pulsing when cold?

[Black_Noise]

i have been noticing this more lately, when I start the MM, wait about 1-2 mins then back out of the driveway, once im in D and under light or normal throttle, the car pulses. after 5 mins or so its done, but it seems to be more noticeable on the 93 tune than the 91 tune. I have also noticed it before i had a programmer.

I searched for pulsing but didnt find anything.

what is it?

[Local Boy]

Mine does it also...I believe it's normal...The EEC is still in the cold start mode (1st five min.), and is cycling the injectors and timing to get it (O'2 sensors) up to operating temps...

ALOHA

[Black_Noise]

can anyone second that?

[whd507]

if its severe pulsing, I'd look at the idle air solenoid.
some variation in speed is normal, but it shouldn't affect drivability.

[Marauderjack]

Mine does it in "Open Loop"......kind of like "Choke On" with carburetor cars??:cool:

Down here it is only through the first set of up shifts since the Wx is fairly warm and "Closed Loop" operation happens fairly quickly!!:beer:

I wouldn't worry unless it is really bad!!:shake:

Marauderjack:burnout:

[Black_Noise]

thanks guys.

[GrazniM]

i have been noticing this more lately, when I start the MM, wait about 1-2 mins then back out of the driveway, once im in D and under light or normal throttle, the car pulses. after 5 mins or so its done, but it seems to be more noticeable on the 93 tune than the 91 tune. I have also noticed it before i had a programmer.

I searched for pulsing but didnt find anything.

what is it?


Holy smokes, and I thought I was crazy. I have a Lidio tune and it is definately more noticeable on the 93 than the 91 - but only cold - and the pulsing is VERY mild; I don't really notice it under any throttle condition.

I did notice this - using the XCAL with a laptop and monitoring the engine while running I recall getting quite a bit of preignition (that could not be felt or heard). By testing different combinations I learned I get the best performace when I use 93 octane fuel with the 91 tune and a spritz of octane boost additive; it's so pronounced my wife can tell whenever I dont drop in some additive.

[Black_Noise]

i have moved from the 93 program to using the 91 program while running the 92 octane.

next time i want to run the 93, will run over to a little town 5 miles away.


:confused:(weird, town of 40-45k people max octane at any station = 92, town of 300? people 93 octane):confused:

[GrazniM]

i have moved from the 93 program to using the 91 program while running the 92 octane.

next time i want to run the 93, will run over to a little town 5 miles away.


:confused:(weird, town of 40-45k people max octane at any station = 92, town of 300? people 93 octane):confused:


I've found when a particular town has a lot of high-end cars / sports cars (also associated with wealthier areas) virtually every pump is 93 octane.

[red]

Mine does it in "Open Loop"......kind of like "Choke On" with carburetor cars??

Down here it is only through the first set of up shifts since the Wx is fairly warm and "Closed Loop" operation happens fairly quickly!!

I wouldn't worry unless it is really bad!!
I agree. :agree: