1990 Gmc Vandura 2500

[kaeraze]

Hi, I'm glad theese forums are here.

 

Model: 1990 GMC Vandura 2500

 

I do not know wether I am asking about a modification or not. Bought it second hand after it was modified. Just say if it's so.

 

The poblem occurs while its idling. The engine begins to miss and shuts off after a few seconds. I'm replacing the vacuum lines but along the way I noticed something odd near the hood.

 

There is (what looks like) a vacuum reservoir attached to the hood. A single vacuum line runs from this. The vacuum line is surrounded by some kind of plug which fits into the vacuum reservoir. Inside the line (and surrounded by the plug) is some kind of valve I'm trying to idenify. The plug itself was taped up and is to worn to leave in.

 

So, I have three questions:

1) How can I stop my engine missing while it idles?

2) What is the valve/object inside the vacuum line?

3) What is the part/plug that keeps the line and valve connected to the vacuum reservoir?

 

I can take pictures if needed.

This is my first vehicle so if I'm missing something obvious please point me to a source, google and yahoo failed.

[bill190]

As to if something is factory or not, you can go to a wrecking yard and look at similar vehicles. See if they have that gizmo too!

 

So far as having your first vehicle, congratulations!

 

As to working on this yourself, I don't know if you have access to tools and repair manuals or not?

 

If you are starting out from scratch and need to buy all this stuff, it can be expensive, but will save money in the long run.

 

So far as service manuals to purchase, you would need to determine if your vehicle has a carburetor or if it is a fuel injection computer controlled engine.

 

If it is a carburetor non-computer engine, then you can pick-up an aftermarket service manual from any auto parts store and this would be pretty good at helping you service your engine.

 

If it is fuel injected and computer controlled, this take a bit of learning and a GM Factory Service Manual set which costs about $135 (order from helminc.com or a GM dealer).

 

There are a lot of electrical sensors on the computer controlled engines and a fuel system which needs to have a certain fuel pressure and flow to operate properly.

 

These things can mostly be tested with a multimeter, a fuel pressure gauge, and the factory service manual set instructions. How to use a multimeter...

http://www.google.com/search?hl=en&saf...ter&aqi=g10

 

The 92 factory service manual set I have has 4 different books. General service manual, electrical diagrams, fuel and emissions (engine and computer), and unit repair.

 

These explain how each electrical sensor operates and what its function is. So a very good source of learning how your vehicle works. Also there is detailed troubleshooting instructions for specific problems like missing, etc.

 

What you would do is test certain sensors with a multimeter to be sure they were working properly. The factory books tell you what reading on your multimeter you should get.

 

Also same for testing fuel pressure. The books would tell you how to test the fuel pressure and what the pressure should be.

 

BUT!!!! If your engine is NOT factory and someone has replaced the engine with something else, then buying these books would be a waste of money!!!

 

So check that out first. Maybe post pictures and someone would have the same vehicle and could tell you. Or maybe ask at a GM dealer if they could take a peek and tell you. And also the wrecking yard thing might be helpful.

 

Let us know if you have a carburetor engine or a fuel injection computer controlled engine. On older GM engines they are "TBI" or Throttle Body Injection and this looks like a carburetor, but it is actually fuel injection.

[kaeraze]

Just tried uploading pics but my internet service won't allow it.

 

Took a trip the the parts store this morning, the 'plug' is just a silicon wad and the part I was wondering about is a plastic tube.

 

Now I'm just down to the engine missing question. Just waiting for that silicon to dry before cranking it.

 

Engine:

5.7L V8 - Fuel Injection

Engine isn't modified from stock, most changes were made to the passenger area. Like a mini-RV.

 

For now just assume I have the tools needed, I can probably buy them.

 

Theese manuals right?

http://www.helminc.com/helm/product2.asp?c...0PUM1CCAXR9DMNF

 

And thanks again.

[bill190]

Yes, that is the manual set. The fuel and emissions book will be the most important for troubleshooting this problem.

 

While that is on order....

 

Might try slightly pressing on the accelerator and seeing if that makes the problem go away or not.

[kaeraze]

Seems so but when I went up a slight incline it stalled out. Automatic transmission.

[bill190]

Ok, you're best to wait for the manuals then and follow the troubleshooting instructions.

 

If the vehicle has not been serviced regularly, might want to do the regular stuff (depending on your budget).

 

Air filter.

Fuel filter.

Oil change, oil filter.

Spark plugs.

Spark plug wires.

Distributor cap/rotor.

 

Check air in tires.

Check fluid levels.

Check all lights; brake, backup, turn. (Use mirror, assistant, or you can see your lights in the reflection of retail store windows from the parking lot.)

 

Check brakes: Find empty parking lot, speed up, then slam on brakes to be sure you stop in a straight line. (If vehicle veers to left or right when slamming on brakes, best to find this out in an empty parking lot!)

 

Check all vacuum hoses for cracks and vacuum leaks. This page has a good test for checking vacuum leaks...

http://www.random-misfire.com

 

Check the battery voltage with a multimeter.

 

The battery should read 12 something volts with just the ignition on (not started).

 

Then start it and it should then read 13/14 volts at the battery. This is the alternator kicking in and charging the battery.

 

Then measure the voltage inside the vehicle as well. Check from the center of the cigarette lighter to ground and you should get about the same voltage as at the battery. Check with just the ignition on and also with the vehicle running like above.

 

Then the factory service manual will have a list of things to check/lubricate/replace every so many miles. Like at 30,000 do this list of stuff. At 100,000 miles do that list of stuff, etc.

 

The owners manual will say what specific type of lubricants and fluids to use. If it says to use transmission fluid of a certain type, GET that type! If an auto parts store does not have it, go elsewhere and find it. Same with other fluids. Use what the owner's manual recommends.

[bill190]

P.S. Get ACDelco factory specification spark plugs if you want to avoid problems.

[vasco]

Hi, I'm glad theese forums are here.

 

Model: 1990 GMC Vandura 2500

 

I do not know wether I am asking about a modification or not. Bought it second hand after it was modified. Just say if it's so.

 

The poblem occurs while its idling. The engine begins to miss and shuts off after a few seconds. I'm replacing the vacuum lines but along the way I noticed something odd near the hood.

 

There is (what looks like) a vacuum reservoir attached to the hood. A single vacuum line runs from this. The vacuum line is surrounded by some kind of plug which fits into the vacuum reservoir. Inside the line (and surrounded by the plug) is some kind of valve I'm trying to idenify. The plug itself was taped up and is to worn to leave in.

 

So, I have three questions:

1) How can I stop my engine missing while it idles?

2) What is the valve/object inside the vacuum line?

3) What is the part/plug that keeps the line and valve connected to the vacuum reservoir?

 

I can take pictures if needed.

This is my first vehicle so if I'm missing something obvious please point me to a source, google and yahoo failed.

 

HI ,

your van have a OBD1 connecter,under de dash,driver side,just below the steering colun.

you can retrive the codes with a clip or a small wire,and see whats going wrong with the van,here is one of many address where you can take the codes /www.extreme-check-engine-light-codes.com/GM OBD1 Decoder.htm

I had a problem with my van too,vacuum lines very old,replace them and the van drives like new.