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

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Old Jun 28, 2016 | 04:33 PM
  #21  
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Originally Posted by Kevova
So at what point did it stop starting? Most mechanics would note distributor position if it was to be removed replace intake. It is easy to be one tooth off reinstalling distributor because oil pump drive rotates as distributor is lifted. When distributor is reinstalled it doesn't fit flush like it should. So then distributor is reinstalled so its flush and end up one tooth off. IDK how aftermarket EFI ties into distributor. With the OEM: if distributor 4 wire connector was unplugged the injectors would be inop. The ignition timing would be fixed at base and it would be possible to use a timing light to get an idea where timing is. The line on balancer and timing tab would have to be a bright color so they are easy to see. There will only be 1 flash every 2 revolutions. Even so it wouldn't show you if distributor rotor was facing #6 and not #1.

Large vacuum leaks like 5/16 or larger ports or hoses disconnected.

If plugs haven't been inspected they maybe fouled. It doesn't take long for an EFI to foul them during a no start situation.

To answer your question: "Yes" air will be pushed out spark plug hole even with valves open (overlap),but with considerably less force than valves closed (compression).
It never started back after the installation of mini ram and procharger. The first mechanic marked thing really bad on the distributor. Aftermarket computer uses all original wires and sensors on the car. Computer is actually inoriginal c4 casing as well. I don't think we have vaccum leaks but hard to know until he car fires. Ok, I will buy new plugs.
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Old Jun 28, 2016 | 05:30 PM
  #22  
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It seems everything points at distributor installation for now. You have enough info that you should know one way or another soon.
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Old Jun 28, 2016 | 08:01 PM
  #23  
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Originally Posted by Kevova
It seems everything points at distributor installation for now. You have enough info that you should know one way or another soon.
Yes, thanks everyone. My only concern is the lack of backfire when sprayed ether........doesn’t make sence if 180 out.
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Old Jun 28, 2016 | 11:41 PM
  #24  
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Originally Posted by Kevova
It seems everything points at distributor installation for now. You have enough info that you should know one way or another soon.
This car has been on mind and remembered one thing......damaged wiring harness coming off ignition control module/distributor. I started doing some research and it appears a bad ICM can cause a no start situation while having spark.

Does this sound reasonable to you? I have to check different things but seems like a place to start.

Oh, I talked to mechanic and he said when restabbing the distributor he did it both ways 0 and 180 just to try.....still wouldn't fire off with ether.
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Old Jun 29, 2016 | 08:03 AM
  #25  
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ICM provides reference pulse to ecm to trigger injector. ICM sends a reference pulse every time coil should spark. l98 is multiport FI meaning ecm triggers multiple injectors every time coil sparks. IF ecm doesn't receive pulse from ICM no fuel pulse to injector. Distributor 180 out would not necessarily has backfire; and it would really be an over fuel situation if it did. With no compression there is no "pop" unless if you have a large build up of fuel. Such as a box intake with fuel pooling in plenum a spark with intake valve open could cause intake to explode.

If timing is close engine should "fire off" with flammable aerosol.

Last edited by Kevova; Jun 29, 2016 at 08:04 AM.
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Old Jun 30, 2016 | 10:41 PM
  #26  
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Originally Posted by Kevova
ICM provides reference pulse to ecm to trigger injector. ICM sends a reference pulse every time coil should spark. l98 is multiport FI meaning ecm triggers multiple injectors every time coil sparks. IF ecm doesn't receive pulse from ICM no fuel pulse to injector. Distributor 180 out would not necessarily has backfire; and it would really be an over fuel situation if it did. With no compression there is no "pop" unless if you have a large build up of fuel. Such as a box intake with fuel pooling in plenum a spark with intake valve open could cause intake to explode.

If timing is close engine should "fire off" with flammable aerosol.

ICM didn't work
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Old Jul 2, 2016 | 10:18 PM
  #27  
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Originally Posted by Eric Macnak
ICM didn't work
Wow, alot of issues fixed still no start.

#2 fuel pump not activating - limited fuel at motor from fuel pump #1 but second fuel pump not working - fixed working
Bad connection on coil/no spark - fixed spark cofirmed
Timing out 180 - fixed
Electric Spark Timing module - checked working
Ignition Control Module - replaced working
Confirmed getting injector pulse at each injector
Oil pressure sensor - cofirmed working over 4 psi on start up
Throttle Position Sensor - confirmed working .54
Idol air control sensor -working
Map sensor - checked confired working



Still need to confirm fuel pressure at fuel rail
Still need to verify injector flowing fuel

Anything we are not thinking about?
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Old Jul 2, 2016 | 10:36 PM
  #28  
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Make sure plugs aren't fouled
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