C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

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Old Apr 15, 2020 | 06:19 AM
  #61  
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Yes,
the panel in the center console that has switches on the left for fuel and engine related information has no power on the right side. So there is no parking break light, check engine light etc. Fuses all appear good. I have not cleaned all of the contacts yet, but any corrosion I find I clean up. I am attempting to get the car to tell me why my engine does not want to go when I punch the throttle. I will check the fuel pressure this weekend. My fuel preasure regulator is not leaking and I replaced the vacuum lines to that as well. When I drive the car and accelerate slowly it runs smooth, punch it and it loses power.
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Old Apr 15, 2020 | 07:20 AM
  #62  
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Originally Posted by ihatebarkingdogs
It was also a very nice today in SoCal. I had to run to San Pedro (about 20 miles each way) so I took the LT5 car. Traffic has been very light, so I knew I'd have fun and catch a couple of low-risk opportunities for excursions to triple digits. I wasn't disappointed.

Cheers.
Very nice. Southern California, ZR1, no traffic, no cops (probably), sounds wonderful.
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Old Apr 16, 2020 | 11:46 AM
  #63  
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Originally Posted by MarkB85vette
Yes,
the panel in the center console that has switches on the left for fuel and engine related information has no power on the right side. So there is no parking break light, check engine light etc. Fuses all appear good. I have not cleaned all of the contacts yet, but any corrosion I find I clean up. I am attempting to get the car to tell me why my engine does not want to go when I punch the throttle. I will check the fuel pressure this weekend. My fuel preasure regulator is not leaking and I replaced the vacuum lines to that as well. When I drive the car and accelerate slowly it runs smooth, punch it and it loses power.
to go over what you have said:

you can get rpms manually by operating throttle at the throttle body. Using gas pedal you only get restricted rpms.
you also stated using gas pedal the butterflies open fully.
car was fine prior to any work you have done.
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Old Apr 16, 2020 | 11:53 AM
  #64  
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Yes, that is correct. The car starts just fine and drives smooth slowly. I plan to verify fuel preasure possibly today.
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Old Apr 16, 2020 | 06:39 PM
  #65  
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I thought you said the butterflies didn’t open all the way, 2mm short or something? That wouldn’t explain the condition you are describing but the throttle should open all the way to the stops.
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Old Apr 16, 2020 | 09:22 PM
  #66  
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Originally Posted by GregMartin
I thought you said the butterflies didn’t open all the way, 2mm short or something? That wouldn’t explain the condition you are describing but the throttle should open all the way to the stops.
some conflicting things said. Work throttle by hand and rpms seem fine. Get in drivers seat and won’t rev up. All this not under load. Those two things don’t add up especially if gas pedal opens butterflies.
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Old Apr 16, 2020 | 11:29 PM
  #67  
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Indeed, when driving, if I open the throttle the engine fades at around 3900. If I accelerate slowly the car will speed up to go fairly fast.
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Old Apr 17, 2020 | 02:38 AM
  #68  
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Originally Posted by MarkB85vette
Indeed, when driving, if I open the throttle the engine fades at around 3900. If I accelerate slowly the car will speed up to go fairly fast.
yeah that sounds like air fuel ratio to me. Could be a few things, fuel pressure, MAF sensor. Do these cars have a MAP as well or just MAF I’m not sure?
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Old Apr 17, 2020 | 06:24 AM
  #69  
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It has a MAF that appears to be sound. My code reader will be here soon so that should help. Actually the MAF looks like it has been replaced before. It looks newer than many other parts on the car. This weekend I should know more.
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Old Apr 18, 2020 | 05:07 PM
  #70  
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Hello all,
preasure tested the fuel system. At idle it is a little low at 32, when I take the vacuum line of off the fuel pressure regulator it goes up to 40. When the car accelerates the preasure drops to about 28 under load. When I shut it down the preasure dropped to 19 and then stayed there for over 30 minutes. So I am guessing I need a new regulator. The fuel pump and filter are new. Any advice would be great, thanks for the support.
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Old Apr 18, 2020 | 09:26 PM
  #71  
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Originally Posted by MarkB85vette
Hello all,
preasure tested the fuel system. At idle it is a little low at 32, when I take the vacuum line of off the fuel pressure regulator it goes up to 40. When the car accelerates the preasure drops to about 28 under load. When I shut it down the preasure dropped to 19 and then stayed there for over 30 minutes. So I am guessing I need a new regulator. The fuel pump and filter are new. Any advice would be great, thanks for the support.
was vacuum line on or off when you accelerated ?
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Old Apr 18, 2020 | 09:36 PM
  #72  
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The vacuum line was in place and there was no sign of fuel leaking either. The vacuum line had good suction and was dry.
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Old Apr 18, 2020 | 11:17 PM
  #73  
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Originally Posted by MarkB85vette
The vacuum line was in place and there was no sign of fuel leaking either. The vacuum line had good suction and was dry.
Try with vacuum line off under load.
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Old Apr 18, 2020 | 11:38 PM
  #74  
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I will, also the preasure gauge I rented from the auto parts store had a messed up o-ring in the connector so I am not sure it got a good reading. When I start the engine it roars to life. No issues at all with starting. More to follow I suppose. I will get a better gauge tomorrow and try again.
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Old Apr 19, 2020 | 01:12 AM
  #75  
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I’m no expert on what the pressures should be on an 85 so I’ll leave it to someone who knows.
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Old Apr 19, 2020 | 07:07 PM
  #76  
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I got 37psi with the the vacuum line off under load. With the vacuum on Inget about 29 under load. Bleed down test drops to 20 and holds
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Old Apr 20, 2020 | 12:28 AM
  #77  
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Why are you thinking fuel regulator bad ?

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Old Apr 20, 2020 | 06:14 AM
  #78  
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Because I don't know what I am doing and I am kinda guessing. I replaced the fuel pump about 4 months ago. That seems to eliminate that. I don't want to go replacing injectors if that is not the problem. I put in a new filter when I replaced the fuel pump.
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Old Apr 20, 2020 | 10:13 AM
  #79  
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Originally Posted by MarkB85vette
Because I don't know what I am doing and I am kinda guessing. I replaced the fuel pump about 4 months ago. That seems to eliminate that. I don't want to go replacing injectors if that is not the problem. I put in a new filter when I replaced the fuel pump.
Go back to the beginning and rethink. This was a new problem after something was done if I remember correctly?? I am confused here myself. Can't keep throwing parts at it. Sometimes the new part adds another problem itself too.
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Old May 5, 2020 | 01:08 PM
  #80  
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Hello all,
my 85 has 16 DTCs, not sure where to start but low voltage may be a key. I will start cleaning contacts. Any advice on where to start will be very helpful. EST is my starting point. Code 41 is for that. I found my EST connector gone and that wire had a house hold wire nut on it. I crimped a connector there but not an OE connector. This I think could be a big part of the no power issue. Code 51 is a big one as well. I don't want to waste anyone's time putting all 16 here. Thanks in advance for any advice.
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