99 LUMINA Hiccups, volt light flashes I'm stumped
 

Hello all. I have a '99 Lumina car, 3100 engine. She starts & runs and will idle. When cold, she hiccups at about 38 miles under load. The warmer the engine gets, the more she hiccups and spits and sputters. I put a used mass air flow on it after I cleaned it, put a different coil pack on 2 of the cylinders. Still hiccups and sputters after she warms up. I'm not getting any codes and no check engine light. The volt light will flash as she sputters. I' wondering if something in the alternator is heating up and not getting enough power to the computer? I put a new Cam shaft position sensor on it because I had a code for that. I cleared the codes and this happens. Again, there are no codes being thrown. I don't think it is the catalytic converter because it idles fine. Does anybody have any suggestions? I'm trying to fix this on the cheap because it was my daughters car and she doesn't trust it anymore so she bought a new car. I want to get it to run right before I sell it or try to drive it. Any help is appreciated. Thanks!!

My guess is idle air control. Should be a solenoid valve on the air inlet

https://cimg7.ibsrv.net/gimg/chevrol...21ff819523.jpg Has the fuel filter been replaced anytime in recent history?

Replaced fuel filter last year. Replaced the fuel pressure regulator recently. I believe I replaced the Idle sensor not long ago. What stumps me is the warmer the engine gets the worse the chugging/hiccupping gets. And the fact that there are no codes.

When you post no codes, is that meaning there is no check engine light, or with a scan tool, no codes?

I'm not sure, if the idle air is bypassed the MAF, if so, that would affect the fuel schedule if the IAC is not in proper position mechanicaly, and the pcm may not report that.

no check engine light and no codes on the scanner. I would think the idle air sensor would effect the idle. she idles fine. the warmer the engine gets and the longer the car is running, the more she stutters, hiccups or stumbles. It does seem like it is air /fuel related as I had a friend follow me home and he said when I tried to accelerate, like to pass another car, he saw Black smoke. Baffling! I might be the Cat. I'm going to try to disconnect the exhaust pipe and see what happens. It will be loud as heck for a while as I drive it, but that could be the problem, I guess. I just don't understand the Volt Light flickering when she chugs?

IMO, it's not the cat. The volt light could be a result of the engine "chugging", I think that's not related to your issue. I have a 3.1 lumina, and I think there is a return to fuel tank line from the fuel system, in other words, supply, and return. You replaced the pressure regulator, check see if the return (excsess) fuel back to tank is free as if not, that gas may be getting into the engine

OK it's really cold outside but I ran a few tests. I connected a fuel pressure gauge to the fuel rail and ran the test described in the book. The book says I should get 50+ psi(I think it is 51psi) with the key on engine off. I get 38psi. I replaced the Fuel pressure regulator within the last year so I don't think it is that. I replaced the fuel filter within the last year so I don't think it is that. I'm thinking it might be the fuel pump.


I also ran the OBD II scanner for live data and on board test. For Test $07 Data, I got ID = OC, MOD = $10, MEAS = FFD3, MAX = 0, MIN = _ _ _ _, STS = FAIL. page 2 of the scan showed ID = OD, MOD= $10, MEAS = FFD3, MAX = 2, MIN = _ _ _ _, STS = FAIL.


I don't know what all of these mean, but it seems as though something is failing. Still no check engine lights are coming on and no codes are being read. Anybody got any ideas?


Thanks!

50-60 psig is what should be at the rail. Electric fuel pump IMO either work, or they don't. Regardless, I feel either pump, or something obstructing the pump. Fuel related issues usually just kill the engine without a code.

Yea I'm thinking fuel pump. I just hate to drop the tank and put one in and it be something else. The gas guage did stop working so it is quite possible it is the pump as well.