Hi guys and gals. I just recently purchased a 96 Cavalier and was trying to replace the fuel filter. I followed the Haynes manual for relieving the fuel system pressure by opening the fuel door and leaving it open and removing the fuel pump fuse. I did that and then started the engine waiting for it to cut off. But in this case it continued to run. How is it possible for the engine to run with the fuel pump fuse removed? I'm lost on this one. Any advice would be greatly appreciated. Thanks in advance.
Can't relieve fuel system pressure
- Thread starter sm00thpapa
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Either the fuel pump relay is mismarked in the manual (entirely possible), or you just didn't run it long enough. On my car, the last time I changed the FF it ran for a ridiculously long time, even though it cut right off in the past. It felt like 30 seconds or more (it was long enough that I was starting to think I pulled the wrong relay).
So, just let it run a little longer.
So, just let it run a little longer.
Did you remove the fuel pump relay-the second relay after the first row of fuses?
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How is it possible for the engine to run with the fuel pump fuse removed?
On a FI engine it shouldn't run long at all, you either didn't get the fuel pump fuse/relay or it may have been rewired.
Easier way is just press the Schrader valve down on the fuel rail (key off, cold engine, watch your eyes). It is covered with a small black screw cap.
How is it possible for the engine to run with the fuel pump fuse removed?
On a FI engine it shouldn't run long at all, you either didn't get the fuel pump fuse/relay or it may have been rewired.
Easier way is just press the Schrader valve down on the fuel rail (key off, cold engine, watch your eyes). It is covered with a small black screw cap.
Well the manual and the fuse box cover location said the same thing and I ran it for over 10 minutes and it kept running that's what stumped me. I just put everything back together and gave up.
Originally Posted By: dave1251
Did you remove the fuel pump relay-the second relay after the first row of fuses?
Yes
Did you remove the fuel pump relay-the second relay after the first row of fuses?
Yes
I just looked at 2 GM fuel rails this vintage and one has a valve the other doesn't, you may have luck if it does.
Originally Posted By: Trav
I just looked at 2 GM fuel rails this vintage and one has a valve the other doesn't, you may have luck if it does.
Ok I'll check thanks. Seems I'm not the only one with this issue on many forums.
I just looked at 2 GM fuel rails this vintage and one has a valve the other doesn't, you may have luck if it does.
Ok I'll check thanks. Seems I'm not the only one with this issue on many forums.
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With the car off put a pan under the filter. Loosen the line and let it fizzle out. Only takes a few seconds.
Sure as long as it doesn't have the connectors that require a tool, the pressure will make it difficult the get the tool in.
I don't know if this GM uses threaded fitttings?
I don't know if this GM uses threaded fitttings?
When I changed the fuel filter in my Focus, I did the typical process of starting the car, pulling the fuse, and waiting for it to die. To my surprise, the car ran for at least 3 minutes after I pulled the fuse - yes, 3 minutes - and would've continued to run if I hadn't have just shut it off. The engine was stumbling and running rough, but it was still running. It must require a very low fuel pressure to idle.
On my last car, it died almost immediately after pulling the fuel pump fuse.
On my last car, it died almost immediately after pulling the fuel pump fuse.
Sure, you can just take the filter off and let the gas run down.
But make sure the engine is COLD! No hot exhaust!
But make sure the engine is COLD! No hot exhaust!
Some GMs only use the relay to prime the injection; once the engine is running the oil pressure switch powers the fuel pump. Though it's wierd that the fuel pump fuse didn't kill it.
But, what Chris said. Just wear goggles and throw a rag over the connection you're opening.
But, what Chris said. Just wear goggles and throw a rag over the connection you're opening.
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