86 'camino problem starting! Help!

[aartod]

I have an old widow lady who lives across the street from me who asked me to try to fix her car... The car was her husbands car, so it does not get driven much- but she starts it up once a week and takes it for a drive about once a month as well. The car is a '86 el camino with a v6 and trottle body injection. Recently it wouldnt start for her so I tried to start it and all it would do was crank and crank without starting. So I checked for spark and it had plenty. So I tried to start it again and it tried to start but died quickly. A few miniutes later I tried to start it agian and it fired up but I had to keep pumping the gas pedal and keep the rpms over 3000- 4000 to keep it running after about 20- 30 seconds it was running perfectly. So then I let it warm all the way up and run for a while just in case the plugs were fouled or whatever. I told her I would come back the next day and see if it would start easily when the engine was cold. So the next day the same thing happened as before. I took it for a drive and it ran fine except for a little hessitation when it was still cold. I am very famillar with working on cars, but I know nothing about this old GM throttle body injection or the GM v6. I suspect it is the injection system. What do you all think?

[cherryelky305]

yeah the fuel system probably needs to be looked at. A clogged fuel filter could be the cause, but it could just as easily be a bad fuel pump. If you had spark then it makes sense for it to be a fuel problem.

It might even be a combination of dirty tank, clogged filter, old gas and old spark plugs. A tune up might bring it back.

[aartod]

Okay I had some time this morning to tinker with the ladys car and I disconnected the fuel line at the throttle body and cranked it over a few times-- alot of gas gushed out at first but then it stopped flowing all together after about 1-2 seconds. So I changed the fuel filter and tried it again- the very same thing happened... bummer. so I guess the only other thing that would cause this is the fuel pump. I didnt want to have to drop the tank- so much for the quick and easy fix!!!

[cherryelky305]

its an old car, things wear out. but the fuel pump may not be the problem. If it has a computer with a crank sensor, the computer may not be seeing the crank signal, and cutting the fuel pump off. Could be a dirty or worn crank sensor. Someone with more knowledge would be nice.

I know a few things but Im no genious. Id wait for, or get a second opinion.

[aartod]

Yes, The pump is pumping for a second or two so maybe it is a sensor not detecting it cranking. If anyone has any knowlege of this please speak up! I need to check for voltage going to the pump during intital start-up and after (while I am cranking)... Hopefully the there is a electical plug that I can disconnect that is not tucked up on top of the tank! It would be a shame to take out the tank if it was an electrical issue the whole time!!!

[wiretwister]

You only get a three second fuel pump run when you turn the ignition on, if the engine oil pressure does not come up the pump shuts off. You need to check fuel pressure with the engine running and shut off. Should have about 30 to 40 lbs. not running and at least 17 to 20 at idle. Does it have a remote mounted ignition coil? If so check both ends of the coil wire for white corrosion, if you find any, replace the wire and the coil or cap whichever end has the corrosion on it. Also have someone crank the engine over while you look at the throttle body to see if it is spraying fuel, if you dont see any fuel use a noid light to check for injector pulses, I suspect you will have the injector pulse, or she would not run at all. Maybe the engine coolant temperature sensor has gone bad, without this it is like starting a carburated engine without a choke.