Mechanics

CHEVY CHEVY VAN WILL NOT START WITOUT

1995 Chevrolet Astro

1995 Chevy Astro 6 cyl Two Wheel Drive Automatic 72k miles

1995 Chevy Astro van, all of a sudden it will not start. SUPER deep cranking power; on the battery. It Wants to start you get the VAwithout the ROOM.

A two second burst of MAF cleaner jump in the van it starts VAROOM and runs strong as an ox. Turn it off (either very cold or very hot ( hot = warmed up 18 mile drive) it will not start up by itself. Changed the fuel filter same same will not start.

Started it on Tuesday using MAF cleaner, idled it for 2.5 hours as I did a side job on Tuesday. It ran great! Would get in move to the next item I was painting and so on. After that I drove home it started a couple times on its own in the hour after I returned.

Changed the fuel pump relay nothing, same same will not start without the 2 second burst of accelerant. Changed the distributor cap and rotor.

What should I check on? It runs perfect except start up. It has muscle just does not want to get going.

Auto parts stores say it is the fuel pump. I don’t understand. If it cannot start the van how is it able to run ( fly down the freeway without a care) and idle perfectly?
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Mangos
November 6, 2008.




If you have that spider fuel system, it is known for problems. Did you check fuel pressure? Are there any codes?

If it is a fuel issue, there are bulletins about the fuel poppets getting clogged. The cleaning procedure is a shop procedure, I don't believe pouring injector cleaner in the gas tank will help.

JDL
Nov 6, 2008.
I have put seafoam in the tank with only 10gallons of gas in the tank then ran the engine pretty hard it had no effect on the issue the van still runs like a pistol.

I ordered a pressure checker yesterday should be here anytime now (NAPA) I only have a obd2 tester not 1 the fuel pressure tester is cheaper today. Tomorrow I may need the obd1 tester.

Thank you for responding

Tiny
Mangos
Nov 6, 2008.
Update

Here is the skinny

With fuel pressure gauge
Turn on ignition pressure goes to 52 psi engine won’t start.
Turn on ignition pressure goes to 52 psi leave ignition on watch PSI drop to 30psi in 15 minutes.

Turn on ignition pressure goes to 52 psi engine won’t start. Spray MAF cleaner in throat it starts runs at 52 psi all of the following tests were started using MAF cleaner

Next try pinching shut the return line start van, pressure slowly climbs to 79psi that was after I pressed down on the accelerator. Otherwise it was stable at 52 psi but running rough WITH the hose still clamped I turn engine off Psi drops form 79 to 66 in Five minutes.

Next try pinching shut the return line, start van pressure slowly climbs to 79psi that was after I pressed down on the accelerator. Otherwise it was stable at 52 psi but running rough. Turn off engine remove clamp quickly. Went from 79 to 60psi just like that. Then bleeds down 60psi-48psi in 5 minutes.

Turn on ignition pressure goes to 52 psi try to start see PSI dropping to 45 over 5 seconds of starter turning. Start using Maf cleaner let engine run PSI holding at 51-52.
Turn off engine clamp return line quickly. PSI goes 50 -10 psi in 15 minutes.

Then I take it for a drive starting as before go to the parts store. Leave parts store turn on ignition PSI goes to 59-60 van starts. Go home try again 12 more times over 10 minutes PSI is at 59-60psi just turning on ignition

I just do not get it. It will start at 59-60PSI won’t start at 52PSI I have read 51-64psi is required. Oh and lastly the van is running at a steady 52 psi once started

I still do not get how all of a sudden after 8 days it is working again, not to say I won’t go downstairs and not start after I send this.

Tiny
Mangos
Nov 8, 2008.
The fuel pressure is critical on this spider system. My info says, koeo, key on engine off, 58 psi or higher. At idle around 54 psi. The regulator is prone to leaking as well as the supply and return line under the upper plenum. And the fuel poppets are prone to problems.

The resistance spec for the injector, at room temperature, is 1.4 ohms. I don't have the bleed down specs in front of me, If you can clamp the return and supply line without causing any damage, does it still bleed down?

JDL
Nov 9, 2008.
Brilliant! Clamp off both hoses if it does go down then it is not the fuel pump. If it does then it is the regulator or Then again you added injectors; I thought I was home free on the regulator oh well.

I took today off on this, said enough just rest. I will try both hoses tomorrow Monday.

Oh it did not start this morning I had about 55-56Psi at 59-60 psi it started every time

Thank you!

Tiny
Mangos
Nov 9, 2008.
Okay help me out here.

The fuel pump is before the regulator Yes?

The pressure should be at 60-62 before the regulator Yes?

The regulator has no effect on adjusting the fuel pump pressure correct?

It should be a constant yes? Especially with pump on but the engine not running.
The regulator just controls what goes into the engine correct?

The regulator is not called into action until the ignition sequence Yes? Or am I off here?

So when you turn on the ignition to power up the pump but not start the van it should be at pressure 60-62 yes?

So when I turn on ignition and it only goes to 52 PSI then try to start it drops to 45 psi
Would that be the fuel pump and not the regulator or injectors?

If the injectors were leaking or the regulator was leaking you would think there would be fuel in the engine to start the van instead of me needing MAF cleaner to add the extra explosion needed to get the van going.

I can here a vibrating noise when the pump first initializes but never more then 52 psi when I heard it make a stronger noise like a pump vibrating it was at 59 PSI and started every time without fail, but that soon ended and I was back to 52 PSI at key on and idle.

When I drive the van with the fuel pressure gauge attached to read, it is vibrating so fast back and forth it is not a steady enough to read like at idle. In the 50’s

SO what am I missing?

Ps I did clamp both lines But I am not sure I clamped hard enough to stop a 50psi pressure to not leak by. Engine hot it took 20 minutes to leak down 8 psi engine cold (but clamps were removed over night then attiached for the cold test) it dropped 8psi and more a lot faster again I am not sure it was clamped tight enough.

Back to when the engine was hot, tested and it only dropped 8psi in 20 minutes or so then I removed the clamps it plummeted to 10 psi. Sadly I did not check with return line removed first or fuel line removed first I removed both clamps and it read 10 psi

Tiny
Mangos
Nov 13, 2008.
(With the engine idling and the pressure gage hooked up, if you open and close the throttle quickly, how does the gage react?
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JDL
Nov 13, 2008.
Well here you go all week it has started. The pressure builds to 60-62 start car, it fires up. Psi is 54 while running.

I have to tell you though I am a bit tired of looking at the engine and the psi gauge hanging from the Fan speed switch (laughing)

It is not too bad at first but once the engine warms up it does get warm in the cabin.

With both front and rear a/c running it is bearable.

So the jury is still out

Could the SEAFOAM gas treatment have cured the situation?

I am still leery of filling the tank. If I have to drop it, it will be a whole lot easier empty. My last 3 fill ups have been 2 gallons only : )

Tiny
Mangos
Nov 21, 2008.
I here you, about all the testing. I've known some mechanics that would replace the pump without testing anything, R& R, mainly because the service writer told them to. Then if they still have the problem, they start testing. I get tired of testing sometimes, but, I think that is better than throwing parts at it.

As far as filling the tank, I hear that also. I helped my son replace his fuel pump in a suburban, by the curb, there at his house. He had just filled it up, over 30 gallons in the tank. We drained the tank there at the fuel filter, did a deadhead pressure check there also. His pump would still run, just not enough pressure. We drained it a gallon at a time, the gas went in four different vehicles. Took a little while.

JDL
Nov 21, 2008.
Well I believe we have closure {literally}.

Since the seafom was added to the tank and within a few days. The van would reach all normal PSI’s as mentioned.

I closed up the cover today, after 3 weeks of hearing the engine and feeling the heat.

I started the van Thanksgiving morning and it ran for 30 seconds turned it off.
Checked it Friday AM it still had 10-14 PSI

So either the check valve in the fuel pump had shellacked and the sea foam cleaned it or the regulator was gummy and the sea foam fixed it.

All I know is; it is working and starting on its own.

I also bravely put a full tank of gas in her today. Better yet it was $2.97 We have not seen under $3.00 for years.

Thanks for the support.

Tiny
Mangos
Nov 29, 2008.

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