knock help

[Mike Marnik]

Ok i have searched the site and couldn't find anything to help me. i don't know if I'm really bad at searching for things or what. But here is my dilemma. I just finished a overhaul of my engine mainly balance shaft removal and new bottom end gaskets and seals. i had the boost set at about 13-14 psi and would creep up to about 15 or so. I wouldn't get any knock till about 5000 rpm where it would hit around 19-23 counts then rise up to 43 or so so i went and turned the boost down to 10 psi and it will creep to about 12 or so. Now the knock goes up to about 14-18 counts at 5k and then up to 36 or so. i don't know why it is doing this all i can think of is maybe a boost leak would cause this or my fuel pump is going out because i can hear is making a loud whining noise at idle. i cant hear it after that because of the damn vibrations from the prothane motor mounts and exhaust i do some time though. I wanna get this figured out so i can get it out to the track before the season gets over to get a base line before winter hits and i start doing the fuel system. thanks for any help guys i really appreciate it.

 

[ddavisaf]

Pull your plugs and check their condition. Post your fuel trim logs?

 

[andymoraitis]

It mentions in your profile that you have an AFC and an otherwise stock fuel system. It would be critical to verify that the AFC is zeroed out. As mentioned above, a log would be helpful as well as pulling the plugs and checking their condition. On a final note, your knock sensor is close to 15 years old. It would be advisable to remove it and see if it has a bunch of goo on it. If so, it's shot and needs to be replaced.

Hope that helps,

Andy

 

[ddavisaf]

I'm was hoping I could lure you out I figured the knock post would get your attention

 

[andymoraitis]

I'm was hoping I could lure you out I figured the knock post would get your attention

Knock, A/F and timing always get my attention. You were certainly right in thinking I'd jump in on this one!

Cheers,

Andy

P.S. No luck on a cheapie 1G for you yet, but I haven't given up

 

[ddavisaf]

Sold my car for 6k Keep an eye out for me buddy

 

[Mike Marnik]

actually my knock sensor is less than 2 weeks old i replaced it with the over haul i did. the plugs are also about a month old but i think i may have fould one or 2 of them so i think im just going to be replaceing them anyway sience its cheap enough. oh and the safc was taken out the previous owner did a poor job installing it. I will do some fuel trim logging also im not sure how to upload them to my computer though if you could help me with that or what thiere supposed to be at. P.S. im updating my profile now. thanks guys

 

[Mike Marnik]

hey i did some logging and found out what my low mid and high fuel trims are. Low = 106% Mid = 100% High= 87%. Also i put some 92 octane in was 91 and it seemed to help a little bit not too much though and i bought some new nkg brp7es i believe at least one is fouling because if i hold the rpms up to 3-4 i can hear it missing, and last but not least i bought some fuel treatment to clean my injectors and fuel system to see if that helps (seafoam). I out half in about 6-7 gallons of gas the rest I'm going to fun threw the engine in a week or so when i need to change the oil. i am going to put the plugs in here in a little bit when the engine cools off and i will get some more logs.

 

[andymoraitis]

Mike,

Sounds good. Once you get us some logs that'll give us concrete data to look at. I'm a bit conerned that you're fouling plugs though. What do you have them gapped to?

Also, a Seafoam treatment is best done by sucking the bottle dry with the vacuum line from the manifold. Hold the RPM's at about 3000 to keep the car from stalling, suck the whole bottle in while pinching the line (she'll smoke something fierce), shut it off and then drive the wheels off of it after letting it sit for 15 minutes. You may be knocking from carbon buildup and that's the best way to get rid of it. Ah, and don't forget to change the oil when you're done.

Unfortunately, the 91 piss water you're running doesn't help. Try to get 93 or 94 if it's available since every little bit helps.

Andy

 

[Mike Marnik]

i already did the seafoam threw the intake mani a month ago but i think i might have let it sit for too long (over nite) because it didn't smoke much at all when i started it the next day although it did when I was sucking it in i will suck the rest of the bottle in soon i just dint wanna change my oil i just did that 300 miles ago and mobile 1 synthetic is expensive for a college student although with the overhaul i should probally change it soon anyway. why would i be fouling the plug though just wondering i do believe that at least one is fouled though. i think I'm just going to do the rest of the seafoam any way i don't like knock . thank you for all the help i really appreciate it here goes.

 

[andymoraitis]

why would i be fouling the plug though just wondering i do believe that at least one is fouled though.

Mike,

You COULD have a bad plug wire or two and the inconsistent spark is causing the plug to foul. Also, make sure that the plug gap is set correctly to .028. If the gap is too wide, it may be too much for the spark to jump without an aftermarket ignition and incomplete fuel burn and an occasional stutter under boost load would be the result.

Hang in there!

Andy

 

[BoostActionBob]

what kind of plugs are you using. ngk bpr7es got rid of some of my high end knock

 

[Mike Marnik]

ya im running brp7es's and my plug wires are brand new also (magnecor 8.5mm) the knock has come down about 7 count still not enough i will e-mail you some of my logs i have made if that will help any if u give me ## e-mail adress. tomorrow i am going to be putting some 93 octane in. i found a gas station with it. Also i am getting boot creep very bad i think it might be because of my boost controller (turboxs mbc) where the 2 o rings are on the out side when i blow into it with the needle valve turned in all the way and then out maybe a turn and the other end blocked off i can hear air coming from the rings i dont know if its supposed to do this or not. hope this helps i really want to get this taken car of it is amazingly the only thing left that is wrong with the car. again guys thanks a million for all this help.