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Stuck lifter?


xtremerevolution
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Yeah. 40-50 knock per 0-45 WOT run. Not good, at all.

 

I had 3/4 a tank in the car, so I filled up the last 1/4 with 93 octane, and put in a bottle of octane booster. Lets see if this makes a difference.

 

I wonder if this had anything to do with my rough idle. Or, I wonder if this did any damage to my engine that is now causing the rough idle. I really don't know. I'd have to think it through for a while longer.

 

My theory is that if I made such a big difference with the heads, I should theoretically get better airflow, which means more air flows into the pistons. If more air flows into the pistons, more air is compressed at TDC, which means my compression is higher, which means I need higher octane fuel.

 

you MAY be on to something there... especially since the MAF reading was still climbing at the shift points of ~5250 RPM... though i wouldn't try to take it any higher, your injectors will have run out of room. and that would be refered to as dynamic compression... you could bleed some off with a cam that has a later IVC... and i say heads because certain types of combustion chambers are more prone to knocking than others. a good example is the hemi-type head on the LQ1: RARELY generates actual knock unless you go fucktarded with the spark advance, but you'll likely have passed the optimal advance for the fuel long before that. i know those iron 3800 heads need lots of advance... i've seen it get to 50* before just on the main spark table... then add in EGR advance and you're potentially talking 55* of advance...

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Do you think this could be causing my rough idle? Any other ideas as to why this is happening? It would certainly explain the vibration I've been having at certain RPM's while accelerating. I wonder how dangerous this is for my pistons.

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Do you think this could be causing my rough idle? Any other ideas as to why this is happening? It would certainly explain the vibration I've been having at certain RPM's while accelerating. I wonder how dangerous this is for my pistons.

 

possibility... if running a better grade of fuel doesn't get rid of/seriously reduce it, it's false knock... which is a whole other ball of worms itself...

 

as for piston danger: detonation WILL damage an engine, pre-ignition WILL destroy it in short order... it's determining which is happening is the problem.

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possibility... if running a better grade of fuel doesn't get rid of/seriously reduce it, it's false knock... which is a whole other ball of worms itself...

 

as for piston danger: detonation WILL damage an engine, pre-ignition WILL destroy it in short order... it's determining which is happening is the problem.

 

I think I had a form of this when I had two wires switched on the Olds. You can definitely tell when it's happening.

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Well something definitely isn't right and I haven't yet figured it out. I put in a bottle of STP octane booster last night, and put in another bottle of "Turbo octane booster" with MMT today, which supposedly raises it to 108 octane. I'll plug my laptop in when I get home from work and see what's going on. I still feel the same vibration under idle, which leads me to believe this might not be the problem and it might be false knock as Robert pointed out.

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Have you hooked a vacuum gauge to the engine? A large vacuum leak would naturally lean the mixture, leading to increased spark knock, and poor idle quality...

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Have you hooked a vacuum gauge to the engine? A large vacuum leak would naturally lean the mixture, leading to increased spark knock, and poor idle quality...

 

here's why i'm going to say that's not happening, or at least isn't the primary issue:

 

at WOT, the engine maintains a good 12:1 AFR.

 

when in closed loop, even though it is running a bit lean, the PCM is correcting for it.

 

EDIT: another reason: the IAC steps are roughly 17 at idle, which is perfectly normal. if air was slipping in elsewhere, the IAC counts would be closer to, if not 0, and the idle would be higher...

Edited by RobertISaar
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octane boosters aren't worth the bottle they come in...

 

Damn. Well in that case, I'll just have to wait for this tank to empty out so I can fill up with premium...

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I don't know if this is your problem, but I've seen it at least twice, on two Buick V-6 engines. The crank position sensor sits behind the harmonic balancer, and is operated by detecting gaps in some rings behind the crank damper. I've seen two cases where the rubber is breaking down, causing the balancer to wobble. Creates a good bit of noise, and confuses the crank sensor, because the rings are no longer a consistent distance from the sensor.

 

I'm clutching at straws here....

 

Also, be sure to check the wiring for the cam position sensor, (best I recall the 3800 uses one)...it may be lying to the ECM...and I have heard of oil leaks in the valley screwing up the sensor on some cars...but I'll freely admit, I'm not certain this is an issue on 3800 Buicks.

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I don't know if this is your problem, but I've seen it at least twice, on two Buick V-6 engines. The crank position sensor sits behind the harmonic balancer, and is operated by detecting gaps in some rings behind the crank damper. I've seen two cases where the rubber is breaking down, causing the balancer to wobble. Creates a good bit of noise, and confuses the crank sensor, because the rings are no longer a consistent distance from the sensor.

 

I'm clutching at straws here....

 

Also, be sure to check the wiring for the cam position sensor, (best I recall the 3800 uses one)...it may be lying to the ECM...and I have heard of oil leaks in the valley screwing up the sensor on some cars...but I'll freely admit, I'm not certain this is an issue on 3800 Buicks.

 

How could I even check if the rubber is breaking down and causing it to wobble? I'll admit this is a possibility, but how I would go about figuring it out is a different story. I've also heard its a huge pain in the ass to get that thing off on some engines. This is a very valid possibility.

 

As for my crank sensor, it appears to be sealed and is held on by one bolt. Its not like the earlier 3800's before mine. Its a $30 part and can be replaced in 2 minutes. I actually replaced it just for shits and giggles when I had my puttering sound before I changed the heads, and it made no difference at all, in absolutely anything, so I put the old one back.

 

I will definitely unplug it and plug it back in to check the wiring.

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The two I diagnosed, I simply started the engine, and watched it. One wobbled when I raced the engine, and the other wobbled so badly, I was surprised the car was even running. In both cases, I found cracks all the way around the "ring" of rubber that separates the inner and outer portion of the balancer.

 

...and yes, some are a pain. The first one took almost all day to fix, the other, the balancer practically fell off the car once the bolt was broken loose.

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The two I diagnosed, I simply started the engine, and watched it. One wobbled when I raced the engine, and the other wobbled so badly, I was surprised the car was even running. In both cases, I found cracks all the way around the "ring" of rubber that separates the inner and outer portion of the balancer.

 

...and yes, some are a pain. The first one took almost all day to fix, the other, the balancer practically fell off the car once the bolt was broken loose.

 

So I take it then that it should have absolutely no wobble at all?

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I've never seen one that had no wobble at all, you're looking for a lot of wobble.

 

...that's probably the most ridiculous sounding thing I've ever written...:)

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I've never seen one that had no wobble at all, you're looking for a lot of wobble.

 

...that's probably the most ridiculous sounding thing I've ever written...:)

 

Ah, well I did check that over several times, and the wobble was not significant. It was barely there if at all.

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Or it could just be your amatuer port job has just cause nothing but issues.

 

And your injectors are running damn near static. Get larger ones in there and somehow tune it. You really dont want the duty cycle higher than 80%

 

And by porting the heads, you changed the engines VE.. which means bare minimum the MAF needs recalibrated and of course your stock spark tables will cause nothing but issues.

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Or it could just be your amatuer port job has just cause nothing but issues.

 

And your injectors are running damn near static. Get larger ones in there and somehow tune it. You really dont want the duty cycle higher than 80%

 

And by porting the heads, you changed the engines VE.. which means bare minimum the MAF needs recalibrated and of course your stock spark tables will cause nothing but issues.

 

I'm going to pretend to ignore the attitude.

 

First off, can I just run L67 injectors, or do I need to tune for them. The Bonneville guys are telling me I need to be closer to 14:1 AFR, not 12:1.

 

Second off, my porting job is decent at worst. I didn't change the shape or the size of the intake ports, and the bulk of the material was removed from the exhaust ports, where it doesn't matter as much anyway. This is not a boosted engine.

 

If you wouldn't mind going into more detail as far as spark tables go, I'd appreciate it. How does changing the VE alter my spark tables? You have to understand I've never tuned a car in my life, so a bit of detail would be appreciated.

 

I'll get on the tuning thing asap.

 

Robert, I need you to help me find each and every component that I need to tune this car, and I mean everything from software to cables to a chip burner, to the bin that I need to use.

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The Bonneville guys are telling me I need to be closer to 14:1 AFR, not 12:1.

 

you show me a gasoline power engine that lasts 60 seconds at 14:1 AFR at WOT and i'll shit bricks on your enemies doorsteps... TWICE!

 

i'll start PMing later this evening about what you'll need...

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you show me a gasoline power engine that lasts 60 seconds at 14:1 AFR at WOT and i'll shit bricks on your enemies doorsteps... TWICE!

 

i'll start PMing later this evening about what you'll need...

 

Well nevermind then, lol.

 

Thanks. I appreciate it.

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I looked through the log a bit more. I'm getting as high as 6.0 KR. I'm really hoping running premium fuel will help my cause a bit.

 

Airflow is at 141 grams per second though at the shit point. Whatever that means. Sure looks higher than the number I used to be getting.

 

Here's to hoping I don't damage these pistons.

Edited by xtremerevolution
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You will have to tune for any injectors that do not flow the same as stock.

 

14:1 AFR = not good!

 

6* of KR on a N/A 3800 is not a very big deal, KR is not a big deal with N/A like it is with F/I.

 

If you can cut it in half you will be just fine. ( Run high test gas, Reset fuel trims, VE tune, MAF tune, And pull timing if need be. )

Edited by MonteCarloDude
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Man I'm going to need a lot of help here, lol. This is me having to learn how to tune the hard way, and on OBD 1.5 to boot. Thank God it can at least be done.

 

I take it that I can tune for higher injectors? If so, GREAT. I'll start looking for L67 injectors.

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Man I'm going to need a lot of help here, lol. This is me having to learn how to tune the hard way, and on OBD 1.5 to boot. Thank God it can at least be done.

 

I take it that I can tune for higher injectors? If so, GREAT. I'll start looking for L67 injectors.

 

L67 are what, 32lb/hr? overkill to say the least... what are the stockers? 19 lb/hr?

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