jamesbob02

I've posted a few times before about how my power seemed to disappear (couldnt even spin tires), and my engine was overheating. Long story short, it turns out that my balancer's outer ring slipped, and was off 35 degrees!! I ordered a Fluidampr, put it on (which was a bitch until I found the right tool), put the car back together, and timed it to 9 BTDC - from 15 ATDC!!! WOW! Throttle response is all back, the car is kicking my *** back into the seat again. I was so discouraged.....its like I have new life lol.

However, I'm getting a lot of pinging, just like there was last time I had the timing correct. I doubt moving it back to the base at 6* BTDC will get rid of it all.....what could be causing so much pinging? I've got a stock setup and am using 91-92 gas, and stock chip......I just don't get it! The power's there, I'm just afraid to use it because of all the knock I'm getting. What should I look to?

Black 91 Z28

Congrats! How'd you figure out it was the dampener? Check the sensor itself and make sure it is ok. Mine a had chunk out of it, though I don't think it made a difference.

Also, how much is "a lot of pinging?" When does it occur?

David

AaronIROCZ

iTrader: (5)

I have found out once I started into the prom tuning there is a setting that asks for the base timing. I left it alone and just adjusted the dist from 6 to 12 and I didn't notice any pinging. But I was getting a whole lotta knock counts after I did it. so I properly tuned the chip and no knock and a little more performance. Bottom line is you are adding 3 degrees more all throught the advance table . There maybe some areas that need more timing but the other areas dont, and the areas that don't you start to ping. Now might be the time to get into prom tuning if you havnt already done so and unlock more power. But I am by no means a expert like TRAXION and others.

8Mike9

Couple things.

My '89 doesn't ping at 6*BTDC, it will ping at 8*BTDC.

I suggest first setting to factory spec of 6*BTDC (assume you're TPI?)

If it still pings, it could be due to excess carbon build up from incomplete combustions from running so far retaded for too long, also may have damaged the cat (check backpressure or vacuum for restriction) which would lend itself to pining.

So, if timing is set to spec, and still pings,

First I'd check for exhaust restriction, use the O2 sensor (good time to replace it too) hole with low pressure gauge...sould be less that 2PSI at 3000RPM's. Mine runs about .75-1 psi, FWIW.

Or, check engine vacuum at idle, stock cammmed engine should be around 20in/hg, then increase RPM (park/nuetral) to 3000RPMs, if vacuum decreases, the exhaust is restriced, beieve GM says 2in/hg loss, but if no restricion you should be at idle vacuum or higher.

If all's weel there, may want to run some GM TopEnd cleaner through it, follow the directions on the bottle. Might be time for a new set of plugs too.

camarojoe

Congrats on solving your power-loss problem. I wish good luck would come my way once in a while! I think with the stock comb. chambers 8* adv. is usually all you can get away with if you're lucky.

jamesbob02

Ok lets see if I can answer all the suggestions......

1) Knock sensor is new, pings just like before
2) New hooker exhaust system headers to tips, no cat, no restrictions.
3) Yeah, its a TPI
4) Plugs are fairly new (less than month)
5) I figured it was the dampener when I turned the timing from "6 BTDC" to "12 BTDC" and the overheating (and header glowing) stopped. I also got a lot of drivability back. I figured it must have been retarded, so I took off the balancer to see - sure enough, it was WAY off.
6)
I get lots of ping when I go WOT, from probably 2200 on up, and it gets heavier if I add a passenger (obviously, increased load).

I'll set it back to 6 and see if that doesnt fix it. I really dont think it will, but I'll try. I'll then try a good engine cleaner and see if that fixes it up. If I can't figure it out I'll come look for more help.

Thanks.

camarojoe

No, set the timing back to zero and increase in increments from there. There should be no detonation there.

Cruzin Kaz

You may even have a EGR or ESC problem too. I found that both these can and will cause ping under heavy load. I am going to assume this car is a 700r4?? If so, try driving in 3rd instead of OD. for a bit and see if this help any with ping. If so, your may have some trans problems too. Just a few other thing to lock at anyway.

jamesbob02

Ok...

1) If it's still pinging at 6*, which is stock, then something is wrong. I'm not going to just accept having to retard past base timing, although the problem may go away. It's a valid suggestion, I'd just rather figure out what is wrong.

2) I get the ping all the way through the gears. Here's a good example....If I just floor it from a stop, from about 2500 rpm (in first gear) all the way up I get pinging, progressively heavier. Obviously, I try not to let it happen too long, but I know if I didn't let off it would just keep getting heavier.

Something I've noticed today....it won't ping if it is dead cold, like I start it up cold, get out on to the street, floor it hard, no pinging. When it warms up, it starts again.

Thanks, keep 'em coming!

Cruzin Kaz

Hmm sounds like a EGR problem possibly then???

jamesbob02

I have suspected that its not working.

However, I will be putting a Stealthram on in the next few weeks, and obviously it doesnt have EGR. What should I expect to happen then? I mean I'm assumning a lot of guys go from perfectly functioning EGR's to a Stealthram and don't get a major pinging problem. What do you think?

Cruzin Kaz

They also remove the EGR from the computer too though I would think no? But serisously, I would still try the 3rd gear idea too, just to be sure your Tranny isn't contributing to the problem.

jamesbob02

Ok I completely disabled the EGR (used a different chip with it disabled), no difference. I really don't think the tranny's the problem, it's fairly new. Especially since I get it through all gears. I'll try it though.

camarojoe

How the hell could the trans. be the problem, you guys got me there? Dude, don't be stupid, retard the timing until it quits, or else risk cracking a couple of pistons in half and possible broken rings. If your dist. is installed right, and you're getting accurate timining, then your problem is probably something like leaky intake gaskets or bad valve seals. Any oil getting past the valves and in the comb. chambers will always give you pinging problems.

jamesbob02

Well the engine was rebuilt about 18 months ago, been treated well, and I know I don't have an internal oil leak. I guess I will go ahead and just retard the timing, I'm just afraid I'll lose my power again. I'm loving my low-end torque, where there is no ping.

How come I'm not getting it when the engine is cold? Is it just easier for the fuel to predetonate when the engine is hot? Is there another explanation?

demicon

Here is an off the wall suggestion..

Did ya try different octane fuel yet?

Another really simple thing ..


How about your fireing order? Did ya doulbe check that one?


No intent to insult your intelligence, but in cases like this I know the simplest things can easily be overlooked.

jamesbob02

No its cool. I use 91 or 92 octane all the time, whatever's the best I can find around. I've never tried higher, but even if it went away it probably wouldnt be worth the expense, this is my daily driver.

I'm pretty much 100% certain its not the firing order. I mean the thing feels like a beast, and only encounters the pinging problem when I mash the throttle and put a good load on it, and only when it's warmed up.

When its cold its crazy.....I'm not used to the car running right, so I don't have a lot of experience, but it feels like a 13 second car easy. That makes me very happy

I'll keep trying.....

88305tpiT/A

iTrader: (2)

Detonation likes heat so if you dont get ping when its cold that means that intake temperature is playing a part in the ping problem.

running with the timing real retarded like that can build up significant problems with coking in the chambers not to mention if you overheated it your head gaskets could be leaking coolant or your intake gaskets could be allowing a vaccuum leak. all of which could cause detonation.

bottom line is -- retard till you get NO knock at normal operating temps. then pull the plugs and look to see if any are white or have a white/yellow flaky buildup (detonation). if you find some plugs that are drastically different then you should look for vacuum leaks in that area.

If you suspect carbon buildups then run 2 bottles of your favorite fuel cleaner with 1/2 tank of 93.

gmgod

What's the compression ratio of the new engine? Try 6 degrees BTDC and see what happens, if you still get knock you may need to pull some timing from the upper tables in the prom.

jamesbob02

The engine was overbored to 357, but the heads are stock, so I'm guessing it's just a teeny bit more compression than stock.

I just got my datalogging to work, and as soon as the PROMinator is released I'll be tuning, but for now I can only look at the data .

jamesbob02

Ooo, I forgot to mention that I don't know what pistons are in it....the engine was rebuilt right before I bought the car, so I guess it's possible that they are not stock deck. I'm guessing they are, though.

camarojoe

I didn't know the engine was recently rebuilt. Maybe I missed you saying that. This being the case brings up 100 new cans of worms though. If you have higher compression than stock, that could be your problem entirely. Those stock heads suck for running much advance. You need to know what compression you have in any engine in order to tune it well. I'd suggest, like I've said, cutting back the timing where it doesn't detonate on the gas you like to run and dig into this problem when you have the time and funds to figure out what all's been done to the motor.

jamesbob02

I'm putting an HSR on soon...I think I'll go ahead and take the heads off to see how it looks under there. I guess for now I'll just cut the timing back.

prostreetpop

To add to this, I have a stock 1987 305 tpi/th700r4 which is set at 6 degrees, in the UK we have 97 octane fuel as std and have the option of 100 octane as well!!
My problem? is that if I use a fair bit of throttle from cold (in first 2-4 mins) not full throttle, just a quick pull out from the end of my road, it knocks like crazy, this is mostly avoidable, the engine is fairly high mileage, but has new valve seals, 02 sensor, Cat removed & chipped for same, MSD coil, new plugs and knock sensor checked, & new dizzy internals, and new top end gaskets (except heads).
So with the knock sensor, how can it knock???

Morley

Because the ECM can only pull out a set amount of timing for knock, Either your ESC isn't working (ie knock sensor or actual spark control) or it has pulled all the timing it can and you are still detonating.

prostreetpop

I have new parts on dizzy (spark control?) and have checked the knock sensor (tapped block with hammer) & all "seems" to work ok, I wondered if it was something to to with the cold start fuel delivery? as it does not happen after about 4 mins.
It will sometimes pink a little under load in top gear (O/D-low revs-going up hill for example) is this normal for a high mileage engine? as I really HATE that sound!!
Is there a better way to check the knock sensor? voltmeter etc?

Morley

No way that I know of to test the KS except hitting the block with a hammer/mallet near the sensor. Thats the only "test" I've ever seen printed for that sensor.

Your startup fueling is out of the picture by the time the engine reaches idle.
The best way to tell what is going on would be a scanner and wideband O2, because it sounds like your open loop operation is running lean.

prostreetpop

Hmmm... does that mean its running lean ALL the time, or just when its cold? it seems to run fine, and gets good mpg, also runs high 15 sec quarters on a temp track (poor traction) with high mileage engine, so would appear to be ok? - or not?

Morley

Makes no sense for it to perform good at WOT when warm but poorly when cold. To my knowledge both WOT and cold starting are open loop, unless there is a difference between a hot open loop and a cold one, but I've never heard of such a thing.

prostreetpop

sounds like I need to find someone in the UK with a wideband scanner thingy, but as it only happens when I give it a bit too much throttle (for a cold engine, anyway) then I will not worry too much about it. Thanks for your input though, the electronic side of the fuel injection is all a bit beyond my knowledge, the mechanics I can deal with!!

JakeJr

If you let the engine idle long enough with the EST disconnected as you set the timing to 6 degrees the headers will turn red. This is normal because the timing, being at only 6 degrees, is so late that the charge is still burning when it enters the header.

The engine will run hot too because of the reduced ignition timing it's seeing.

Once you shut down the engine, clear the error code and reconnect the EST wire, you shouldn't have either of those conditions again.

6 to 8 degrees is what most L98 guys run. More than that usually causes pinging problems.

Don't get hung up on the "number" - 6, 8, 10 whatever - as someone already said back off on the initial until the ping stops. Continuing to drive the car that way - pinging - is definitely going to call for major repairs down the road.

I'd also suggest you hook up with someone who has a ScanTool or Diacom and make sure the ECM is pulling out timing when the Knock sensor detects detonation. It will show up as Spark Control Counts and Knock Retard (Diacom) on the screen.

Jake

jamesbob02

No the overheating and header glowing was when my timing mark was off, and with the EST connected. Now that the mark is right, those problems are gone. Now it's just the pinging.

I've done some runs using Moates and am trying to analyze the data but I can't get Performerz Analyzer to work, it locks up, so I can't see the data really.....and I'm not looking at it while I'm driving, obvously.
I'm just gonna turn the timing back til it stops.

TravisZ28MAXX

I just thought of something , and this is probably stupid but, your in oklahoma right? dont you guys have that alcohol type fuel or whatever, do you know what Im talking about? that probably has a higher octane rating than regular fuel but it takes alot more of the alcohol based fuel to burn properly than it does with regular fuel and our "stupid" computers cannot compensate for it, just a thought.

jamesbob02

I have no idea what you're talking about, but that doesn't mean it's not true about our gas here.

radiateu2

Have you tried a top end cleaning. There additives out there to clean the intake and exhaust valves. This should eliminate the ping. I am willing to bet you have a bit of coking going on. What headsdo you have and work has been done to them what is your compression ratio. You know carbon in the chambers can increase your compression ratio causing the PING

jamesbob02

Yeah I really need to try a good cleaner - what do you guys use?

As for the heads, I'm pretty sure they're just stock. The c/r is a bit more because the bore is .040 over, but can't be much.

radiateu2

I heard Marvels mystry oil work pretty good. But, Probably a couple of cans of some good carb cleaner or fuel injector cleaner would help a bit GM has an engine oil supplement that supposedly works pretty well as well as a cleaner that can be sprayed in to carbs and throttle bodies. Probably nothing more than carb cleaner too. Are your plugs fouled with oil or gas, you might need a different heat range for plugs?

jamesbob02

No they look pretty ok. Sometimes they have inconsistent dark spots on them, but they're not burnt white, oil fouled or anything. In fact, now that I think about it, the inconsistency is probably a result of the way they're indexed.

BIRD91ZRAG

iTrader: (1)

Maybe I'm out in the woods on this, but from what I've read in this post, I've concluded that it's running real lean. Here's my reasoning... 92 350 TPI car=Speed Density system. SD runs off of VE tables. Headers and no cat, performance exhaust=no longer stock. Moving more air=need for more fuel???
Possibly increasing fuel pressure=temp fix until prominator???

radiateu2

Hey Bird he said his plugs looked good. I would have thought he would have seen a lean condition on his plugs (white)

jamesbob02

I bet it runs a little lean. For one thing, it has 19lb SVO's that are running approximately 21lb at stock psi, but apparently not very lean, as the plugs are definitely not that bleach white you'd expect with a seriously lean condition. I didn't buy an AFPR because I just got my HSR with the AFPR rail set, so once I swap that on I'll definitely need to do some major tuning, but for now I'll get by on turning the fuel up once I get the swap done. I know its not the right way to do it, I just don't have the equipment to tune it yet.

Something of note: I mentioned that it acts the same way it did a while back when it ran right, as far as the pinging goes. Well, the injectors then were the stock ones. So they're definitely not the cause of the problem, but they may be perpetuating it in leaning the mixture up a bit.

Also, I turned the timing back to 5*, but it only seemed to help a little bit. It took away a lot of my power, too. SOTP, anyways. Can't wait to get chip tuning so I can add back in that timing down low to get that low-end grunt back. It's still decent now at 5*, but it was GREAT before!

Hg

The earlier post was talking about gasahol. It's like a mixture of gas and alcohol.. they did that back in the day because it was cheaper I think it was... haven't seen it around here in OKC/MWC... my dad said they used to have it around here, but a long time ago.

I used redline fuel system cleaner, it's not bad...

jamesbob02

To clean the engine, or what?

I ran FI cleaner through my system nonstop when I thought it was my injectors causing the headers to glow - (obviously it was the timing), but then I read some posts about hardcore FI cleaners screwing up the inner wax or something on the injectors. Don't remember the statement but it made me think twice about using the stuff again. The next time I think I need in injector cleaned, I'll send them off to Cruzin, and flush the lines myself.