Hi, here is my story, sorry if I'm a little long winded but it's been going on for over a year now and I don't want to leave anything out. Last July I accidentaly left my window open and it rained the over night, when I went out to start my car it would crank but not start. I took it to my mechanic and he said it was my fuel pump which he replaced. A week later as I was driving the car shut off on me, after a few minutes I could start it again but as the rest of the summer went on the problem got worse, it would shut off more frequently and it would take longer and longer to start back up. After several trips to the mechanic he changed the fuel filter, ignition module and cap and rotor, he also noticed that often when you sprayed carb cleaner into the plellem through the throttle body it would start back up and run like new, but, obviously that was not the fix I wanted. Over the fall and winter I didn't have any problems at all except on days when it was very damp outside(rain, or alot of snow) on one of these days I pulled off a sparkplug wire and it sparked against the block, so I know it is a fuel problem, but once it ran it ran fine. As soon as the weather got warm in spring it wojuld start shutting off again and now the carb cleaner in the intake does nothing, I recently noticed that whenever it doesn't run I don"t hear the fuel pump, whichI dont understand how thatcould be connected to the carbp cleaner which always worked before. I'm kind of at my wits end and any help out there would be greatly appreaciated. sorry again about the long post.

 

Have you verified fuel pressure? 96+ Fuel System Diagnosis?

Do you know what brand of fuel pump was installed by the mechanic? Do you know if he replaced the connector to the pump? It may be a problem with the splice joints if he did replace the connector. It could also be a weak aftermarket pump.

Also, if it has more problems in damp weather, you may want to check into a possible ignition system problem (coil, wires, cap/rotor, etc).

 

First off what year, make, and model is your car? Have you put any fuel additive in the gas tank- water remover? Sounds like you may have water in the fuel. However, your problem does sound like your cap has a crack in it allowing moisture into your distributor causing the misfire. I had a very similar issue with a 73 Chevy with a 350ci engine. One real hot day of a typical Texas summer, I decided to clean my engine compartment after school and got my distributor wet. (I know that was dumb but I was eighteen and it was my first vehicle). After calling my Dad and listening to him chew me out for about an hour and him explaining why we don,t spray hot plastic with cold water, he showed me the wet rotor and the cracked cap. The lessons we learn the hard way right? Let me know if that helps

 

thanks for the help when the pump runs, it had between 50-60 psi, I have also put fuel additive in numerous times, as for the wet weather, when it wouldn't start i pulled a spark plug wire and it would spark against the block, does that mean it isn't a problem with the spark? I'm thinking that the pump may be bad but I also am wondering why then the carb cleaner in the air intake had any effect at all, Is there anything in there that could be shutting off the pump because it is going bad, by the way my blazer is a 95 cpi 4.3 thanks againg for all your help

Just one more thing I have also heard that most fuel pumps have a ground strap on them, where would that be located on my blazer? I looked all over and havent' found anything that looks like one, I'm also gonna call him tomorrow and ask about the splices and if he remembers what kind of pump.

 

when was your last tune up? sounds like a cap and rotor problem to

 

If you get fuel/ignition system work done, please get AC Delco parts... yes it's more expensive but the parts will last much longer and you'll save yourself alot of headaches

 

if the problrm started after you left your window open i would look in to the stearing collum and the ignition switch sounds like something is not making contact when you turn the key check for corosion in the wires on that switch

 

coinsidence maybe on the open window and fuel pump crapping out? Maybe. but it sounds like the fuel pump they installed is now the problem itself. Used to work for auto parts and oh boy let me tell u the return rates on aftermarket pumps is incredible. or attempted returns I might say, most only come with 1yr warranty. good idea though on the ingnition switch and under dash wiring coming from fuse block? good luck

 

i had the same problem when i changed my fuel pump. It would also start when i hit it with starting fluid. Turned out i forgot to tighten my negative battery terminal. Works great now, worth a shot.