Help 86 v6 starting problems!

[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?

[maxwedge]

Start with changing the fuel filter then scan it and look for coolant temp sensor readings cold, for starters.

[MagicRat]

Does this lady know that a rarely-driven, little-old-lady Elco is extremely rare, quite collectible and is worth something? If she ever wants to sell, you should make an offer.

[aartod]

What do you mean by "scan it"??? Isnt it too old to have a computer to scan or does it have an OBD1 style computer? It is not my car and I dont have a manual for it so I am at a loss there... What about the fuel filter-- if it was bad wouldnt it run poorly all the time, not just at start up? I dont know- maybe someone could enlighten me of something I am not aware of. Also if the fuel filter is not bad I dont want to replace it because it isnt my car and I dont know how much this repair is going to end up costing... I dont want to make her pay a fortune in parts that she doent have! Thanks for your reply!

[MagicRat]

The solution may be very simple. If the car ran fine several months ago, you may simply have bad gas, because it's been sitting so long and rarely used.

The gas can go stale, that is, start to separate and form varnish/gunk in the tank, which also may clog the injectors. Also, the more volatile parts of the gas can evaporate. The gas gets more viscous, which makes for harder starting and poor or non-existent idling.

If the tank is less than full, you can get condensation building up in the tank and settling to the bottom.

The tank may be rusty and may be allowing rust to clog the filter.

If this were my car, my first step would be to drain the tank, best as possible, drop the tank, remove the sender unit and look inside.

Is the tank clean, or full of rust? If it's rusty, replace the tank and change the fuel filter. Otherwise, take the tank to a coin-operated car wash and wash the inside with the high pressure wand. Dry it out, reinstall and refill with fresh gas. Add good fuel - injector additive to the gas and give it a good long drive.

Be sure to add some fuel stabilizer to the gas and suggest to the lady she try to keep the tank full. This reduces the chance of condensation.

Take a look at the old gas. Does it seem a bit thicker than normal? Does it smell odd, like varnish? Chances are, it will run fine with the new gas.

FWIW this is a common problem with cars that are used very little for a long time.

[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!!!

[family_dad]

sounds like its only doing the prime of when you first start the car, you may have to replace the pump its self.

[aartod]

Yeah I figured as much... However, I will try to check that the fuel pump is getting voltage all the time, not just at start up. It would be a shame to take out the tank if it was an electical issue! Hopefully there is a plug that i can disconnect that is not tucked up on the top of the tank!

[SS402]

Coolant temp sensor and/or idle air control valve..