Plenum Removed - Now No Secondaries - Page 2 - ZR-1 Net Registry Forums

S.hafsmo · 09-23-2019

Aren't there some pins that can get bent on the ignition module under the plenum? Would that cause a similar issue?

Bob Eyres · 09-25-2019

On the ign. Module, hard to screw up. Those plugs are a positive fit.

Here are the current symptoms-
I put some fresh plugs in today, the old plugs looked ok, but it looked like they were running a little lean.
Starts immediately with very little cranking. Normal driving is smooth, up to about 4K then it starts to break up, cutting out, missing repeatedly.
Although if you can gradually build revs it’s very smooth, but If you put the hammer down, at any rpm it will break up and miss like mad. So far, no check engine light, no codes have been set.

We’re going to start looking at sensors next.
??????

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Ccmano · 09-25-2019

Check your fuel pump pressures and amp readings. A bad secondary pump will act like that. See post #16 in the attached thread to test the fuel pumps. I like the amp test the best. Both pumps running should draw 8-10 amps. Any less you have a pump issue. Half that and one pump is out. Also check your fuel filter, that will show up as low fuel pressure at WOT.
http://www.zr1.net/forum/showthread.php?p=182376
H

Bob Eyres · 09-30-2019

Fuel pump pressures were within spec, but I still installed two new ones. Same symptoms remain.
From these symptoms (above) it seems to me the secondary injectors may not be firing even though I know the secondary butterflies are working. Lean condition after test, and breaking up over 3K rpm.
What could shut off just the sec. injectors?

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Ccmano · 09-30-2019

Are there any codes? I assume you changed the filter too? Did you answer the question about the vacuum pump? Does it run normally, on, off, on, off when only the ignition is on without starting the engine?

As for the main DIS Module connector at the back of the module, it’s surprisingly easy to bend a pin on reassembly. A recheck of that is worthwhile.
H

jss06c6 · 10-01-2019

Bob, is there anyone near you that can datalog your car? TunerCATS or TunerProRT? Hard to diagnose without some data to look at..

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Bob Eyres · 10-02-2019

I will check on avail of datalog unit.
Vacuum pump is good. At start it cycles on for 2-3 seconds only, Then remains off.
We are going to look at Map sensor next.
MAP sensor is relatively cheap, so I may get a fresh one and plug it in.
Has anyone bought one lately? They’re made by Delco, and several other companies. What do you like, and best source?
Thanks again.
BTW, new fuel filter was installed when pumps were changed.

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rkreigh · 10-08-2019

time for a methodical approach

and if you need some help, please look up Aaron Scott at SGC down your way

it's easy to disturb the connectors to the injectors and pop them off to when a secondary injector doesn't fire and that cyl goes lean and stumbles

you are likely right it's a fuel problem, but I'd stop changing parts

it ran fine before the plenum pull, so fuel pumps and fuel pressure are likely OK. Pull the plenum again and find out what went wrong.

Check the connectors to the DIS and make sure you don't have a bent pin

conesare2seconds · 10-08-2019

Could the plenum gasket be the culprit? Perhaps it got pinched on reinstall and i# drawing air through the gap. Just a SWAG.

Bob Eyres · 10-27-2019

I fixed it! It was a bad,(corrosion), secondary injector controller box. Caused by a water leak near the driver side hood latch. It seemed like we went through just about every other possibility before I bought a used box, plugged it in (10 minute job), and it lit right up. It was terrible driving around with no secondaries.

It occurred to me, after the fact, that I could have tested the boxes without diagnostics by just swapping them and see how the engine behaved. seeing how they are actually the same part, and part#.

Thanks for all the posts, and I hope this thread will add to our diagnostic knowledge. Seeing as this engine is the only one I know of that has two interrelated, but separate injection systems.

Now... 7K every time out!

Bob.

09-23-2019	#11
S.hafsmo Join Date: Nov 2016 Location: Norway Posts: 397	Re: Plenum Removed - Now No Secondaries Aren't there some pins that can get bent on the ignition module under the plenum? Would that cause a similar issue? __________________ - '90 ZR-1

09-25-2019	#12
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	Re: Plenum Removed - Now No Secondaries On the ign. Module, hard to screw up. Those plugs are a positive fit. Here are the current symptoms- I put some fresh plugs in today, the old plugs looked ok, but it looked like they were running a little lean. Starts immediately with very little cranking. Normal driving is smooth, up to about 4K then it starts to break up, cutting out, missing repeatedly. Although if you can gradually build revs it’s very smooth, but If you put the hammer down, at any rpm it will break up and miss like mad. So far, no check engine light, no codes have been set. We’re going to start looking at sensors next. ?????? Sent from my iPhone using ZR-1 Net Registry __________________ "It's about the car, not the people." 1991 ZR-1 White/Black #1236 (Owner since 1994). Stock engine with bolt-ons: Hurst shifter,"Forced Air" intake, Coplon duct, Bee Cool Radiator, Demon coils, Jeal prom, Watson headers, X pipe, 3" B&B's, Rippie flywheel, 4:10 gears, A molds, Toyo Proxes-R888's 12.06@117mph. 1.76 60ft.

09-25-2019	#13
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Plenum Removed - Now No Secondaries Check your fuel pump pressures and amp readings. A bad secondary pump will act like that. See post #16 in the attached thread to test the fuel pumps. I like the amp test the best. Both pumps running should draw 8-10 amps. Any less you have a pump issue. Half that and one pump is out. Also check your fuel filter, that will show up as low fuel pressure at WOT. http://www.zr1.net/forum/showthread.php?p=182376 H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold. Last edited by Ccmano; 09-25-2019 at 04:08 PM.

09-30-2019	#14
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	Plenum Removed - Now No Secondaries Fuel pump pressures were within spec, but I still installed two new ones. Same symptoms remain. From these symptoms (above) it seems to me the secondary injectors may not be firing even though I know the secondary butterflies are working. Lean condition after test, and breaking up over 3K rpm. What could shut off just the sec. injectors? Sent from my iPhone using ZR-1 Net Registry __________________ "It's about the car, not the people." 1991 ZR-1 White/Black #1236 (Owner since 1994). Stock engine with bolt-ons: Hurst shifter,"Forced Air" intake, Coplon duct, Bee Cool Radiator, Demon coils, Jeal prom, Watson headers, X pipe, 3" B&B's, Rippie flywheel, 4:10 gears, A molds, Toyo Proxes-R888's 12.06@117mph. 1.76 60ft. Last edited by Bob Eyres; 09-30-2019 at 08:06 AM.

09-30-2019	#15
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Plenum Removed - Now No Secondaries Are there any codes? I assume you changed the filter too? Did you answer the question about the vacuum pump? Does it run normally, on, off, on, off when only the ignition is on without starting the engine? As for the main DIS Module connector at the back of the module, it’s surprisingly easy to bend a pin on reassembly. A recheck of that is worthwhile. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

10-01-2019	#16
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: Plenum Removed - Now No Secondaries Bob, is there anyone near you that can datalog your car? TunerCATS or TunerProRT? Hard to diagnose without some data to look at.. Sent from my SM-G950U using ZR-1 Net Registry mobile app

10-02-2019	#17
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	Plenum Removed - Now No Secondaries I will check on avail of datalog unit. Vacuum pump is good. At start it cycles on for 2-3 seconds only, Then remains off. We are going to look at Map sensor next. MAP sensor is relatively cheap, so I may get a fresh one and plug it in. Has anyone bought one lately? They’re made by Delco, and several other companies. What do you like, and best source? Thanks again. BTW, new fuel filter was installed when pumps were changed. Sent from my iPhone using ZR-1 Net Registry __________________ "It's about the car, not the people." 1991 ZR-1 White/Black #1236 (Owner since 1994). Stock engine with bolt-ons: Hurst shifter,"Forced Air" intake, Coplon duct, Bee Cool Radiator, Demon coils, Jeal prom, Watson headers, X pipe, 3" B&B's, Rippie flywheel, 4:10 gears, A molds, Toyo Proxes-R888's 12.06@117mph. 1.76 60ft. Last edited by Bob Eyres; 10-02-2019 at 10:03 AM.

10-08-2019	#18
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: Plenum Removed - Now No Secondaries time for a methodical approach and if you need some help, please look up Aaron Scott at SGC down your way it's easy to disturb the connectors to the injectors and pop them off to when a secondary injector doesn't fire and that cyl goes lean and stumbles you are likely right it's a fuel problem, but I'd stop changing parts it ran fine before the plenum pull, so fuel pumps and fuel pressure are likely OK. Pull the plenum again and find out what went wrong. Check the connectors to the DIS and make sure you don't have a bent pin __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)

10-08-2019	#19
conesare2seconds Join Date: Jul 2016 Location: Greater St. Louis Posts: 482	Re: Plenum Removed - Now No Secondaries Could the plenum gasket be the culprit? Perhaps it got pinched on reinstall and i# drawing air through the gap. Just a SWAG.

10-27-2019	#20
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	Re: Plenum Removed - Now No Secondaries I fixed it! It was a bad,(corrosion), secondary injector controller box. Caused by a water leak near the driver side hood latch. It seemed like we went through just about every other possibility before I bought a used box, plugged it in (10 minute job), and it lit right up. It was terrible driving around with no secondaries. It occurred to me, after the fact, that I could have tested the boxes without diagnostics by just swapping them and see how the engine behaved. seeing how they are actually the same part, and part#. Thanks for all the posts, and I hope this thread will add to our diagnostic knowledge. Seeing as this engine is the only one I know of that has two interrelated, but separate injection systems. Now... 7K every time out! Bob. __________________ "It's about the car, not the people." 1991 ZR-1 White/Black #1236 (Owner since 1994). Stock engine with bolt-ons: Hurst shifter,"Forced Air" intake, Coplon duct, Bee Cool Radiator, Demon coils, Jeal prom, Watson headers, X pipe, 3" B&B's, Rippie flywheel, 4:10 gears, A molds, Toyo Proxes-R888's 12.06@117mph. 1.76 60ft.