Bogs for a second and then takes off - ZR-1 Net Registry Forums

StickWalker · 09-14-2014

First off, I replaced the injectors with new FIC injectors and pinned the secondaries open with Hiabecks chip for 2ndy deletion. I did this swap around 500 miles or so ago and also changed the fuel filter at the same time.

Now the issue starts after a few minutes of driving before that it runs great. (Never has an issue from a stop) When the issue occurs I am in a gear coasting (foot off the gas) at around 2-4000 rpm, and when I hit the gas pedal it bogs down for a second or so and then takes off and pulls to 7000 no problem. It only ocurrs after a moment of high vacuum once its warm. I have replaced the MAP sensor and hose with no change, drove around with a fuel pressure gauge on the windshield which shows around 41 psi with the foot off the gas, and goes up to 51 when I press on the gas.

I've checked for vacuum leaks and cant find any. The only thing I have noticed is that #4 cylinder plug seems like it's running rich, Ohm's 16 when cold, havent checked when hot.

If anyone has any other ideas without just throwing parts at I would appreciate it.

Thanks,
Don

Roadster · 09-14-2014

IMO, it may depend on what gear you are in at the time you hit the gas pedal, and the speed that you are traveling. When I first got my Z 6 months ago, I noticed a similar situation, but found out that if you drop a gear or two and bring up the r's, no problem. I thought that at any gear with the LT5 it would be instant, and again depends on your speed and what gear you are in.

I don't think that one plug even if running rich would cause that situation, IMO, it would have to be loaded and fouled out for you to feel anything.

Just had ours out today, always a great ride.....have fun.....

XfireZ51 · 09-14-2014

Did this happen before the 2ndaries were deleted?

StickWalker · 09-14-2014

Dom, this didnt happen before the secondaries were deleted, and there is not bogging for 5 minutes or so after starting it. Then ,only after coasting with the foot off the gas and like your slowing down for a light and then you get back on it, it falls on its face for a second and then takes off like it never happened.

Don

We Gone · 09-14-2014

I'm sure the secondary injectors are not on in the first 5 min. after start up as the temps have to be up before they will go active. This may be why you don't have an issue in the first 5 min. or with no secondary's are the injectors all working from start-up?

StickWalker · 09-15-2014

Steve, I believe the secondaries are all on all the time with the deletion chip. Plus this didnt happen for the first 3-500 miles after I deleted them. After searching some older threads I'm wondering whether an O2 sensor has died since the car has 100K miles on it.

Don

Dynomite · 10-16-2014

I have a 91' with secondaries eliminated and RC Injectors.

Three 90's all with RC injectors and secondaries including starter reconditioned like new.

All four ZR-1s have Haibeck chips.
All four have TB coolant blocked at Injector Housings.
All four have the Starter Relay installed.
All four have Jerry's gaskets and SS bolts.
All four have full compliment of Carter Bling

All four accelerate like greased lightning with NO bogging or hesitation in any gear at all RPMs

Oh.........And a 90' (L98) with Haibeck Chip......also greased lightning

WVZR-1 · 10-16-2014

Quote:

Originally Posted by Dynomite

All four accelerate like grease lightening with NO bogging or hesitation in any gear at all RPMs

Oh.........And a 90' (L98) with Haibeck Chip......also grease lightening

Just what is "grease lightening"?

I've seen "GREASED LIGHTNING" used in reference to maybe fast or speedy BUT "LIGHTENING" confuses me.

Dynomite · 10-16-2014

Quote:

Originally Posted by WVZR-1

Just what is "grease lightening"?

I've seen "GREASED LIGHTNING" used in reference to maybe fast or speedy BUT "LIGHTENING" confuses me.

I am a poor speller

Just got done making a set of New Oil Cooler SS Braided Hoses with Aeroquip re-usable fittings for a 90' ZR-1 and they fit perfectly first try.
I cannot spell "Aeroquip re-usable" sometimes but the hoses are perfect

I will take a photo tomorrow after I degrease (here I go again

) the little bit of oil spilled while doing the change over to SS Braided hoses.

I will try some runs tomorrow also to see if I can get it to bog or hesitate at all.

WVZR-1 · 10-16-2014

Quote:

Originally Posted by Dynomite

I am a poor speller

LOL - me too I believe

09-14-2014	#1
StickWalker Join Date: Jan 2012 Location: Delaware Posts: 20	Bogs for a second and then takes off First off, I replaced the injectors with new FIC injectors and pinned the secondaries open with Hiabecks chip for 2ndy deletion. I did this swap around 500 miles or so ago and also changed the fuel filter at the same time. Now the issue starts after a few minutes of driving before that it runs great. (Never has an issue from a stop) When the issue occurs I am in a gear coasting (foot off the gas) at around 2-4000 rpm, and when I hit the gas pedal it bogs down for a second or so and then takes off and pulls to 7000 no problem. It only ocurrs after a moment of high vacuum once its warm. I have replaced the MAP sensor and hose with no change, drove around with a fuel pressure gauge on the windshield which shows around 41 psi with the foot off the gas, and goes up to 51 when I press on the gas. I've checked for vacuum leaks and cant find any. The only thing I have noticed is that #4 cylinder plug seems like it's running rich, Ohm's 16 when cold, havent checked when hot. If anyone has any other ideas without just throwing parts at I would appreciate it. Thanks, Don

09-14-2014	#2
Roadster Join Date: Mar 2014 Location: Warrington PA Posts: 1,913	Re: Bogs for a second and then takes off IMO, it may depend on what gear you are in at the time you hit the gas pedal, and the speed that you are traveling. When I first got my Z 6 months ago, I noticed a similar situation, but found out that if you drop a gear or two and bring up the r's, no problem. I thought that at any gear with the LT5 it would be instant, and again depends on your speed and what gear you are in. I don't think that one plug even if running rich would cause that situation, IMO, it would have to be loaded and fouled out for you to feel anything. Just had ours out today, always a great ride.....have fun..... __________________ Tom 1994 ZR-1 #009 "captured test fleet car" 1974 LS4 454 Vert 1982 L83 CFI...now a retired "dd"....Sold WAZOO Member

09-14-2014	#3
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,696	Re: Bogs for a second and then takes off Did this happen before the 2ndaries were deleted? __________________ [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

09-14-2014	#5
We Gone Join Date: Apr 2004 Location: ATL. GA. Posts: 2,168	Re: Bogs for a second and then takes off I'm sure the secondary injectors are not on in the first 5 min. after start up as the temps have to be up before they will go active. This may be why you don't have an issue in the first 5 min. or with no secondary's are the injectors all working from start-up? __________________ Steve 1990 Steel Blue/Black #2355 1990 Red/Red #1473 1991 Quasar /Black #118 Sold 1991 Turquoise/Black #766 Parted Out 1993 Yellow/White #179 Sold 1990 Black/Gray #1361 Headers/4:10s Sold Last edited by We Gone; 09-14-2014 at 08:12 PM.

09-15-2014	#6
StickWalker Join Date: Jan 2012 Location: Delaware Posts: 20	Re: Bogs for a second and then takes off Steve, I believe the secondaries are all on all the time with the deletion chip. Plus this didnt happen for the first 3-500 miles after I deleted them. After searching some older threads I'm wondering whether an O2 sensor has died since the car has 100K miles on it. Don

10-16-2014	#7
Dynomite Join Date: Aug 2009 Location: South Dakota/California Posts: 3,791	Greased Lightning I have a 91' with secondaries eliminated and RC Injectors. Three 90's all with RC injectors and secondaries including starter reconditioned like new. All four ZR-1s have Haibeck chips. All four have TB coolant blocked at Injector Housings. All four have the Starter Relay installed. All four have Jerry's gaskets and SS bolts. All four have full compliment of Carter Bling All four accelerate like greased lightning with NO bogging or hesitation in any gear at all RPMs Oh.........And a 90' (L98) with Haibeck Chip......also greased lightning __________________ Left Clickable links -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 10-16-2014 at 09:01 PM.