Hiccup from Stop When Hard Accelerating AFTER Engine is warmed

matreyia

Major
Apr 19, 2017
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335i e93
OK folks... I have solved the hissing sound, but the hiccup still persists. Here is the summary:

From full stop, hard acceleration in any drive mode results in hiccup... this happens AFTER engine reaches operating temperature. It does not do this if cold start and before reaching 160F. This leads me to suspect the PCV Solenoid hose is not working correctly since the PCV solenoid activates only after reaching operating temperature and not otherwise. This hose/solenoid comes out from the firewall and connects directly to the throttle body and the RB external low side catch can hose connects perpendicular to this hose at the mouth of the throttle body.

This is what has been done so far:
1. Replaced all hoses and connections, clamps and couplers to all possible hose connection points on every engine and turbo part.
2. Replaced with brand new throttle body.
3. Cleaned all PCV valve adapters.
4. Replaced crankcase sensor.
5. Ran Fuel Cleaner for e85 tank.
6. Reset all adaptations in MHD
7. Battery is 100% level, all connections checked and tightened front and rear.
8. spark plugs new.
9. spark plug wires, new.
10. replace both camshaft sensors.

This is what will be done next:
1. replace PCV hose/solenoid
2. check transmission fluid level.

This problem manifests in any drive mode and regardless of traction control on/off state.
Again...only after operating temperatures are reach does it begin to hiccup and only hard acceleration from full stop.
It does not hiccup AFTER going into motion no matter how hard I slam on the pedal.
It does not hiccup from full stop IF I feather the pedal conservatively and ease into motion.
The engine feels and sound super strong, stable, smoother in idle, in park, or in drive with the brakes depressed, or in reverse with brakes depressed, and after it is in motion and under WOT. When in motion, throttle response is predictable and stable... only from a dead stop after operating temps reached does it hesitate under hard pedal press.

The last option is contacting my tuner to check the tune and logs.

Any ideas welcomed.
 
Last edited:

doublespaces

Administrator
Oct 18, 2016
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2009 E93 335i
But who in the world does that regularly enough to care?

First gear is basically unusuable for anyone except for staging and people with a big single, the gears only purpose is to get into second gear lol. If that's the only time it happens I'd call your solution solved at this point
 

dcafs

New Member
Apr 27, 2019
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2008 135i
1 to 2nd. Only after warmed up engine. It was a combination of the trans and the engine tuning that caused the issue. It is now 95% gone. The only time it comes back and backfires is from a stop and I suddenly slam the pedal all the way to the floor in D mode.
Yeah...the clue for me was that the tranny has cold engine tables and warm engine tables. Mine shifts perfect on a cold engine and only displays a problem similar to yours once warmed up.

The only other tables that I know of that have a cold engine cycle are the vanos.
 

matreyia

Major
Apr 19, 2017
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335i e93
But who in the world does that regularly enough to care?

First gear is basically unusuable for anyone except for staging and people with a big single, the gears only purpose is to get into second gear lol. If that's the only time it happens I'd call your solution solved at this point

My issue is not whether I use it enough or not, but rather it never did this before so this to me is a problem that needs to be fixed. I almost never slam it to the floor when in D mode at a stop light because it's not good for the transmission or driveline. But if I did do it, I would expect it not to sputter off.
 

doublespaces

Administrator
Oct 18, 2016
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2009 E93 335i
My issue is not whether I use it enough or not, but rather it never did this before so this to me is a problem that needs to be fixed. I almost never slam it to the floor when in D mode at a stop light because it's not good for the transmission or driveline. But if I did do it, I would expect it not to sputter off.

Yeah I see what you mean, sounds like the problem is tune related though if it doesn't do it under any other circumstance. Let us know what happens when you get the new one
 
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matreyia

Major
Apr 19, 2017
1,780
711
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335i e93
Yeah I see what you mean, sounds like the problem is tune related though if it doesn't do it under any other circumstance. Let us know what happens when you get the new one

Very excited to see the difference. Right now car runs very lean. LFTF is 17 on bank one and 24 on bank two. STFT goes to max...like 34-35 on both if I accelerate hard. So I think I am going to drive very conservatively to avoid any possible damage.