OT, GMC Question

[Red Dave]

Off Topic, I know, but this about the best place to get a straight answer.

I have a '96 GMC Safari Van with a V6. (Same as a Chevy Astro). Last night it was running fine when I pulled into a parking place, shut it off came back less than 5 minutes later and it would not start. Battery and starter are fine, it turns over OK, just won't start.

I've owned it from new, it has 108,000 miles on it and it never let me sit before. It has never even started hard in the past 12 years. But last night it went dead as a hammer.

Anybody have an idea what the heck went wrong? Do these things have a history of this kind of thing that happens to them? Thanks for you help.

 

[Tim Shaw]

Can you hear the fuel pump running in the tank when the key is turned to the ON position?

 

[Allan in NE]

And, they are so darned much fun to work on, right? :>)

First order of business is to make sure we still have a functioning fuel pump. Can ya hear it run for a few seconds when you turn the key?

Allan

 

[Dave from MN]

Check ALL fuses, as stated below, fuel pump could be issue, when they go they go. I hope it isnt, I know for trucks they are close to $600 to have a dealer replace. Where are you located, most folks on here would be glad to help a neighbor.

 

[Anonymous-0]

Does a Gm product have an impact safety switch for the fuel pump under the dash like a Ford. Could be tripped and need to be reset. See your owners manual.

 

[Allan in NE]

"Most folks on here would be glad to help a neighbor".

Well, yeah.

Unless of course, it is a Chevy fuel pump; then you're totally on your own. :>)

Allan

 

[Clint Youse MO]

either a fuel pump or the module in the distributor cap have done both to my 96 pickup with V8 fuel pump is about $40, alot of cussing and about 4 hours work the distributor parts and labor cost me $250 at the local repair shop.

 

[Bob]

Smack the middle of the bottom of the fuel tank with a blunt object (2X4) a couple of times, using REASONABLE force.

I've driven more than one to the shop for fuelpump replacment after doing just that, to jar the fuel pump into running one last time.

 

[Allan in NE]

How do you accomplish that "reasonable force" part? :>)

Allan

 

[Bob]

You have to TRY not to be angry and frustrated with it!!!

 

[bradk]

IF you can hear the pump,most likely is the pulsator connecting the pump to the sending unit assy.The rubber gives away and can't build 'nuff pressure to start.Ignition modules have been known to fail also.

Pretty easy to pull dog house off and check for spark also.You're NOT wearing a pace-maker right??

 

[Anonymous-0]

AS you stated it is 12 years old. Anything made by man won't last forever.

How do you know that the battery is good?

Inspect The Battery. Look for obvious problems such as a loose or broken alternator belt, low electrolyte levels, a dirty or wet battery top, corroded or swollen cables, corroded terminal mating surfaces or battery posts, loose hold-down clamps, loose cable terminals, or a leaking or damaged battery case. Repair or replace such items as required. Distilled water should be used to top off the battery fluid level.

Measure The State-Of-Charge. To determine the battery's State-of-Charge with the battery's electrolyte temperature at 80° F. The Specific Gravity or Open Circuit Voltage readings for a battery at 100% State-of-Charge will vary by plate chemistry, so check the manufacturer's specifications for a fully charged battery. If there is a .050 (sometimes expressed as 50 "points") or more difference in the specific gravity reading between the highest and lowest cell, you have a weak or dead cell(s). Using the battery manufacturer's recommended procedure, applying an Equalizing charge may correct this condition.
If the battery will not recharge to a 75% or more State-of-Charge level or if the built-in hydrometer still does not indicate "good" (usually green or blue, which indicates a 65% State-of-Charge or better). If a digital voltmeter indicates 0 volts, there is an open cell. If the digital voltmeter indicates 10.45 to 10.65 volts, there probably is a shorted cell. A shorted cell is caused by plates touching, sediment ("mud") build-up or "treeing" between the plates.

Load Test The Battery. If the battery's State-of-Charge is at 75% or higher or has a "good" built-in hydrometer indication, then you can load test a car battery by applying a load equal to one half of the CCA rating of the battery for 15 seconds. The minimum voltage under load should not be less than 9.7 volts at 80ºF.

Bounce Back Test The Battery. If the battery has passed the load test then it should be OK. If not, remove the load, wait ten minutes, and measure the State-of-Charge. If the battery bounces back to less than 75% State-of-Charge (1.225 specific gravity or 12.45 VDC), then recharge the battery and load test again. If the battery fails the load test a second time or bounces back to less than 75% State-of-Charge, then replace the battery because it lacks the necessary CCA capacity.

 

[bradk]

I take that back about the ign module.The 96 4.3(w) has the CMFI system which doesn't have a module in the distributor.

I'd be checking fuel pressure.Accessible under dog house.

 

[Red Dave]

Thanks for all the replies. You guys are thinking along the same lines I was, fuel pump or ignition.

I don't want to tackle the fuel pump by myself so I'm gonna have a local independant guy (Who formerly worked for a GM dealer) look it over. I don't have a good place to work on it, and it's too cold out to try to do it in the driveway, so I think I'll just let him fix it.

Dave from Mn, I appreciate the thought, but I'm in Pennsylvania, thanks anyway.

I can fix the old stuff myself, but these newer ones need somebody who is a lot skinnier and bends in more places than I do. I can't even get my arm in to the places you need to get to on these things.

I had it hauled to the garage last night, it's AWD, so it shouldn't be towed. Maybe I'll get their report later.

Thanks All!

 

[JDemaris]

I had two of them do the same thing. Both as the 120-140K mile mark. A 95 and a 96, both with 4.3 VIN code "W" have the new injection systems at that time - NOT TBI. It is known for all-of-a-sudden no-starts with no previous warning signs. The check valve in the central-port-injection unit needs 43 pounds of fuel pressure to open. The fuel pump in the tank is set at 57 to 61 PSI. If cranking fuel pressure drops below 57 PSI, it usually results in a no-start. It's a Go or NO-go situation. Either it starts fine, or doesn't even try. And, it's hard to diagnose since these pressures are so close to each other. A drop in just one PSI can change a good starter - to a no starter.
Most later 1995s have CPI, and most 1996s have CSFI. The only big difference with the latter is - there are more indiviual parts available, and the fuel pressure runs a little higher - 60 to 66 PSI with the key on, engine not running.
You need to pull the engine-house off, and stick a pressure gauge on the Schrader valve on the engine. It is put there just for this test. If you don't have the fitting kit, an older air conditional gauge connection for Freon will fit.

 

[Anonymous-0]

did you cheek the gas filter. that is where i would start. it might be full of rust and junk frome the botum of the tank.

 

[El Toro]

I had a Chevy Citation to do the same thing, had plenty of fire to the plugs and was getting fuel.
It was the ECU. Hal

 

[Dan-IA]

I had to do that one once. Have somebody else twist the key while I lay under the car, smaking the bottom of the tank with the tire iron. The tapping is enough to get past a dead spot in the start windings on the fuel pump in the tank. Then drive home 260 miles nonstop. I'm pleading the 5th if you ask me about fueling while running or the big-slam soda-bottle portapotty!

 

[dlplost]

I believe jdemaris has the answer, fuel pressure.

We have a '95 blazer did the exact same thing, was a bi%%h to figure it out, but those engines require about 60 psi fuel press or they just wont start. A tiny leak in the fuel line or weak pump and it wont start.

 

[37 chief]

I have a 99 GMC van also, and am waiting for that to happen, which it probably will in time. My neighbor had that happen. I squirted a small amount of gas in the intake, and it fired a few seconds. I told it her it was probably the pump. I was correct. Let us know how you make out. I also had a problem with my van when it was still under warrenty. It would just stop. It took several times being hauled back to the dealelr before the problem was corrected. It was a elect connection somewhere. Stan

 

[LenND]

A friend of mine had that happen to his van and he was complaining about it. I asked him how many miles it had and he said 145,000. And told him to think how much gas that little thing has pumped in those miles. Their is nothing wrong with those pump with over 100,000 miles on except they are plain wore out from normal use.

 

[Anonymous-0]

Sonds like the fuel pump.... heres what a Mechanic friend of mine does in his checks for pump operation 1) turns the key on , gets under the auto and uses a stick(stehoscope) to listen for the pump humming sound, 20 if he cannot hear it he raps real hard on the tank and most of the time the pump will start up and if it doesn't it's bad anyways, 3) if it is pumping to begin with he then checks the pressure at the regulator rail and the filter, 4) if pressure is good and it stays for 12 hours give or take, he checks the regulator for faults..... most of the time the pump is not running when checked underneath and as soon as he raps on the tank and it starts up he calls the customer and tells them of what the expense "may be".. becuse it can be involving i.e. fittings, sender , ect. may want to begin with currrent at the pump and filter ?good luck

 

[Tomben5]

I have a 96 safari that will not start, there is fire at the coil but not at the plugs. Replaced the distrib cap and rotor still no fire at the plugs. The pill was checked o.k.

 

[bradk]

TomBen are you getting spark to dist cap from coil? May be bad coil lead.Faulty cap or rotor also maybe.You can test them with an ohmmeter.