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#11 |
![]() Join Date: Nov 2016
Location: Norway
Posts: 397
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Aren't there some pins that can get bent on the ignition module under the plenum? Would that cause a similar issue?
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#12 |
![]() Join Date: Jul 2005
Location: Jupiter, Fl.
Posts: 813
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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 |
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#13 |
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,843
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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 ![]() Last edited by Ccmano; 09-25-2019 at 04:08 PM. |
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#14 |
![]() Join Date: Jul 2005
Location: Jupiter, Fl.
Posts: 813
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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 Last edited by Bob Eyres; 09-30-2019 at 08:06 AM. |
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#15 |
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,843
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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 ![]() |
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#16 |
![]() Join Date: Aug 2015
Location: Magnolia, Texas
Posts: 884
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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 |
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#17 |
![]() Join Date: Jul 2005
Location: Jupiter, Fl.
Posts: 813
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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 Last edited by Bob Eyres; 10-02-2019 at 10:03 AM. |
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#18 |
![]() Join Date: Jan 2004
Location: Alex VA
Posts: 1,080
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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 |
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#19 |
![]() Join Date: Jul 2016
Location: Greater St. Louis
Posts: 490
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Could the plenum gasket be the culprit? Perhaps it got pinched on reinstall and i# drawing air through the gap. Just a SWAG.
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#20 |
![]() Join Date: Jul 2005
Location: Jupiter, Fl.
Posts: 813
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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. |
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