454 Gasser. Meth injection?
 

Have a 97 Chevy k3500 dually. 454 Vortec. Clean old truck. Runs great, tows good. It has a custom tune in it from that Blackbear performance guy, meant for 89 octane. Anyhow, last week, I did some data logging with it.

Timing map calls for 20* spark timing, at WOT. I am getting 6* of spark retard, in 3rd gear wot, not towing, on a cool day, 180* deg coolant temps and IAT temps in 80's. Stock timing map, was 12* I believe at WOT.

Once I run the 87 fuel out, I plan to fill with 93, and see if I am still getting this knock retard. Thinking about a meth kit, to help cool things down, and eliminate spark retard from knock. Anyone ever try meth/water injection on a N/A engine?

Might sound silly, but It probably be cheaper to run a meth kit, than using 93 gas all year. Main thing is i'd like to be able to cool things down when towing on those hot humid summer days, plus, im bored.

not at all silly,guys have been doing it for a long time at the track.it is just a tool in the toolbox of speed.on those hot humid days the air entering the engine can reach 175 deg or more so cooling the intake charge makes for a denser charge and we all know cooler denser charge makes for a happier engine.

Just took it for a ride today. Was 55-60 deg ambient. Idle iat temps get up to 120 degrees . On highway, they drop down to 75ish. Stock intake setup. Gotta burn out the 87 gas, then put in 93 and see if its still getting knock retard. It was getting it again today when i floor it on the highway . Wanna make sure its octane related knock, and not false knock, or something else.

Thing has no timing in it as it is, dont need to be pulling another 4-5 out of it lol

wouldnt it be easier to figure out why a truck that should run on the cheapest crap speedway has at the pump is detonating?? A fancy tune on an otherwise stock 97 truck motor really isnt going to ad much I wouldnt think

Nt to sound like an ass, but is the gain really worth the expense?

Actually, it made a big difference , once the stock torque management was removed, and at light throttle position, etc.

Gotcha... I thought being a 97 it would have been before all that type stuff... My Denali has so much computerized bullcrap its not even funny.

dumb question but have the intake gaskets been changed? mine is the same truck but a '96. I finally quit putting it off and changed the gaskets (280,000 miles) and was surprised at how bad they were. I am sure that I had a vacuum leak at the gaskets that was causing a lean condition. truck runs much better now.

Yes, I did them about 15k miles ago. They were weeping coolant .

Truck runs great. Would not have known it was pulling timing, without the snap on scanner that records live data

Great cost effective option, especially if the 93 shows improvement, plus it could even help more than higher octane fuel alone!

True Gearheads always trying to improve our toys! Nothing better than that!

Your long term and short term fuel trim's good ? ie: not + or - a big % ?

I have only put 20k miles on the truck, in the last 5 years. Its not a daily driver or anything like that. I use it to tow the boat, or occasional a trip to home depot and what not.

I bought it with 87k miles, it now has 108k miles. Since I have owned it, it has got

Plugs, wires, new distributor, fuel pump, fuel psi regulator. New LS injectors (one of reasons for tuning). New intake gaskets, Stewart HD water pump, HD fan clutch, 180* stat. New rotors, new drums, new hub bearings and rear bearings, new calipers, new rubber brake lines. New hoses, new belts. New tires. New pitman arm. New shocks. New starter, new battery. New headlamp and park lamp assemblies. New A/C lines. Added Autometer trans temperature gauge and HD derale transmission cooler with its own fan. Removed stock hitch, for a class V curt hitch. Replaced stock muffler, with a Magnaflow. Only thing it NEEDED, was a fuel pump. That crapped out on me. Other than that, the rest was preventative. Removed the overload leaf spring stops from the frame. That really made it ride better on the bumpy illinois roads.

Have a set of stainless Edelbrock Shorty TES headers, that have been sitting here a long time. Just never got around to putting them on. Its pulled the boat from Chicago to loto several times, about 1000 mile round trip, Traverse city Mi, and locally. Pulls good, stops good, and stable. Best thing I did was modify the proportioning valve in the brakes. Stock, the rear braking sucked.

Cheap to own, cheap to insure, easy to repair, and best part, no monthly payment for something I rarely drive. I'd love a new Chevy/GMC 1 ton , they are awesome. But the 70 grand price tag, eh. I'd rather burn that money in boat gas.

joe,your old stock injectors are still working good in my buddy,s 96 one ton dually plow truck.

Nice. He couldnt beat the price on them.

Only real reason I swapped to the LS injectors, was in case I added headers, a tune, etc. I believe the stock 454 vortec injectors, had a very high duty cycle as it was , stock.

Im gonna do another log on those tomorrow. I will report back

Carbon build up will cause the computer to retard timing due to small amounts of spark knock picked up by the knock sensor. One of the easiest ways to cure the issue is to get a quality fuel flush that works off compressed air
then disable the vehicle fuel system and run a good cleaner through the fuel system. Snap on has a nice set up for this and dealers normally keep the flush additive on their trucks. It will clean carbon build up off the valves, combustion chamber and your timing will come back. I didn't believe it would work until I tried it, but sure enough my snap on dealer wasn't blowing smoke.

Besides meth can be some bad stuff. If your truck uses it, you will start to find the truck on street corners. The truck will have track marks of oil everywhere and the flywheel teeth will start to fall out.

You got my wheels turning on the carbon buildup. I may try the decarbonizing route. If still getting knock, try 93 octane.

When I was looking at it for the boat you had to tune for it , seems like it`s really not bolt on mod and with the inability for easy tuning options on that truck you could be opening a can of worms and extra work.

Seafoam that thing , maybe it`s carbon.

years ago an old timer told me an easy way to clean the carbon out of a combustion chaimber,hold the rpm,s to 3500 and pour water down the intake till the engine is almost ready to die,keep at it until you go through a half gallon of water,believe it or not,it works.if you pull the spark plug and look in with a bore scope it looks like it got steam cleaned.joe,when the guy reprogrammed your computer did he set it up somewhat rich or lean?i think gm sets it up on the lean side.

Find someone that has a Motorvac and have them do the service. I sold them when I worked for Snap-On and they truly work miracles on older gas engines

Fooled around with it today a little bit. Stopped at a Jeep dealer, and picked up 2 cans of mopar combustion chamber cleaner. Read a bunch of hype about it on the web. Soaked the engine with it, let it sit a few hours, then took the truck for a ride. Smoked like mad for a bit, then cleared up. After a quick 10 mile ride on the highway, i hooked the scanner up. Did a few full throttle runs from 60mph and up. Still was getting 4-6 degrees of knock retard.

Stopped and filled the tank with fresh 93 octane. It took exactly 16 gallons, and it has a 34 gallon tank. So pretty much a 50/50 mix of 87 and 93. On the way home, did some more full throttle runs from 60mph and up. Maximum knock retard was 1-2 degrees.

It also appeared, to pull the timing for a split second, and bring it back in, where as on straight 87, it would retard , and pretty much stay retarded until I let off the pedal.

Tried something else this morning otw to work

I immediately got on the freeway, and waited till coolant temp hit 150 degrees, and floored it from 60 again. I got 0 knock retard. Once coolant got to 180, floored it again. I then got 2-3 deg of retard.

Could it be a cooler running engine, is less prone to spark knock? Ive always ran my boat engines cold water temp wise for that reason.

It goes into closed loop around 115*, so that wasnt a problem.

I could believe that to be true, I have no data but it makes sense to me, the first time my Harley shut down the rear cylinder because it was getting hot in stop and go traffic, I freaked out never had it happen before, as soon as I got moving and the cylinder temp went back down the ECM relit the plug.

I know back in the day, when my truck was fairly new, hypertech offered a programmer kit, that came with a 160 stat. Ordered a 160 stat to try

One of the tricks from back in the day was to run a cooler t-stat. The problem was that the cooler coolant temps were outside the range of what the computer would accept so companies like hypertech addressed that with their computers. Make sure whatever computer/ tune you're using has had the coolant temp parameters changed.

I would replace the injectors, you can find new ones pretty cheap now days, I'm betting they are clogged, have a 11 avalanche, right at 100k started setting a lean ck engine light bank 2, cleared it truck ran fine, would come back every 2-3 weeks, talked to my GM guy said had a injector issue. I ran across a guy on ebay selling complete new sets of delco injectors for $50+, put a set in throttle response perked right up and no more light

Not getting any misfire codes or any bad running symptoms. Injectors have like 20k miles on them

If it wasn't so close to boating season I'd say pull the heads. At your mileage a valve job wouldn't hurt it and then you'd know the extent of your carbon buildup. Short of that I would try what snapmorgan suggested. Can't hurt anything other than your wallet!

AMEN to no payments

I considered pulling heads, swapping the lame cam out, and doing headers at that time.

The vortec heads have very small chambers, around 100cc if i recall. I see engine quest now makes a replacement head for these engines. Might be something to fool with come next fall.

She doesnt burn a drop of oil or smoke on startup after sitting for long periods. Guessing the guides and seals are still good.

Have you ever tried reducing that dumb (my words, lol) .060" gap down to something like .040" ? Your motor, as you know, does not have COP, so that large gap is quite hard on everything else ignition related. I wonder what heat range those stock plugs are ? I only know / relate heat ranges by the old AC #'s, not the newer one's.

You might be on to something Scott.

I replaced those plugs with delco R44LTS6 that I do believe they come gapped at .060, and honestly, can't remember if I gapped them at .045, or left them alone, Its been a few years now. The plugs probably have 15-17k miles on them, along with the wires, cap & rotor, etc.

I have no idea where I got the R44LTS6 number from. Probably was from Rockauto. But just broke out the owners manual for the truck, which lists the replacement spark plug, as a AC Delco, 41-932. Apparently, from some googling, that number has been superceded to 41-933, which is a Irridium plug. The ones in my engine now, are standard plugs.

IDK what the delco plug heat ranges translate to . I know the R44, would be a step hotter than your typical plug in say a 454 merc engine? Dont they usually run a "43" heat range?

Either way, I think i am gonna order some fresh plugs, and a new delphi cap and rotor kit.

Went to Ac delco website, shows for my truck, original equipment replacement, is 41-979 ac/delco, which is a double platinum, .060 gap. Also lists the R44LTS6 as an optional plug.

Should I order the 41-979's, or stick with a standard plug? Maybe a slightly cooler plug?

Definitely gonna try the .045 gap. .060 is a bit much, or seems like it.

Does the 6 stand for .060" gap ? If so, I'd get the LTS without the 6. Shouldn't have to bend ground strap as much to get to the .040"

And yeh, a 200 ton :) Dually is a lot of load by itself, so I'd go with the 43's.

==========================================

On to another possibility - by chance have you seen if these knocks where result of trans shifting a little to quick (a little too low rpm) or if trans does not downshift quick enough ? Or lock up clutch a applying a little early ? You see where I'm going with this.

Yes, i believe it does stand for .060. The "6" that is.

I can go 0-60 with no knock retard. Only on the hwy, when i floor it from 60mph and hold it there, in 3rd gear. I believe last check i had KR at 3250rpm .

It will be interesting to see what it does pulling the 38 in the hills near loto with the a/c crankin when its 95 degrees out !

It might take a dump....lol you'll need to turn the AC off, what HP is that thing making.

Last summer it pulled the hills fine there, but didnt have the scanner looking at knock retard either. Last time we came down, had the cruise set at 70, and only one hill on hwy 54 knocked it down to 65ish. Im sure it was pulling some timing though!

That pretty impressive, whats your rig weigh ...........

Truck and boat 20k lbs. Boats around 13-14 on trailer depending on fuel