First Plenum Removal
Thread Starter
Cruising
Joined: Mar 2006
Posts: 11
Likes: 0
From: Eagan MN
First Plenum Removal
I'm going to pull my plenum for the first time and need some advice from the Pros here at the Forum. My Z is a 92 with 50,000 + on it. I would like some advice on what I should be replacing at this time. I've had the car for three years and don't have complete records of its maintance. I've already bought the injectors for FIC and Mark Heibecks CD. Would it be smart to replace spark plug wires and coils at this time as well? Anysuggestions on additonal items or places to buy parts, would be appreciated. 
Burning Brakes
Joined: May 2001
Posts: 895
Likes: 1
From: Austin TX
Now would be a good time to check over the secondary vacuum system. Look at all the hoses and connectors, and replace what looks suspect.
Wires are a good idea. There are some instructions on this forum about testing the coils. But, some people have tested them good and they are still bad.
When I replaced all my coils, they didn't have all 4 in stock, and I had to wait a few days. But, I am the type of person who replaces things since I am there, and that is what I did.
Wires are a good idea. There are some instructions on this forum about testing the coils. But, some people have tested them good and they are still bad.
When I replaced all my coils, they didn't have all 4 in stock, and I had to wait a few days. But, I am the type of person who replaces things since I am there, and that is what I did.
Tech Contributor
Joined: Aug 2006
Posts: 9,933
Likes: 103
From: Peoria Arizona.. Resident Gold Cylon
I'm going to pull my plenum for the first time and need some advice from the Pros here at the Forum. My Z is a 92 with 50,000 + on it. I would like some advice on what I should be replacing at this time. I've had the car for three years and don't have complete records of its maintance. I've already bought the injectors for FIC and Mark Heibecks CD. Would it be smart to replace spark plug wires and coils at this time as well? Anysuggestions on additonal items or places to buy parts, would be appreciated.
Drifting
Joined: Jul 2002
Posts: 1,932
Likes: 116
From: LPE Aerobody 416 ci, Oklahoma
New injectors should come with all the o-rings you need EXCEPT for the lower o-ring seal inside the injector housing on the primaries. I recommend these o-rings for replacement bucause they are old and no longer seal as effectively as new ones. Lower o-rings leaking will result in vacuum leaks & idle problems.
Regarding secondary actuators: If they look like they are installed incorrectly with the arm at an angle, leave them alone as long as the secondaries were working OK before you pulled the plenum. The actuator can be rotated to make the arm straight to the linkage but the actuator will not work as smoothly as before.
Tighten the crankcase breather box bolts. They are probably loose and seeping oil into the valley.
Obtain some silicone grease and use it on all the electrical connection weather seals when you go back together. It is also useful on the plug wires at the coils and a little on the plug boot makes for a better seal and easier to install & remove.
LT5 coils have a history of failures ranging from discreet to total. It doesn't seem to be related to mileage either. Replacement depends on how big a deal pulling the plenum is to you. If you do decide to replace the coils, remember the silicone grease on the coil base contacts & seals. I would advise staying away from the big name aftermarket coils and go with Delco.
Plug wires? I would put in the same category as coils. It takes a plenum pull to replace them. Your call. I agree completely with Goldcylon's recommendation on wires.
You can go deeper if you want, but it requires starter removal to clean the valley and make sure the drain hole is clear.
PS: I can provide all the LT5 gaskets & seals you might need. www.jerrysgaskets.com
Regarding secondary actuators: If they look like they are installed incorrectly with the arm at an angle, leave them alone as long as the secondaries were working OK before you pulled the plenum. The actuator can be rotated to make the arm straight to the linkage but the actuator will not work as smoothly as before.
Tighten the crankcase breather box bolts. They are probably loose and seeping oil into the valley.
Obtain some silicone grease and use it on all the electrical connection weather seals when you go back together. It is also useful on the plug wires at the coils and a little on the plug boot makes for a better seal and easier to install & remove.
LT5 coils have a history of failures ranging from discreet to total. It doesn't seem to be related to mileage either. Replacement depends on how big a deal pulling the plenum is to you. If you do decide to replace the coils, remember the silicone grease on the coil base contacts & seals. I would advise staying away from the big name aftermarket coils and go with Delco.
Plug wires? I would put in the same category as coils. It takes a plenum pull to replace them. Your call. I agree completely with Goldcylon's recommendation on wires.
You can go deeper if you want, but it requires starter removal to clean the valley and make sure the drain hole is clear.
PS: I can provide all the LT5 gaskets & seals you might need. www.jerrysgaskets.com
Instructor
Joined: Feb 2007
Posts: 210
Likes: 6
From: Ann Arbor Michigan
Plenum Pull
Got your gaskets, Jerry - thanks for the excellent service!
Folks,
Like Sodak, I am about to do my first plenum pull primarily to replace the injectors as a precautionary measure. Having read an excellent thread that's been running for three years on the ZR-1 Net Regisrty site (titled: "91 ZR-1 Cutting out under load"), I purchased four ignition coils to put as much new stuff as possible under the plenum while I have it removed.
I followed a lead on the Registry site and purchased what were advertised as "D545" coils (supposedly GM replacements). Now that I have them, the part number on the replacements is slightly different (10482928). Furthermore, the primarly windings are measuring 1.7 ohms vs the .5 ohms specified by GM. The secondary windings seem ok (the new ones are measuring 5.6K to 5.8K which is close to the 5.6-5.7K quoted by GM).
I am about to pull the plenum, and I wondering whether I should swap the coils or not. Any words of wisdom from brothers that have been down a similar road?
Thanks,
Bob
Folks,
Like Sodak, I am about to do my first plenum pull primarily to replace the injectors as a precautionary measure. Having read an excellent thread that's been running for three years on the ZR-1 Net Regisrty site (titled: "91 ZR-1 Cutting out under load"), I purchased four ignition coils to put as much new stuff as possible under the plenum while I have it removed.
I followed a lead on the Registry site and purchased what were advertised as "D545" coils (supposedly GM replacements). Now that I have them, the part number on the replacements is slightly different (10482928). Furthermore, the primarly windings are measuring 1.7 ohms vs the .5 ohms specified by GM. The secondary windings seem ok (the new ones are measuring 5.6K to 5.8K which is close to the 5.6-5.7K quoted by GM).
I am about to pull the plenum, and I wondering whether I should swap the coils or not. Any words of wisdom from brothers that have been down a similar road?
Thanks,
Bob
Drifting
Joined: Jul 2002
Posts: 1,932
Likes: 116
From: LPE Aerobody 416 ci, Oklahoma
CAVEAT: I'm no expert on the subject but think I understand the principal according to the following tech article.
Transformers/Ignition coils
Transformers step-up (increase), step-down (decrease), or pass-through (same level) AC voltage or pulsed DC voltage. A basic power rule applies to transformers; power-in equals power-out. The unit of measure for Power is the Watt. 1 Watt = 1 Volt x 1 Amp.
A transformer has three main components:
An iron core - The iron core is wrapped with two separate coils of wire. The job of the iron core is to strengthen the magnetic fields of the transformer.
Primary winding - The input side of the transformer. This coil of wire is tightly wrapped around the iron core of the transformer.
Secondary winding - The output side of the transformer. This coil of wire is tightly wrapped around the primary winding of the transformer.
There are three basic types of transformers:
Step-up transformer - The primary coil winding has less windings of wire than the secondary coil does. A 1:2 step-up transformer has half as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 24 V AC will be induced into the secondary winding, however, the output amperage will be cut in half to 6 amps.
Step-down Transformer. - The primary coil winding has more windings of wire than the secondary coil does. A 2:1 step-down transformer has twice as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 6 V AC will be induced into the secondary winding, however, the output amperage will be doubled to 24 amps.
Pass-through transformer - In a 1:1 transformer, the primary coil winding has just as many windings of wire as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 12 V AC will be induced into the secondary winding, and the output amperage will be 12 amps. The advantage of a 1:1 transformer is that there is not a direct electrical connection between the two coils. If one side of the circuit gets short circuited, the other side will remain isolated.
Examples of transformer use on automobiles:
Ignition coils - An ignition coil is an example of a step-up transformer, the primary coil input voltage is 12-15 V and the secondary output voltage is 20-60 kV. This means for every primary coil winding there are at least 2000 secondary windings. This also means that the output amperage will be at least 2000 times smaller than the input amperage. Secondary ignition voltage is high voltage, but amperage is low.
Since only resistance is known and number of windings is unknown, I assume that winding wire size & type is the same, therefore resistance is a function of length of wire in the windings.
I interpret your findings to show that the resistance of the primary windings in the eBay coil is 3.4 times that of the OEM LT5 coil, meaning it has more windings. If the resistance of the primary windings is higher and the secondary windings resistance is the same, that means the voltage output would be lower than the OEM LT5 coil, i.e. coil discharge voltage is not as high as the OEM LT5 coil.
My non-expert opinion, don't use them. The spark is not as hot.
However, I do have my flame suit on!
Transformers/Ignition coils
Transformers step-up (increase), step-down (decrease), or pass-through (same level) AC voltage or pulsed DC voltage. A basic power rule applies to transformers; power-in equals power-out. The unit of measure for Power is the Watt. 1 Watt = 1 Volt x 1 Amp.
A transformer has three main components:
An iron core - The iron core is wrapped with two separate coils of wire. The job of the iron core is to strengthen the magnetic fields of the transformer.
Primary winding - The input side of the transformer. This coil of wire is tightly wrapped around the iron core of the transformer.
Secondary winding - The output side of the transformer. This coil of wire is tightly wrapped around the primary winding of the transformer.
There are three basic types of transformers:
Step-up transformer - The primary coil winding has less windings of wire than the secondary coil does. A 1:2 step-up transformer has half as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 24 V AC will be induced into the secondary winding, however, the output amperage will be cut in half to 6 amps.
Step-down Transformer. - The primary coil winding has more windings of wire than the secondary coil does. A 2:1 step-down transformer has twice as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 6 V AC will be induced into the secondary winding, however, the output amperage will be doubled to 24 amps.
Pass-through transformer - In a 1:1 transformer, the primary coil winding has just as many windings of wire as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 12 V AC will be induced into the secondary winding, and the output amperage will be 12 amps. The advantage of a 1:1 transformer is that there is not a direct electrical connection between the two coils. If one side of the circuit gets short circuited, the other side will remain isolated.
Examples of transformer use on automobiles:
Ignition coils - An ignition coil is an example of a step-up transformer, the primary coil input voltage is 12-15 V and the secondary output voltage is 20-60 kV. This means for every primary coil winding there are at least 2000 secondary windings. This also means that the output amperage will be at least 2000 times smaller than the input amperage. Secondary ignition voltage is high voltage, but amperage is low.
.....the primarly windings are measuring 1.7 ohms vs the .5 ohms specified by GM. The secondary windings seem ok (the new ones are measuring 5.6K to 5.8K which is close to the 5.6-5.7K quoted by GM).
Since only resistance is known and number of windings is unknown, I assume that winding wire size & type is the same, therefore resistance is a function of length of wire in the windings.
I interpret your findings to show that the resistance of the primary windings in the eBay coil is 3.4 times that of the OEM LT5 coil, meaning it has more windings. If the resistance of the primary windings is higher and the secondary windings resistance is the same, that means the voltage output would be lower than the OEM LT5 coil, i.e. coil discharge voltage is not as high as the OEM LT5 coil.
My non-expert opinion, don't use them. The spark is not as hot.
However, I do have my flame suit on!
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Verdad Gallardo
Pro
Joined: Sep 2008
Posts: 541
Likes: 0
From: Colleyville Texas
CAVEAT: I'm no expert on the subject but think I understand the principal according to the following tech article.
Transformers/Ignition coils
Transformers step-up (increase), step-down (decrease), or pass-through (same level) AC voltage or pulsed DC voltage. A basic power rule applies to transformers; power-in equals power-out. The unit of measure for Power is the Watt. 1 Watt = 1 Volt x 1 Amp.
A transformer has three main components:
An iron core - The iron core is wrapped with two separate coils of wire. The job of the iron core is to strengthen the magnetic fields of the transformer.
Primary winding - The input side of the transformer. This coil of wire is tightly wrapped around the iron core of the transformer.
Secondary winding - The output side of the transformer. This coil of wire is tightly wrapped around the primary winding of the transformer.
There are three basic types of transformers:
Step-up transformer - The primary coil winding has less windings of wire than the secondary coil does. A 1:2 step-up transformer has half as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 24 V AC will be induced into the secondary winding, however, the output amperage will be cut in half to 6 amps.
Step-down Transformer. - The primary coil winding has more windings of wire than the secondary coil does. A 2:1 step-down transformer has twice as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 6 V AC will be induced into the secondary winding, however, the output amperage will be doubled to 24 amps.
Pass-through transformer - In a 1:1 transformer, the primary coil winding has just as many windings of wire as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 12 V AC will be induced into the secondary winding, and the output amperage will be 12 amps. The advantage of a 1:1 transformer is that there is not a direct electrical connection between the two coils. If one side of the circuit gets short circuited, the other side will remain isolated.
Examples of transformer use on automobiles:
Ignition coils - An ignition coil is an example of a step-up transformer, the primary coil input voltage is 12-15 V and the secondary output voltage is 20-60 kV. This means for every primary coil winding there are at least 2000 secondary windings. This also means that the output amperage will be at least 2000 times smaller than the input amperage. Secondary ignition voltage is high voltage, but amperage is low.
Since only resistance is known and number of windings is unknown, I assume that winding wire size & type is the same, therefore resistance is a function of length of wire in the windings.
I interpret your findings to show that the resistance of the primary windings in the eBay coil is 3.4 times that of the OEM LT5 coil, meaning it has more windings. If the resistance of the primary windings is higher and the secondary windings resistance is the same, that means the voltage output would be lower than the OEM LT5 coil, i.e. coil discharge voltage is not as high as the OEM LT5 coil.
My non-expert opinion, don't use them. The spark is not as hot.
However, I do have my flame suit on!
Transformers/Ignition coils
Transformers step-up (increase), step-down (decrease), or pass-through (same level) AC voltage or pulsed DC voltage. A basic power rule applies to transformers; power-in equals power-out. The unit of measure for Power is the Watt. 1 Watt = 1 Volt x 1 Amp.
A transformer has three main components:
An iron core - The iron core is wrapped with two separate coils of wire. The job of the iron core is to strengthen the magnetic fields of the transformer.
Primary winding - The input side of the transformer. This coil of wire is tightly wrapped around the iron core of the transformer.
Secondary winding - The output side of the transformer. This coil of wire is tightly wrapped around the primary winding of the transformer.
There are three basic types of transformers:
Step-up transformer - The primary coil winding has less windings of wire than the secondary coil does. A 1:2 step-up transformer has half as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 24 V AC will be induced into the secondary winding, however, the output amperage will be cut in half to 6 amps.
Step-down Transformer. - The primary coil winding has more windings of wire than the secondary coil does. A 2:1 step-down transformer has twice as many primary windings as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 6 V AC will be induced into the secondary winding, however, the output amperage will be doubled to 24 amps.
Pass-through transformer - In a 1:1 transformer, the primary coil winding has just as many windings of wire as the secondary coil does. This means that if you apply 12V and 12A to the primary winding, approximately 12 V AC will be induced into the secondary winding, and the output amperage will be 12 amps. The advantage of a 1:1 transformer is that there is not a direct electrical connection between the two coils. If one side of the circuit gets short circuited, the other side will remain isolated.
Examples of transformer use on automobiles:
Ignition coils - An ignition coil is an example of a step-up transformer, the primary coil input voltage is 12-15 V and the secondary output voltage is 20-60 kV. This means for every primary coil winding there are at least 2000 secondary windings. This also means that the output amperage will be at least 2000 times smaller than the input amperage. Secondary ignition voltage is high voltage, but amperage is low.
Since only resistance is known and number of windings is unknown, I assume that winding wire size & type is the same, therefore resistance is a function of length of wire in the windings.
I interpret your findings to show that the resistance of the primary windings in the eBay coil is 3.4 times that of the OEM LT5 coil, meaning it has more windings. If the resistance of the primary windings is higher and the secondary windings resistance is the same, that means the voltage output would be lower than the OEM LT5 coil, i.e. coil discharge voltage is not as high as the OEM LT5 coil.
My non-expert opinion, don't use them. The spark is not as hot.
However, I do have my flame suit on!
Jim
Le Mans Master
Joined: Jan 2006
Posts: 5,695
Likes: 2
The "pull" is the easy part. It's putting it all back together that's the trick....kinda like a watch.Just TRIPLE CHECK EVERY TUBE, LINE, CONNECTION, AND COMPONENT before sealing it all up. Use sealant on the connections and study the reference material from this site and the ZR-1.net.
Most of all....TAKE YOUR TIME.
And not too much beer (that's for at least 3rd and 4th timers).
Most of all....TAKE YOUR TIME.
And not too much beer (that's for at least 3rd and 4th timers).
Race Director
Joined: Dec 2003
Posts: 14,150
Likes: 937
From: Fremont Ca
2022 C4 of the Year Finalist - Modified
The one thing that seems to trip people up is the cork screw line that slips out of the rubber connection down in the valley.An easy check is to seat the plastic line in the rubber fitting,wrap some masking tape around the line once seated in the rubber fitting and look at the tape as the plenum comes down,if the line pops out of the rubber fitting you will be able to see it.
Thread Starter
Cruising
Joined: Mar 2006
Posts: 11
Likes: 0
From: Eagan MN
I haven' started yet, but I should have all the parts and wires by the end of the week. I've reviewed Mark Heibecks CD a few times, which really helps. I'm going to take everyones recommendation and take my time and do it right. Thanks to everyone for their help. I'll let you know how it turned out.
Burning Brakes
Joined: Jul 2002
Posts: 1,050
Likes: 59
From: McLean Va
One more advice.
When assembling, clean the torx head bolt of all grit hand tighten all bolts before progressively torquing them down. It is real easy to strip threads in aluminum lower intake casting.
I know, I stripped two of them...
When assembling, clean the torx head bolt of all grit hand tighten all bolts before progressively torquing them down. It is real easy to strip threads in aluminum lower intake casting.
I know, I stripped two of them...
Melting Slicks
Joined: Jul 2004
Posts: 2,907
Likes: 3
From: Jupiter Florida
You might find this link interesting>>
http://www.zr1netregistry.com/forum/...ead.php?t=7614
Michael
http://www.zr1netregistry.com/forum/...ead.php?t=7614
Michael
Le Mans Master
Joined: Jan 2006
Posts: 5,695
Likes: 2
Thread Starter
Cruising
Joined: Mar 2006
Posts: 11
Likes: 0
From: Eagan MN
I just finished my first plenum pull. Everything works great. It took me about 12 hours but for my first time it all worked out OK. I put in new injectors, plug wires and coils. Car runs like new.
Thanks to all of you for your advice and assistance. You guys are great.
Sodak52
Thanks to all of you for your advice and assistance. You guys are great.
Sodak52
