Sputtering around 20mph

[LisaM]

I am new to this forum and not sure what the problem is with my 1994 Chevy Astro Van, it has almost 264,000 miles on it!! This does not happen all the time, around 20mph the van will sputter and jerk, almost like there is air in the gas line. The van is "new" to me. The one time I tried to drive over 50, it started to sputter and jerk and would not stop until I was driving 45 or lower, ended up turning around and coming home!! The fuel filter has been replaced and it drove ok in the city the other day, sputtered once. I have not been anywhere to go over 50 since then. Just wondering if anyone else has had a similar problem. Thanks for any help

[Jasen]

Welcome to A/S
No SES light? have you done a tune up.

[LisaM]

My nephew who is a mechanic is supposed to come by sometime and check it out. He has already done a few things to it. My brother replaced the fuel filter. He did go over everything and it was a well maintained van, even have the original owners manual with notes in it from the owner!! Everything looks new, clean, just had oil done, transmission fluid is good. Just have no idea what the "sputtering" could be??

[Jasen]

There are better diagnostic people here then me, and I don't know a lot about GenI's.
I'm sure one of them will chime in.

[chevymaher]

first things I would check are fuel pressure running. Sounds like it is running out of gas.
Second check the EGR see if it is stuck partially open.

[Leeann_93]

Yup, what Randy said. Fuel pressure test first thing.

[LisaM]

Thanks everyone, I will pass the info on to my brother and nephew. What is an SES light and EGR??

[Jasen]

service engine soon warning light

exhaust gas recirculation, it's control valvue

[LisaM]

Went out today to start the van and nothing, not a sound!!! No warning lights on at all. Brand new battery put in two weeks ago!! Have only had this van for about 3 weeks!

[LisaM]

Here is a pic of the van

[Sailing_Faith]

Hello Lisa,

These vans have a lot of interior lights, I bet one was left on. The ones in my rear console (over the passengers) have a habit of not coming on when I hit the button, but come on later. I wonder if you have an interior light that was on overnight?

Another thing to check are the connections on the battery. Side post batteries (which our vans have) are known for getting a bad connection where the connections to the battery are made. If you grab the big red wire and big black wire where they go into the battery you should not be able to turn them side to side at all.... If you can they are too loose. If you can move them, try to start the van again and see if it starts.

If not, just have it jump started and drive it around for a bit so the battery can charge.

[LisaM]

Thanks for the info. I actually have not turned on any of the interior lights but my brother and nephew may have. I only drive during the day so I have not noticed if one was on or not. Will check the battery too. My brother was here two days ago and tightened the cables up because I had the same problem, van would not start. He did that then he had to jump start it. Thanks everyone for the suggestions. It would be nice to be able to drive this thing around!!

[Sailing_Faith]

As for your original problem, I am surprised no one has mentioned the spark plug wires as a possible culprit. The sputtering you describe can come from several causes, both the EGR valve and fuel pump are possibilities (as have already been mentioned).

There are tests for all of these problems, and they are not too hard to do. It is good for whoever is working on a problem like this to take a systematic approach to cut down on the expense of changing parts for no reason.... Unfortunately many (most) shops seem to be "parts changers".

First test I would recommend is to look under the hood while it is running at night. If you see sparks jumping from anywhere you have ignition problems. It can be really hard to see from the front, but opening the hood is a lot easier then removing the "doghouse" over the motor.

If you see sparks, you likely need a new distributor cap, rotor, and plug wires. Possibly a new coil.

Are you going to do the work yourself, or have someone work on the van for you?

If you are doing it yourself, the next step will be to remove the doghouse. I don't know if it is in your owners manual, but it is not hard and there are write ups on this site to tell you how.

After you have the doghouse off, you can see the motor much better. Run the engine and check again for sparks.

[LisaM]

No, I don't do the work myself, my brother and my nephew do the work. I will give them this message. Hopefully they are going to be taking it this weekend to work on it. I've gone a year and a half without a car so I really hope they can fix it!!

[Sailing_Faith]

The next check (which you also need to have the dog house off for) is fuel pressure.

There is a small cap on the fuel line that covers a fitting that has a valve like a bicycle tire. There are gauges you can buy or rent from an auto parts store (some even let you borrow them for free) that you can connect to this fitting.

Once you connect the gauge, you start the van and see what it reads. You may have to drive the van and see what kind of pressure reading you see when driving. Take notes on the numbers and post them here and we can help you figure out if that is the problem. You will likely see it stay pretty close to 60psi if it is good, but it may drop into the low 50psi range when you notice the stumble.

[Sailing_Faith]

For testing the EGR valve, what I do is make a block off plate out of an aluminum soda can.

The EGR valve uses exhaust change the fuel mixture of the engine to try to make the exhaust cleaner. It does this by opening a passage between the intake of the motor and the exhaust. When it goes bad, it normally sticks open. This can cause the problem you are having just like the ignition and fuel pump.

What I do to test the EGR valve is block the passage between the intake and exhaust with a plate I make out of a can. Basically what you do is remove the EGR valve (easy, just a couple of bolts) and them use the gasket as a pattern to cut a flat bit of can into a gasket with no holes.

You reinstall the EGR valve, with the plate between it and the motor. If you run the van and the problem goes away you know it is the EGR valve. You can leave the plate in but it will set a code in the computer which will turn on your Service engine light.

[LisaM]

thanks for all of the suggestions, I will pass them on to my brother.

[Sailing_Faith]

These three tests should help you find the problem, and get you on the road.

The ignition system is where I would look first. There is one other possible problem which these vans seem to have. The distributor drive is made of plastic and gets worn with age. Mine was bad, and I bought a new one from RockAuto.com that is metal. The new distributor came with a well made distributor cap and rotor and made my van run better then it ever had.

If whoever is helping you work on the van removes the distributor cap, they can try to move the rotor back and forth (and up and down) to check for wear. The bushings get worn out, as does the "drive gear" that turns the distributor. I there is much play, it needs to be replaced.

I know I just hit you with a lot of information, this forum is a great resource.... I hope you get your van running well soon!

[Sailing_Faith]

Ok, one more post.

Here is a thread on changing spark plugs and wires (I had a melted wire) that might be helpful.

Here is a thread on troubleshooting and replacing the distributor drive, with some pictures to help explain what I was talking about in the post above.

[LisaM]

Thank you!!