Engine Mechanical problem
1998 Oldsmobile 88 6 cyl Front Wheel Drive Automatic 139000 miles
I have a 1998 Olds 88 with a v6. I drive the car 45 miles each way a day. Two days ago, it began to act as if it was running out of fuel about 1 mile from my destination. It did not cut off, but ran as if it was missing. I cut it off and went into work. When I got back in it a few hours later, it would not start. The starter turns as it always has and the battery is fully charged. The spark plugs are firing and the fuel pump is working. The fuel pump cuts off after a few seconds after cranking. I check the fuel pressure release valve after each crank and fuel shoots out for a couple seconds then dies out. After cranking for a while it smells like it is flooded. I checked the codes and it does not have any. Any suggestions?
It is possible that there is a problem with the rpm signal. With the engine cranking, is there an injector pulse?
Pressing the schrader valve to see if gas will squirt, is not conclusive, because of the initial prime. You will have an initial prime even without an rpm signal. You can't check for correct fuel pressure, doing that.
I guess you could, turn on the key to the run position, no crank, wrap a rag around the schrader valve so gas doesn't spray everywhere, bleed the pressure, then turn the key to crank for a few seconds, don't recycle the key. See if there is pressure then. There could be a safety issue, spraying gas from the valve, don't start any fires.
December, 18, 2008 AT 10:43 AM
Hi and Thanks, I just went out and popped the hood and bled the line and it shot gas out. I turned the key to the on position and bled the line and it shot gas out. I then cranked it, bled the line and gas shot out. I cranked it again without turning the ignition off and gas shot out. What generates the RPM signal? How do I check for injector pulse?
December, 18, 2008 AT 11:31 AM
I just researched the crank position sensor and what I found says that once the CPS stops working the car will continue to run for a few minutes and will not re-start once it cuts off. That's what happened. About a month ago the belt flew off when the idler pulley ceased up and flew to pieces. I believe the CPS could have been damaged but possibly continued to work. I looked for it on the crank and I know that they protrude over the crank. The only wires that I see running to the crank run to a connector, but there is no protrusion. So I'm guessing that it finally broke off. I won't get to delve into it until the weekend. Thanks.
December, 18, 2008 AT 1:50 PM
If you have fuel pressure with the engine cranking, then it may not be the rpm signal, that is a dual crank sensor, four wire connector.
You can take connector loose from one injector, use an led testlite between the two terminals. Have a helper crank the engine, see if the lite pulses. If you smell gas, they are probably working. If you have good spark everywhere and the injectors are working, I'm not sure why the engine doesn't hit? Unless it might be a timing issue, do you have good cranking vacuum?
Do you think it might be flooded? Some systems have a clear flood mode, if you push the gas pedal down while cranking, the computer may shut-off the injectors.
You may need to put a pressure gage on it, to see correct pressure and see if the pressure bleeds off.
January, 11, 2009 AT 6:49 PM
Hello - I just got back to looking into my car's problem this weekend.
All the plugs fire, all the injectors pulse, the fuel pressure is 50lbs at the schrader valve. I pulled one valve cover and all of the valves are moving up and down. There are no codes.
I pulled the vacuum line off the valve that is on the fuel rail next to the schrader valve and there is no vacuum when cranking. It actually blows out in a regular pulse.
I also pulled the brake booster vacuum line and it does the exact same thing.
The exhaust pipe blows out, but has a blast off air at the same pulse that the vacuum lines have.
Any ideas where to look next? Thanks.
January, 12, 2009 AT 10:30 AM
I've never checked cranking vacuum at the regulator hose. If you have no cranking vacuum anywhere, you may have to do a compression test.
Have you tried unplugging the cam sensor and then see if it will start?