence, I finally realized that what must have happened was that when I revved the engine with the hold-down of the distributor shaft only loosly held, it must have damaged the crank-angle sensor (inside the module) and improper signalling from the sensor would make the ECM unable to correctly know when to give a signal to fire the next spark plug. I still believe that is what happened.

All that said, here is my problem. I went to a nearby LKQ and got an ignition module from a 1994 Corolla (don’t know the model specifics, only that it was a 7AFE engine.) Today, I realized that the ignition module for my ST is Toyota part number: 19020-16280, while the module I took from the Corolla of the same year has a Toyota part number: 19020-18250. The question then becomes “are these two parts interchangeable”? I do not want to put a module in that could blow the transistor inputs at the ECM.

The modules look identical. They both have two connectors, one with two wires, the second having 6 wires. If you do not know the answer, do you know what I could do, or where could I go to determine if they are equivalent parts? I need to know asap because I just know she is going to run when she has a good ignition module, I only had to pay $30 for the junkyard distributor, and I am determined to get her running NOW!

Sure hope people still use this site, even though I can no longer find 6th gen Celicas in the junkyards.

[enderswift]

Rock auto.com my man. Just order the parts you need and be on your way. It’s not worth experimenting with other parts

[Langing]

Rock auto.com my man. Just order the parts you need and be on your way. It’s not worth experimenting with other parts

Well thanks for your response. I counted 21 Rock Auto car magnets (for the same car) hanging on my filing cabinet just now, so indeed I understand where you are coming from. Just looked and I could have bought one there for $150 on up. I had been in a big hurry to get the car running, wanted a very low cost option and had heard that Corolla used the same 7AFE engine for several years and I found a 1994 Corolla at a local LKQ (junkyard) and already had it in my garage when I wrote for help.

Meanwhile, another friend suggested I start by doing the FSM tests I has already done on the one I damaged, so I did that while comparing the two modules to make sure they were identical. The tests worked out ok, cleaning was easy, confidence was gained each step of the way, so I took a chance by installing that unit with a different Toyota part number where the damaged one once was, reconnected the spark plugs and air intake and sensor, climbed in and started her up. Success!!

Surely the formation of a spark signal must depend on factors like hp, total displacement, etc, and I do not know how that Corolla was set up at the factory, but all the test specs in the FSM for my Celica were passed. I suspect I will need to do more testing now that the car can start and run. I couldn’t run it more than a few seconds because I am working warm in my garage. As soon as daytime temp gets reasonable, then I will set the timing with my timing light and move on to what’s left to do.

Thank you very much for being there to help. I remember your name from back when I was a more active member of this site. I know there will be more problems to solve before the car gets back on the road, so please check back from time to time.

6th Gen Celicas don’t seem to make it to the junkyard very often.

This post has been edited by Langing: Jan 30, 2020 - 6:30 PM

[Bitter]

The pickup coils are indeed, as you found, interchangeable. The ignition modules I also believe can interchange also, and those are usually the failing part with age on the 7A and 4A engines for the Corolla and Celica. There's a huge thread at Toyotanation in the 7th gen Corolla forum dedicated to detailing distributor problems and the consensus is that aftermarket parts suck.
https://www.toyotanation.com/threads/list-o...issues.1239322/
Some people have taken to mounting the module externally and having it cooled by the airflow through the airbox to keep old OE or new aftermarket parts working at their peak for the rest of the vehicle life. Heat is the killer of electronics.