May have a handle on my hesitation issue

[Kevin]

I took the car on a 20isj mile drive this morning. Drive it easy for the first 10 or so but went wide open in 5th a few times and it ran fine, this was on the highway so 65 to 80ish mph. Got off the highway sat at a light for a bit, went wide open in 1-3 and the rear end broke loose on me on the 1-2 shift. Slow down to 60 or so then got back on it in 5th and t started missing again, stated in it a few seconds and sure enough a service engine soon light came on the dic. So I backed off, and it went away as soon as I did. A few miles later a friend of kind with a Ferrari passed and I sped up to follow him. Right around 3000 rpm the service engine soon light came in. I guess this is a good thing as I have a code to work off now. Ill keep you guys posted. I'd pull the codes now but I don't have the groundin plugs at cars and coffee and I'd prefer not to pull the codes in a parking lot at a show anyway. It can wait till I get home

[scottfab]

I'm thinking a LEAN code.

[SteelBlueZR1]

Had exact same issue. Turned out to be a failing secondary solenoid - intermittent. Good luck Kevin. Hope it's something ez. Also check and clean map line and position so oil doesn't collect in line.

[Kevin]

I was thinking either running out of vacuum, though Marc checked that at Carlisle or running out of fuel

[scottfab]

Had exact same issue. Turned out to be a failing secondary solenoid - intermittent. Good luck Scott. Hope it's something ez. Also check and clean map line and position so oil doesn't collect in line.

I think it is Kevin with the hesitation issue. I have hesitation sometimes but that's when I pee :p

[Kevin]

pulled the codes, code 16 dis system fault line circut. so it's either the dis, the wire from the dis to the ecm or the ecm....which means I need to replace lots of expensive parts and hope for the best

[FU]

Recently pull the plenum ?

[Kevin]

Recently pull the plenum ?

Twice in the last 2 years

[scottfab]

pulled the codes, code 16 dis system fault line circut. so it's either the dis, the wire from the dis to the ecm or the ecm....which means I need to replace lots of expensive parts and hope for the best

could just be the connector at the back of the DIS.
Let's hope.

[Kevin]

could just be the connector at the back of the DIS.
Let's hope.

either way I still need to remember how to pull the plenum and go after this. I haven't personally done it in probably 10 years. I'm a little rusty

[XfireZ51]

Before pulling the plenum, just unbolt the DIS connector, check the pins and then re-torque. See if that helps. Also make sure connector isn't loose in the first place. Probably not it, but check the easy stuff first.

[Kevin]

Before pulling the plenum, just unbolt the DIS connector, check the pins and then re-torque. See if that helps. Also make sure connector isn't loose in the first place. Probably not it, but check the easy stuff first.

i thought the dis was under the plenum...where'd i put that service manual

[ZZZZZR1]

Kevin

Did you replace your injectors? I remember you saying you needed to,
right?

What has been done?

Coil packs?

Wires?

Injectors?

Plugs?

Cheers

David

[Kevin]

Kevin

Did you replace your injectors? I remember you saying you needed to,
right?

What has been done?

Coil packs?

Wires?

Injectors?

Plugs?

Cheers

David

David,
wires, plugs, injectors were all changed out last year. FIC injectors were used, GM wires and plugs were done at the same time. Plenum came off again this year for ac replacement. Coils haven't been replaced. Spoke with Marc about it at carlise and he didn't think they needed to be replaced. Glad I decided to try and play with that 430 today, least I know where I am now

[Tyler Townsley]

I have a dis checker. You use a scope and watch the waveforms as you vary the rpm. I had a dis module that started breaking down at 400 rpm and you could see it on the scope as the waveform went crazy. The checker I have is used for almost every GM dis equipped car in the 80s and 90s so check with a Chevy/Buick technician that works on those models he may have one you can use.

Tyler

[Kevin]

I have a dis checker. You use a scope and watch the waveforms as you vary the rpm. I had a dis module that started breaking down at 400 rpm and you could see it on the scope as the waveform went crazy. The checker I have is used for almost every GM dis equipped car in the 80s and 90s so check with a Chevy/Buick technician that works on those models he may have one you can use.

Tyler

Very interesting idea Tyler, I have a buddy who works for a local chevy dealer, wonder if they would have one kicking around...though I would have no idea how to use it. My mechanical ability sorta peaks at oil changes and brake jobs :mad:

[XfireZ51]

:fahne:i thought the dis was under the plenum...where'd i put that service manual

You can reach the connector from the back, under the FPR. 1/4" socket.

[Vetman]

Mine will miss some at WOT if I have run in town with the AC on, a otherwords heat build up under the hood. I have assumed it is ignition related like coils or wires which are orginial. Car is at 63,000. Stock never raced. Car runs perfect otherwise. I hope to
Get it to Marc in the next year or two for him to work his magic.

[Dynomite]

either way I still need to remember how to pull the plenum and go after this. I haven't personally done it in probably 10 years. I'm a little rusty

:sign10:

See #2 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)
TB Coolant Elimination is Item #4 LT5 Eliminated Systems (http://forums.corvetteforum.com/c4-zr-1-discussion/2942569-tech-info-lt5-eliminated-systems.html")

A. Tools for Plenum Removal.
Two Allen Head wrenches (6mm and 3mm),
Two flat head Screw drivers and ...................................1/4 inch socket wrench with 1/4 inch socket
TB bracket wrenches (7mm and 9mm)..........................and short extension for DIS Connector
http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/cd1f898d-6255-439d-af9e-ab8bfbaea4b9.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/cd1f898d-6255-439d-af9e-ab8bfbaea4b9.jpg.html)http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/7d184269-e7b8-4563-bb79-10ded592ab5c.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/7d184269-e7b8-4563-bb79-10ded592ab5c.jpg.html)
B. Plenum Removal Steps (assuming you have TB Coolant Blocked). If not.....remove some coolant before you start.
1. Disconnect Battery (Check Battery Condition and Jumper GOOD Battery as FIRST CHECK).
2. Remove Samco (or stock) Air Duct (large flat screw driver).
3. Remove Oil Catch Can Hose (If Oil Catch Can Installed) to Plenum and PCV Dual Connector on back of Plenum (small flat screw driver).
4. Remove Throttle Body Cables (two including TB Shield and two top (I have 3mm SS Allen Head) screws on Plenum) and TB Connector (7mm and 9mm wrenches).
5. Remove Fuel Regulator Vacuum Hose "L" rear of Plenum.
6. Disconnect MAP Vacuum hose from MAP (Manifold Absolute Pressure) and from rear of Plenum.......
(in case it gets intangled with other wires/hoses as MAP is not disconnected from Plenum).
7. Disconnect Passenger Side Plenum Vacuum (and Drivers side Plenum Vacuum if secondaries not removed).
8. Disconnect Brake Boost Vacuum line Drivers Side Rear of Plenum.
9. Remove three 6mm Allen Head SS Fuel Line Bolts and two fuel lines (6mm Allen Ball Head Socket) or Torx-40 stock bolts.
10. Open gas cap to prevent fuel lines from leaking when removed from fuel rail.
11. Remove 12 Allen Head SS Plenum Bolts (6mm Allen Ball Head Socket with Extension) or Torx-40 stock bolts.
12. Lift Plenum from Gasket (front only) and remove two Cam Cover PCV Vent Rubber Connectors to Air Horn.
13. Disconnect two DIS (Distributorless Ignition System) Connectors front of DIS.
14. Disconnect large Purge Vacuum line under front of Plenum (91')......
(90' has small vacuum line only under front of Plenum going to Charcoal Canister under left head light).
15. Disconnect two small electrical connectors rear under Plenum (MAP and DIS).
16. Unscrew 1/4 bolt in Main DIS Connector rear of Plenum.
17. Remove Plenum.
C. Starter Removal.
18. Remove Coil Pack Connector and 4 bolts (two pairs 8mm hex heads 6mm bolts front, 10mm hex heads 8mm bolts rear).
19. Remove Coil Packs with plug wires attached (remove all 8 plug wires from Cam Covers).
20. Check starter with hot wire but then disconnect Starter Solenoid connector.
21. Disconnect main HOT wire from Battery to Starter.
22. Remove two starter mounting bolts (13mm Hex Head 10mm bolts) and lift starter out of Valley.

http://i287.photobucket.com/albums/ll142/dynomite007/D%20Engine%20LT5/f6da30fd-c4c0-4c81-9e31-f7510aaf14f2.jpg (http://s287.photobucket.com/user/dynomite007/media/D%20Engine%20LT5/f6da30fd-c4c0-4c81-9e31-f7510aaf14f2.jpg.html")

[Kevin]

thanks for the write up. I wish I had a local crew to help me like the wazoo guys have, but we can't all be that fortunate

[Dynomite]

thanks for the write up. I wish I had a local crew to help me like the wazoo guys have, but we can't all be that fortunate

You got to find a couple of other like minded ZR-1 owners around Pittsburgh and start your own PIRATES gang ;)

Some Pennsylvania ZR1 owners.....
ZR1 2CTRPTR
ZR1 4CAM LT5
ZR1 KWK -PHKR
ZR1 LOGON
ZR1 MR ZR1
ZR1 OBSSSD
ZR1 RPO-ZR1
ZR1 WIKDZR1
ZR1 ZR1
ZR1 ZR1 ADCT

[rkreigh]

Hi Kevin,

if you have some hesitation about pulling the plenum, I highly recommend Marc Haibeck's DVD he walks you through it step by step, and has great tips. well worth it.

look up the fellow brotherhood of the beast in the PA area and I'm sure you can find someone to give you a hand.

or just drive that beeotch over here to wazoo land and come visit.

have someone follow you in case you need to leave the car to find parts.

lots of options

it's AIDA time (see Glengary Glenross)