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Mike S.
Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 7368
Experience:  ASE Certified Master Technician
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93 Lt1 vet starts and runs 2 seconds and shuts of ran codes

Customer Question

93 Lt1 vet starts and runs 2 seconds and shuts of ran codes module 1 ccm 41 liss serial communication module 4 ecm ERR MODULE 9 71.oil pressure above 30 don't think it's fuel pump can hear it cycle. Trying to give it more gas when shutting down has no effect
Submitted: 1 year ago.
Category: Chevy
Expert:  Mike S. replied 1 year ago.

what is a ccm and err?

Also is this a vin P engine or the vin J in a ZR1?

Expert:  Mike S. replied 1 year ago.

The vin J should have 48-55 PSI of fuel pressure and the vin P 41-47 PSI, so either way 30 psi isn't' enough. In order to change the fuel pressure regulator on the vin J, you must remove the intake plenum and fuel rail assembly, on the vin P remove the left fuel rail cover from the vehicle.

Customer: replied 1 year ago.
Module 4 is displaying capital letters ERR instead of a numberCCM COMPUTER CONTROL MODULEEMISSION CONTROL MODULE (the big black box above battery
Expert:  Mike S. replied 1 year ago.

Ok, I thought this had an engine control module. nonetheless, the fuel pressure isn't enough and you didn't answer if this is a vin p or j.

Customer: replied 1 year ago.
Vin 1g1yy23p95118313It may indeed be an engine control module a large black box with 4 large cables with 4 square plugs that look like the maine wire harness
Customer: replied 1 year ago.
The oil pressure gauge goes over half way mark I have not measured fuel pressure but I can smell that it is getting gas it starts quickly then shuts down in 2 seconds
Expert:  Mike S. replied 1 year ago.

Ok, I see the 8th digit is the engine P number.

that fuel pump should be putting out 41-47 PSI

the oil pressure gauge goes over the 1/2 mark after the engine runs for only 2 seconds?

Oh, I thought that 30 psi was the fuel pressure, sorry.

Ok back to the codes isn't this an OBDI and you are counting the check engine light flashes for codes?

Customer: replied 1 year ago.
No i am using a wire between pins a and g the obd1 terminal under steering wheel
for codes to display on speedo
Expert:  Mike S. replied 1 year ago.

I thought a and g ran the fuel pump. a and b is to retrieve codes. Let me double-check that a and g.

Expert:  Mike S. replied 1 year ago.

Yeah a and g is to run the fuel pump, https://www.obd-codes.com/faq/gm-aldl-connector.gif

Customer: replied 1 year ago.
My vette in a 93 lti 6 speed if that matters.the codes are preceded by either h for history or C for current
Customer: replied 1 year ago.
This was direction to retrieve codes by Chevy without a scanner that all use in the corvette club
Expert:  Mike S. replied 1 year ago.

Ok, I had a little trouble understanding what this meant, can yo correct the spelling or punctuation or whatever so I can understand it, " ran codes module 1 ccm 41 liss serial communication module 4 ecm ERR MODULE 9 71"

Customer: replied 1 year ago.
Module 1 is the computer control module which gave code c41 loss of serial data communication, module 4 is the engine control module displayed ERR, Module 9 is the radio electronics etc,code c72 which has to do with disconnect of battery and not resetting radio before driving
Expert:  Mike S. replied 1 year ago.

I get code 41 refers to a 1x reference circuit fault.

72 is loss of serial data.

I don't understand what is going on here. a and g is supposed to run the fuel pump. Hold on, let me check a different manual.

Customer: replied 1 year ago.
If it helps the car will not restart without turning the ignition off and removing key and starting the starting procedure over
Expert:  Mike S. replied 1 year ago.

Ok, I see now, a and g are for CCM diagnostics.

Let me read this. Hold on.

Expert:  Mike S. replied 1 year ago.

Ok, this is what I read but nothing in there says what a to g does, I do see the terminal g n the diagram though.

Expert:  Mike S. replied 1 year ago.

This is what this manual says but I still don't understand why you are not retrieving codes from a and b?

Code 41 Cam sensor or cylinder select circuit fault ignition control (IC) reference pulse system fault or Electronic Spark Timing (EST) circuit open or shorted

Code 72 Gear selector switch circuit

Customer: replied 1 year ago.
Optispark?ECM?
Expert:  Mike S. replied 1 year ago.

optispark is the ignition and ecm is the engine control module. Are you asking me what these are or if these ma be the problem or what?

Expert:  Mike S. replied 1 year ago.

If this has the ignition timing wire that you unplug in order to check and adjust the ignition timing, make sure it isn't still unplugged.

Customer: replied 1 year ago.
Are they the problem
Expert:  Mike S. replied 1 year ago.

Then check the fuses for the ecm.

Customer: replied 1 year ago.
I can check fuses when I get homeThis problem was progressive and the care would stay running but over time it took more attempted starts to current situation which is constant
Expert:  Mike S. replied 1 year ago.

See if the engine will continue to run for more than 2 seconds if you continue to spray small shots of starting fluid into the throttle body. If not, then the problem is most likely with the ignition. If it does run, then the problem is most likely with the fuel system. Let's ignore those codes for now.

Expert:  Mike S. replied 1 year ago.

Change the fuel filter.

Expert:  Mike S. replied 1 year ago.

Then clean the fuel injectors if it does run with the starting fluid.

Customer: replied 1 year ago.
Okay I can't get to the car till tuesday
Expert:  Mike S. replied 1 year ago.

Ok, check back with me Tuesday.