Tune up

[RiceEatingZR1]

I have to replace my plugs and wires, I have never removed the plenum before. How complex is it? also while I have it off should I replace the coils? I just turned 51k miles.

[LGAFF]

Anyone who is decent with tools can do it, have at it!

[RICHARD TILL]

Its not so bad. Pulled mine today. Am installing MSD coils. Had a bad one several months ago and replaced it with a used one from a 3800 V6. Underneath, watch for the vacuum lines in the front and the wires to the module in the rear. You`ll have to raise it with one hand while disconnecting with the other. A manual would be worth its weight in gold if you plan to keep the car.

[Dynomite]

I have to replace my plugs and wires, I have never removed the plenum before. How complex is it? also while I have it off should I replace the coils? I just turned 51k miles.

Check Injector Resistance.....I would replace Injectors before I replace Coils :thumbsup:

Removing Plenum (including the 10 minute Plenum Removal) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581663365)

Some Tips on what to do under the Plenum for the first time Low Mileage ZR-1 Restoration (Audio, Injectors, Starter, Clutch Hydraulics) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581644913)

[Paul Workman]

Might be a good idea to pull the starter and service the solenoid terminal posts and the ring. (New posts can be had on ebay for under $10.) And, using sand paper, clean up any pits on the copper contact ring** (you'll see it).

**A WORD OF CAUTION: Should you opt to buy one of the Denso solenoid rebuild kits, which includes not only new contact terminal posts, but also the armature/plunger with a new copper contact ring as well, compare the length of that long, skinny (push rod) that forces the starter gear to the flywheel ring gear. I bought such a kit and the (push rod) was short by approx half the width of the starter gear. Had I used it, the starter gear would only engage about half the width of the gear..not good! (That's why I simply cleaned my old one up with sandpaper. Took maybe 20 minutes tops to sand it bright again.)

Another point worth mentioning, inspect the pins of that long connector at the back of the plenum (that connects to the digital ignition module). The pins are small, and if one is leaning a little compared to the others, you'll want to carefully straighten it or it might get folded over when reinstalling the connector. I'm NOT raising a warning flag, necessarily, but it is reasonable to pay special attention to align the connector before cranking down on the clamping bolt: not the time to be in a hurry, or have your pet gorilla install your connections - THAT one in particular.;)

[Dynomite]

Might be a good idea to pull the starter and service the solenoid terminal posts and the ring. (New posts can be had on ebay for under $10.) And, using sand paper, clean up any pits on the copper contact ring** (you'll see it).

**A WORD OF CAUTION: Should you opt to buy one of the Denso solenoid rebuild kits, which includes not only new contact terminal posts, but also the armature/plunger with a new copper contact ring as well, compare the length of that long, skinny (push rod) that forces the starter gear to the flywheel ring gear. I bought such a kit and the (push rod) was short by approx half the width of the starter gear. Had I used it, the starter gear would only engage about half the width of the gear..not good! (That's why I simply cleaned my old one up with sandpaper. Took maybe 20 minutes tops to sand it bright again.)

Another point worth mentioning, inspect the pins of that long connector at the back of the plenum (that connects to the digital ignition module). The pins are small, and if one is leaning a little compared to the others, you'll want to carefully straighten it or it might get folded over when reinstalling the connector. I'm NOT raising a warning flag, necessarily, but it is reasonable to pay special attention to align the connector before cranking down on the clamping bolt: not the time to be in a hurry, or have your pet gorilla install your connections - THAT one in particular.;)

Concur....but that is a given with Paul :thumbsup:

See Starter, Starter Relay, Wiring Harness, Battery, and Plugs Tricks (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-3.html#post1581564085)

[XfireZ51]

I have to replace my plugs and wires, I have never removed the plenum before. How complex is it? also while I have it off should I replace the coils? I just turned 51k miles.

It may have only 51k but it is 23 years old. When I got my 92, I decided to upgrade the coils and injectors since I was porting the plenum anyway. Of course, I've had reason to pull the plenum on NUMEROUS occasions since then.;)
But not because of injector or coil issues. I also agree w Paul. May as well
clean up the starter while ur in there, check secondary throttle and vacuum,
making sure no throttle blade screws are loose.

[Karl]

With my recent top end upgrade I installed new coils and spark plug wires. Well worth it especially since you are in there anyway.

[XfireZ51]

With my recent top end upgrade I installed new coils and spark plug wires. Well worth it especially since you are in there anyway.

Karl,

Yes that's a special rule for LT-5s. Its the "while you are there anyway" rule.