wagon cranks won't start, stuck at work

I drove my 96 RMW to work today and for the first time ever, it won't start. I've never had any starting problems with it before, almost always starts on the first crank. I'm hoping I can get it going before I go home in the morning!

It cranks fine, but won't catch at all. So, spark or fuel? I had the fuel pump replaced several months ago, with a GM part. Should I be able to hear the pump working from underneath the car with the ignition on? I tried that and didn't hear anything.

Could it be the opti? I've had the car 4 years and never replaced it, don't know about before that. I've been lucky, this is my fourth LT1 B-body and I've never had an opti go out or had to do anything to an ignition system besides plugs and wires. The car is 101k mi now and I've got replacing the plugs on my to do list.

I did wash the car this evening, but didn't get any water under the hood.

Any other good ideas? Thanks!

You will only hear the pump prime the system when you first turn the key to ignition. It takes about 3-4 seconds, then shuts off. You can hear it from the driver's seat if you have everything turned off. It will make a faint whirring sound. If you can not hear it, have someone listen close to the tank while you cycle the key.

You can get a spark checker, and connect between a plug and its wire. There are a number of designs, and they are pretty cheap.

You can also get a fuel pressure gauge, and it will fit on the Schrader port on the fuel rail.

Missing spark is more likely the ignition module, rather than the opti.

You have some trouble shooting to do.

Thanks. Where is the ignition module? I've never had an encounter with one. Is it difficult to get to?

I had a helper turn the ignition on for me. I couldn't hear anything from under the tank immediately after turning the ignition on. There is a click from under the hood area, but definitely no whirring sound. I even took a stethoscope to the fuel tank and didn't hear anything.

I think you will be replacing the fuel pump. That's exactly how they go, no issues then the next time you go to start it, nothing.

Tom

I second that motion, or non-motion, as it might be. Get the jackstands, and the wrenches out.

You might try to spray a bit of of starting fluid in it. If it briefly fires then look at the fuel system. I've heard people say that a smack on the bottom of the tank under the pump area will sometimes get it started again, if only temporarily.

So, figuring your opinion on the fuel.pump was right, I had the car towed from work this morning. I had the pump replaced last year by a garage ( I just wasn't up to tackling that big of a project at the time) , so it should be covered under warranty. They dropped the tank and found the wires to the sending unit were burned up. They are planning to replace that and the pump (my problem last year was actually the sending unit, I just had them go ahead and replace the pump too while they had the tank down so I wouldn't have any more problems. Guess that didn't work out....)

I have had a problem with excessive pressure building up in the tank. I removed the EVAP cannister and it was still doing it, so I figure it must be the EVAP pressure Valve. I'm having them check that out as well.

Someone at work mentioned the banging on the tank with a hammer method. Tried it, no luck!

The evap canister has a valve on it that keeps the proper pressure in the tank so that everything works correctly. If you removed it, that can cause problems.

Question on your burnt wiring: was the plug in 4 in square or 4 in a row?

I haven't seen the pin, the shop told me about it.

I've been trying to diagnose the pressure buildup problem with my FSM. I removed the cannister and bench tested it with a hand vacuum pump according to the procedure in the manual. It test fine, moreover removing it made no difference in pressure in the tank, so my assumption is that the EVAP pressure relief valve at the top of the tank is not working.

And it's a LOT of pressure in the tank, especially in warm weather. Crack the cap and it will hiss out for a good minute, twist the cap off and you can feel it pushing the cap off.

I just replaced a fuel pump in an Astro with a Delphi unit and they include a flat 4 connector to splice into the harness to replace the square 4 one. I was told that the reason for the change was the square one is known to overheat and burn.

I have the same tank pressure issue with my 96 RMW. Its the worst when it's very hot out and the tank is low. Interested in what you find out.

The pressure you feel is actually normal. As you deducted, it is controlled by the multi-valve on the Evap canister. Even a very low pressure in a twenty gallon reservoir will seem like a lot.

Don't be smoking when releasing the cap.

My previous b bodies did have some pressure in the tank in warm weather IIRC, but not this much. If it's controlled by the EVAP cannister, when that is removed, it shouldn't have any pressure, right? My concern is that it still has excess pressure with an open line instead of the cannister. Also, I don't smell.any fumes from the front of the car when the cap is on.

Your evap line is probably collapsed, or pinched. If you replace it you should solve your problem with overpressure.

I picked up the car Tuesday morning and am delighted to say that the garage didn't charge me anything for the repair, even though it had been 13 months since the original work on the sender and pump. He replaced the bad sender and went ahead and replaced the fuel pump as well just to be sure. I only paid for the tow.

The bad news is that I am getting a faint gas fume smell that I haven't totally located. Seems to be coming from the rear of the car, but I think I am getting a little inside the car as well. Not positive about that. The other problem is that the gas Guage is totally inaccurate. It read 3/4 after the repair and for about 30 miles it didn't change. I went ahead and filled it up, it took 15 gallons and it still read 3/4. I drove another 25 miles or so and it dropped to 3/8. I talked to the garage owner and he asked me to bring it back after I drive the fuel level down some.

Good news is that driving it yesterday, there didn't seem to be any excess pressure in the tank. I need to reinstall the  EVAP cannister before concluding anything about that or the gas fume smells.

Thanks to everyone who gave tips during my little crisis, I appreciate it!

1. The faint fuel smell, where it's from the back of the car, I would guess the vent from the sending unit is not connected to the evap cannister line. They probably left that not connected, so pressure wouldn't build up. They didn't fix that problem.

2. Your gas gauge is off, I'm betting they bent part of the internals when putting the fuel pump back in.

Tom

I hope you tipped the guy or at least brought him a 6-pack

The big o-ring that goes around the sender might be U/S. If he has to redrop the tank, slip him whatver amount is required to replace the bulkhead connector and solder it. You can look that up on here or ISSF.

There is a clip that holds the float arm to the potientiometer, and it is easy to dislodge. It would cause the symptom you have.