1990 Toyota Camry Bad ECM or something else?

Tiny
QETZAL
  • MEMBER
  • 1990 TOYOTA CAMRY
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 220,000 MILES
Sorry - this will be long so as to provide all relevant details. My questions are at the end. First, the details of what's happened so far.

Car ran OK before-hand. Slight roughness at idle, very rare stalling when attempting to accelerate from stop, but always started fine. Did routine tune up incl. Oil & filter change, new plugs, wires, dist. Cap, rotor, & fuel filter. Now won't start. Main problem (that I could find so far) is no spark.

Two thing noted during tune-up:

1) Tried to remove connector to air flow meter on air filter housing (just to get it out of the way). Removed screws & tried to remove connector but it seemed stuck, so left it on & reinstalled screws. I mention it only in case I might have cause some short that led to ecm or other problem (see below).

2) When I pulled the old dist. Cap, there was some engine oil pooled inside the cap & on the underside of the internal coil. (Dist. Oil seal must have had minor leaking.) Wiped it all out as best I could. Again, not sure if that might have caused a problem.

I am not getting spark from the plug wires. I've checked repeatedly to be sure all wires & connectors are reconnected and appear sound. The fuel pump is coming on & pumping fuel at least through the filter. I'm not sure how to tell if it's reaching the fuel rail or if the injectors are pulsing.

I tried reinstalling the old cap, rotor, & wires in case one of the new parts was bad. Still no spark.

I checked the coil primary & secondary resistances, as well as the resistances of the G, G-, & Ne terminals on the dist. Those were fine. One mechanic thought the dist. Might still be bad so I tried replacing it with another from a junkyard. Still no spark.

I tried to check for codes but the check engine light doesn't come on - even when the key is first turned on! I have seen in a couple of forums that this is supposedly a sign of a bad ecm. Service dept. At one local Toyota dealer said the same, & said they could check the ecm if I brought it in. Just in case, I even pulled the instrument cluster & checked to be sure the check engine bulb wasn't burned out - it's fine. Also, the wiring between the ecm connector and check engine bulb tests OK. I could also confirm that the wires from the B+ at the ecm to B+ at the diagnostic connector in the engine compartment had connectivity. Ditto for E1 at ecm to E1 at Dx connector, & for BATT at ecm to positive battery cable (disconnected from battery during test, of course). Would have tested more, but wiring diagram in my Haynes doesn't exactly correspond to my ecm, so I can't match up all the wire colors.

QUESTIONS:

Is ecm likely to be bad? Since it's not lighting the check engine light, even at initial key on, is that really a strong indicator (as some have suggested)?

Is there something else I should be looking at here?
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Tuesday, January 26th, 2010 AT 10:59 AM

3 Replies

Tiny
RASMATAZ
  • MEMBER
Hi qetzal, Welcome to 2carpros and TY for the donation


http://www.2carpros.com/forum/automotive_pictures/12900_ignitor_2.jpg



Get the ignitor tested
The igniter, located near left strut tower before you bring in the ECM

Okay-the computer has to get the Ne and G signals in order to ouput an Igt signal telling the ignitior to fire the coil when it happens an Igf will go back to the computer indicating that combustion has occured this process repeats to all cylinders
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Tuesday, January 26th, 2010 AT 5:54 PM
Tiny
QETZAL
  • MEMBER
Thanks for quick response!

I've seen the ignitor, but my Haynes says there's no test I can do on it for my vehicle. Dealer can test it if I take it off the car?

Also, what do you think about the idea that no check engine light at initial key on = bad ecm? (Assuming bulb, wiring, & power are all OK of course, which seems to be true for me.)

Is there any place I can get an accurate wiring diagram for my ecm, along with a list of the voltages that should be at each pin, that I could test for myself? I've seen references to that on other forums, but no specific info for my ecm.

Thanks!
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Tuesday, January 26th, 2010 AT 7:06 PM
Tiny
RASMATAZ
  • MEMBER
If your wires are good to the computer from the distributor and ignitor checked out-last place is the ECM
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Tuesday, January 26th, 2010 AT 7:45 PM

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