How to check the MAF connector
12-10-2018, 05:45 PM
#1
Track Day
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How to check the MAF connector
This is for my 1986.5.
I recently replaced the spark plugs and disconnect the MAF. I noticed that the MAF connector wires were slightly exposed and corroded. So here's what happened:
- Car was running fine. After reconnecting the MAF it would not idle and if I tried to accelerate would detonate.
- Disconnected the MAF and it would idle very high and rough, but it would idle.
- Cut the MAF connector and re-connected to the harness with wire butts. Looked OK.
- But, still does not idle.
How can I check the MAF connector?
Can it be that the MAF went bad?
Thanks for any help.
Elias
I recently replaced the spark plugs and disconnect the MAF. I noticed that the MAF connector wires were slightly exposed and corroded. So here's what happened:
- Car was running fine. After reconnecting the MAF it would not idle and if I tried to accelerate would detonate.
- Disconnected the MAF and it would idle very high and rough, but it would idle.
- Cut the MAF connector and re-connected to the harness with wire butts. Looked OK.
- But, still does not idle.
How can I check the MAF connector?
Can it be that the MAF went bad?
Thanks for any help.
Elias
Last edited by eliasmazur; 12-10-2018 at 06:35 PM.
12-11-2018, 05:37 PM
#2
Rennlist Member
It's possible since the MAF connector was bad that the CPS sensor was bad also and with jarring things around in there disrupted that one as well...
12-11-2018, 09:13 PM
#3
Nordschleife Master
Well, since nobody else seems to want to answer your question (Checkmate's suggestion is not a bad one, but doesn't address your question):
I would guess a bad MAF.
You can't really check the connection of the plug. They go bad over time.
By connecting the wires without the plug, you are making the connection.
With the car running somewhat with it unplugged, and not running with it connected, that strongly suggests a bad or way out of adjustment MAF.
It's called 'limp home mode', where the motor will run badly with the MAF disconnected.
It's odd that it went bad when you changed the plugs, but it's possible.
I think there are checks you can do on the MAF to see if it's within spec (resistance checks IIRC).
I would guess a bad MAF.
You can't really check the connection of the plug. They go bad over time.
By connecting the wires without the plug, you are making the connection.
With the car running somewhat with it unplugged, and not running with it connected, that strongly suggests a bad or way out of adjustment MAF.
It's called 'limp home mode', where the motor will run badly with the MAF disconnected.
It's odd that it went bad when you changed the plugs, but it's possible.
I think there are checks you can do on the MAF to see if it's within spec (resistance checks IIRC).
12-12-2018, 08:54 AM
#4
Rennlist Member
If the wrong wires touch then that can blow up the MAF. i.e if 12v pin 2) is connected to the output (pin5). I see quite a few of those.
Remove the engine air filter so you can see into the MAF. Start the car and get it up to temp, give it some revs if possible, switch off and then look into the MAF.
After a few seconds you should see the hot wire glow orange for 1 second. If you don't see that, it's a bad sign.
Remove the engine air filter so you can see into the MAF. Start the car and get it up to temp, give it some revs if possible, switch off and then look into the MAF.
After a few seconds you should see the hot wire glow orange for 1 second. If you don't see that, it's a bad sign.
12-14-2018, 02:48 PM
#5
Track Day
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If the wrong wires touch then that can blow up the MAF. i.e if 12v pin 2) is connected to the output (pin5). I see quite a few of those.
Remove the engine air filter so you can see into the MAF. Start the car and get it up to temp, give it some revs if possible, switch off and then look into the MAF.
After a few seconds you should see the hot wire glow orange for 1 second. If you don't see that, it's a bad sign.
Remove the engine air filter so you can see into the MAF. Start the car and get it up to temp, give it some revs if possible, switch off and then look into the MAF.
After a few seconds you should see the hot wire glow orange for 1 second. If you don't see that, it's a bad sign.
Thanks for the reply. This same situation happened a year ago when I disconnected the MAF to check the heater valve. When I put back the car would not idle and detonate. I disconnected and connected the MAF and it ran fine. Something is definitely up with that connector.
I sent the MAF to Kevin at Injection Labs and he said was not too bad but had drifted out of tolerance. He's fixing it and will see. I also will get a new connector.
How can we check continuity from the connector to the ECU?
Thanks
Elias