Problem o' the day... - Page 2 - ZR-1 Net Registry Forums

KILLSHOTS · 08-11-2014

UPDATE: This afternoon, I went through and rechecked every vacuum connection that I could touch, including the entire PCV assembly and MAP. Everything fine there. I wanted to make sure that my plug wires weren't causing the stumble, so I removed them all and put a small dab of DE in each one and ensured they were tight. (Marc said it's HIGHLY unlikely that the plugs are actually fouling.) Also unhooked the battery and removed and reseated the PROM that I had just installed.

Fired it up, it raced to 2000 again and hung there for about 2 minutes. Finally dropped off and sounded like it was just about to stall, when it jumped to 1200, then dropped to 900, then 1200, then 900, over and over again. Went for a drive of probably 2 miles, and the light-throttle stumble was DEFINITELY still there. Hammered it hard a few times and brought it up to temp. Pulled back in the garage and it was idling perfectly smoothly at 700ish. Shut it down for a few minutes and restarted and everything was fine. Went for another quick ride and no stumble. I hope this gremlin is gone for good but they sure are frustrating when they're completely random, here one moment and gone the next. I'd feel better if it hadn't reappeared after I made those few little adjustments, only to then disappear for no apparent reason.

Schrade · 08-11-2014

It IS possible for wireless log on internet, for Marc (or anyone else) to look at operating parameters, real time. NO special equipment necessary, except internet on both ends.

XfireZ51 · 08-11-2014

By any chance had you unplugged the IAC? Also, if not up to temp, it very likely will stumble. Be interesting to see how it starts again once its cold.

Schrade · 08-11-2014

... and I think the hesitation, that Marc says ALL LT5's have, is exacerbated by time, and having the wrong parameter being borderline - perhaps KS's case here...............................

KILLSHOTS · 08-11-2014

Quote:

Originally Posted by XfireZ51

By any chance had you unplugged the IAC? Also, if not up to temp, it very likely will stumble. Be interesting to see how it starts again once its cold.

No, hadn't touched the IAC. Agreed, I'm anxious to see what it does when it becomes cold again. Although, when both the stumble and high idle first occurred on Saturday, it was 105+ outside and the car was FULLY warmed up.

08-11-2014	#11
KILLSHOTS Join Date: Feb 2014 Location: AZ Posts: 860	Re: Problem o' the day... UPDATE: This afternoon, I went through and rechecked every vacuum connection that I could touch, including the entire PCV assembly and MAP. Everything fine there. I wanted to make sure that my plug wires weren't causing the stumble, so I removed them all and put a small dab of DE in each one and ensured they were tight. (Marc said it's HIGHLY unlikely that the plugs are actually fouling.) Also unhooked the battery and removed and reseated the PROM that I had just installed. Fired it up, it raced to 2000 again and hung there for about 2 minutes. Finally dropped off and sounded like it was just about to stall, when it jumped to 1200, then dropped to 900, then 1200, then 900, over and over again. Went for a drive of probably 2 miles, and the light-throttle stumble was DEFINITELY still there. Hammered it hard a few times and brought it up to temp. Pulled back in the garage and it was idling perfectly smoothly at 700ish. Shut it down for a few minutes and restarted and everything was fine. Went for another quick ride and no stumble. I hope this gremlin is gone for good but they sure are frustrating when they're completely random, here one moment and gone the next. I'd feel better if it hadn't reappeared after I made those few little adjustments, only to then disappear for no apparent reason.

08-11-2014	#12
Schrade Join Date: Dec 2012 Location: NC Posts: 1,786	Re: Problem o' the day... It IS possible for wireless log on internet, for Marc (or anyone else) to look at operating parameters, real time. NO special equipment necessary, except internet on both ends. __________________ I'm getting my snappics / threads removed blindly as fast as I can, to get in compliance with copyright / license TOS on the boards here (lots of FSM pages and other copyright / license violations on my part; sorry guys). And thanks to all the guys who didn't whine when I posted those FSM copyrighted / licensed stuff in my threads... ( :thumbsup: [b]and to think I complied with a mod's request to delete a pic of him in a Challenge Car in NCM Museum, so he wouldn't get in hot water)[/b] Thanks to several guys here for sending parts FREE; BearlyFlying, WeGone, Geezer, GoldCylon, and more there, TonyD, mike100, fletchusmc... 1990 #2794; 4L60e Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless, Power Effects 3" [IMG]https://lh5.googleusercontent.com/-GHpfzty7DVU/UQn-0Ru2xAI/AAAAAAAAA14/08mz1p4QLD4/s445/Screenshot-5.png[/IMG]

08-11-2014	#13
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,700	Re: Problem o' the day... By any chance had you unplugged the IAC? Also, if not up to temp, it very likely will stumble. Be interesting to see how it starts again once its cold. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

08-11-2014	#14
Schrade Join Date: Dec 2012 Location: NC Posts: 1,786	Re: Problem o' the day... ... and I think the hesitation, that Marc says ALL LT5's have, is exacerbated by time, and having the wrong parameter being borderline - perhaps KS's case here............................... __________________ I'm getting my snappics / threads removed blindly as fast as I can, to get in compliance with copyright / license TOS on the boards here (lots of FSM pages and other copyright / license violations on my part; sorry guys). And thanks to all the guys who didn't whine when I posted those FSM copyrighted / licensed stuff in my threads... ( :thumbsup: [b]and to think I complied with a mod's request to delete a pic of him in a Challenge Car in NCM Museum, so he wouldn't get in hot water)[/b] Thanks to several guys here for sending parts FREE; BearlyFlying, WeGone, Geezer, GoldCylon, and more there, TonyD, mike100, fletchusmc... 1990 #2794; 4L60e Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless, Power Effects 3" [IMG]https://lh5.googleusercontent.com/-GHpfzty7DVU/UQn-0Ru2xAI/AAAAAAAAA14/08mz1p4QLD4/s445/Screenshot-5.png[/IMG]