1987 420SEL starts, runs, idle jumps up, then dies??
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Joined: Oct 2004
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From: Michigan
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1987 420SEL starts, runs, idle jumps up, then dies??
Posted in the 126 forum as well, but I would guess this issue could happen on any 1987 gas Benz. Please read and help if you can...
This is my kid's car. Here's the entire serious of checks and the symptoms. I haven't worked on the car at all until recently; I got all my info from Kev, my son.
The first thing I told him to check was the fuel filter. He did, and it was partially clogged. he replaced it.
He then told me no fuel was coming out of the tank. I told him to look at the repair cd's to make sure he was looking at the correct line. He's too smart to do that, so he pulls the tank. It was clean, the screen was clean, he was checking at the fuel filter outlet. The line coming from the tank flows fuel freely.
I am sure this is not a fuel problem.
He had the car at a buddy's shop. They put a real battery load tester on the battery and it failed miserably. Replace battery. Thats seemed to help. He went to pick up the car and a block away from the shop, the car dies again.
They test the alternator. It is marginal. They replace the marginal alternator. Seems fine, until he drives away.
So now I get involved and visit the place he has the car.
here's how it goes:
Cold start, fires right up, idles fine, and at around 50c coolant temperature or so, the idle jumps up to about 2200 rpm or so. It runs like this for anywhere from 15-45 seconds, then abruptly shuts off. It doesn't spool down slowly; it shuts off.
If restarted immediately, it jumps up in rpm almost bright away, and dies after about 15 seconds.
While in this process of dying, I sprayed started fluid into the air valve. The engine did not pick up at all in RPMs and died. So, something electrical.
What could cause the engine to shut down electrically AND cause the rpms to jump up for 15-45 seconds? Does anybody here have the suspect controller we could borrow and try out, and then buy if needed?
If after the first event, the car is allowed to cool down, it takes longer for the process to occur. So, somehow, this is related to coolant temperatureas well.
He had a known good OVP and tried it. Nope.
What do you think the issue could be? I am not around to help him, but I'd like to save him some money. He's going to tow it to a Euro-car repair place. I can just see the $$ racking up and he doesn't save money like kids should.
This is my kid's car. Here's the entire serious of checks and the symptoms. I haven't worked on the car at all until recently; I got all my info from Kev, my son.
The first thing I told him to check was the fuel filter. He did, and it was partially clogged. he replaced it.
He then told me no fuel was coming out of the tank. I told him to look at the repair cd's to make sure he was looking at the correct line. He's too smart to do that, so he pulls the tank. It was clean, the screen was clean, he was checking at the fuel filter outlet. The line coming from the tank flows fuel freely.
I am sure this is not a fuel problem.
He had the car at a buddy's shop. They put a real battery load tester on the battery and it failed miserably. Replace battery. Thats seemed to help. He went to pick up the car and a block away from the shop, the car dies again.
They test the alternator. It is marginal. They replace the marginal alternator. Seems fine, until he drives away.
So now I get involved and visit the place he has the car.
here's how it goes:
Cold start, fires right up, idles fine, and at around 50c coolant temperature or so, the idle jumps up to about 2200 rpm or so. It runs like this for anywhere from 15-45 seconds, then abruptly shuts off. It doesn't spool down slowly; it shuts off.
If restarted immediately, it jumps up in rpm almost bright away, and dies after about 15 seconds.
While in this process of dying, I sprayed started fluid into the air valve. The engine did not pick up at all in RPMs and died. So, something electrical.
What could cause the engine to shut down electrically AND cause the rpms to jump up for 15-45 seconds? Does anybody here have the suspect controller we could borrow and try out, and then buy if needed?
If after the first event, the car is allowed to cool down, it takes longer for the process to occur. So, somehow, this is related to coolant temperatureas well.
He had a known good OVP and tried it. Nope.
What do you think the issue could be? I am not around to help him, but I'd like to save him some money. He's going to tow it to a Euro-car repair place. I can just see the $$ racking up and he doesn't save money like kids should.
