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Fails to accelerate whit the lever in Full mode ZR1 1992

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Fails to accelerate whit the lever in Full mode ZR1 1992

 
Old 04-16-2019, 11:11 PM
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Leo79
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Default Fails to accelerate whit the lever in Full mode ZR1 1992

My C4 ZR1 has a fault that when put in Power mode to accelerate the car more, does not accelerate evenly, appears to be an electrical failure.
Using the car in normal mode does not present failure to accelerate.
I've Already changed the coils, I'll try to change the spark plugs. Which Ones do I recommend the double platinum code 19301811?
It occurs to them that it can come from another part: for example computer? I bought the car and the previous owner gave it to me with a module that seems to be a booster of the car, but is not placed at this time.
Except for this defect, the car is spectacular.

Thank You all in advance for the answers and excuse my English, the guilty is Google Translate :-)

Last edited by Leo79; 04-17-2019 at 10:37 AM.
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Old 04-17-2019, 11:21 AM
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ccmano
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Coils and ignition are less likely since you say it runs well in standard mode. Most likely is your secondary throttle system is not working due to a vacuum leak from a failed system component. A failed secondary fuel pump is also a possibility. Is the “SES” light on and does it show any codes? Do you know how to check for codes?

Give us a more detailed description of what happens when you accelerate. Failed secondary injectors are a possibility too.

If you have some technical skills these items will be easy to fix once you learn the system a bit. Get a factory service manual. If you don’t your better off finding a shop that knows LT5 engines(not easy) or at least another local Z owner with some skills.
Good luck and keep us posted. This doesn’t sound too serious.
H



Here’s how to check for codes.
http://tech.corvettecentral.com/2011...trouble-codes/
Here’s how to check the secondary system.
http://www.zr1specialist.com/HAT%20W...%20Working.pdf

Heres a list of known shops that work on LT5 engines.
http://www.zr1.net/forum/showthread.php?t=28634

Last edited by ccmano; 04-17-2019 at 11:25 AM.
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Old 04-17-2019, 11:45 AM
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[color=rgba(0, 0, 0, 0.87)]First of all, I greatly appreciate your response and the time it took.[/color]
[color=rgba(0, 0, 0, 0.87)]At this moment I am on a trip so I can not check what you ask me, but I remember that sometimes a light comes on but I do not know what code it refers to. I changed the coils. I have to change the spark plugs, I bought AC DELCO platinum the code seems to be 41-950 (19301811), are they the ones that recommended me, do you think is correct or do you recommend others?[/color]
[color=rgba(0, 0, 0, 0.87)]I will take into account everything you tell me and as soon as I return I will give you an answer.[/color]
[color=rgba(0, 0, 0, 0.87)]I will check the forum if they recommend a mechanical workshop in Miami-Florida that serves Vettes[/color]


Originally Posted by ccmano View Post
Coils and ignition are less likely since you say it runs well in standard mode. Most likely is your secondary throttle system is not working due to a vacuum leak from a failed system component. A failed secondary fuel pump is also a possibility. Is the “SES” light on and does it show any codes? Do you know how to check for codes?

Give us a more detailed description of what happens when you accelerate. Failed secondary injectors are a possibility too.

If you have some technical skills these items will be easy to fix once you learn the system a bit. Get a factory service manual. If you don’t your better off finding a shop that knows LT5 engines(not easy) or at least another local Z owner with some skills.
Good luck and keep us posted. This doesn’t sound too serious.
H



Here’s how to check for codes.
http://tech.corvettecentral.com/2011...trouble-codes/
Here’s how to check the secondary system.
http://www.zr1specialist.com/HAT%20W...%20Working.pdf

Heres a list of known shops that work on LT5 engines.
http://www.zr1.net/forum/showthread.php?t=28634

Last edited by Leo79; 04-18-2019 at 03:17 PM.
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Old 04-18-2019, 09:20 PM
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ccmano
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As I mentioned coil or spark plug issues are less likely to be the issue. A good test is to drive at low speed in standard mode, put the car in a high gear like 4th or 5th and accelerate slowly. If the engine starts to shake a coil, wire or plug is likely the problem.

To my knowledge the AC 41-950 is not a correct spark plug for the LT5. Correct is the AC 41-602 copper core or the AC 41-800 platinum.
Keep us posted and good luck
H
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Old 04-19-2019, 08:36 AM
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Paul Workman
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100% with Hans (aka ccmano). Just to ask a question and share some things I found with my ZR-1:

IF the SES light comes on at all, the secondaries WILL NOT open. And, as Hans points out, it seems to be isolated to the secondaries. And, if the SES light comes on intermittently, here are some more things to consider:

The stock injectors of 1990 thru 1992 ZR-1s were NOT alcohol tolerant. The ALL will need to be replaced with some that are: FIC or Accel #150821 (Summit Racing) will set you up nicely.
  • Verify proper current draw by measuring amperage between the batter (+) and the diagnostic test point (the RED 2-3 cm long test wire and connector jutting out of the big wire loom, near the windshield motor, nest to the firewall). With the ignition switch OFF, you should measure between 8 and 10 AMPERES total for the two pumps. A reading of 4-5 amps indicates one of the pumps IS NOT working.
  • And, also measure fuel pressure at the Schrader valve on the front of the passenger side fuel rail (near the alternator). Pressure with both pumps active and the ignition switch OFF should read 53± psi.
  • Many of the "accordion" air ducts between the air filter and the throttle body horn sometimes collapse during full acceleration, pinching off the air causing the motor to loos much of its power. Marc Haibeck makes some wire hoops to insert inside that hose to prevent it from collapsing. Or, you can fashion an aluminum sleeve to fit inside of the hose to keep it from collapsing and smooth the air flow into the throttle body. Or, Jerry's Gaskets can perhaps supply you with a new hose.

All of these things are fairly common to ZR-1s that have some age on them. But, once addressed (fixed) your car will have no further issues with those items. And, all of them can be easily done w/o going to a mechanic for service.

Also, you might consider joining the ZR-1 Net Registry. There is a good chance of finding a member near you that can assist you with a variety of "new car" items!

WELCOME TO THE BROTHERHOOD OF THE BEAST!
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Old 04-19-2019, 10:49 AM
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hey welcome, it is an addiction, lol

I want to add that there are vacuum canisters, one on each bank that pull the secondaries open under power in full power mode. If they go bad/fail to open the secondaries fully, but do not fail enough to set off a secondary vacuum code, this could be your problem as well. keep in mind that one or both sides could be bad, giving different degrees of power loss. In my case, the engine/air temperature affected how well the drivers canister sealed and power loss was greater the warmer the motor got. they sit in the valley, under the plenum.

easy diagnosis, vacuum the can and see if it leaks/operates at all. hard part is to find a good one, they are not reproduced to my knowledge.

there is a test you can do to activate the vacuum. you have to ground a terminal in the ECU harness and you should see the secondary mechanics open and close by looking down into the plenum with the plenum in place...this will show an overall leak, you probably will not be able to tell which side....or pull the plenum and get vacuum to the back of them.

John
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Old 04-21-2019, 09:46 AM
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Leo79
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Hello friends! You are very kind with all your answers! I am new with the Vette and in the USA too, so "chapeau" for your comments I want to have 10 points. It complicates me that I do not speak English well and sometimes technically I do not understand. As I can do to join the group you mention (NET REGISTRY), I would like to connect with people who are knowledgeable in Vettes and who are in Miami / Florida. I will ask in another post about it. Many thanks to all friends!

Originally Posted by Paul Workman View Post
100% with Hans (aka ccmano). Just to ask a question and share some things I found with my ZR-1:

IF the SES light comes on at all, the secondaries WILL NOT open. And, as Hans points out, it seems to be isolated to the secondaries. And, if the SES light comes on intermittently, here are some more things to consider:

The stock injectors of 1990 thru 1992 ZR-1s were NOT alcohol tolerant. The ALL will need to be replaced with some that are: FIC or Accel #150821 (Summit Racing) will set you up nicely.
  • Verify proper current draw by measuring amperage between the batter (+) and the diagnostic test point (the RED 2-3 cm long test wire and connector jutting out of the big wire loom, near the windshield motor, nest to the firewall). With the ignition switch OFF, you should measure between 8 and 10 AMPERES total for the two pumps. A reading of 4-5 amps indicates one of the pumps IS NOT working.
  • And, also measure fuel pressure at the Schrader valve on the front of the passenger side fuel rail (near the alternator). Pressure with both pumps active and the ignition switch OFF should read 53± psi.
  • Many of the "accordion" air ducts between the air filter and the throttle body horn sometimes collapse during full acceleration, pinching off the air causing the motor to loos much of its power. Marc Haibeck makes some wire hoops to insert inside that hose to prevent it from collapsing. Or, you can fashion an aluminum sleeve to fit inside of the hose to keep it from collapsing and smooth the air flow into the throttle body. Or, Jerry's Gaskets can perhaps supply you with a new hose.

All of these things are fairly common to ZR-1s that have some age on them. But, once addressed (fixed) your car will have no further issues with those items. And, all of them can be easily done w/o going to a mechanic for service.

Also, you might consider joining the ZR-1 Net Registry. There is a good chance of finding a member near you that can assist you with a variety of "new car" items!

WELCOME TO THE BROTHERHOOD OF THE BEAST!
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