Spark knock, hard starts and Sea Foam

L05 engine. Experiencing occasional hard starts. Car is pinging off the line at light throttle till you push the pedal down a little more, up hills ect. I am going to assume it is carbon build up. Will seafoam in the brake booster line help clear up these issues?

If it's an LO5 TBI, you can just dump it down the throttle body, it will achieve the same results as the brake booster hose. You can do both ways though if you want, I have.

I've never been sure about Seafoam, I've done it a bunch of times on different vehicles, but I was never certain I wasn't just experiencing some sort of a placebo effect with it. Did seem to get a lot of the crap out of the engine.

I read to pour the sea foam in the booster (I have done that before) and use the deep creep spray down the throttle body after stalling the engine.

"From what I've heard", you only need to use the booster hose on a car with port fuel injection, etc. since that's the best way to get the Seafoam to the top end of the engine, on TBI and carbs you can just dump it down each barrel to reach each bank of cylinders.

I've never actually stalled the engine out on purpose while doing this, just shut it off when it started to noticeably choke on the Seafoam. Let it set a while, then started the vehicle up and drove the hell out of it while fogging the neighborhood for mosquitoes...

You can actually just use the Deep Creep spray by itself with the TBI, and let the engine suck it all down, but I don't know if it would achieve the desired effect like dumping the straight fluid down to sort of choke the engine's combustion chambers with it. FYI, Deep Creep is nothing more than regular Seafoam in an aerosol can, so I don't see how using that in addition to Seafoam in a can would change anything.

Is this engine in question tuned up? Is it throwing codes or anything? Maybe there's a timing issue or a bad sensor, something making the car run too far advanced or something...

TBIs are reliable as hell, but a PITA at the same time...

No check engine light.

Does anybody know if an LT1 EGR valve will work on a TBI car?

Not sure if it's "tuned up". I don't want to throw parts at it if I don't need to.

Sounds like it is carbon build up as you suspect. After seafoam, put some in the tank along with some 93 or 94 octane, and take it for a shakedown up and down 95 a few times. should clear out. If it continues, a tuneup with distributor adjust might be needed

I never realized carbon buildup could cause pinging. The 74 does that, and sometimes is hard to start. The valve seals are GONE so maybe I'll get that out of the way in the next few weeks before the roundup!

Carbon build up is usually the #1 cause of pinging. That or bad gas, which was my first thought. But, history of the car is grandma owned since 95 and her grand daughter owned it the last few years.

it will ping if it's too lean, to test the EGR just cap the vacuum line to it

So pull off the vac line and stick a screw in it to see if it solves some pinging? If that's the case r&r the EGR? EGR for this car is like $70 which is more than an LT1 car.

yes just cap it and if it's better then change the EGR

EGR test completed and it was still pinging. I poured a can of seafoam into the gas tank and I poured half a can down the throttle body. Damn thing was pouring smoke before I even finished. Then, a huge cloud of smoke 10 minutes later after I started it up. It is still pinging. I am going to try doing another treatment with the rest of the can. This engine must be loaded with carbon. Amazingly, this car is great with fuel economy. Which also means I have to wait a long time 'till I can put some 93 in it to see if that helps my problem. My old 92 Caprice used to ping unless I used 93 octane.

How is the timing? Is it set correctly?

I'm hoping you were smart enough to read the plugs at the beginning of this adventure. Before you pumped degreaser all over them and lost out on the chance for an accurate reading

IMPALADAKID wrote:

How is the timing? Is it set correctly?

I dont know but I guess it should be checked.

Also, I have no pinging when the car is cold. Only when it warms up does it ping... and it pings pretty bad.

So I am going to try:

1. Another seafoam treatment. Let it soak in longer this time and let it just idle after starting up.

2. Run seafoam treated gas tank to empty and then fill with 93 octane.

3. Check timing and adjust as needed to reduce pinging.

any other ideas?

If all else fails should I try a MotorVac treatment?

Why? you know where to get a MotoVac treatment?
I'd like to know if you do.

There is a place in blackstone MA.

Wait, what car is this for? You pick something else up?

Maybe.

Ok so the thing was still pinging like crazy after a sea foam treatment so I did another treatment. More giant white smoke clouds and still more pinging. I burned up all the gas that was in the tank and filled it with 93 octane and it is still pinging. My next step is to check the timing. Where do I go from there? Could the plugs be wrong? Knock sensor? I am sure there is still carbon built up inside the engine but at $10 a can sea foam is expensive to keep running through the engine. It really sucks because when I go outside and fire up the car for the first time of the day it runs like a champ and does not ping at all.

Ok, so this probably wont help, but I'll think out loud.

Detonation is usually caused from bad timing or from a lean condition. You say the engine runs fine when you first run it which means after sitting overnight. That would make me think it's an issue with the car warming up and then causing the detonation. I'd say that the condition is mainly or possibly only in closed loop mode. If that's the case I'd say the engine is getting a bad signal from a sensor and leaning out the mixture. On an LO5 my guess would be an o2 sensor reading rich which is making the car lean out a bit. Either that or the injectors in the throttle body are just not keeping up with the fuel demands.

I'd start the process by adjusting the timing and making sure the balancer isn't spinning on the hub. Also check to make sure the advance canister is hooked up and there are no vacuum leaks.

Then I'd clean the fuel injectors and making sure they have a nice smooth and even fuel spray pattern. Just remove the air box and watch the injectors spray into the tb as you move the throttle linkage.

If that checks out then test the o2's and the temp senosr to make sure those are working at spec.

After all of that I'd do a fuel pressure check to rule out a fuel starvation issue.

balancer spinning on the hub, I actually had that happen years ago on a 305, what a PITA trying to figure that one out.

Wouldn't a faulty sensor or anything like that set off a CEL? There is no CEL and yes, the bulb works.

GasTT wrote:

Wouldn't a faulty sensor or anything like that set off a CEL?

No. Not all of them. You can have a faulty 02 sensor that may, or may not set cel.

I would take Brads advice and start with timing, O2s, temp sensor?

What's a good brand for the O2? Should I just get an AC delco or is the Denso brand good?

I appreciate the help and answers guys, diagnostics aren't really my thing.

disconnect the battery to reset the PCM then unplug the O2's then go for a test drive

GasTT wrote:

What's a good brand for the O2? Should I just get an AC delco or is the Denso brand good?

I appreciate the help and answers guys, diagnostics aren't really my thing.

AC Delco. But I would have it timed before throwing parts at it.

I would just stop wasting money on it. Drive it till it stops running, then throw it away.

I can't listen to that pinging anymore and if it costs a few dollars then so what.

Sell it to me. You have enough cars.

GasTT wrote:

What's a good brand for the O2? Should I just get an AC delco or is the Denso brand good?

I appreciate the help and answers guys, diagnostics aren't really my thing.

I've always used Bosch in all our cars without problems.

We threw bosch into the '94 and didn't have any problems. The trick is to use matched pairs. The cheap ones get a bad rap because one Bosch and one AC-Delco are not going to read quite the same.

There is only 1 o2 in this car so that shouldnt be a problem. I would like to use AC Delco if I can I've heard bad stuff about bosch o2 sensors.

Dude, borrow a damn timing light (if you don't have one) and spend 30 seconds to verify your timing is right! No sense in throwing parts at it if you don't start with the FIRST step.

Time it, then run it for a bit and time it again. Sometimes the balancer can slip or the hold down can not quite snag enough to hold the timing. This will rule that stuff out as a culprit. Also make sure you check the plugs, wires, cap, and rotor because if any of them are misfiring it can cause all sorts of issues. Carbon tracks in the cap or a corroded rotor tip can make the car fire the wrong plug at the wrong time. It's the same as having bare plug wires touching.

Relax, I am going to check the timing tomorrow. I havn't bought anything except some $15 shocks to stop the floating..

I'm perfectly relaxed. My first idea was get better speakers and a new CD and the bad noise will go away.

Sorry Timmy, I re-read that and it sounded way harsher than it was intended to. My bad. I am relaxed.

BTW, if they'll help, if you need any of the wiring or engine diagrams out of my FSM for the 5.7, i'll try and post them. I assume they'll mostly be the same between the Caprice and the Roadie.

Thanks guys, the timing was off.

No more pinging, she purrs like a kitten now and I didn't even throw any parts at it. LOL

Awesome! Good to hear.

Oh, and LMK what your post winter plans are with it

GasTT wrote:

Thanks guys, the timing was off.

No more pinging, she purrs like a kitten now and I didn't even throw any parts at it. LOL

Brilliant!

Cadet57 wrote:

Awesome! Good to hear.

Oh, and LMK what your post winter plans are with it

Send it to the crusher

GasTT wrote:

Cadet57 wrote:

Awesome! Good to hear.

Oh, and LMK what your post winter plans are with it

Send it to the crusher

That bad? Cuz my brother is lookin for a first car/ b-body.

It was a joke, the car has decent miles no rot and goes down the road and takes turns smoother than my caprice. I will probably keep it as a daily driver.

GasTT wrote:

It was a joke, the car has decent miles no rot and goes down the road and takes turns smoother than my caprice. I will probably keep it as a daily driver.

Ahhh. Appears i'm slow on the uptake

Good deal on the timing. Hopefully you got a bargain cause of the "problem".

Now that you are done throwing money at it does that mean Doug's 5.3L is up for grabs again?

I think I got a bargain anyway. I did not even know of the pinging. The test drive was short due to the coolant leak so it never got the temp up for me to hear the ping. Had I known about it I would've told the girl, "the motor is knocking and its junk, here's $200 for the shell".

GasTT wrote:

.............I would've told the girl, "the motor is knocking and its junk, here's $200 for the shell".

Should've started with that line anyway

Glad to see it worked out for you!

FYI, even if you've had good luck with the Bosch sensors, never use them in at least a TBI engined car. They are notorious for being out of calibration in the TBI Chevy Trucks and cause minor issues if not more! AC Delco is the only way to go with these, even for spark plugs.