Five
05-14-2007, 09:24 PM
I recently had an issue where I started up the Diablo (99 roadster) and ended up with half power. The car would run but would almost stall out of first. And you'd have to rev it to like 3K RPM to get going.
No engine lights went on. There were no funny sounds or anything but a kind of an air sound. So, after driving a block or two, I figured half the engine was running and half wasn't (the Diablo engine is essentially two 6 cylinder engines in one).
It was half power right from startup. I shut the car off and turned it back on and had the same thing. Then I shut it off, armed/disarmed, turn it back on and it was back to full power.
After that it was fine. I sent a message to my mechanic and he said to check the exhausts if it happened again to see if it was running on half the cylinders.
The problem happened again after a while and this time the Left Check Engine light went on after a while. I put my hand of the exhausts in the back and one was just lukewarm while the other was hot. So, it was running on half bank (just the right bank). It worked again after the shutoff/start, etc.
So I called him back (it was Steve at Driven Exotics again) and he said he remembered one issue with a 99 Roadster with the security system and the fuel pumps and he thought given the symptoms, that was the problem.
After talking with him, it matched what was going on exactly.
What happens is this. There are two fuel pumps in the back of the car. And the security system has a fuel supply valve on each one. By default, the valve is closed so the security system does not allow any fuel to flow by default.
When you disarm, it opens the valve. Over time, those valve can get stuck and you end up with a car with a sticky valve that doesn't get fuel to one of the engine banks. The bank that isnt getting fuel just spins and eventually the Engine Light goes on when it figures things out (that takes a while).
I brought it in and Steve bypassed the valves. He kept the computer connected to them so it would be happy and the bypass was simple. It has run great ever since. I think it even runs better now (like the valve wasnt opening completely before anyway) but its probably just psychological.
No engine lights went on. There were no funny sounds or anything but a kind of an air sound. So, after driving a block or two, I figured half the engine was running and half wasn't (the Diablo engine is essentially two 6 cylinder engines in one).
It was half power right from startup. I shut the car off and turned it back on and had the same thing. Then I shut it off, armed/disarmed, turn it back on and it was back to full power.
After that it was fine. I sent a message to my mechanic and he said to check the exhausts if it happened again to see if it was running on half the cylinders.
The problem happened again after a while and this time the Left Check Engine light went on after a while. I put my hand of the exhausts in the back and one was just lukewarm while the other was hot. So, it was running on half bank (just the right bank). It worked again after the shutoff/start, etc.
So I called him back (it was Steve at Driven Exotics again) and he said he remembered one issue with a 99 Roadster with the security system and the fuel pumps and he thought given the symptoms, that was the problem.
After talking with him, it matched what was going on exactly.
What happens is this. There are two fuel pumps in the back of the car. And the security system has a fuel supply valve on each one. By default, the valve is closed so the security system does not allow any fuel to flow by default.
When you disarm, it opens the valve. Over time, those valve can get stuck and you end up with a car with a sticky valve that doesn't get fuel to one of the engine banks. The bank that isnt getting fuel just spins and eventually the Engine Light goes on when it figures things out (that takes a while).
I brought it in and Steve bypassed the valves. He kept the computer connected to them so it would be happy and the bypass was simple. It has run great ever since. I think it even runs better now (like the valve wasnt opening completely before anyway) but its probably just psychological.