any experts on fuel system and codes/ Geno or anyone

Greenemachine

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I got 3 codes I have no idea about.

175-no ego switch at adapt limit bank 2
176-ego not switching lean exh-bank 2
524-low spd fuel pump ckt open(batt-eca)

from what I gathered in the archives they seem to be all related. and the 524 fuel pump could be causeing the car to run lean. however I don't know where to go from here. I changed my o2's a while ago, they have probally less then 3-4000 miles. I just changed my pump to a 255lph, I was getting these codes before I changed that. I have a feeling it has to do with the fuel pump circuit. where would be the first place to start? I heard that the vcrm could be bad is that common with a high mileage car? thanks
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

I did a little bit more research on the vcrm and heres what came up.

"The Variable Control Relay Module is used to perform the following functions: fuel pump control; engine cooling fan control; A/C clutch control; A/C head pressure control; supply VPWR to the EEC-IV system and powertrain Control Module. In addition to these functions, the VCRM performs diagnostic checks of its system. Information on any failure that is detected by the VCRM is sent via DCL (DATA+ and DATA- circuits) to the Powertrain Control Module (PCM). This failure information is output as Diagnostic Trouble Codes during EEC-IV Self-Test."

Is it possible that just the fuel pump control is messing up inside the vcrm and nothing else? however it says the vcrm checks its systems and sends any info on faults to the pcm. so maybe it is just sending a code about the fuel circuit to the pcm, 524. The car seems to drive fine, and other than a slight hesitation/stummble under light throttle the other day(first and only time it happened, but no chk engine light) the car works fine. any ideas?
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

Do you have a chip? Maybe that would have something to do with it?

<shrug>
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

since you obviosly have a scan tool, do the PCM reset sequnce and see where you end up. Ill scan my service CD (GET ONE FROM LEO!! Worth 10x the $13) and see if i come up with anything else
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

I don't have a tool. but anyways the cars computer was reset already when I was changing the alt... so all the codes are new. and I've had the chip in for a while now. and till recently I didn't have any problems.. however I'll take it out and then reset the comp. but I had the scanner on it with the chip in and the 524 never came up.
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

What is your fuel pressure?? Actual to the rails?
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

pressure is normal. only way I can check under a load is if I pay 60-70 bucks for a new gauge cause the one I have is too short.
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

so no one knows anyting about the vcrm or the fuel circuit? I have a service info cd that I bought on e-bay but I really don't like it. My brother has this huge service manual for his 91 camaro, and that goes into alot of detail, whereas the cd I have is more general mark 8.
 
RE: any experts on fuel system and codes/ Geno or anyon

RE: any experts on fuel system and codes/ Geno or anyon

«1993 Mark VIII Table of Contents»

«Group 10: FUEL SYSTEM»
«Section 10-00: Fuel System--Service»
«DIAGNOSIS AND TESTING»



PINPOINT TEST A: FUEL PUMP DIAGNOSIS

A1: INITIAL SYSTEM INSPECTION
A2: FUEL PUMP FUNCTIONAL CHECK
A3: FUEL INJECTION SUPPLY MANIFOLD--STATIC PRESSURE CHECK
A4: FUEL INJECTION SUPPLY MANIFOLD --STATIC LEAKDOWN TEST
A5: VEHICLE LOAD TEST
A6: FUEL PUMP VOLTAGE SUPPLY
A7: ELECTRICAL RESISTANCE OF FUEL PUMP
A8: FUEL PUMP--STATIC PRESSURE CHECK (IN-LINE FUEL FILTER CHECK)
A9: FUEL PUMP CHECK VALVE TEST
A10: STATIC FUEL PUMP CURRENT DRAW
A11: FUEL PRESSURE REGULATOR CHECK
A12: FUEL PRESSURE REGULATOR CHECK
A13: FUEL PRESSURE REGULATOR LEAK TEST
A14: CHECK FUEL INJECTOR FUNCTION
A15: CHECK FUEL INJECTOR RESISTANCE
A16: CHECK FUEL INJECTOR ELECTRICAL CONTINUITY SIGNAL
A17: CHECK FUEL INJECTOR FLOW AND LEAKAGE
A18: CHECK FUEL RETURN SYSTEM FOR HIGH PRESSURE CAUSES
A19: CHECK FUEL RETURN SYSTEM PRESSURE
_____________________________________

Where do you want to start?:)
 
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