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Old 09-11-2017, 05:53 PM   #16
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Re: misfire under load

Ok. Thanks for the help. It feels like it has gotten worse. Now when starting slow in first, it sounds and feels like it dropped a couple cylinders until I give it more gas. If I shift to second too early, it will do it then too until more gas is applied.
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Old 09-11-2017, 07:04 PM   #17
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Re: misfire under load

Have you checked the fuel pressure, out on the road, with the engine under load? Seems OK in power enrichment mode, but why does is lean out for a few seconds at idle? Both sides could be erratic fuel pressure, one side could be an injector. But you have both situations happening.

There's also a lot of drift up an down in the idle RPM. When the engine is warming up, it's surging up to 200 RPM above target idle speed. That can be a peculiarity of the cam surge, and how well the tuner was able to control it.

Who assembled the timing set? Could it be off by a tooth?

Do you have any lifter noise that comes and goes from tine to time?
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Old 09-13-2017, 02:49 PM   #18
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Re: misfire under load

A new member (GarageBuM) mentioned he had a similar problem, and it turned out to be a screw on the Opti rotor that fell out and was bouncing around in the cap. He asked if you used Loc-Tite when you installed the rotor?
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Old 09-13-2017, 02:59 PM   #19
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Re: misfire under load

My engine builder did it along with the engine but I'm guessing he didn't. I was going to take it apart this weekend and take a look at it. Don't want to but I think I have to.
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Old 09-14-2017, 05:07 PM   #20
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Re: misfire under load

Quote:
Originally Posted by Injuneer View Post
A new member (GarageBuM) mentioned he had a similar problem, and it turned out to be a screw on the Opti rotor that fell out and was bouncing around in the cap. He asked if you used Loc-Tite when you installed the rotor?
So I got the opti apart. The rotor screws were not loc-tite but they were tight. the contact on the rotor looks dirty or corroded. Is that normal? And the case had some crud on the inside. See pics. Everything else looked good. I was hoping that was my issue 😣
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misfire under load-tmp_26353-img_20170914_165943461661932870.jpg   misfire under load-tmp_26353-img_20170914_1659327761440967924.jpg   misfire under load-tmp_26353-img_20170914_1659049201157653208.jpg   misfire under load-tmp_26353-img_20170914_165809026861875451.jpg  
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Old 09-18-2017, 02:27 AM   #21
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Re: misfire under load

I did a full tune up fuel pump fuel filter when it warms up it idles crazy when I stomp on it bogs out if I drive it like my grand would it's fine besides the hesitation in idle going up and down when it warms up please help it starts right up every time I turn key

Msd Optispark spark plug msd wires fuel filter throttle position sensor water pump K&N air box oil change battery I cut the cats off map sensor fuel pump fuel filter stuff I done already
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Old 09-18-2017, 10:47 AM   #22
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Re: misfire under load

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Originally Posted by Tr1ggger View Post
I did a full tune up fuel pump fuel filter when it warms up it idles crazy when I stomp on it bogs out if I drive it like my grand would it's fine besides the hesitation in idle going up and down when it warms up please help it starts right up every time I turn key

Msd Optispark spark plug msd wires fuel filter throttle position sensor water pump K&N air box oil change battery I cut the cats off map sensor fuel pump fuel filter stuff I done already
Might want to add a signature so we know the year, etc. Not all years of the LT1 are identical.

https://www.camaroz28.com/forums/lt1...nature-879835/

Also better to start your own thread, rather than hijack someone else's. Gets too confusing when people are responding to two different topics.

Did you buy the MSD Opti recently? Most of the MSD's sold over the past year (maybe 2 years) or so have had problems with erratic idle, due to issues with the optical cam position module. Easy to track down with a data log of the PCM. I have provided proof of this to MSD through one of their employees on another LT1 site. Last feedback was that they have resolved the problem by changing their optical modules.

Have you scanned it for codes? Did you have either of these problems (bogging, erratic idle) BEFORE you did the "tune up"?
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Old 09-18-2017, 11:44 AM   #23
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Re: misfire under load

95 z28 a4 stock got my optispark 2 months ago from team c it was doing this when I bought the car it had a black opitpark didn't know how to start my own thread new to this stuff I changed all those parts to fix this problem the car has 118 on it og the ac works for crying out loud I'm stuck
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Old 09-18-2017, 02:55 PM   #24
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Re: misfire under load

Best thing to do is download Scan9495, get a 16-pin OBD-1 cable (recommendations in the link) and run a data log of the car from cold startup, idling through closed loop to reveal the erratic idle speed, and then street driving it under the same conditions that produce the bog.

Attach the data log to a post so I can download it, and take a look at it.

https://www.camaroz28.com/forums/com...95-lt1-874306/

The author of Scan9495 is a member here, and can help with any problems encountered with the install or operation. He does live in Florida, and is struggling with restoring his home, so can't guarantee that the response will be immediate.

Can't guarantee it will diagnose the problem, but it has helped a lot in the past. To repeat my earlier question, HAVE YOU EVER SCANNED IT FOR CODES?

To start a new thread, open the forum you want to post it in. At the top of the topic listing (just above the "Threads in Forum" solid red bar) for the forum is a "NEW THREAD" button.
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Old 09-18-2017, 03:10 PM   #25
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Re: misfire under load

Your very helpful I appreciate it it will give a code even if the check engine light not on it works cause I took the maf plug off and it came on I will buy the ob1 and do the data scanasap
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Old 09-18-2017, 03:29 PM   #26
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Re: misfire under load

There are some codes that do not turn on the SES light. But the codes are stored, like all codes that set, and can be picked up with a code scanner. The Scan9495 software will record codes.

In addition, it gives you a record of all the sensor readings, and the calculated PCM parameters like injector pulse width, spark advance, knock retard, commanded idle air counts, target idle RPM, etc. By looking for places where the symptoms show up, like idle surge, and looking at what info the PCM was receiving, and how it responded, it is often possible to identify the cause of the problem.
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