how do these look.

[85burb]

How do these plugs look. My truck has been running funny. Had it tuned a while back. It ran way better after it was tuned but lately it has been felling like the throttle response is less. Sounds like we are hauling from the exhaust note but the truck does not move like it used to. Kinda feels like the timing is off or something. I figured I would check the plugs and see what they look like.

[jjzepplin]

Not too bad. My gramps always said you want them "cocoa brown" and they look like that to me.

[Hart_Rod]

The plugs look fine. I'm guessing you are not throwing any codes? Have you checked your fuel pressure at the rail? If it is low, that can degrade your performance.

[BR3W CITY]

I may be the disenting opinion. Copper plugs? they are done. Tr55's? definately done.

I've noticed that even with upgraded wires, copper plugs will eventually lead a shorter life on these trucks. I had about 15k on a set (first set since it was built), and started to get a little "grumble" from the engine.

If you spin high rpm's, you may actually be chewing up the plug because of a problem with the truck-style coils. They have a longer dwell time than the cars, and can get choppy on the high end, especially if the plugs or wires are worn at all.

I'd try swapping the wires around and see if the problem "moves". I also wiggle the plug wires while the engine is running. I have had an internal break in a plug wire cause issues in a different vehicle.

[85burb]

They are the high doller iridium plugs. I omhed out the msd wires and they had 85 ohms. Way way better the 860 I took off our new gmc. No misfires just kinda laggy. No high rpm most my trans will let is shift at is like 46-4800.
Posted via Mobile Device

[truckdude239]

Are those autolites? All i run in chevys is ac delo ive had issuses with autolites
Posted via Mobile Device

[85burb]

I think they are. I am gonna get some tr6 ngks maybe tomorrow.
Posted via Mobile Device

[BR3W CITY]

Have you also checked stupid stuff like the wiring connections on the coil harness?
The dwell issue I suggested is a hella longshot as I didn't even believe it until I saw it.

Does any 1 plug look worse than the others?

[Jon01]

Those plugs look fine.
Autolite/AC/Whatever is played out. I wouldn't waste $ pulling good Autolites just because they're a "Ford" brand.

Check your fuel pressure.

[85burb]

Checked fuel pressure and put tr6 plugs in. Also changed oil and filter. Has been over a year on oil. 3 on plugs. Never checked fuel pressure. It has 52 psi with vacum line hooked up and 58 with it off. About to go drive it and see if it helped. If not looks like I have a good set for wife's 5.3 in her 85 long bed.
Posted via Mobile Device

[Jon01]

That's about right for fuel pressure.

Are you sure you're not imagining the decrese?

Also - ambient air temp will take power. My truck is a turd with it being this hot out.

[85burb]

I am 98% sure I am not imagining the power loss. My wife even noticed it. It pulls as hard as ever up top. May or may not have bounced off the rev limiter side ways testing top end. Under 3000 it is crap. I used to push the pedal a little and the wife's head would be pulled to the seat. It just wind do that anymore. It may be cause it is hot out but in the last like 3-4 times driving it it has fallen off power big time. Could a converter starting to fail cause this? It stalls at 2000-2200 still. Supposed to be 18-2000 rpm.
Posted via Mobile Device

[BR3W CITY]

Most will flash higher than the actual "rating".
Any other problems like with shifting or anything?

No codes being shown?

How about oil on the maf/dirty maf, or an exhaust leak small enough to randomely throw off the upstream o2's, but not always.

[85burb]

No codes. The maf is clean I am pretty sure. I have a dry air filter not oiled. I may get a can of maf cleaner to clean all my trucks. I made sure I didn't have exhaust leak when I did oil and plugs. I know converters will stall higher or lower then advertised due to motor power. I just remember in my class at school that we had a converter jacking up and the motor would make 20-40 less hp each time we dynoed it. But the stall is close so it is prob not my converter.
Posted via Mobile Device

[Blackpony]

Personally I would suggest throwing those in the trash and running an ngk tr55 plug. I have seen better performance from a good copper plug over any brand platinum plug. Every car I build only gets a copper plug. Platinum plugs are for your grandmas mini van. Ill see if I can find some of the old dyno pulls. Everytime we get a car in with some sort of platinum plug it runs like crap and wont take much timing. We swap in a copper and can add sometimes as much as 2-3* timing and gain 5-10 hp to the tires.

Your average n/a ls engine a tr55 gapped at .055 will suffice, most boosted or nitrous ls engine a tr6 gapped at .028 will suffice up to around 700 rwhp then past that a bp7efs gapped at around .025 will do.

Just my .02

[Jon01]

I don't see a mild build like that having much to gain from coppers. F/I sure, but not a mild build like burb's.

[Super73]

First things first, reading a plug with miles on it, well is the wrong way to do it. It is best to put fresh plugs in, make a wot pull then shut off at the finish line pull them and read them. But, what I see with the plug based on a Historical out look..

Pics 1 and 2
Plug looks too cold to begin with. The heat is all the way at the base of the ground strap where it should be in the middle of the bend.
There is ever so slight peppering which tells me there was some detonation at some point in their life.

Pics 3 and 4
The heat range of the plug looks more on
But again, looks to be a little detonation at some point.


If you are experiencing part throttle and low rpm wot power loss, there is a good chance the motor is seeing knock retard in the lower rpms. Perhaps there is too much timing down low for your current weather or it is too lean/rich there. Yes too rich will cause knock retard as well.

Have you seen a temp/humidity change since the power loss?
Posted via Mobile Device

[BR3W CITY]

I'll also throw in that if the misfire counter-thingy (i forget what its actually called in HPT) can mask spark issues sometimes. It gets changed in the tuning when you are running a larger cam on an auto, because the false misfires the cam throws can cause lock-unlock issues with the converter. If its set high to avoid these false misfires, or is set too high and should not be, you might be hiding a REAL misfire related code, which will now not throw the CEL unless the count gets even higher....sometimes high enough that by the time the code has thrown, you've got WAY too much miss.

[85burb]

My tuner said he had the air/fuel commanded at 14.7 everyware but wot. For a while I was setting knock codes but I filled up with fresh gas and that issue has went away so far. Never a misfire code after it was tuned. Tons before. I plan on getting hp tuners program in a few months to see what the ECM is set on. The tune was done about 3 months ago so the temp was about the same as now.
Posted via Mobile Device

[Super73]

Are you still using a mass air flow sensor?
Did your tuner leave your front O2 sensors active?

If so, the PCM will always strive for stoich (14.7) in closed loop which is typically above 140* and idle/part throttle. WOT puts you in open loop which should command a richer AFR. Most people like to set it around 12.8.

If you were seeing enough KR to previously set codes, my guess is there is still some present even with your better fuel. You have to be seeing KR more or less ALL the time to have a code pop on it.
Posted via Mobile Device

[Jon01]

You really need to get a scanner on it and see what's going on.
Get a good long log out of it and we'll be able to tell you where to start.

KR is a bad, bad, bad thing. It will destroy your motor in short order.

[Hart_Rod]

Originally Posted by Jon01

You really need to get a scanner on it and see what's going on.
Get a good long log out of it and we'll be able to tell you where to start.

KR is a bad, bad, bad thing. It will destroy your motor in short order.

I guess I missed it, what's KR? Knock Retard?

[BR3W CITY]

Originally Posted by 85burb;

Never a misfire code after it was tuned. Tons before.
Posted via Mobile Device

This sounds like part of what I thought; big cam threw misfire codes, tuner just turned misfire count higher, codes went away, problem was never solved.

Originally Posted by Hart_Rod

I guess I missed it, what's KR? Knock Retard?

Yep its knock.....retard
(ya its knock retard, the value is represented in tuning software and calculations as "Kr", i.e. the amount of knock the engine sees and how much timing it tries to pull to prevent it.

[Jon01]

As usual, Brew is right on.

In this case, knock is detonation/pinging. You won't usually hear it unless it's REALLY bad.

[85burb]

Originally Posted by Super73

Are you still using a mass air flow sensor?
Did your tuner leave your front O2 sensors active?

If so, the PCM will always strive for stoich (14.7) in closed loop which is typically above 140* and idle/part throttle. WOT puts you in open loop which should command a richer AFR. Most people like to set it around 12.8.

If you were seeing enough KR to previously set codes, my guess is there is still some present even with your better fuel. You have to be seeing KR more or less ALL the time to have a code pop on it.
Posted via Mobile Device

Yes I have a maf. I would hope he would leave them active. I wish I had money for hp tuner right now. All I have is a crappy scanner for now.
Posted via Mobile Device