So driving to work on Tuesday, CEL comes on. Car starts to sputter and has some lag when accelerating. I figure its a vacuum line. Get to work. Go out on lunch and try to move it elsewhere in the parking lot to work on it. Wont start. I talk to a few other car guys I know and they don't have a clue. One suggests to unplug the MAP sensor. I do that, and it starts up, then stalls and dies. Wont come back to life. I get a ride home that night, and a ride back yesterday morning. I borrowed a friend's OBDII scanner, and it comes with P0107 and P0171. So its the MAP sensor, making the engine run too lean.
I get the car towed that afternoon to an AutoZone a few miles away, buy the MAP sensor, install it and run the codes again. No codes. Car still wont start. It wants to. Its cranking, sounds like a slow start on a cold day, but doesn't catch. I leave the car there overnight and get a ride home from a family member.
I've got spark, and I can smell fuel strong in the engine bay after a few failed start attempts.
No clue what else it could be. Maybe something going on with the fuel pressure regulator or injectors? I pour a bottle of Lucas in every 4 or 5 tanks of gas.
Okay, have an update.
Plugged a diagnostic tool into the OBDII, and when we turn the car to on (not started), it shows my engine at being 100% load.
Thinking my ECM might be fubared...
Dude, this is stream of consciousness, so, forgive me if I omit some important details:
DIAGNOSING NO-START CONDITIONS WHEN THE ENGINE CRANKS (i.e. engine spins when the key is turned)
Q: Is the engine getting spark on all cylinders?
D: Remove an ignition wire one plug at a time and install a spark tester at the end. Set the gap to 30kv, ground the tester, crank the engine, look for the spark to jump. Do this for every cylinder. Tell me the results...
Q: Is the engine getting fuel?
D: Install a fuel pressure gauge between the rail and the input line, turn on the key, check the pressure. Tell me the number. If it's zero, your pump is either not turning on or it died. If it's not zero, record the pressure as you crank the engine. Tell me the results...
Do this and get back to me. And for god's sake, plug all of your sensors back in before doing this... Give me the full list of any codes you may have stored in the ecm...
~Anthony
All the sensors are plugged back in. No more codes since I erased P0107 2 days ago.
Its got half a tank of gas, and can smell gas in the engine bay after failed start attempts. Its got spark on all cylinders.
Ran a diagnostic on the ECM. With the key turned to on (not running), it showed my engine under 100% load, and was trying to subtract 100% of fuel flow.
Got towed home last night. Tow driver wailed on the gas tank with a hammer and the car would run, then stall out as soon as he stopped hitting it.
Went out today and just for @!#$s n giggles, tried to start the car. Fired right up, idled fine. Left it running for a minute, turned it off, and it fired right up again.
I'm guessing there has to be a short circuit or bad ground somewhere. Just to be safe, I'll change the fuel filter tomorrow.
If it runs when beating on the tank, I'd bet you have a bad fuel pump. The pump went out on my truck once and I was able to start it and limp home after beating on the tank. You need to check the fuel pressure.
2.2 97 Cavalier......the "Crapalier"
I would concur, but it seems that now it runs without banging on the tank.
Ridge wrote:I would concur, but it seems that now it runs without banging on the tank.
I had the same problem with a van once. would only start once in a while when you kicked the fuel tank. other times it started and ran fine. eventually the fuel pump gave out all together and needed to be replaced. Ya might want to replace it now before it leaves you stranded somewhere.
Yeah I'm going to do the fuel filter tomorrow, and if that doesnt work then fuel pump is probably next.
Yesterday it would start up, then stall a moment later.
Dave, put a fuel pump in it. Electric fuel pumps are little electric motors basically in a j-body. The brushes get worn down and weld them selves to the rotor. When you bang on the tank it breaks them loose and they will work again. 9 times out of 10 they will do it again, its just a matter of when. Putting a fuel filter in it is not going to help you IMO. I would recommend buying a fuel pump from GM and not a junk one from a parts store. Get a hold of Skyler and have him price on for you. I think the one for my 98 sedan cost $350 OEM. I know you used to work at Autozone but a fuel pump in a j-body is something I would go OEM on. As for the ecm saying 100% load without the engine running, they ALL do that when they are not running, that is normal. My .02 cents..
Okay, Ryan. I'll buy that. I'm waiting for Jason to get back to me with Skyler's number.
Just for @!#$s n giggles, it probably is a good idea to change the filter. But for the life of me, I cannot find the tabs I have to press down to release the input line into the filter. Know where they hide?
hey im havin a similar problem except no codes it just starts and dies
I replaced the fuel pump and filter, and that ended up being the solution.
