1998 Silverado Passlock Issue ---- ugh

[Pinger]

That I believe I can answer. To the best of my knowledge PassLock cannot intrude on the operation of an already running engine. What makes me say that is there's a specific bypass method which involves switching a signal wire and interrupting the PassLock signal while the vehicle is running, and no mention of the engine dying when you do so.

https://www.gmupfitter.com/files/media/photo/284/Bulletin_20.pdf

Cheers.
First observation - PL interrupts fuel injectors - for some reason I thought it interrupted pump operation.
Second - though I must be reading it wrong - it reads initially that PL can be disabled with a switch. Presumably any attempt to key start with it disabled that way re-enables it.

But yes, seems that once the engine is running PL can be reactivated via its newly installed switch and the engine motors on. With remote start though, what do you do on entering the truck? Insert the key and turn to 'run' for all the other 'hot when in run' circuits?

Still not clear how with a dodgy PL it will momentarily fire up. My assumption of residual fuel (no pumping) would permit that but not immediate injector cut off.

Either, pump disabled early (residual fuel theory) OR, time delay before injector cut off. Which I wonder?
(Even with a dodgy PL as long as it briefly fires (and can repeat that) and can't stop a running engine - it wouldn't matter if mine was dodgy as I can switch to LPG in that brief fire up and over to gasoline at the first sign of running low on LPG. The repeatability at start up would be needed though).

 

[df2x4]

Second - though I must be reading it wrong - it reads initially that PL can be disabled with a switch. Presumably any attempt to key start with it disabled that way re-enables it.

From what I gathered in that document, the newly installed switch is used to interrupt the PassLock signal while the vehicle is running. That last bit is apparently important, because doing so will bypass PassLock entirely until the switch is reset, or the battery goes dead. Page 3 in that document is what I'm referring to.

I have aftermarket remote start systems in both of my '97s and the procedure after entering the trucks is key-on to the run position and tap the brakes.

 

[df2x4]

Either, pump disabled early (residual fuel theory) OR, time delay before injector cut off. Which I wonder?

The latter would be my guess, mainly because I seem to recall reading that some people with this issue could get their trucks to fire up multiple times in a row. I would think that if the pump were disabled the pressure would bleed off too quickly to enable multiple restarts, but I'm pretty much talking out of my ass at this point. I think I've exhausted all my useful information on this subject.

When in doubt, tune it out!

 

[Pinger]

The latter would be my guess,

Unless each attempt re-primes the pump/lines.....

mainly because I seem to recall reading that some people with this issue could get their trucks to fire up multiple times in a row. I would think that if the pump were disabled the pressure would bleed off too quickly to enable multiple restarts, but I'm pretty much talking out of my ass at this point. I think I've exhausted all my useful information on this subject.

When in doubt, tune it out!

That's the bit I was looking for though - that multiple attempts result in firing up each time. And the inability of PL to stop a running engine.
Both of my questions answered - thanks!

 

[Pinger]

When in doubt, tune it out!

In ****** Blighty - that's just not an option - unfortunately.

 

[df2x4]

In ****** Blighty - that's just not an option - unfortunately.

You could always buy HPTuners and do it yourself... Although at $4-500 US that's a pretty big tool investment. You could mess with all sorts of other cool stuff though. I wish the '96-'97 PCMs were supported but unfortunately it's only '98+.

 

[Pinger]

You could always buy HPTuners and do it yourself... Although at $4-500 US that's a pretty big tool investment. You could mess with all sorts of other cool stuff though. I wish the '96-'97 PCMs were supported but unfortunately it's only '98+.

With LPG under its own ECU control (which I have software for) It would only give me control over ignition - and the ability to delete PL. Even dodgy PL shouldn't hurt me though - if it fires up on gasoline one blip of the throttle changes it over to LPG and so long as I switch back to gasoline (if needed) with the engine still running - no problem. Moot point given the gasoline side isn't working at all right now and it aint the PL at fault. These trucks just love to torment us....

I'm hoping Wurth software (when I get it loaded) will cover sensor and other stuff. Only the sensors that control ignition not fuelling apply here. Money needed elsewhere too.

 

[brian c lindsey]

i have a 98 , and my passlock module went out year before last , it was hard to get to ,(under radio and behind cd player ) but i did , and bought a reman out of st louis , mo for less money that the tune would have cost, they have a lifetime warranty, rock auto also sells them

 

[Pinger]

i have a 98 , and my passlock module went out year before last , it was hard to get to ,(under radio and behind cd player ) but i did , and bought a reman out of st louis , mo for less money that the tune would have cost, they have a lifetime warranty, rock auto also sells them

The ones from Rock Auto - straight forward replacement or is some sort coding required?

 

[Pinger]

. Moot point given the gasoline side isn't working at all right now and it aint the PL at fault. .

Or maybe it is PL.
Fuel pressure returned yesterday - lots of it. But no start on the key and wouldn't continue running when switched from LPG to gasoline.

When fuel pump goes bad - does it stay bad? Or can they be a bit intermittent?