no vacuum

[Carson21R]

yup still working on it. 89 base 3.1. it has no vacuum. nothing. nothing comes out of the brake booster when the hose is disconnected. The car wont run. but it will fire with starting fluid. What can cause no vacuum?

[DTMAce]

Well, what have you done so far?

Obvious thing to do is check all of the vacuum lines. Most of these cars have a map of the layout under the hood someplace. You want to look for cracks, holes, loose hoses, disconnected hoses, missing hoses, etc.

If in doubt, hit an auto parts place and pick up a repair manual for beretta's. They will have some diagrams, etc that can help you.

Good luck.

[Carson21R]

replaced all of them this past weekend.

[DTMAce]

The only other thing I can think of, would be a serious issue with the engine itself... Some kind of internal leak, as vacuum is created while the engine is running... Ruptured seal, failed manifold... Hell I don't know.

Or you are simply missing something, that is either broken or not there, not allowing the vacuum to build up.

Thing is, if the engine isn't running, you aren't going to have any vacuum. The engine has to be able to run enough to create a vacuum first... At least from what I know... You don't have an electric vacuum pump on your car do you? I know my old Caravan did, but mainly just for the brakes. I wasn't aware of any beretta's, let alone many Chevy's that had electric ones, but I don't know everything either.

And vacuum is not going to keep your engine from running either. So something else seems to be wrong with this picture. If you are getting to to run a short bit with starting fluid, that means you may not be getting fuel delivery. On these cars, fuel is delivered by a fuel pump in the tank, it goes through a filter just outside the tank, then up to the fuel rail on top of the manifold, and even has a return line back to the tank for the excess.

You may want to check that you have the following:

Good gas, and plenty of it.

Fuel pump is working. Simple test, switch the key to the "on" position and see if you hear a whine or motor run for a few seconds. That should be your fuel pump.

Check for fuel pressure at the rails. There usually is a pressure gauge tap on the rail, however you will need a fuel pressure tester, NOT an tire pressure tester. Should be like at least 30-40 PSI, when the pump shuts off, after turning the key to "on". If the pump runs, but the pressure doesn't build up, may have a plugged up fuel filter, or the pump is bad, or something has clogged up the fuel rails going to the injectors.

Last the injectors themselves could have a couple of possible issues, one being that the wires connected to them have come loose, or at the main junction, or something like that, so check the hookups going to them and from them. They could have clogged up with dirt, or have gone bad. Weak voltages (in the case of a low charge on the battery or a non-working alternator) could cause problems with them as well, along with other things though, so highly uncommon, but ya never know.

Check your firewall ground, and other points of ground around the engine, make sure they are tight and free of corrosion.

Not sure what else to suggest.

[Carson21R]

yea its got good fuel pressure. 45-50 psi then key off it drops ~2-3 psi. injectors have power. has great spark.

[DTMAce]

Then I don't know what else to suggest. Maybe someone else can.

Good luck.

[beretta]

this is a weird situation, do a compression test on all cylinders. and check there there is no vacuum leaks anywhere, if it has a major vacuum leak somewhere that might cause it not to run, or super high idle or something abnormal.

have you had the intake off at all by chance ?

[3X00-Modified]

you wont get VAC unless its running so if it wont run for a sustained period of time then there is no way to test for VAC.

If it fires off of starting fluid then that tells you that you have a major fueling issue.

It should also hold fuel pressure after you turn the key off for at least 30min if not longer. Its should SLOWLY drop down to 0, not drop off instantly.

[SuzukiGhostRider]

^^^^^

What he said....

And I'll add this. Sounds like a bad check valve in your fuel pump assembly allowing drain back. Also, sounds like the pump is weak and on it's last legs. Time for a new fuel pump and assembly you ask me.

[Carson21R]

you wont get VAC unless its running so if it wont run for a sustained period of time then there is no way to test for VAC.

If it fires off of starting fluid then that tells you that you have a major fueling issue.

It should also hold fuel pressure after you turn the key off for at least 30min if not longer. Its should SLOWLY drop down to 0, not drop off instantly.

I checked the injectors with a DMM and they have voltage but I really need a noid light to make sure there working. The FP held really nice it just dropped 1-2 psi with key off.

[Carson21R]

^^^^^

What he said....

And I'll add this. Sounds like a bad check valve in your fuel pump assembly allowing drain back. Also, sounds like the pump is weak and on it's last legs. Time for a new fuel pump and assembly you ask me.

Pump was brand new. strainer and filter too.

[3X00-Modified]

The FP held really nice it just dropped 1-2 psi with key off.

Your original statment made it sound like it dropped off to 2-3psi, not only lost 2-3psi...

So yes in this case you need to check your injectors to see if they are even firing.

[SuzukiGhostRider]

^^^

Ditto.