2003 cavalier

[TexasT]

Just to wrap up the Malibu, we swapped in a $300 wrecking yard engine. Fans seem to work wife been driving it to work. I have to get the ac blowing cold. Sure wish Charlie was around to bounce my silly questions off of. I put dye in it and now need to look at the joints to see if I can see where it is leaking. Put. Some 134a in and could get it to about 40psi on the low and 200-240 on the high side. I'm thinking I will get a dryer and new office tube piece and install when I find the leak . Also got a box of the hbnr o rings from harbor freight to fix the leak with.

Alright, on to the actual problem. Cavalier, when it starts it starts well and runs fine. When it doesn't the fuel pump wont run. Tried several different relays, goofed with cutting the yellow wire in the column(and have since reattached), bought a bcm but that just locks up the radio and I guess requires the reflash from a dealer to work.

It seems sometimes I can pull the fuses to the bcm and the two pcm and it will reset the computer and the pump will run and all is right. Last time that didn't work so I resorted to disconnecting the battery and letting it "reset" over night . So my question becomes what is shutting the fuel pump off and/or not turning it on? I'm thinking of hitting the wrecking yard and getting a matched set of computer(pcm) and body computer(bcm). Is this what it takes to get it to work? I guess I need the radio too. So silly. I get they want a stream of revenue, I just don't want to pay them to flash something that may or may not be wrong with the car . Yes I know I'm cheap.

My next thought involves buying a roller with bad engine and swapping this engine into it.

I think of these as crash cars as the kids generally crash em. So I don't want too awful much cash in em.

Any thoughts are welcome. No I'm not buying a new one, and I will wrench on it I'm sure.

[good2win22]

Low side numbers and high side numbers look good for the outside temps.  Orifice tube is where I would go.  Can't help with the fuel pump issue

[Scoobum]

Wire the fuel pump direct with a switch you can throw within reach. Did that with the 94 Impala I had. Fukn fuel pump would kick on/off whenever it wanted.

[xpander343]

PM me your email if you want rich, I can send you the fuel pump wiring diagram saturday.  Might help you out tracing whats going on.

[TexasT]

that would be awesome.

[xpander343]

hey rich


Here is the wiring diagram, hopefully this works.


stephen

[TexasT]

Thanks I will try to print it out when I get home . I sure appreciate it.

[aminga]

Just to throw out another theory does any of the parts come from a car with passkey?

[TexasT]

Awesome another mind to try to come up with solutions.


Here is a synopsis of what I know. Car came from oldest daughters boyfriend/now husband"s grandfather who I think bought it new. Was given to soninlaw then to daughter and didn't have probs(at least not a crank no start) until the last eight months or so.


Went to get car first time, relay good and clicking but no fuel pressure, bad pump or at least I thought. Installed new pump. Good for a few days then started again. Daughter pretty frustrated and impatient so she went and bought another vehicle and gave this one to middle daughter, who is just as impatient but doesn't have the means to do anything about it and expects me to fix her car.


read some stuff watched some vids and cut the yellow wire on key switch. This worked for a few days but the security light stayed on. no prob that is what electrical tape is for. then as well as it worked, it didn't and we are at crank no start with no fuel pressure again. got a bcm and swapped it in. locked the radio and sisnt do any good so I guess this needs 'flashed' at a dealer to work but I don't want to spend money on that if it isn't the problem.


Reattached the yellow wire, security light seems to work. and I must have jostled enough wires around as car started and ran good for a few days. then it didn't. pulled the three fuses for pcm(two) and bcm(one) and car started and ran for a few more days. Until it didn't. Pulled the fuses again to get the thing to reset but it didn't work, so we disconnected the battery and it sat over night to try to get a reset. didnt work.


Mr Stephen has graciously sent a wiring diagram. I'm going to go get the car and bring it to my house and commence some wire tracing and meter reading to see what I can find. Hopefully it is a frayed, broken or something easily spotted. 


SO bottom line I'm not sure on the passkey though it doesn't have a special key. The security light will come on with the rest of the dash lights and when it goes off we crank the engine. some times it starts, and then some times it just cranks. This is when I am getting the no fuel pressure situation. I think it is a power to the relay prob as the relay wont click, have swapped relay with the one next to it, tried a different relay and all have worked at one time and then not worked also. But I didn't have a meter to see if we were getting voltage to the relay.


Any thoughts are welcome here as I'm not getting very far with this thing other than buying a fuel pump it probably didn't need. Thanks.

[aminga]

Pass key started in 89 or so and the later key's didn't have the little embedded resistor like some of the 3rd gen trans ams.  My 99 silverado had it and just had what looked like a regular key
someone with hp tuners could look at it cranking and tell

[TexasT]

I will see if I can find a local with the hptuners thing. Is it something I can download on a laptop? Might need to invest some money if that is a good wy to see things.

[nocooler]

Hptuners is a godsend at times but it’s an investment. It can only program the pcm, not the bcm, and abs stuff. This sounds like a vats issue but I’m no expert. To disable vats with hptuners is going to burn $100 of software credits. This is the stuff where a tech 2 or equivalent is handy. There are $25 vats bypass modules but they don’t give a definitive list of the years models they work with.

[TexasT]

Probably way more than I'm willing to invest.  Mr Xpander sent me a wiring diagram. So , I will do some wire chasing and see what I can find. The light on the dash comes on and then goes off, so I cant really see that it is a security issue but who knows. Like the suburban with the burned pigtail I bet this is something like that but I have to track it down.


Thanks for all the ideas, I really appreciate it.


Got another project dumped in my driveway.