Re: Ruff Idle ,Huge Loss of Power
 

My iWatch runs a little bit faster:) Thanks for pointing that out.:handshak:

I pulled that tech info from the Corvette Forum.

Re: Ruff Idle ,Huge Loss of Power
 

My stumble be a stumble ! !! Maybe coincidentally it was shortly after changing plugs. I did use some dielectric grease in the spark plug boots, which I normally don't do. Since it is non conductive I don't think that is an issue. Of course once I tested the fuel pressure the Schrader valve started to leak. I haven't looked at that but ?rdered a new valve. Need to get it sorted out as I love driving this thing. Just love shifting gears. I think I will do the fuel filter as I ran a substantial amount of cleaner through it last tankful. I was going to change it anyway, so I will change it and go from there .

Re: Ruff Idle ,Huge Loss of Power
 

Did a spark test a few times actually to make sure and #8 is very weak compared to the rest . Found a way to get a spark tester hooked to the plug so all had a nice full colour accept #8 .
I removed the evaporator coil cover to get to #8 plug a lot easier and placed a cardbourd over the coil so not to bend the fins accidentally .


Mike

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Re: Ruff Idle ,Huge Loss of Power
 

ZR2 and Tripler - We gotta do process of elimination to narrow it down.


ZR2 - If you suspect it is a plug issue, you might want to remove one plug wire at a time and run the engine to isolate the cylinder that is possibly acting up. If you pull a wire off and there's no change in the idle, you've isolated the faulty cylinder.

Tripler - If #8 is suspect, pull the plug wire and run the engine. If the engine idle is not affected by 8 missing, likely something is amiss with 8.

Verifying the spark to all 8 cylinders is straightforward. Testing the injectors and the ECM transistor (-) drivers to the injectors is a bit tricky.

Re: Ruff Idle ,Huge Loss of Power
 

Thankyou Macroblock . I will give that a shot tomorrow and let you know .

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Re: Ruff Idle ,Huge Loss of Power
 

I agree. I have been redoing a house to get it on market for sale, so time wise I need to find the time. Of course when I tested the fuel pressure the other day to see if the FPR was acting up and if I had the proper pressure the schrader valve needle starting leaking........so I ordered a couple of them and some AC Delco plugs based on a few recommendations here. It is odd it happened after the plug change, but **** breaks I guess. I think what I will do is 1st change the fuel filter and see where I am. Then maybe check the plug wires by pulling off one at a time and see what happens. I got a feeling that this lovely motor want me to pull of the plenum and freshen her up with new injectors coils and wires etc.....but before her makeover I will see if the simpler items have any effect. I just gotta remember....Air......Fuel......and Spark. I had a 91 ZR1 that I bought from a dealer in Washington State. Thats what drinkin on a Friday night on E Bay can do for you.....ask me about shipping to the east coast!!!! He wasn't the most honest, it was on E bay about 4-5 years ago. It was a nice car, but it had bad secondary injectors, a few of the Bose speakers were blown and one of the Low Pressure Tire Sensors was always on, so I learned the hard way to take the plenum off and I replaced the injectors with FIC injectors. I did it 3 times in a matter of days......one time big vacuum leak, another time a big coolant leak and the 3rd time was the charm. Definitely ordered multiple gasket sets from Jerry's and the thicker plenum gaskets. It ran really hard once I was done. We'll See and I will report back in. Thanks for everyone's help in advance.

Re: Ruff Idle ,Huge Loss of Power
 

Pulled the #8 plug wire and saw no difference when it was plugged in or not plugged in . #8 is kaputz I think .


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Re: Ruff Idle ,Huge Loss of Power
 

Tripler - sounds like cylinder #8 is off-line. Its waste-spark partner is cylinder #5, so try the test by removing that Hi-Tension lead to see if doing so has any affect.

If #5 and #8, together or one at a time, have no affect on engine idle, then it could be an ignition coil, the ignition module or the wiring between the two.

If only 8 has no affect on idle, then it's possible the primary injector at #8 is not pulsing. This could be a faulty injector, the ECM or the wiring in between.

Re: Ruff Idle ,Huge Loss of Power
 

Pulled #8 and #5 at the same time and it idles ruff and sounds the same .


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Re: Ruff Idle ,Huge Loss of Power
 

Also someone had asked before if the fans were running when I start the car and I confirmed today that they do not run on startup

;-)

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Re: Ruff Idle ,Huge Loss of Power
 

To double check, start and run the engine with 5 and 8 disconnected. Connect 5 and note any changes in idle. Connect 8 and note any changes in idle.

If connecting 5 and 8 didn't have any affect, it's pointing to an ignition problem. Perhaps a coil or the Ignition Module (DIS).

Sounds like you'll need to pull the plenum to test and repair further.

With the plenum off you can test the ECM (-) outputs to the injectors. A couple of noid ("solonoid") lights will come in handy for this. A basic 12v test light will be needed to simulate a Crank Hi signal to spoof the Ignition Module and ECM.

Let us know when you have the plenum off.

Re: Ruff Idle ,Huge Loss of Power
 

5 & 8 are the same coil... seems like that might be the problem

Re: Ruff Idle ,Huge Loss of Power
 

I fully expected to pull the plenum again . Will keep you updated .


;-)

Re: Ruff Idle ,Huge Loss of Power
 

Yup sounds like it - unless the Hi-Tension lead going to #8 is the issue. Perhaps the lead is creating high resistance or shorting to ground.

Re: Ruff Idle ,Huge Loss of Power
 

You can take a look at my thread on chasing knock. If u go here, you can see what you may want to check for regarding ur coils.

http://www.zr1.net/forum/showpost.ph...8&postcount=16

Re: Ruff Idle ,Huge Loss of Power
 

Wow, thanks for that . Very interesting .
Since the coils are 25+ years old I will switch those out first with new wires and plugs . If it still idles ruff and has no power then back to checking more bits .
I will need a bit of instruction on how to test the injector cables to make sure they are putting the right amount of voltage to the injector .

Thanks



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Re: Ruff Idle ,Huge Loss of Power
 

I got the plenum off again . What are the steps to test the Coils .
Thanks


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Re: Ruff Idle ,Huge Loss of Power
 

Yes, good idea to change the ignition coils and perhaps the hi-tension leads while you have the plenum off.

The coils are all the same so if you want to test for the sake of testing you could exchange the coil that serves 5 and 8 with another coil and see if this moves the symptom to another cylinder pair.

If the problem moves, it's likely the coil but if it remains on 5 and 8, the problem could be a bad hi-tension lead or leads, bad plug or plugs or an issue with the Ignition Module.

-----------------

To test the ECM and injectors with the plenum off you will require a test light and at least one 'noid' light.

Put the key to "ON". Connect the test light alligator clip to the battery (+) and quickly and repeatedly connect and disconnect the probe end to the Crankshaft HIGH pin on the Ignition Module Test Port.

Pulsing a signal to the Crankshaft High line will spoof the ECM into thinking you are making a start attempt (i.e. <400 RPM). You will notice the fuel pumps come to life and a few other devices. All primary injectors will fire at the same time.

Now disconnect all the primary injectors. Put a 'noid' light on each injector connector or do one connector at a time if you only have one 'noid'. Spoof the ECM again and verify that each primary circuit lights up the noid.

Note 1 - The ECM output to each injector is (-).
Note 2 - If you don't have a 'noid' light a test light can be substituted.
Note 3 - Link to image of Ignition Module Test Port:
http://www.zr1ecm.com/img/blog/detai..._TEST_PORT.jpg

http://www.zr1ecm.com/img/blog/detai..._TEST_PORT.jpg

Re: Ruff Idle ,Huge Loss of Power
 

Here?s a good thread re: checking coil packs.

http://zr1.net/forum/showthread.php?...ignition+coils

Re: Ruff Idle ,Huge Loss of Power
 

Shame the forum does not have a thumbs up option because I would really like to thumb up everyones posts . Extremely helpful . I have never heard of noids before lol but I see I can buy them here at our Canadian tire . On Monday I will check the ohm readings on the coils and attempt a test of injector electrical leads .

Thanks for that pic of the service module plug and coil ohm info


Thumbs Up

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Re: Ruff Idle ,Huge Loss of Power
 

Let me second the need for a Thumbs up or Like button. I have liked those on all the other forums; maybe this is another symptom of the aging vBulletin sites. Any way to add this feature to our existing forum site? --Bob

Re: Ruff Idle ,Huge Loss of Power
 

Not a bad idea. I have put in a request. Keep in mind we are limited to forum capabilities which are out of our hands.

Of course you can simply use an emoji from the Selection to the right of the message box when you write the post.

:thumbsup:

H
:cheers:

Re: Ruff Idle ,Huge Loss of Power
 

Thanks Hans. I realize some things are out of your control and some just can't be done with a specific platform. --Bob

Re: Ruff Idle ,Huge Loss of Power
 

Found 2 coils that have zero ohms readings and the other 2 work fine . Ordered 4 new from Corvette Depot .
There on back order so a few weeks to receive them .


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Re: Ruff Idle ,Huge Loss of Power
 

Did the noid test . All primary injectors lit up .
[emoji106]

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Re: Ruff Idle ,Huge Loss of Power
 

Awesome - Great Job!:thumbsup:

Re: Ruff Idle ,Huge Loss of Power
 

Thanks Mac [emoji106] . Is there any other tests I need to do ?


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Re: Ruff Idle ,Huge Loss of Power
 

Tripler - it sounds like you narrowed it down to an ignition issue. Once you replace the coils and reassemble the plenum, you'll be able to test.

Coils that are not providing adequate voltage are a sign of trouble and will cause the driveability issue you describe.

Re: Ruff Idle ,Huge Loss of Power
 

I am hoping that's all it is . I have replaced all the 25 year old bits that needed upgrades so far and I sure am looking forward to putting it back together . Again a huge thank you and thumbs up ...



[emoji106][emoji846]

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Re: Ruff Idle ,Huge Loss of Power
 

No sweat. Let us know how you make out.

Re: Ruff Idle ,Huge Loss of Power
 

Just got the new set of ignition coils . 2 of the packages had the orange replacement rubber seal that sits under the coil on the ignition module . Do I need to replace them or am I ok to use the originals because I only have 2 replacements .
Thanks

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Re: Ruff Idle ,Huge Loss of Power
 

U should be ok. Use the ones from the good coils just for a bit of margin.

Re: Ruff Idle ,Huge Loss of Power
 

I called the supplier but won't know until Tuesday if they will send the 2 missing grommets. Would like to have new if possible . I can wait a little longer if I have too and then original ones actually look good and are still soft and not gotten brittle being 25 years old or more .
Thanks

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Re: Ruff Idle ,Huge Loss of Power
 

Up and running again . Idle is smooth . Sounds really good so far . Taking it for a test drive tomorrow .
Thanks again for all the help trouble shooting the trouble [emoji16].
Ride tomorrow will show if it's working correctly.
[emoji846]

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Re: Ruff Idle ,Huge Loss of Power
 

Well done Mike, you stuck with it and sure that you have solved the problem!

Re: Ruff Idle ,Huge Loss of Power
 

Thanks Charlie . Tomorrow will tell the tale .
Looking forward to the test drive . Weather looks good with cool air temperatures so the Z is gonna enjoy that [emoji1]

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Re: Ruff Idle ,Huge Loss of Power
 

Well scratch the drive tomorrow . My dog just got nailed by a skunk . Jumped in the bath with her to try the tomatoes juice trick . Whole house stinks including me because I had to pick her up and pull her off the skunk .
Not getting in the Z with this smell on me lol . Sitting up all night with her . Locked her in the front foyer with a baby gate . Poor thing . Spray got in her eyes .
Her name is Pogo by the way and she is a Beagle/ Whippet mix .
Tapatalk wont let me upload photos anymore
[emoji19]

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Re: Ruff Idle ,Huge Loss of Power
 

I have been skunked before it takes about two weeks to wear off!

:-x

Re: Ruff Idle ,Huge Loss of Power
 

We've got two Jack Russell's that can't pass on any opportunities to "Hunt", no matter the consequences!

Use Dawn soap (cuts the oil) and baking soda. It's the oil you need to get rid of. Anything you touched in the house is now contaminated! May require professional cleaning or replacement (personal experience!)

Great news on the coils! I had same on my '91! Stumbled under load..

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Re: Ruff Idle ,Huge Loss of Power
 

You're not coming to coffee tomorrow smelling
like that are you?