Dads 92 astro wont start

[notverrysmart]

Ok, as the title says, my dads 92 chevy astro 4.3l tbi will not start. It was having issues with cold start and he replaced the cap, rotor, and plug wires, and the plugs were replaced not too long ago. The cold start issue seemed to be cleared up and he had no problems for a couple days, then they returned with it running like crap once it started. He limped it home, and when he got home it wouldnt start and we traced it back to a bad fuel pump. Wouldnt turn on when jumped directly from the battery.
We replaced the fuel pump and you can hear it turn on, however it still will not start. when cranking instead of a cone spray from the injectors it is just dripping at about the same rate on each injector.
My thinking is there is not enough fuel pressure at the injectors since I doubt both would fail at the same time and at the same rate and the dripping (only while cranking) tells me the ecm is telling them to open.
Im 90% sure that the hoses from the tank are hooked up correctly since once again the injectors are getting fuel.
So Im leaning towards a pressure regulator or possibly a clogged line. Also the fuel filter was replaced somewhat recently.
So am I heading in the right direction? What would be the best/most simple way to test this? If Im missing any info please let me know and I will add it and if I think of anything I will add it.

 

[notverrysmart]

So things we tried today, we used a 9v battery to jump the both the injectors and the each dripped about the same. I pulled my old TB out of storage and tore it apart so we could see what we may be getting into and after it was apart we filled the fuel bowls with carb cleaner and I jumped the injectors getting about the same drip pattern. So my assumption is for some reason my dads injectors are not getting the pressure needed. We both believe it is getting enough pressure (still without a gauge since we dont have one) up to the throttle body, but for some reason the injectors dont have that pressure.
But the only thing I can think of between the throttle body feed and the injectors is the regulator, but after seeing it apart I dont see how it could leak without it dripping out of the bowl for the spring.
He said he is going to get a new fuel filter tomorrow if we dont get any other ideas before then. Other than that our only next option (unless we are missing something) is to pull the tb apart and clean and rebuild.
One other thought we have is somehow a gasket may be broken in some way to cause it to go into the return line instead of the injectors.
our confusing point is the evenness of the dripping is so uniform and the way it was so sudden.

Also the van will burn gas if we dump it directly into the tb bores, but just to burn off what is in there and not stay running.

Any ideas?

 

[bucket]

It's hard to say without known good fuel pressure. Right now my hunch is you put in a bad fuel pump. Where did it come from?

 

[notverrysmart]

It's hard to say without known good fuel pressure. Right now my hunch is you put in a bad fuel pump. Where did it come from?

It is possible that it is bad, bought it from autozone so it could be bad off the shelf.
He bought a new fuel filter and relay, and a tb rebuild kit should be in this afternoon. We are not ones to throw parts at a problem, but for the price of these parts we will at least know that those parts are good.
Know of a good pressure tester that wont break the bank? The one I have wont work with gm throttle bodies.

 

[bucket]

I have a pressure adapter I bought from Snap-On, it was probably expensive.

Rebuilding the TB won't really do anything unless it leaks or the internal screens are clogged. For the screen to be clogged, it would have to get past the fuel filter. I've torn apart a lot of TBs and never found a single screen that was clogged... and usually I was tearing them apart to replace the injectors with a horrible spray pattern.

 

[tanz45]

Did you check voltage at the pump? Bad, corroded ground?

 

[notverrysmart]

I may try going to a pull a part and get a bit of the line so I can make one or something so we can find out what the pressure is.
I checked the voltage when the battery was low and it was at 9 volts, the connector and ground looked good probably wouldnt hurt to clean up the ground a bit though.
He said when he took the tb apart he couldnt see any bad gaskets or o-rings and the screens were clean.
If we have no change we will probably be dropping the tank again and Ill get another look at the ground, there was no corrosion or build up on it.
Thanks for the help so far.

 

[Jims86]

Since you said you replaced the pump, here are some possibilities.
Clamps on new pump to outlet hose accidentally left loose, or said hose was bad and not replaced...could have a hole in it that does not present its self unless pressurized.
Crimped fuel lines when the tank was re mounted.
Dirty plug at the tank...I have seen as much as a 3 volt drop at the pump with crappy greasy terminals.
fuel filter clogged.
bad new pump very possible....I like NAPA pumps if you have one local.

If you have the TB kit, do the rebuild by all means, but do it after this running problem is figured out. New screens on the injectors can do wonders.

 

[notverrysmart]

Since you said you replaced the pump, here are some possibilities.
Clamps on new pump to outlet hose accidentally left loose, or said hose was bad and not replaced...could have a hole in it that does not present its self unless pressurized.
Crimped fuel lines when the tank was re mounted.
Dirty plug at the tank...I have seen as much as a 3 volt drop at the pump with crappy greasy terminals.
fuel filter clogged.
bad new pump very possible....I like NAPA pumps if you have one local.

If you have the TB kit, do the rebuild by all means, but do it after this running problem is figured out. New screens on the injectors can do wonders.

The bad hose was what I was hoping for when we pulled the pump, it was replaced with a new one in the kit as well as new clamps closed with pliers.

the crimped fuel lines is a possibility, we wont be able to see until we drop the tank.
I cleaned the terminals with contact cleaner and a tooth brush and we have a new fuel filter installed.

We are getting more drips now than we were before so if anything we are at least getting better. Ill see if I can talk my dad into pulling the fuel pump and see if autozone will take it back. I think there is a napa around here somewhere but ive been gone 5 years so I could be wrong. Maybe we will get lucky and we crimped a feed hose lol.

As for the tb rebuild, my dad already did that.

 

[Jims86]

The bad hose was what I was hoping for when we pulled the pump, it was replaced with a new one in the kit as well as new clamps closed with pliers.

the crimped fuel lines is a possibility, we wont be able to see until we drop the tank.
I cleaned the terminals with contact cleaner and a tooth brush and we have a new fuel filter installed.

We are getting more drips now than we were before so if anything we are at least getting better. Ill see if I can talk my dad into pulling the fuel pump and see if autozone will take it back. I think there is a napa around here somewhere but ive been gone 5 years so I could be wrong. Maybe we will get lucky and we crimped a feed hose lol.

As for the tb rebuild, my dad already did that.

At least check for crimped lines before that...maybe drop the tank a few inches and see how it runs.....do the easy stuff first.

 

[HotRodPC]

It's hard to say without known good fuel pressure. Right now my hunch is you put in a bad fuel pump. Where did it come from?

This would have been my next guess and item to test. How cold is the weather where you're at? It's common in OK, when we have a real cold snap, which is rare for us, but I know some in the country are having some real cold weather, that any water in your fuel lines, pump or tank will freeze. You won't get it turn until you thaw the lines and pump. THEN you can put HEET in the tank to discipate the water and dry it out. If it's alot of water, might even need 2 treatments, but the **** does work here.

Thing is, people think once their lines are froze, they can put the HEET in it will start. NO. The HEET has to have been run through the fuel system. I've known newer cars NOT to start for 3 days. It came down to where they were buying their gas. It real easy to figure out when you see a station with NO customers. Reason being , all their customers are broke down at home and can't go anywhere.

 

[roadtriper]

I may try going to a pull a part and get a bit of the line so I can make one or something so we can find out what the pressure is.
I checked the voltage when the battery was low and it was at 9 volts, the connector and ground looked good probably wouldnt hurt to clean up the ground a bit though.
He said when he took the tb apart he couldnt see any bad gaskets or o-rings and the screens were clean.
If we have no change we will probably be dropping the tank again and Ill get another look at the ground, there was no corrosion or build up on it.
Thanks for the help so far.

Checking for voltage in a circiut when the battery is at 9 volts ??? stop and get the battery up to snuff before doing any diagnostics or testing
and testing for voltage at the fuel pump can and will Bite you in the ass. (I speak from experience!) a single strand of wire will carry 12.6 volts and will read good at the fuel pump connector, BUT won't carry enough amperage to run the pump. I like to use some sort of a load like a sealed beam headlight bulb to see if the circiut will carry the load. test lights don't require enough amperage to be trusted either

as for the fuel pressure tester, just remove the pressure line from the TB and plumb it into your guage with a piece of hose and clamps. sure it's better to plumb it inline with a propper fitting but this will at least give you dead head pressure that the pump is capable of 13-15 psi should be enough to properly run the TBI dead head pressure on the pump will be higher than that if it's working properly and the lines are clear. if you have decent pressure there hook it back up to the tbi and see if you can find a spot to pinch off the return line and see what your pattern looks like. if it comes back to a decent spray then the regulator is bad.. Just some thoughts! RT

 

[Jims86]

Checking for voltage in a circiut when the battery is at 9 volts ??? stop and get the battery up to snuff before doing any diagnostics or testing
and testing for voltage at the fuel pump can and will Bite you in the ass. (I speak from experience!) a single strand of wire will carry 12.6 volts and will read good at the fuel pump connector, BUT won't carry enough amperage to run the pump. I like to use some sort of a load like a sealed beam headlight bulb to see if the circiut will carry the load. test lights don't require enough amperage to be trusted either

as for the fuel pressure tester, just remove the pressure line from the TB and plumb it into your guage with a piece of hose and clamps. sure it's better to plumb it inline with a propper fitting but this will at least give you dead head pressure that the pump is capable of 13-15 psi should be enough to properly run the TBI dead head pressure on the pump will be higher than that if it's working properly and the lines are clear. if you have decent pressure there hook it back up to the tbi and see if you can find a spot to pinch off the return line and see what your pattern looks like. if it comes back to a decent spray then the regulator is bad.. Just some thoughts! RT

Dead head pressure should be 18 to 20 on a tbi pump.
9-13 regulated.

 

[notverrysmart]

Well he has work tomorrow so depending on how dry it is I may go out there and lower the tank a bit to see. I'm also going to grab my gauge out of storage and see if we can come up with a way to hook it up or make an adapter for it.
The frozen lines were/are a thought since it was getting down into the 20s, but yesterday was mid 30s and today was 40 most of the day so youd think it would have thawed out by now. Tomorrow should be the same, so I guess we will see.

I even asked him if he pissed anybody off recently lol

Edit
RT the only reason we were checking the voltage with a dead battery was to ensure the relay was triggering
the rubber hose may work for a getto rigged gauge so we can at least have an idea

 

[notverrysmart]

We used a chunk of hose on the end of the feed line at the tb and got 18-19 psi.

Is there any sensors that could affect this or possibly a bad signal from the ecu?