Car erratic jerking and misfiring

K-Series Programmable ECU installation questions / support issues
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Hondata
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Re: Car erratic jerking and misfiring

Post by Hondata » Fri Jul 29, 2016 10:58 am

What is the fuel pressure? I think you have a combination of injectors near their minimum opening and poor spray pattern. Higher fuel pressure can help the spray pattern.

First pull the plugs and check for carbon after a couple hundred miles of normal driving. If they don't all look the same I'd suggest getting the injectors cleaned and flow tested. If they have a lot of carbon then I'd think about raising the fuel pressure to try to improve the spray pattern. Or run 8 staged injectors so you can run small injectors at cruise...
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vjunior714
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Re: Car erratic jerking and misfiring

Post by vjunior714 » Wed Aug 03, 2016 12:21 pm

Sorry for the late reply, I've been trying to borrow a friends kpro to try out and see if that helps my issue before I spend money on getting the fuel injectors checked out. But the fuel pressure is set at 60psi. I did remove the spark plugs and this is how they came out in order from Left to Right. Only two were black and the other two were white.
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vjunior714
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Re: Car erratic jerking and misfiring

Post by vjunior714 » Fri Aug 19, 2016 11:07 am

Update: Misfiring issue solved. PCV was shut closed causing so much crankcase pressure that oil gasses were going through rings into spark plugs causing misfire. Replaced PCV and issue fixed. Never thought that little shit would cause so much of a headache.

Still leaves me with the bunny hop/ jerking issue

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Re: Car erratic jerking and misfiring

Post by Hondata » Fri Aug 19, 2016 3:08 pm

Thanks for the update.
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Gtstwincam
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Re: Car erratic jerking and misfiring

Post by Gtstwincam » Thu Sep 12, 2019 2:06 pm

Sorry to bump an old thread but I can’t PM the original poster.

Have you resolved the bunny hop/ hesitation problem?

I have an 02 SI with Type S cams and valve train with reverse pin set up with SRI and Header and it was recently dyno Tuned.

I have an intermittent wild bunny hop taking off from 1st gear and a severe bog/hesitation going into 3rd gear in normal driving.

I have the KPRO in open loop now and the bunny hop is gone but I notice the bogging once in a while.

I recently put the stock ECU to pass smog and it can drive fine.. just feels like a normal a3 again.

I’d like to put the kpro back in but I’m afraid to drive in in bumper to bumper traffic

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Spunkster
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Re: Car erratic jerking and misfiring

Post by Spunkster » Thu Sep 12, 2019 2:16 pm

Have you discussed this issue with your tuner?

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Re: Car erratic jerking and misfiring

Post by Gtstwincam » Thu Sep 12, 2019 2:30 pm

Yes. I sent him a datalog and He suggested a new 02 sensor but problem still exists.

When I was monitoring the Kpro App, it was saying I was in 6th gear but I have a stock ep3 5spd.

Could this have anything to do with it? Maybe wrong gear ratios?

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Re: Car erratic jerking and misfiring

Post by Spunkster » Thu Sep 12, 2019 2:33 pm

That is a possibility. The tuner should be able to assist with settings for that and looking at the datalogs to see what is actually happening.

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Re: Car erratic jerking and misfiring

Post by Gtstwincam » Mon Sep 16, 2019 8:05 pm

Update

Tuner says to get a new O2 sensor and TPS.

The car is not safe to drive so in the meantime I uploaded a civic si basemap and car runs and does not bog or jerk.

I reviewed the tune before uploading a new basemap and noticed my tuner tuned my car using the Type S (PRB) ecu (ITR with toda header Injen Intake muteness twin loop exhaust )

Could this be my bogging/jerking Problem since my ECU is PNF?

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Re: Car erratic jerking and misfiring

Post by Gtstwincam » Mon Sep 16, 2019 11:59 pm

Update.

Problem solved.

Scaled tps and problem appears to have gone away.

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Re: Car erratic jerking and misfiring

Post by Gtstwincam » Mon Sep 16, 2019 11:59 pm

.

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