new ZR1 owner with a few questions.

[DScott600]

I have recently purchased a white 1991 ZR1 with 70,000 miles. The car is great, just needs a little paint work on the front bumper and some maintenance items taken care of. I usually don't post because I find everything I need to know form searching. I never had to ask anything about my 03 Z06. I have access to all the tools I need and a lift. I'm also pretty good at working on cars. I plan on removing the plenum and and replacing plug wires, coil packs, spark plugs and injectors while I have it off. I will be using the Bosch injectors from FIC. I will also change the PCV, thermostat, oil, brake fluid, transmission and rear end fluid just for peace of mind. My question is I have a small vacuum leak that needs addressing. What parts would I need to replace while I'm under the plenum to after I find the leak? Would the standard vacuum hose rebuild kit from white racing address most of the area under the plenum and if not what else would I need and where would you get it? Also at appears the secondary vacuum pump is bad, I will remove it and see if it is a simple problem but if it needs replacing I read there is a GMC truck that uses the same pump, just different connector. Where would I get that from?

[cuisinartvette]

Sounds like youre going to town on some P.M. and straightening the car out.

Was that the white/red one up for sale recently,mind if we ak what you gave for it?

Enjoy.

[DScott600]

It is the white with grey interior. I am the second owner. It has a borla catback and SLP cold air intake. I have all the maintenance records and there is no indication that any work has been done under the plenum or the serpentine belt has ever been replaced either. I would feel much better if I got all this stuff out of the way. The original owner did some things that make me question his treatment of the car. (passenger window strached due to sheet metal screw sticking out in the door panel when window rubber was replaced, after market CD player installed without dash kit, front spoiler/air dam removed.) I paid 16K for the car. It is at the shop now getting the paint fixed, and I got the window replaced and all of them retinted. Help with the other PM parts is appreciated. :)

[jonszr1]

sounds like you got a nice deal on her . i would test the vacume lines first before paying the 300 that curt wants for the setup . you my find that it could be a ck valve a actuator , or another single piece , that might solve the problem . i rebuilt my whole system for 50. by doing it myself .if you didnt get a helms/ factory service manual with the car i would invest in one now . it sure makes trouble shooting easier . enjoy your new ride . these are amazing cars . caused me to by 2:mrgreen: . ps headers and upper end porting can put you in the 400 rwhp zone and then these cars get really fun

[jonszr1]

one last thing without the air dam they tend to get hot

[DScott600]

thanks for the info, I was just trying to get an idea about parts, so I wouldn't have to pull the plenum any more then i have to. I already replaced the air dam so hopefully no problems there. But what about the vacuum pump? I know it isn't coming on, hopefully it is just the inline fuse from the battery I read about but if not does someone have the part # of the one from the GM truck that uses the same one? I work at a college and will be using the automotive shop while we are on break so I hoped to get all the parts I need before I started. The only part I'm really worried about is the vacuum lines under the plenum and the pump.

[cuisinartvette]

There was one from I think a Kodiak truck and another one from a Jetta that worked I think. Ive seen the PNs before here and didnt wriote them down.

Someone will pipe in with them, be patient. THese guys have all the answers.

[flyin ryan]

it's a little hard to totally diagnose the vacuum leak with out pulling the plenum first. you might have one leak or ten. i know what your trying to do, you have shop space for XXX amount of time. if that's the case you'd better have everything (parts) on hand, whether you need them or not:dontknow: .

[DScott600]

So would the standard vacuum hose rebuild kit from white racing take care of everything under the plenum? Or is there a better solution for these lines? The leak sounds like it is coming from the back of the intake. I guess I will just get it looking and running good for now and then next year look into headers and getting the plenum and injector hosing porting and refinished. I would also like to get the shocks rebuilt and do some suspension stiffening. Thanks for the input so far guys. When i get it back from the paint shop I'll post some pics.

[jonszr1]

the leak could also be comming from the pvc hose thats in the back .it has a tendancy to rot if its the factory piece . you could get it from curt 200 or get creativce and make your own for a lot less . all depends on what way you want to go . vac lines are easily made by buying buck line and using a hair dryer to form them to match the originals. on the corvette action center is a good thread on the pump . it has a tendancy to corood inside .but it could be the fuse also . the pump if you need one is about 125 for the kodiak truck.good luck

[DScott600]

I don't mind making my own vacuum lines. Where is a good place to get the lines and fittings and such. Is there a thread anywhere showing how to do it?

[Kevin]

the the air duct will collapse if you have the stock one, you need to reinforce it somehow. Since it seems the inexpensive ones are no longer made a coffee can cut down the side with the bottom taken out inserted inside the duct will work

[tomtom72]

Not to be a cheap s.o.b. but my pump was corroded & I took it apart & cleaned it up & now it works just fine. Check the plug for it & if it has melted plastic then the insides of the pump are corroded from moisture and it's a bit seized up. A little contact cleaner & some patience on the electrical connector should put it right. Same thing with the inside parts...just the moisture over time and if you clean it up, it should work just fine.

I'll post up the p/n of the truck pump when I get to my tool box & look at my inventory sheet.:redface:

Have the injectors been done? May want to think this thru slowly about all the "wear" items that are antique under there: actuators, tank, control solenoid, CCVB gasket, CCVB hoses, temp sensors (ECM & Gauge), coils....etc, well you get the idea, right, I could go on and it can get expensive in a hurry. If you want p/n's on this stuff let me know as I think I have most of them.

Good luck with your new toy & welcome to the BOB!:thumbsup:

Tom

[DScott600]

Thanks for the tip, I did plan on taking the pump off when I get the car back at the end of this week. I teach electrical and electronics so if it is just seized up from corrosion and such I wont have a problem taking it apart and cleaning it up, but I would like to have the part number for the new one just in case. It would be appreciated if I could get a list of part numbers for all the vacuum stuff under the plenum too.

[Hammer]

GM Part #94669091.
Your local dealer can get one, or you can get it from P & G Chevy. Don't wait 'cause the price is going up slowly. This part was an exact fit on my '91, nothing to change or modify.

[DScott600]

I have all receipts of the work done to the car so it doesn't look like the injectors have ever been replaced. While I have it all apart I'll be sure and address the air duct too.

[flyin ryan]

I'll be sure and address the air duct too.check the duct while running the car, before it all comes apart, until you get too carried away. when it's warm/hot is it soft or firm, sounds dirty:???: , i personally believe the duct collapsing is a little bit of an urban myth:eusa_shhh thing. i mean ya sure it's possible if the engine temp. gets way up there, 250° F or so & the paper air cleaner is plugged. with a clean/semi-clean K&N well...:rolleyes:

[DScott600]

I remember the duct collapsing was a problem on C5 cars if you were running boost. But if it doesn't restrict airflow and is easy to do I guess it wouldn't hurt to give it some support. Imports do the coffee can exhaust :) haha

[flyin ryan]

Imports do the coffee can exhaust :) hahai don't give them that much credit, fart cans:cool: , totally stock cars with a fart can:sleepy1:, uh...ya, whatever. has to be ssooo big it lights off sparks going down the road because it's 17X's too big for the car:rolleyes: , how'd i end up on this:icon_scra , oh well i'm done:happy1:

[HAWAIIZR-1]

I have recently purchased a white 1991 ZR1 with 70,000 miles. The car is great, just needs a little paint work on the front bumper and some maintenance items taken care of. I usually don't post because I find everything I need to know form searching. I never had to ask anything about my 03 Z06. I have access to all the tools I need and a lift. I'm also pretty good at working on cars. I plan on removing the plenum and and replacing plug wires, coil packs, spark plugs and injectors while I have it off. I will be using the Bosch injectors from FIC. I will also change the PCV, thermostat, oil, brake fluid, transmission and rear end fluid just for peace of mind. My question is I have a small vacuum leak that needs addressing. What parts would I need to replace while I'm under the plenum to after I find the leak? Would the standard vacuum hose rebuild kit from white racing address most of the area under the plenum and if not what else would I need and where would you get it? Also at appears the secondary vacuum pump is bad, I will remove it and see if it is a simple problem but if it needs replacing I read there is a GMC truck that uses the same pump, just different connector. Where would I get that from?

http://www.corvetteactioncenter.com/forums/showthread.php?t=14272

Here is the best information I have found when attacking the same issues.

[DScott600]

Great write up from the Corvette action center. I have been looking that over good for a few days now. Ricers make me laugh, 1.5 to 2" exhaust with a 15" tip. :sign10: :worship: all hail the mighty civic. haha

[rhipsher]

check the duct while running the car, before it all comes apart, until you get too carried away. when it's warm/hot is it soft or firm, sounds dirty:???: , i personally believe the duct collapsing is a little bit of an urban myth:eusa_shhh thing. i mean ya sure it's possible if the engine temp. gets way up there, 250° F or so & the paper air cleaner is plugged. with a clean/semi-clean K&N well...:rolleyes:
It is an urban myth unless you live in palm springs or death valley. Mine stays stiff all the time no viagra needed.:dancing

[Kevin]

check the duct while running the car, before it all comes apart, until you get too carried away. when it's warm/hot is it soft or firm, sounds dirty:???: , i personally believe the duct collapsing is a little bit of an urban myth:eusa_shhh thing. i mean ya sure it's possible if the engine temp. gets way up there, 250° F or so & the paper air cleaner is plugged. with a clean/semi-clean K&N well...:rolleyes:
the duct collapsing is not an urban myth. I'll testify to that as can Keith. pop the hood on your car in the sun, let it sit for an hour then come back and squeeze it. I'd be willing to bet that you will be able to almost collapse it. I can remember watching the duct get sucked closed on keith's car on the dyno in BG several years ago. The stock duct sucks. I went though 4 before I got smart and bought the coplin duct.

[Kevin]

It is an urban myth unless you live in palm springs or death valley. Mine stays stiff all the time no viagra needed.:dancing
actually it's not

[flyin ryan]

the duct collapsing is not an urban myth. I'll testify to that as can Keith. pop the hood on your car in the sun, let it sit for an hour then come back and squeeze it. I'd be willing to bet that you will be able to almost collapse it. I can remember watching the duct get sucked closed on keith's car on the dyno in BG several years ago. The stock duct sucks. I went though 4 before I got smart and bought the coplin duct.i can squeeze the stock duct cold if i want, not a big deal, i'm not saying they are all perfect but i don't believe they are ALL junk either. i'm not one to wave the General's banner, believe me. depends. it's all about draw. where's it drawing from (air cleaner inlet) & how much is the draw (stock LT-5 or modified) . a person can put their hand over the end of a vacuum cleaner & watch the hose snake up on the floor. i'm trying to help DScott600 by keeping his eyes open before he goes & spends his money with both fist's. check it out first, doesn't cost anything:dontknow: . how many cars did we chassis dyno at the PNW gathering a few weeks ago, eleven i believe. inside a building (warm) i didn't see any duct's get yanked off because of the infamous collapsing. again, not saying it's never happened. i see guys overbuild stuff that just doesn't matter all the time. i try to focus my attention (time,effort,money,etc.) on things i KNOW help.

[Kevin]

i can squeeze the stock duct cold if i want, not a big deal, i'm not saying they are all perfect but i don't believe they are ALL junk either. i'm not one to wave the General's banner, believe me. depends. it's all about draw. where's it drawing from (air cleaner inlet) & how much is the draw (stock LT-5 or modified) . a person can put their hand over the end of a vacuum cleaner & watch the hose snake up on the floor. i'm trying to help DScott600 by keeping his eyes open before he goes & spends his money with both fist's. check it out first, doesn't cost anything:dontknow: . how many cars did we chassis dyno at the PNW gathering a few weeks ago, eleven i believe. inside a building (warm) i didn't see any duct's get yanked off because of the infamous collapsing. again, not saying it's never happened. i see guys overbuild stuff that just doesn't matter all the time. i try to focus my attention (time,effort,money,etc.) on things i KNOW help.
I don't think that all of them are junk, but time + heat = junk. you can see the duct sucking down under load, but since it's kinda hard to drive with the hood up or off, it's nearly impossible to see. Keith's car is a low mile stocker that had a very low base line reading, knowing the car was a low mile 90 we were thinking anything from bad plugs to bad prom to bad injectors. It was mark haibeck who thought to check the duct and sure enough it sucked down like an accordion. If you don't want to believe that the stock duct is not the most high quality piece ever made, so be it. However, since the coplan duct is no longer made (cost all of $25 back when he had them), and the haibeck duct is all of $40 http://www.zr1specialist.com/HAT%20Web/products/hoops.htm what is the harm in reinforcing it and just making sure? If you drink coffee it is free to reinforce. there are very few parts offered by people like haibeck or coplan for these cars that don't help to improve performance.

[Z51JEFF]

Heres what your looking at.Best thing to do is strip everything from the valley.There is a small drain hole that plugs very easy,it plugs up you get a water cooled starter,not good.http://i10.photobucket.com/albums/a136/FLYTYM/IMG_0058.jpghttp://i10.photobucket.com/albums/a136/FLYTYM/IMG_0023-2.jpg

[cward]

Great pics for what you see under the plenum. Just my $.02 on the vacuum pump: My Z did not have one and ran pretty good. I was told by someone (Graham B) that the Yanks made them put one on for some edge of the envelope cases. I drove my Z pretty hard both on the street and racing of all different kinds and to my knowledge did not suffer from vacuum loss. However, I know many of the Z owners will say they need the pump. Just saying that mine did not. And that old Z of mine did run pretty good for what it had done to it.

Curtis

[Aurora40]

the the air duct will collapse if you have the stock one, you need to reinforce it somehow. Since it seems the inexpensive ones are no longer made a coffee can cut down the side with the bottom taken out inserted inside the duct will work
FYI, I bought a new duct for maybe $15. Much stiffer than my 18 year old one. I have the Haibeck inserts, but really I think with a new duct, no reinforcement is needed.

[DScott600]

The car does run fine with the pump not working, but it is nice to know it is there and easy to tell if you have a vacuum leak if it doesn't go off or cycles on and off. Since the part is less then 100.00 right now I think I'll go ahead and get it if the one I have can't be fixed.

[DScott600]

The car runs fine without the pump, but it is nice to have it working so you can here it cycling on and off if you have a vacuum leak. I'll try to fix the one I have and order a new one if it can't be fixed since the price is less then 100 right now.

[Kevin]

FYI, I bought a new duct for maybe $15. Much stiffer than my 18 year old one. I have the Haibeck inserts, but really I think with a new duct, no reinforcement is needed.
I thought the same thing till I bought a new one off curt white in BG in lets say 04 (the year isn't important). By the end of the weekend I was able to collapse it fully with a very soft squeeze. However I'm not going to convert any non-believers around here so I'm going to let this die

[flyin ryan]

I'm not going to convert any non-believers around here so I'm going to let this diei personally don't want to steal any more of DScott600's original thread, to be fair to him:eusa_shhh .

[DScott600]

No problem, hey it is all educational. :)

[jonszr1]

people sharing their thoughts on things pro/con is why i love this forum.whats that old adage no such thing as a stupid ?or answer . dustin your pkg from me will go out wed . please pm me your mailing to make sure this old guy with (C.R.S.) has it right .

[DScott600]

PM sent, thanks again.

[DScott600]

Well I got the car back from the paint shop and she is looking mighty fine. I took the vacuum pump off and brought it to work to day. There was a lot of corrosion and the motor was seized up. Cleaned it up real good and cleaned the contacts on the switch and a little spray lubricant and it is running perfect now. :) Now when I put it back on I just need to find and replace the fuse since it should be bad since the motor was seized. By the way anybody got any tips for repairing a sagging headliner on the painted top? Slowly but surely she is shaping up.

[Kevin]

Well I got the car back from the paint shop and she is looking mighty fine. I took the vacuum pump off and brought it to work to day. There was a lot of corrosion and the motor was seized up. Cleaned it up real good and cleaned the contacts on the switch and a little spray lubricant and it is running perfect now. :) Now when I put it back on I just need to find and replace the fuse since it should be bad since the motor was seized. By the way anybody got any tips for repairing a sagging headliner on the painted top? Slowly but surely she is shaping up.
i've heard 3m spay adhesive works well but have no experience with it

[Aurora40]

Just replace the headliner. It's easy to do since the top comes out of the car. There are a few threads on this. :)

[DScott600]

pics 1991 ZR1 #205

[DScott600]

more pics

[DScott600]

pics

[DScott600]

pic