95 Astro - Fuel problem

[DaveG_01]

Can you guys please help me?

I have a 95 astro which I recently replaced the fuel pump.

Since replacing I have drove one 300 mile trip and about another 300 miles of city driving (with no problems).

Last week it got real cold like 4 degrees or so. And I started having problems. The truck kind of wanted to stall when I tried to give it more gas. This problem progressed over a couple days (60 miles of driving). I had not changed the fuel filter yet, so I replaced it last Saturday and it seemed to fix the problem. You could not blow through the old filter.

Then the problem started up again this week, after 50 miles of driving, only 10 miles of driving after filling up the gas (15 gallons).

The problem is getting worse.

Here are a couple more facts I have put together.

The original problem started after I filled up with gas (Thursday 16 gallons). After about 5-10 miles of driving.

The problem re-occurred after filling up with gas from the same gas station (Tuesday -15 gallons, After 10 miles); there were no fillups between this and the first.

When I noticed the original problem the first thing I did was add 2 (maybe 3 cans) of gas antifreeze. It did not help.

I only added 1 can immediately after filling up the second time (15 gal of gas). Then added another can later. It did not help.

The problem completely goes away if I shut the van off then turn it back on. Of course it slowly returns after a few minutes of driving.

The problem is progressive. It starts off mild and continually gets worse until the vehicle will stall. Right now it takes about 7 miles of city driving @30 miles/hour (stop and go) to get real bad.

Sorry for the long post. Do you guys have any idea on what I might check next?

I am thinking about changing the fuel filter again (and never going back to that gas station). I think that gas was 10% ethanol.

Any suggestions would be greatly appreciated.

Thanks,


Dave

[DaveG_01]

Please keep in mind that any of the facts above could be coincidences. Maybe the gas from that gas station is just fine and has nothing to do with the problem. Maybe it was brought on by the cold weather.

What could cause stalling like this? Could it be a clogged EGR valve?

[Kings-x59]

The fuel injection pressure regulator might be suffering a slow death, or you might have water in the gas tank from your (former) favorite gas station. If you don't have a manual on the van try www.autozone.com - fair amount of free repair info there.

[CD Smalley]

Check your fuel pressure. If you aren't seeing 55-60psi when you first turn the key, and holding at least 40psi overnight, you need to replace the fuel injection spider. Start looking on ebay for a new AC-Delco unit. Expect to pay about $250USD.

[DaveG_01]

Is the spider the same thing as the CPI unit?

I read up on the CPI unit and it seems like most ppl that had CPI units that were leaking internally, also had starting issues.

My van starts very easy. Does this rule out a bad CPI unit?

Mabye it is just the fuel filter again. I will take it off and see if i can blow through it this weekend. I would have done it already, but the damn cold, snow, and extra low running boards turn a 2 min task into an hour one

[DaveG_01]

btw... the check engine light is NOT on.

[CD Smalley]

Spider =CPI unit.

Mine started just fine too with the bad spider.

When you changed the fuel filter....did you have to bleed off the pressure from the system? I mean did you disconnect the fuel pump wires, then start the van and let it run until it stalled? If you didn't do this and just went and took the fuel filter off without getting soaked in 40psi of fuel pressure, then you have a bad spider.

[DaveG_01]

I did not bleed off the pressure when i changed the fuel filter. I just opened the lines and let the gas squirt.

I'm not sure what 40psi of fuel pressure looks like, and really dont remember how much came out...

Because the old filter was clogged, I kindof think the fuel filter might be a good place to start. I will change it tomorrow and post the results. Please let me know if you have any more ideas.

I guess if that does not work, the next step will be to conduct the fuel pressure test you outlined earlier

[Tiger397]

Originally Posted by DaveG_01

I did not bleed off the pressure when i changed the fuel filter. I just opened the lines and let the gas squirt.

I'm not sure what 40psi of fuel pressure looks like, and really dont remember how much came out...

Because the old filter was clogged, I kindof think the fuel filter might be a good place to start. I will change it tomorrow and post the results. Please let me know if you have any more ideas.

I guess if that does not work, the next step will be to conduct the fuel pressure test you outlined earlier

Wow, I can't believe it. We are having the same problem with our Astro Van.

We have replaced the following parts:
egr valve
fuel pump
fuel filter
throddle body
cleaned injectors and fuel line
catalytic convertor and exhaust system
tune up
numerous relay switches
transmission filter and strainer
replaced several vacuum lines and hoses
Also filled up with premium gas and added a few gas cleaning additives.

and it's still doing the exact same thing.

I've read a few trouble shooting guides that said it could be a knock sensor or possibly something called a lifter in the engine.

I am just clueless. We were hoping to get it running good enough to trade it in. This has been going on for a month now. Replacing part after part leaving seasoned mechanics clueless.

I don't know what to do next.

[CD Smalley]

Tiger,

Have you checked your fuel pressure? Which year and engine do you have?

[DaveG_01]

My van is
1995 CHEVROLET TRUCK ASTRO VAN 2WD
6 Cylinders 262 W 4.3L CPI

The problem is getting worse... now i cant drive over a mile or so. I have not yet determined if the problem starts after it warms up or just a period of time.

I really suspect the fuel filter, but dont want to change it right now because there is a damn blizzard outside. I will wait until morning i guess.

I will post the results.

[DaveG_01]

Okay... I just took off the fuel filter. The filter is fine. I can easily blow through it.

The bad thing is there was no pressure when i took the line loose. There was plenty of fuel in the filter, but the gas did not squirt.

Is this the problem? Does this mean my fuel system as a leak somewhere? Is the most likely location the spider as suggested earlier? Is the spider the first place i should start, or is there an easier/cheaper place to start?

Thanks for the advice guys... I really appreciate it!

[CD Smalley]

If you did NOT burn off the pressure before you changed the filter, and only had a small amount of gas that dripped out vs. sprayed. Then yes I think the spider has failed. Start checking on ebay for a replacement. Make sure you get a new GM part. Get the whole spider. Don't mess with just the fuel pressure regulator. It might be one of the poppets has failed as well. Expect to pay roughly $275 including shipping. Here's the seller's address that I bought mine from [email protected]. He shipped promptly and the part was new GM part in the box as advertised. $255 to my door.

[DaveG_01]

Man... I can't get the plenum to come off. I took out all 10 bolts/nuts.

I have tried pulling on it. Prying on it. I can't get it to budge. Is there something I am missing, or a certain technique to use?

How stuck are the usually?

[DaveG_01]

Never mind... i missed the front center bolt. It was much easier to find in the day