fuel problem
 

whats up all.. sorry if this has been discussed before, just havent found the answer... NEway. got a 95 blazer that wont start. perty sure its not getting gas to the engine. its cranking like a champ but wont catch. i hear the fuel pump cycling on, and after i turn the key off. i did a pressure test, when i turn the key to on it goes to a little under 60 then drops slowly back to 0. since it wont start i cant check it at idle. havent been able to rap on the tank while someone tries turning it over(limited hands). i feel its the filter,, mines old and rusty, didnt take it off and check it or anything really just praying its not the pump,,, but totally lost.. is there something im missing, or another way to tell before pulling the old filter out and replacing it???? any ideas would be great!! thanx for any help

if the blazer has been sitting around a long time with gas in the tank. you are going to want to drain it. and if it has been sitting and you have been cranking it fuel pump is probably plugged up. my advice get tank cleaned out new fuel pump/fuel sending unit and then drain your lines and finally a new fuel filter. if you put a new fuel filter on now and it has bad gas its only gonna plug up a new fuel filter. if its bad enough you might have plugged fuel injectors i dump some fuel injector cleaner in first that is if you get it running.

fahzie,
Since you are asking questions and not submitting an article you have written, I moved this to '2nd Gen Tech'. From what you say, I would suspect a bad fuel pump because of the quick pressure drop.

Are you certain that this is a fuel problem? Have you checked for for good spark ect?
There are a lot of things that can cause your truck to not start besides a bad fuel pump or clogged fuel filter.

Go through and check all the electrical portions of the ignition system first before you go and start replacing parts for the fuel system.

Make sure that you have spark before you do anything else. Then try a shot of gas or starting fluid/carb cleaner into the intake and see if it fires at all.

If you have spark and it fires at all with the gas/starting fluid in the intake only then should you move on to diagnosing a potential problem with the fuel system.

Though regardless if it is the problem or not, if your fuel filter is old and rusty then it is probably well overdue to be changed out.

today with the help of some starting fluid and a battery jumper, it started. i put the new fuel filter in but its still not holding pressure. it drops to fast to start, at idle its like 47 48.

i would guess fuel pump if its not keeping constant pressure

Sounds more like a fuel pressure regulator then a pump since the pressure goes up to just under 60 and then starts to drop to 0 fast.

That most often means that the regulator is leaking rather then the pump is not putting out enough pressure.

where is the regulator? i thought my truck has it built in to the pump assembly, as in you cant just change that by itself.. not sure. but the pressure wont even get past 50. we put a switch to the relay so it will stay on until the truck starts (its not even 30 degrees out here, and no garage) just until it warms up so i can change the pump myself, or get it done. little worried about doing it, never dropped a tank before. but if its just a regulator under the hood or whatever,,,, im down!

Replacing the regulator in these trucks isn't always a quick and simple task as the regulator is attached to the fuel injector spider assembly inside the intake housing.

I have not changed one myself on a 95, only on an 01 and a 2000 so I won't try to give you the details as your engine setup may be slightly different then mine.

There are however a number of good how to guides for this project to be found on these forums along with more then you ever wanted to know about testing the fuel system of your truck.

It is always a good idea to run all the tests right down to testing the wire harnesses before starting to replace parts. Unless of course you happen to have money and time to burn.

It is real easy to drop the tank. on a 97 it is two bolts, two hose clamps, two wire harnes conectors, and three fuel conectors, and yes the one vent hose on the foward end of the tank. The 97 pumps are expensive, and not the same as the 95.