1999 Chevy Astro Van Fuel Pump or What???

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#1
My son is working on his van. 1991 Chevy Astro Van, 4. 3 liter. It would only start intermittently. If you crankred on it for a while then left it alone for about half an hour then try it again, it would start. Now it will not start at all. He took the fuel line off upstream of the fuel filter (which he changed out) and there is no fuel. He swapped the AC relay and the fuel relay and still no fuel. Before he buys the fuel pump, is there anything else he can check? Thanks, everyone. Larry
 
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#2
Give us the 8th charactor of the Vin# this will help us recognise the engine- CPI TBI ....

did you check fuses?
Is the check engine light on?
If applicable this year, is security light on?

The fuel pump will only energize for 2seconds if engine is not running/started, So turning key on and climbing to check by yourself won't work. There is a fuel pump test circuit, a red wire by fuel pump relay to assist this test...
If you can locate it use a 12v test lamp see if it has 12v when key first moved to start...

The fuel pump harness for 12v gray wire.

You can use a fused jumper to power this circuit and test fuel pump pressure...
A FUSED jumper!!
 
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#3
Thanks, kev2, the 8th character is "N". The fuse checked okay. There is no security light. I'm talking long distance to my son as he works on it. He said the check engine light was on and the code was for "mass air flow sensor circuit low". He said he check and there was 12 volts going to the fuel pump. Thanks again. Larry
 
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#4
kev2, is there something else I can get that will help diagnosis this problem. I've never heard of a circuit low code. Anyway, thanks again for the help. Larry
 
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#5
that is for a MAF code?  could you post the code number (Pxxxx) number we see many WRONG descriptions for codes....
P0101 P0102 P0103 all MAF codes

PS vehicle is STOCK no modifications add ons or aftermarket parts?
 
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#7
LarryEd44 said:
My son is working on his van. 1991 Chevy Astro Van, 4. 3 liter. It would only start intermittently. If you crankred on it for a while then left it alone for about half an hour then try it again, it would start. Now it will not start at all. He took the fuel line off upstream of the fuel filter (which he changed out) and there is no fuel. He swapped the AC relay and the fuel relay and still no fuel. Before he buys the fuel pump, is there anything else he can check? Thanks, everyone. Larry
91 or 99?
If a 99 check engine cranking fuel pressure before throwing fuel pump at it.
You need 64-65 lbs of pressure for a cold start Nto squirt injectors
yOU CAN NOT LEAVE HOME WITHOUT IT.
To test For a fuel delivery problem give it a squirt of carb cleaner and see if it will start.
On the MAF sensor code clear code and check the fuse and get it running and recheck for what code comes back.
Make sure you have air intake stuff all on and pluged in before trying to start or run.
Crunch
 
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#8
Must be a 1999 to throw a P0102
I did get confused on first post......

to get you started......Always easy first,,,without scaner
DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency

Check for the following conditions:


A misrouted harness. Inspect the MAF sensor harness in order to ensure that it is not routed too close to high voltage wires such as spark plug leads.
A damaged harness. Inspect the wiring harness for damage.
A plugged intake air duct or filter element*
.
A poor connection
Rubbed through wire insulation
A broken wire inside the insulation

Check for the following conditions:
Objects blocking the MAF sensor inlet screen.
Crankcase ventilation valve malfunction, missing or incorrectly installed.
Vacuum leaks in the following areas:
Throttle body
EGR valve flange and pipes
MAP sensor seal
EVAP canister purge valve seal
Fuel meter body seal

*MAF sensors &  K&N filters  A BIG BIG no no
A cleaning with MAF cleaner will not hurt...

I cannot paste and copy ....will try at work Wed,
 
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#9
kev2

My dad has been using this forum to find an answer for the fuel problem I'm having with my 99 Astro Van.
There are couple things I've noticed on your last response to him.
1. Wiring? I changed the O2 sensors, I used the universal sensors and I think I wired them according to the instructions. The Van seemed to be fine after that but a few days later the problem started.
2. Vacuum? I replaced the vacuum line that apparently had something to do with the AC. I'm not quite sure what that line all does but my AC was not blowing. After I changed that vacuum line the AC was working again. I haven't seen any other Vacuum lines.
3. I did not know about the K&N filter, I have been using it for years?
4. Can the MAF keep the fuel pump from working.

Thanks for everyones help, I will check all the other things you mentioned. I'm planning to spentd this next weekend up to my elbows in grease. It'll help to be armed with the most info.
 
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#10
what is status of fuel pump.....dad said you had 12v at pump and it did not run...is this correct?

You did read about the need to test for 12v in 2sec?


NOTES
Remove the K&N and give to someone you do not like... POS .........
WIth emission parts unless you are parts savy always use OEM especiaally for emission and computer related components...
 

wap

GO MOUNTAINEERS
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#11
12 volts is one thing, but amperage is another. check with a test light. test battery with test light and make note of the brightness. if that bulb burns very dim a f/p wire harness, suspect wiring issue, ground problem, ign switch. in other words, you might have voltage, but no current, or insufficient current to run the pump.
 
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#12
I think the fuel pump is ok. I check the Batt. first and then check all the connection to the fuel pump and the pump by it self all seemed ok.
 
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#15
Well put a 12 volt fused jumper on the gray fuel pump feed wire or fuel pump test plug.
And make sure it is getting voltage all of the way back to pump and also ground.
Then If pump does not run it is bad pump.