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5M-GE weird starter and ignition issue

1K views 9 replies 4 participants last post by  CS1984 
#1 ·
Hi guys,

I have an 84 Crown (europe spec, so no EGR, no O2 sensor, no cat) with a very weird electrical issue:


It started with a weak starter motor, it turned the engine very slow and especially when it was cold it took up to 10 times starting until it fired up. I thought it might have been a weak battery so I put in a new one (90Amps instead of the original 60Amps, fits perfect to the original dimensions).

Then one day the whole electrical system went weak(lights very dim, getting better when I turned off the vent) and I just managed to drive it to my brothers house then it stopped working.
I left it there and tried to start it the next day. The starter just clicked like when the battery is low. I checked with the multimeter and the voltage was 12.2V so it couldn´t be the battery.

We tow-started it and it ran fine... after driving it to my garage I tried starting it and it worked again fine.

But I found out the main wire between battery and fusebox was halfway broken and the main fuse holder(60A and 30A - thats where the Celica supra has the fusible links) was fried.

So I decided to replace a few things:

All wires to the Battery - Starter and alternator with at least double the size wires. Main fuses and fuseholder.
Starter motor, cold start injector, distributor cap, ignition wires, alternator (the Camry 80Ah unit), spark plugs
some other unrelated stuff - Thermostate, fan clutch, all belts

All the stuff I changed are good brands - Aisin and Denso


Now I have new issues:

The starter turns fine and really fast (same as on my celica supra - not "something is broken" fast) but when I turn it more than 1-2 seconds or when I stop starting it sometimes makes a loud clonking noise and starts smelling fried - I checked all the wires and it seems to be fine

I get no spark - I checked all the fuses, they are ok, I get current on the ignition coil. I changed the ignition coil with a replacement, ECU seems to work (when I turn on ignition and move the afm flap I can hear something move at the throttle body - I think it tries to compensate the idle?)

I don´t have a wiring diagram for the crown but I tried to check it with the celica supra one - they are a bit different but understandable

Any thoughts on those issues? Did I do something wrong maybe or was the initial issue something different that I havent checked yet?
 
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#2 ·
Sounds like one of the starter bolts got loose.
Check for spark out of the ignition coil. Make sure the ignition rotor inside the distributor cap is spinning during cranking.
 
#4 ·
How are you testing for spark? The safest method is to put a small tester on the #1 plug. Alternatively you can hold the HT lead to one of the suspension bolts, but beware, even with rubber gloves on I've been zapped doing this! There's some tests for the coil in the Haynes manual and TSRM, checking the resistance.

If you have spark at the coil, as Dave suggests, try removing the air filter and spraying Easy Start (or similar) past the AFM flap while someone turns the key. If it fires, you've got a fuel problem. If not, it's electrical. I ran through a lot of scenarios with the 5M's EFI system a few years ago, thread is linked in my signature. I don't think my specific fault is the same as yours, I had a sticky relay that stopped power getting to the ECU, but like Schrodinger's Cat, the problem went away as soon as I put a multimeter on the power terminals so I chased my tail for months. However, there is a wealth of information on possible causes in the thread.

The buzz you hear from the throttle body is the Idle Speed Control Valve, so yes, it does sound like your ECU is working fine.
 
#5 ·
Thanks a lot for your suggestions! It took me until last weekend to find time to try a few things:

I doublechecked all the ground wires. Everything is fine there.

I have checked for spark directly from the coil by taping the spark plug first onto the minus pole and then to the intake manifold. The coil was dead but I have two spare coils that work.
Still the engine wont start but at least I have a spark on the plug - But it still doesnt start even with spraying in Easy start or brake cleaner...

I have got an ignition timing pistol so i will check timing this weekend, it can just be that anymore. But what concerns me is that I have andjusted the distributor to the exact same position as it is on the Supra (also the inner gear) and it doesnt fire at all.
Shouldnt it at least run very bad even if the timing is off a few degrees?
 
#6 ·
Ok, stupid me solved the problem that I created myself...

So I have mounted the distributor the first time and tried to start... It did not run and there were weird "clonks" sometimes while starting.

I compared the distributor orientation with that of the supra that was standing nearby (where i took off the cap and rotor to put them on the crown because they are new) and saw its 180deg off...

I had some people to chat in the garage was not that concentrated... so I took the distributor off and turned the rotor... but somehow i did not turn it, it was still in the same position...

Yesterday I doublechecked everything with the timing pistol and therefore made a switch to start the car while standing in front... after the first start I heard the "clonk" again - which now clearly sounded as misfiring, so the timing must be far off...

Long story short... I turned the rotor again - this time correct - and it fired up immediately
Fine (as fine as it is possible with the unclear marks) tuning of the ignition to 10 deg and it works perfect again :)
 
#8 ·
Oh, I am sorry :) I can be a bit confusing and english is not my native language, I guess that makes it worse :/

Long story short:
The distributor was 180 degree off.

I corrected it but was distracted so i did it wrong again.

I thought that it was ok and searched everywhere else and did not find the problem.

I hope thats not so confusing :D
 
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