I thought I was special, but it looks like I need injectors....

[bowtiguy]

I finally took the plunge on my first C4Z earlier this fall. I brought home #1631, a 1991' Dark Red Metallic/Black interior. Now we have two in the family ( my parents have a 91' Quasar/blue car w/ 19K on the clock).

I wasn't "looking" for a C4Z but have found memories of these cars as I graduated HS in 89'. But I have to say, the Dark Red Metallic is growing on me and it pulls to 7K better than my C6Z did. This was a one family car w/ 9,600 miles. Its spent its entire life here in Colorado.

Prior to purchase, the previous owner had the original selling dealer, "Purifoy Chevrolet" in Fort Lupton, replace both fuel pump assemblies and a bad oil cooler line. Other than that, this car is BONE STOCK even down to its period correct gatorbacks (still has the TPS sensor stickers on the outer rim lips).

Service procedures completed so far

-full oil change including draining the oil cooler/filter
-ZF transmission fluid change
-tighten ALL oil pan gaskets
-replaced power steering fluid
-cleaned coolant overflow tank/topped off.

After securing a set of original ZR-1 A-Molds from my father and getting new PS2's mounted, I've noticed the higher RPM cut out signifying fuel starvation. No vac leaks and secondaries are definitely working.

Combine this with the loss of factory paint on the passenger side plenum & cam cover after the oil line fiasco and it looks like I'm pulling the plenum...

Considering the cars low miles, I'm looking for any recommendations on what to do "while I'm in there" .... before I lite up the CC at Jerrys and Marc's.

After doing a bit of searching and attempting to keep the car as stock as possible in case I decide to go for NCRS or sell it in the future, I've come up with the following list.

- pull plenum/TB/injector housings ( strip & paint these pieces)
- replace ALL top end gaskets
- inspect gas tank( work done by the dealer)
- install new fuel filter
- replace all 16 injectors/gaskets
- replace spark plugs
- TB coolant bypass pipe (vs. plugs)
- test factory coils
- test secondary vac system.
- clean out the engine valley after the residents were evicted
- flush coolant system/install new thermostat
- flush brake all brake fluid
- change rear diff fluid
- stage 1 prom swap from Marc H.
- Bolt on my Borla Cat back.
- drive it!!!

Items on the fence about..

-starter/solenoid
-coil replacement

Any suggestions “while I’m in there”?

[32valvZ]

Hey, just a hello from Canon City Colorado!

[owwdee]

That’s a pretty good list.
I would replace the coils, relatively minor cost. Also maybe new plug wires.
I too need to pull my plenum and do a few of the things on your list, especially painting of plenum and cam covers.
Good call on checking the fuel pumps. Factory replacement senders have plastic tube clamps I believe. Seen many things on the forum of the clips breaking and is best to go to stainless clamps.
I’m near DIA. Hope to see your Z around!

[bowtiguy]

Originally Posted by 32valvZ

Hey, just a hello from Canon City Colorado!

right back atcha

[bowtiguy]

Originally Posted by owwdee

That’s a pretty good list.
I would replace the coils, relatively minor cost. Also maybe new plug wires.
I too need to pull my plenum and do a few of the things on your list, especially painting of plenum and cam covers.
Good call on checking the fuel pumps. Factory replacement senders have plastic tube clamps I believe. Seen many things on the forum of the clips breaking and is best to go to stainless clamps.
I’m near DIA. Hope to see your Z around!

NOTED on the plastic tube clamps. I'll check that out.

Q: Do coils go bad with age or cycles. With 9600 miles on it, its seen less cycles than normal.

And yes, I WILL be driving it. Especially if I get the A/C working.

[owwdee]

Originally Posted by bowtiguy

NOTED on the plastic tube clamps. I'll check that out.



Q: Do coils go bad with age or cycles. With 9600 miles on it, its seen less cycles than normal.



And yes, I WILL be driving it. Especially if I get the A/C working.

Good question on the coils. Search the forum. I think you can check the resistance to indicate if it’s good or not.

Colorado Auto Air in Northglenn did my A/C this summer. He has R-12. Had a leak in one of the tubes but he was able to repair it very easily and quickly. With your very low miles your compressor might have a significant leak at the shaft. Plenum would need to be off to replace the compressor so that might be an optional item to add to your list.

Very happy to hear you are going to drive it. These cars are too awesome to just be parked.

[Z51JEFF]

I’d replace the coils, one of my new OEM coils died at 8000 miles,replaced with MSDs. Sounds like you pretty much have a game plan set in motion.

[Paul Workman]

Welcome to the family of the BEAST! There are several ZR-1 owners in CO and they all like to drive um from what I've seen. (I used to live in Bailey and Franktown too [just east of Castle Rock]).

There is a recent post RE injectors, and although you want to keep it stock, you'd want to draw the line @ injectors! It's the alcohol and the water attracts that is the issue for all ZR-1s from 90-92 (water being less of a problem where you live perhaps than in other climates). In 93 the switch was made to alcohol tolerant injectors which ended the alcohol related problems.

Particularly popular for the stock and ported 5.7L LT5 are the stainless steel, alcohol tolerant injectors by RC Injectors, Accel (150821s from Summit Racing = my personal choice), and the SS injectors available from FIC.

Note: Stock injectors are rated at 21# at 43# psi. ALL of these injectors (mentioned) are apparently good choices for our 5.7L LT5s making up to 510 chp. And, there may be others too, as long as they're alcohol tolerant and not prone to rusting (i.e., stainless steel construction).

[efnfast]

Correct me if I'm wrong, but if you buy stock, OEM injectors from Chevy, they will be the same as what you have, I.E. still not ethanol tolerant.

[A26B]

Originally Posted by efnfast

Correct me if I'm wrong, but if you buy stock, OEM injectors from Chevy, they will be the same as what you have, I.E. still not ethanol tolerant.

Steve & all,

I think this could be a mixed bag. Although not likely, if a dealer still had some very old stock, circa 90~92, the injectors could be original replacement for the 90~92 ZR-1 and NOT Ethanol tolerant. The PN's for these would be:
17069647-(Primary)
17069648-(Secondary)

More likely, any dealer with inventory, would be for the 93~95 injectors which ARE ethanol tolerant. The PN's for these would be:
17109952-(Primary)
17109953-(Secondary)

OEM Injectors
All models, 90~95 both PRIMARY & SECONDARY are the same flow rate.

Injectors O-ring Seals
90~92 PRIMARY & SECONDARY, Upper/Top Seal is the same, PN 17112222
90~92 SECONDARY, Lower/Bottom Seal ONLY, is a larger o-ring seal, PN 10067600, which is located inside the injector housing and seals on the injector o.d. body.

90~95 PRIMARY & SECONDARY use the same o-ring seal, both TOP & BOTTOM, PN 17112222.

OEM Applications & Crossover
93~95 OEM injectors are direct replacements for 90~92 with the following parameters;
PRIMARY; Remove/Do not install, the lower o-ring seal that comes with the injector. The larger, Lower o-ring seal, PN 10067600 will be required. It is not necessary to grind/remove the lower flange from the PRIMARY injector nozzle.
SECONDARY; Requires no change for 90~92 application

OEM Visual Difference
90~92 PRIMARY (original): the absence of any o-ring seal or seal flange on the bottom of the injector nozzle.
SECONDARY: no difference.

BIG DIFFERENCE IS COST: Dealers will charge at least double the cost of aftermarket injectors.