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Knock Retard - Stock

rfmgtp02

rfmgtp02

New member
Hey guys. Recently my car has had somewhat of a starting issue. Car would have trouble starting cold. She cranks fine and usually it just takes a couple turns of the starter to get her to fire up. Most of the time when its warmed up, there is less of a problem. At first it was random as to when it would do this but has become more consistent lately. Couldnt hear the fuel pump priming properly so i changed it... seems slightly better but still not "turn key".

Along with this starting issue... i had begin to notice a high rpm "flutter".... installed an aeroforce and i see im getting KR whenever i get into boost. Prior to changing the pump i figured that the pump possibly wasnt giving the motor enough fuel... however the KR remains. This flutter of the tachometer has gotten progressively worse over the past couple months. I assume what im seeing/feeling is knock retard. Otherwise the engine runs perfectly. No trouble codes or misfires showing up.

I have a good understanding of what KR is and its purpose however i dont understand why i have so much. Ive seen as high as 8 degrees and at that point i stopped using boost... this is definately not false knock. The car is basically stock. I have a CAI, stock 3.8", silencer slits filled and a very slight port job on the blower. I know some people dont like filling the slits but its been holding up for over a year and a half and no problems. Tune is stock as well. All the maintenance is good on the car.... plugs... filters... fluids.. etc. Shes got 136,000 miles. No vacumm leaks that i can finsd. LIM done 40k ago.

Parts that have been recently changed are:
Fuel Pump
FPR
O2 Sensor
MAF
IAC


I honestly have no clue as to why i have so much KR (or any at all for that matter)... i could use any advice you guys may have. thanks in advance
 


The KR you have is pretty much normal. You will have more in the cold weather too.

Im in the same boat, my car is 99% stock and I get 5-6 kr at WOT, thats what my aeroforce says. Some cars will have more KR than others.

Im kinda at a loss to with your starting problem. All the guess I had about things that could be bad, you have already replaced.

Im sure somebody else will chime in.
 
a couple of degrees of KR might be normal on a stock car... but not 8+ degrees... and that wasnt even WOT.... trust me its not normal... this high rev flutter never existed until recently
 
I don't like the slits because you don't know what happens to them...are they still in the blower? Have you checked that they haven't fallen into the engine and been chewed up? Just sayin'.

Anywho...Check the motor mounts...they might be shot...could very well be false KR...Also...might be the downpipe making contact with the sway bar if the mounts are shot. Gotta rule out that stuff first. Also...think about it this way too...if you have more air coming INTO the engine; eg: Intake/Ported Blower...and you have everything factory exhaust wise...eg: CAN'T BREATHE...It's possible that could be where a good amount of your knock is coming from too. At least get a downpipe...quit chokin' that thing. When you changed the plugs did they look good? Condition? Color? Were the electrodes fine? Just trying to rule everything out for you...
 
Blower slits are solid. Aluminum epoxy and there's really no way they could fall out. . 40k miles running them filled. I inspected them recently. No problems till the last couple months.
Motor mounts are a possibility. I'll check them out this weekend.. Any tips with inspecting them other than visually. I know you should check for excessive engine movement obviously. Don't even really hear and clunks or louse noise from the front so I never really considered them.

Plugs I changed a few months ago. Also inspected today electrode looks good. Gapped at .060". TR55. Considering throwing 104s in but I don't see why I should need a colder plug on a 3.8". Car never seemed to have this kr before so I feel something is bad. The only things I can think of would be maybe the cat or egr valve but I would probably have a code by now.

You do make a good point about the exhaust. I've considered putting headers on the car... I'd want to get it tuned at that point then as well bc I'm sure the motor would be lean if it isn't already. Alot of money to do it right..... I'd want to put a new cat on at the same time. Still doesn't explain where mu starting issue is coming from unless the injectors are beat. I'm gonna check to see if they leak shortly.
The only reason I'm skeptical that the exhaust being stock is my problem is because I've had the car set up like this for a while. Granted I didn't have the aeroforce that whole time so i don't really know I didnt have kr. I could feel this problem before I hooked the gauge up unfortunatly. So I don't have much to run with in that sense
 
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My car doesn't like the really cold weather either. It's rough starting, and sometimes needs another crank, but starts and runs fine.
 
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