Knock

[achalmersman]

If the strainers are jacked up and restricted he could have good pressure at idle but as the need for more fuel is there the restriction won't allow it. Just like having a jacked up filter. He saw a big difference when changing the filter and I bet he will be seeing the same junk in the tank. I have stock coils on my gn as many do and have been mid 10's with more left in it....it's not his coils. I would have found a cheapo fuel pressure gauge that can be temporarily routed where he can see it and when all the issues are there he will see fuel pressure dropping a lot. Wish you were near me cause this would be fixed in a quickness.

that is why I said under WOT if it does not drop. I'm just trying to save the guy some trouble.
If he puts a fuel pressure gauge on the windshield so that he can read it while driving and while running WOT the pressure does not drop (do this several times while duplicating the problem) there is no "volume" problem. This is very basic drivability troubleshooting.

 

[EYE-OPENER]

Wot one too many times and he's picking up pieces of head gasket in his oil pick up and hopefully it's that small of an issue. Less than 30 minutes and the tanks on the ground and able to see what's going on in the tank. If the filter helped his issue then he's heading down the right road.

 

[achalmersman]

Wot one too many times and he's picking up pieces of head gasket in his oil pick up and hopefully it's that small of an issue. Less than 30 minutes and the tanks on the ground and able to see what's going on in the tank. If the filter helped his issue then he's heading down the right road.

WOT using common sense. Watch the pressure and let off when you verify the concern. I'm not debating here. I'm telling you how to diagnose/confirm fuel pressure issues the correct way. Not spend time guessing and playing around. If you like tinkering fine, every TR tank out there could probably use a cleaning. But he needs to determine if there even IS a fuel problem. If He drops the tank and sees no restriction what is he going to do?

Put fuel pressure gauge on windshield. Drive car duplicate issue and verify if fuel pressure is consistent. If it is, end of story. Start hunting down another cause. If it is falling under WOT pull the tank down and inspect as stated above. If no problem is found and tank is clean you won't wast precious time (time is money) by reinstalling the tank and wondering if you STILL have a fuel problem because you never properly diagnosed the pressure problem in the first place. You will know to do voltage drop tests, etc to determine if the pump is weak or if you have a potential electrical issue. If the pump is weak and there are no electrical issues you replace the pump and reinstall the tank. No pulling, reinstalling, over and over. No guessing. This IS the right way to diagnose a suspected fuel pressure problem. Now if you like guessing and tinkering by all means. I don't have the time. The more time I spend on my own vehicle the less I spend fixing customers vehicles which is what keeps the business running. Take y advise. Take 5 min and drive the car with a fuel pressure gauge. Then you will know if your heading down the right path or not.

 

[TurboBuRick]

Gauge on the windshield does not always tell the story.

Data logs are the real way to go.

Rl

 

[EYE-OPENER]

He doesn't have a scan tool and obviously no pressure tester either. Filter was junked up and it ran better after replacement. If you polled every tr owner here that popped a gasket with similar issues and trying to figure out an issue you might be surprised. Common sense isn't roll into boost with an obvious lean condition but to try and figure out the issue. And from what it seems as he is working in his garage or driveway with minimal tools it makes sense to check out the simple obvious problems. We can measure our junk by slinging our ase certificates and what our parents did for a living but sometimes keeping it simple and to suit what some people actually have the tools and abilities to figure it out with. I'm a master tech btw and us posting that means crap because it's not info that will help him figure out his problem. Sometimes keeping it simple is the way to go. So again, he dropped the filter...it was junked up....a new one made a good difference....but still has knock and an obvious lean/ detonation issue. So why not completely rule out the tank being full of particles and strainer being jacked up before looking anywhere else? I agree there could be many other things causing this issue....but stay in one direction til you know that's not the issue.

 

[achalmersman]

He can do as he wishes. How do you know he is lean? No scan tool. No fuel pressure readings? No anything. My definition of simple is borrow a gauge if he doesn't have one. Without a scan tool or accurate pressure readings while road testing you are guessing. Be my guest. I'm trying to save time lol. I just can't believe you would not recomm end the guy to properly test his fuel delivery system. I'm sure there is someone that would loan him a gauge if he doesn't have one.

Also. Buy a scan tool if you plan on keeping the car. You don't even know if the ECM is retarding the timing correct? I assume it is? I've given my suggestion which is the way its done in the field. There isn't time to guess and I would never trust my guess. If I thought my car was lean I would have pressure gauge on it in 2 min

 

[achalmersman]

True. Does not ALWAYS tell the whole story. But for a buy without a scanner it is the starting point.

Agreed about the data logs. Definitely the best but I don't think he has a scanner

 

[EYE-OPENER]

Post 40 I suggested the pressure tester. If he has no pressure tester, scanmaster, or any way to log what's happening he may be stuck with my suggestions. Hopefully he can borrow some basic testers. If he had access to the testers most of us have already then I would have never suggested dropping a tank or even a filter unless it was an apparent lean issue. Every tr owner should have a knocks sensor with audible tone, scanmaster, and a fuel pressure gauge inside. I know most of us have more than that going on though. So hopefully he can get her figured out and definitely give feedback as to what he finds out.

 

[achalmersman]

Put a scan tool on it and get rid of the light show. The scan tool will tell you how much timing is being taken out (how bad the knock is). And let you know what your sensors and computer are seeing. Without that your just shooting in the dark. Pull the plugs and look at them. I doubt the coil is the problem. They usually start to break up when they get hot or miss like he!! when they die. Clean the tank out and put a pump and hotwire kit on it. Get a manual for the maf translator and make sure it's set properly for your maf. Make sure there is nothing loose or rattling on the car. Could he false knock.

This is the best advice you have been given so far. Troubleshooting issues like this is a multi-step process. Verify the ECM is retarding timing, and at the same time look at the data and see if the car is running lean. If its running lean, proceed to fuel pressure troubleshooting which has already been discussed in great detail. Obviously we have our disagreements on that process. I just don't want you chasing your tails in circles. Follow the multi-step process. I have been there. It's hard figuring out what others before you have done

 

[jdanna]

OK I finally got my turbotweak chip and scanmaster installed.

Now when i slam the gas, or on a hard shift, and every so often when i lift off quickly when its at WOT, im getting between 0-2 deg KR.
Once i saw a 3.7 and a 4.something when i just planted the throttle and the transmission kicked down hard.

Fuel pressure is set at 43psi with the vacuum line off.

Is that an OK amount of KR for a car with just mild upgrades like mine?
What else can i tweak to try and get it to 0 all the time?

 

[jdanna]

I should add say that the scanmaster isnt reading any codes, and the o2 sensor, BL, and other readings seem to be pretty close to what the scanmaster manual says they should be.

 

[jdanna]

Also - TPS is reading .4-4.2 (or 4.22)
The idle o2 reading may be a bit low, o2 sensor is reading between .400 and .600

 

[turboTchris]

i would take the car to a really good mechanic, i found one on the board so just put it out there and someone will point you in the right direction, i would not run the car@ WOT until you get this figured out before you blow a head gasket. i had a similar problem and got the car up to date now I'm running 20lbs no problem with no knock but i keep one eye on the road and one on my gauges. your car is old and it may have some bugs,these cars are tricky i mean GM never built anything like these cars and whatever you do don't take it to a buick dealer.

 

[HouTX87]

I was getting knock at 15psi on 93 octane. I just started adding 20% xylene, no more knock and I have the boost turned up to 18psi now. Get it at sherwin williams or lowes but add a few ounces of marvel mystery oil for lubrication.

 

[jdanna]

I've got it to the point now where the only knock i ever get is on a shift of when i first punch it or let off hard
I think it may be false knock because i have an intermittent rattle like a loose heat sheild i havent been able to find yet.

its all on hold til my new radiator comes in - then i can get the car back together and try to hunt it down.

But i think that 16psi at WOT with 0 KR is progress