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1987 Corvette Won't Start after New Engine Install

 
87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/01/12 10:16 AM

Absolutely awesome info!  This is what I needed.  I also received your PM.  I will jump on it shortly.  The printer may need to be loaded several times with all of this info Grin  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/01/12 11:00 AM

Well, just for the fun of it, I went out and started the car to try something.  I was scanning doing a live datastream watching the tps voltage.  It was at 0.63 volts.  I adjusted the tps down to 0.52 as suggested and WOW! what a difference in how she sounds.  I was actually confident enough to go on a two mile maiden voyage.  It worked great!  I would never have thought that slight of a voltage change could have that great of an effect.  The tps installation instructions simply say to adjust the voltage between 0.50 and 0.75, so 0.62 seemed to be the number.  WRONG!!

Keep you fingers crossed for the cold start tomorrow......

Thanks Wayne!

Now onto the "battery going dead" issue.....Hmmmmm Confused  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/02/12 10:38 AM

Damn!  Still hard starting cold.  Goint to replace the sensor on the front of the manifold as suggested by Wayne.  Will advise.  

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waynep71222
My first time was in a Chevy
Posts: 241
Joined: 04/12
Posted: 05/02/12 12:11 PM

cold start system has diagnostics  to make sure the sensor is bad before replacing it...      because of the location.. i have found bad wires at the pigtail...

were you able to plug in and see the injector pulse width...   the MAF flow reading..  the idle air control counts...  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/03/12 12:52 AM

No, not yet.  Going about this one thing at a time.  

I currently have three Kawasaki crankshafts on the bench.  They all came in yesterday.  Also a U-joint job pending on a Deutz Allis tractor as well as a door and quarter panel replacement on a 4th gen Camaro. And a belt and tensioner job on a 98 Mustang.  Not an easy job as it is equipped with a supercharger (very tight space).  

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waynep71222
My first time was in a Chevy
Posts: 241
Joined: 04/12
Posted: 05/03/12 05:24 AM

can i come over and work in your shop... that sounds like a great place to work in..   never know what's coming in.. never boring...   i only have a dozen forums to keep up with.. an explorer with a weird loose gear shift.. and rear wheel bearings on a voyager. and probably a subaru with parking lights that won't turn off.  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 02:12 AM

Sure!  Come on over anytime Grin  Waiting on the sensor from rockauto.  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 11:28 AM

Bought a new fuel pressure tester today.  Key on and the tester went to 38 then slowly dropped to around 20 in about 10 seconds.  I was able to get her running and pressure held around 38-39.  When I shut it off, pressure held at 41 and did not drop.  While cranking I noticed it would be around 25 and bounce for a split second to 0 then back to 25 (no start at this point).  The needle would do this every second or so.  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 11:55 AM

How does the oil pressure switch work and is there a way to bypass this for testing purposes.  Looking for a way to tell the computer I have above 4 psi.  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 01:57 PM

I don't have a tool to measure the pulse width.

Everthing was in closed loop at 167 degrees and around 700 rpm:

The MAF (gr/S) reading was 2048
MAP (V) 2.20
IAC Pos 55
TPS 0.51-0.53
CCP solenoid off
BLM enabled (kept switching between yes and no every 5 - 10 seconds or so)
Spark advance 22  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 02:00 PM

Also, I don't know if I mentioned this before, but I have the pressure regulator going directly to manifold vacuum.  

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waynep71222
My first time was in a Chevy
Posts: 241
Joined: 04/12
Posted: 05/04/12 02:08 PM

absolutely... most corvettes have over near the master cylinder a single connector for the fuel pump prime circuit....   i don't know exactly where the wire is.. it is shown on diagrams..  but i have not needed it on the cars i have worked on so i never looked for it...

a great diagram of how the fuel pump is wired is this 83 camaro crossfire wiring diagram.. just look at this for the fuel pump wiring..  thats the only reason i am putting this up..

you can see that the oil pressure switch and the fuel pump relay are in parallel...

if you take a rocker switch.. toggle switch.. add some wires to it..   put some 1/4" male quick connects on the end..   you can.. reach in.. unplug the 2 prong oil pressure operated fuel pump switch.. and plug the switch harness directly into both sides...

warning..  this is a LIVE CIRCUIT... IT IS NOT SWITCHED..  if the battery is hooked up.  the ORANGE wire is going to have power on it..

i worry that since you car has been apart a few times.. that if you are having problems like you describe.. that the connectors embedded in the rubber are LOOSE and not properly contacting the oil pressure switch blades...

this is the oil pressure switch that controls the fuel pump...

the terminals are ISOLATED from ground..



the connector for this switch is a wells  1053   you can duplicate this with some 1/4" female insulated quick connects..

Showpartimage

83Camarocrossfirewiring  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 02:20 PM

Thanks.  Please read the rest of what I posted when you have time and comment.  Also, what is the BEST multimeter I can buy?  

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waynep71222
My first time was in a Chevy
Posts: 241
Joined: 04/12
Posted: 05/04/12 02:22 PM

now.. you had peaked my curiosity...  i looked at page 3 of the diagrams that were linked and the wiring diagram back on the few few pages of this thread...

PIN G is on the ALDL connector under the dash board is the fuel pump PRIME connection...

you need to find a power source and a proper connector to allow you to probe that connector with the IGNITION KEY OFF..  sending 12 volts positive to pin G on the aldl connector will energize the fuel pump directly bypassing both the oil pressure switch and the relay..

since this PIN G is fed through the fuel pump relay normally OPEN contact.. you may be able to monitor the voltage once the fuel pump relay turns off...

in the crossfire diagram directly above this post.. you will see the fuel pump relay with a RED wire that says to the ALDL connector.. that goes to Pin G...

Aldl


sounds like we are getting closer to cruising..  

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87corvette
My first time was in a Chevy
Posts: 171
Joined: 03/12
Posted: 05/04/12 02:27 PM

That's right. I completely forgot about the pin on the ALDL.  Now my curiosity is piqued.  When it cools off a bit (too humid out) I am going to probe that pin and see what we have.  Laugh  

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