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Discussion Starter #1
My 2zz swapped mr2 randomly dims power to the lights radio everything as I drive. Then if the battery is under 12.4v the lights will not work and it will not start.charge it to 12.7 no problems again. The battery tests as good. The alternate tests as good. But sometimes when I check the battery when it is running I see 12.5v and slowly dropping. .other times it shows 14v when running. No idea. Just cleaned every ground in the engine bay and yes battery terminals and wires. Although they were really clean. Any ideas of some relay or control module that might be acting up? I think maybe the alternator is possibly intermittently acting up. I took it out to test it... but that was so much fun that I think I will just replace it anyway. Not much room in there.
 

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This is typical of a failing alternator issue. Where was the alternator sourced from for the 2ZZ swap?

I would test the diode pack by measuring the AC voltage.
 

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If your alternator does not make 14 volts, it is scrap unless you want to rebuild it. If this has been going on for a while, then your battery is probably scrap too. A lead-acid battery will quickly deteriorate if it is not kept fully charged.
 

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Discussion Starter #4
Yea it was with the 2zz in the Matrix xrs I pulled it from. The matrix was rolled so I know battery acid got on some stuff. Maybe that is causing weird issues. I cleaned everything else and used the mr2 wire harness. I grabbed a new alternator today. So will try that and get a new battery. I checked and the matrix used a higher cca battery. More like 650 plus vs the mr2 400 ish. Let's see what happens. At least the engine runs perfect aside from this issue.
 

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I have had alternators that checked good, we’re intermittent and left me high and dry. Check your grounds and battery connections if good change the alternator.
 

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Yea it was with the 2zz in the Matrix xrs I pulled it from. The matrix was rolled so I know battery acid got on some stuff. Maybe that is causing weird issues. I cleaned everything else and used the mr2 wire harness. I grabbed a new alternator today. So will try that and get a new battery. I checked and the matrix used a higher cca battery. More like 650 plus vs the mr2 400 ish. Let's see what happens. At least the engine runs perfect aside from this issue.
You don't need the 650cca battery as that is just going to add more weight to the car upwards of ten pounds over stock.
You also need the alternator for the 2ZZ. If you buy a remanufactured alternator like the ones you get at an automotive store you might end up with the same problem in a short period of time.
 

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Discussion Starter #7
Here is the latest. New alt and new batt. Started right up. Left it sit for 5 hours. Turn key nothing. No headlights nothing. Batt full charge still. No relays clicking when I do.. well anything. Check the fuse box by the batt. 12.7 v no problems. If I push the brake petal I lose the stupid door chime. Funny kind of like that. I cannot stand that stupid chime when the key is on and the door is open.
 

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Discussion Starter #8
Ok... give the fuse box next to the batt a few solid taps. Not in anger.. lol but to shake it.. boom power back. Is there something in these that fail?
 

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Discussion Starter #9
Hmm. Randomly lose daytime running lights and cornering lights. Too. Something else is going on here. Weird. I have have owed several Chryslers. So I should be good at this weird stuff...
 

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Just to clarify, these issues only occurred after the swap? Nothing occurred other than swap between system working and not working?

The brake vs. door chime. Is that removing the power or removing the ground to the circuit?

Without connection to any other item, is it plausible that this is an ECU issue?
 

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It is just a bad connection. It could be one that was made poorly during the swap, or it could be any other connection in the power tree. Check for something loose first. Check for corrosion, oxidation, or signs of overheating. Make sure that mating contact surfaces are not just clean, but bright. Make sure that any spring contacts have enough tension to make good contact, including fuse contacts.
 

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Will the horn blow when everything appears dead?

If not, then its probably a connection between the battery, fusible link, and/or body.

If it does, then chances are the issue may be with the ignition switch.

Then again, every fuse block also has a 12 VDC buss connection.

Pull out a fuse from each fuse block and check to see if 12 VDC is there when referenced to the chassis.

It is hard to help with test data...
 

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Discussion Starter #13
I did not drive it much pre swap. All the stuff in the back checks out. Power to the fuse block all grounds clean and tight. Nothing even looks worn. I get 12v to the front box by the door. But nothing to the headlight relay under the hood. I take a break and come back. Everything works perfectly. So rules out fuses. Now prior it had issues with the DRL randomly working some days. And if they don't the cornering lights will not work either. The prior owner put cheap ebay hid lights. I pulled those off and put back to stock with new headlights. It still does that. Also when driving the radio / dash board lose power randomly but only for a sec or two. Then they work perfect. Is it possible the body control unit and/or running light relays are acting up?
 

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Discussion Starter #14
Oh no the horn does not work when everything is dead. I do hear a relay lightly clicking when I push the horn. Then hours later everything works again. I wish whatever the problem is would just die completely. Makes it so much easier to find.
 

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Did you use the swap harness?
 

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Since it is not a switched ignition problem, I would move the fusible link around to see if its broken/intermittent.

I would also go back and check the connectors on the wire/cable ends since you cleaned the other mechanical connections.

It appears to be directly related to the battery area if I am interpreting your symptoms correctly.
 

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I'd check in the fuse box on the drivers side in the engine compartment to see if the nut is loose . The one you have to remove to get the 1zz engine harness out .... that one would be easy to forget to tighten on the re-install .
 

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Try moving the battery cables. If the battery cables are not tight it will click and shut off.
 

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Discussion Starter #19
Finally following up on this one. I replaced all bulbs with factory style. Dished all LEDs and bought a used daytime running light relay. No more problems. When I tried the alternator replacement (that did not fix the issue) I found a document in the box that stated matrix xrs had an issue when the battery got low it would damage the daytime running light relay. Causing electrical issues. So maybe that was it. My diner was a xrs
 
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