Chasing Hesitation/bog - Page 2 - ZR-1 Net Registry Forums

FixxerAuto · 07-05-2018

Yeah, i see your point... Maybe nitrogen or CO2 would be better...

Update: I went out and got on it at full throttle. Around 7000RPM you could feel some slight missing and it didn't feel like all the power was really there. But, at the top of first, i got a SES light that told me codes 22 and 46. TPS voltage low and VATS communication fault. Also, the next time i started the car, the idle was at 3000rpm. I had to limp home that way and when i got here, the idle was at 2000. So, i removed the IAC valve and put it in a rag, then shorted A to B on the ALDL. When i checked it, the pintle had come all the way out like it should. I reinstalled the IAC and the idle was back to 1000rpm as usual...

So, i am thinking that the high idle must have been in response to the TPS voltage discrepancy. So now i need to figure out if the problem is with the TPS or the wiring. I am guessing that it is the wiring because, i don't think a failed TPS would be intermittent. So i am contemplating on running new wires from the ECM to the TPS to avoid another Plenum pull... What do you guys think?

XfireZ51 · 07-05-2018

What you need to do is get a scantool and see how the TPS v reacts to input. A wiring issue would be a lower priority for me.
Also, you should not remove IAC and then have it extend. Good way to ruin an IAC. Multiple fault codes are a red flag for me about prom or ECM ground.

Ccmano · 07-06-2018

Do yourself a favor and get a factory service manual. Follow the diagnostic trees published there. There are diagnostic trees for both code diagnosis and symptom diagnosis. While getting the excellent advice available here is valuable, without a good understanding of what your doing your just guessing. In some cases you may do more damage if you not careful. Or like I have done you jump to conclusions that turn out to be false. Most of the time you will be dealing with component failure on these old cars. Once all the components have been ruled out and only then should you consider wiring issues and things like cold solder joints.

Or bring it me in Reno and we’ll get it sorted.
H

07-05-2018	#11
FixxerAuto Join Date: Jun 2018 Location: Nampa,ID Posts: 6	Re: Chasing Hesitation/bog Yeah, i see your point... Maybe nitrogen or CO2 would be better... Update: I went out and got on it at full throttle. Around 7000RPM you could feel some slight missing and it didn't feel like all the power was really there. But, at the top of first, i got a SES light that told me codes 22 and 46. TPS voltage low and VATS communication fault. Also, the next time i started the car, the idle was at 3000rpm. I had to limp home that way and when i got here, the idle was at 2000. So, i removed the IAC valve and put it in a rag, then shorted A to B on the ALDL. When i checked it, the pintle had come all the way out like it should. I reinstalled the IAC and the idle was back to 1000rpm as usual... So, i am thinking that the high idle must have been in response to the TPS voltage discrepancy. So now i need to figure out if the problem is with the TPS or the wiring. I am guessing that it is the wiring because, i don't think a failed TPS would be intermittent. So i am contemplating on running new wires from the ECM to the TPS to avoid another Plenum pull... What do you guys think? Last edited by FixxerAuto; 07-05-2018 at 08:51 PM.

07-05-2018	#12
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,701	Re: Chasing Hesitation/bog What you need to do is get a scantool and see how the TPS v reacts to input. A wiring issue would be a lower priority for me. Also, you should not remove IAC and then have it extend. Good way to ruin an IAC. Multiple fault codes are a red flag for me about prom or ECM ground. __________________ [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

07-06-2018	#13
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Chasing Hesitation/bog Do yourself a favor and get a factory service manual. Follow the diagnostic trees published there. There are diagnostic trees for both code diagnosis and symptom diagnosis. While getting the excellent advice available here is valuable, without a good understanding of what your doing your just guessing. In some cases you may do more damage if you not careful. Or like I have done you jump to conclusions that turn out to be false. Most of the time you will be dealing with component failure on these old cars. Once all the components have been ruled out and only then should you consider wiring issues and things like cold solder joints. Or bring it me in Reno and we’ll get it sorted. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.