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OT chev won't start

D

Delvaughn

Member

Have a 95 cavalier, 2.2. Fuel pump won"t run. Checked fuse, ok. Replaced relay from napa no help. So thinking pump was bad. Replaced pump but the pump still won"t run even for the normal 2 sec when key is turned on. Have no voltage were the pump wireing harness plugs into the car harness junction block at the fuel tank with the key turned on in the run prostion.

Any ideas on what to check next? Oil pressure switch maybe? Thanks in advance.
 
I checked the trunk for a emergency shut off like you said but I didn't find anything that looked like a shut off switch in there.
 
Been a while since I looked at one of these, but do you have
power AND ground to your fuel pump relay activating coil?
The safety shutdown relay (ASR I think it's called)
shuts off one or the other if the sensors tell it to.
I can't tell you what all sensors there are to cause this to happen,
others may be able to. Hobo probably works on these things.
IIRC a fuel leak or an air bag sensor are a couple that can shut it off.
Basically the same thing the in trunk crash sensor would do in a Ford.
 
Does the fuel pump relay "click" on, then off in a couple of seconds when the key is cycled?

The computer and relay are the primary means of activating the fuel pump. The oil pressure switch is there for a BACKUP, "cuz if the primary setup fails the oil pressure switch WILL energize the fuel pump after a long enough period of cranking to build oil pressure, the computer/relay system activates instantly upon detection of cranking.

Will a schematic help?

0900c1528003cfe0.gif
 
You must be a dorF and Goat mechanic, Royse!

(Don't get mad, I'm just teasing you a little!)
 
You need to find out if it's on the control side of the fuel pump or the power side. Terminals 87 to 30 "jump" the relay and supply power to the pump. Look at the relay terminal end for the numbers. I would do that to see if the pump operates. If it does, it's the control side. If it doesn't it may be the power side. Use the test light upstream of the relay to check for voltage there too then work your way down. Always check the power side of the fuel pump circuit with a test light not a volt meter. One strand of wire will show voltage presence, but not carry a load. Hope this helps. Gerard
 
"You must be a dorF and Goat mechanic, Royse!"

My favorite goat, The Judge, has a mechanical fuel pump! :)
At least we both suggested he check the control/activation circuit.
BTW, you said the PCM will energize the primary circuit as soon as
it detects cranking? What tells the PCM that the engine is cranking?
 
(quoted from post at 07:31:23 05/03/13) "You must be a dorF and Goat mechanic, Royse!"

My favorite goat, The Judge, has a mechanical fuel pump! :)
At least we both suggested he check the control/activation circuit.
BTW, you said the PCM will energize the primary circuit as soon as
it detects cranking? What tells the PCM that the engine is cranking?
Click to expand...

I have no specific knowledge of that systm but crank/cam position sensors would be one really easy source for that input.

TOH
 
Wow thanks for all the help!
Bob--the relay clicks on than off in about 3 sec.
thanks for the schematic.

ASFguy--I jumped the #87 (it is hot with the key on) and #30. The pump didn't run. So you are saying to check from the relay termial #30 power side an see were the power drops off using a test light?
 

Bob , where did you find that schematic ? I need to get one for my '95 Cutlass Supreme 3.1L

I went to the hardware store and when I came out the car would not start , no fuel pressure . I trailered the car home where it promptly started no problem . There have been a few times when it acted up but eventually started . If nothing else , maybe I can wire in a emergency hot switch .
 
(quoted from post at 09:23:55 05/03/13)
Bob , where did you find that schematic ? I need to get one for my '95 Cutlass Supreme 3.1L

I went to the hardware store and when I came out the car would not start , no fuel pressure . I trailered the car home where it promptly started no problem . There have been a few times when it acted up but eventually started . If nothing else , maybe I can wire in a emergency hot switch .
Click to expand...

I buy an OEM Shop Manual as soon as I get a new vehicle. If you are a "barely used car" guy like me you can usually get a set for $50 or so on eBay. The '95 Cutlass seems to be a cheapy:

Cutlass Shop Manuals

To paraphrase Mr. Rosser - "has all that good chit in it" :roll:

TOH
 
When the PCM "sees" pulses from the crank and/or cam sensors this indicates the engine is actually turning over) Some GM cars used a wire direct from the "START" circuit to the PCM. Didn"t look closed at the schematic for this particular car, though.
 
YAHOO!! The car started!! It had a bad connection were the wiring harness that comes from the engine compartment to the inside wiring harness of the car connect.

I did what ASFguy said an put a jumper wire from #87 to #30 on the relay an while I was moving the harness inside the car the test light came on.

I than just bypass the connector with a short wire an it started. Without ASFguy an Bob's help I wouldn't have known how to do the jumper trick.

Now I have to change the head gasket. For about a year I have had to add water about once a month. But it has gotten to be every week now. After it sets it will run bad until the water gets out of the cyl than it runs good. It is starting to cut out some going down the road now.

THANKS VERY VERY MUCH FOR THE HELP!
 
The relay kicks on for three seconds or so to build static fuel pressure to aid in quick starts. You need to verify 12 volts with a test light upstream from the relay at the relay first. Make sure you have a bright test light for the power lead into the relay when in ignition run position. If you do go to the next downstream(from the relay) connector and back probe the connector to see if the light is bright. Continue on until you lose test light brightness. Make sure each location tested has a bright light. A dim light means excessive resistance and probably not enough voltage to light the light and therefore not enough to power the pump. Don't rule out corroded terminals or loose terminals.
 
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