01-17-2019 | #11 |
Join Date: Oct 2013
Location: Spokane Valley, WA
Posts: 115
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Re: 1990 ZR-1 Hesitation when full Power
Mike, Long time since we last talked. Yup, surprised about finding the catalyst collapsed. After all the troubleshooting we did and not getting the stumble/lag resolved, especially when real-time testing with your Tech. I only stumbled on it when shelving the old exhaust manifolds and hearing the rattling around in the cat. Looking back, it was a classic symptom of blocked exhaust.
Recently had a cousin with the same symptoms on his daily driver and he found the catalyst collapsed in the converter. Replaced it and now runs like it should. In chasing the symptoms you and/or I validated the operation of the secondary vacuum system, the FI drivers, replaced the injectors with FIC injectors, replaced coils, replaced O2 sensors, upgraded the fuel pumps, validated the secondary and FI signals from the ECM, and the prom. Not all for not but a lot of time and money. Again, thanks for all the help. Tony - Tnova |
01-17-2019 | #12 | |
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Re: 1990 ZR-1 Hesitation when full Power
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
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01-24-2019 | #13 |
Join Date: Dec 2018
Location: Long Beach, CA
Posts: 73
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Re: 1990 ZR-1 Hesitation when full Power
Alright guys, im back. All injectors tested to be 14.7-14.8 ohms, the secondaries freely open with 10 hg pressure, the reservoir holds a vacuum, and so does the solenoid. Vacuum pumps up to 15 hg, and cycles every 15-30 seconds, no obvious vacuum leak. I read online to jump the C17 connector pink wire; but I tried to jump what I thought it was and it just sparked. Any advice on what to try next? All of the coils also gave me 5.5-5.6 ohms when set to the 20K setting.
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01-24-2019 | #14 |
Join Date: Dec 2018
Location: Long Beach, CA
Posts: 73
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Re: 1990 ZR-1 Hesitation when full Power
Just tested the solenoid, jumped the C17 wire, and the secondaries are opening smoothly
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01-24-2019 | #15 |
Join Date: Dec 2018
Location: Long Beach, CA
Posts: 73
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Re: 1990 ZR-1 Hesitation when full Power
So when I reassembled everything, the right bank of secondaries got caught up a bit, and I noticed that the tab leaving the vaccum thing was bent, bent it straight and it seems to be a lot smoother opening. Resealed the PCV while I was in there, and blocked off all the coolant ports.
Does the injector housing gasket need sealant on it? Torque specs on the Injector housing, and PCV cover? Also, where can I find a shop manual, as I can't find any of this stuff online. Thanks, Francesco |
01-25-2019 | #16 | |
Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,797
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Re: 1990 ZR-1 Hesitation when full Power
Quote:
Since you have coolant in Injector Housing I always use a bit of Permatex on both sides of the Injector Housing Gasket. Since you blocked coolant (at Injector Housing??) you would not have coolant through TB so I do NOT use sealant on Plenum Gasket and do not torque Plenum as much as stated in Post #8 of -Solutions-. All of this "stuff" is in my Signature......just left click any item. |
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04-10-2019 | #17 |
Join Date: Dec 2018
Location: Long Beach, CA
Posts: 73
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Re: 1990 ZR-1 Hesitation when full Power
Been a while, but I'm back. Ended up picking a MT2500 snap on scanner, and here are my results, let me know if anything seems out of wack. Car seems to hunt for an idle like crazy sometimes, and has a misfire, which you can hear out of the right exhaust bank at idle.
According to the scanner, the TPS is at 0.44V and should be a couple millivolts higher. Could this cause an issue? IAC counts at idle is 0, but when revving it it goes to 30 and stays. It mentioned some starter test for AC voltage leak down, but I don't think I have that issue. Other than that, everything seemed normal. Going to do a drive and see if I can get anything else to pop up. Also to the people saying cats, I smacked them and heard no rattling, and when I did my clutch it looked pretty normal to me, I'm not sure if you can notice a ruined cat vs a healthy one though. Last edited by frantinoro; 04-10-2019 at 12:03 PM. |
04-10-2019 | #18 | |
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
Quote:
Go through this Haibeck article on vacuum leaks before you start. H http://www.zr1specialist.com/HAT%20W...5%20Engine.pdf
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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. |
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04-10-2019 | #19 |
Join Date: Dec 2018
Location: Long Beach, CA
Posts: 73
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Re: 1990 ZR-1 Hesitation when full Power
The secondary system was gone over, and had no leaks. I have plastic wire tied every single connection to minimize leaks. I will test it again though. For the main leak area, the IH has been resealed, and the plenum as well. Throttle body was resealed via the Jerry's Gaskets kit. PCV grommet was replaced, and the map sensor definitely isn't leaking. Are there other areas of leakage I should be concerned with?
EDIT: Everywhere I've looked the ZR-1 TPS shouldn't be adjustable. But mine looks like it is. Is it? Last edited by frantinoro; 04-10-2019 at 01:15 PM. |
04-10-2019 | #20 |
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
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Re: 1990 ZR-1 Hesitation when full Power
The TPS sensor should have slotted mounting holes. If not you have the wrong sensor. You simply loosen the mounting screws slightly and rotate the entire sensor slightly to get the right voltage. Should look like this....
H
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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. |
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