sparkplug diagnosis help
 

I have recently installed a JMS chip and my plugs look very weird. I don't have an e-pic of the plug but the electrode looks like it's silver and it's just bare metal (shiny, rainbow-like color). The best way I can describe the electrode's color is like that of the T2 terminator (the liquid metal guy). Funny thing is that I thought for the first time that I heard a backfire at WOT, which isn't good.

Does this mean I'm lean and I should bump up the fuel pressure?

This car starts really hard too....always taking 3 turns to fire (when cold only). Doesn't timing affect the starting of the car?

Too much timing will make it hard to turn over, do you know how much the chip advanced the timing? Also, was it supposed to change the air/fuel ratio? I'd call whoever you bought the chip from and see what they say

ok thx...I'll call them. Maybe I need to back the timing off to 10 degrees and let the chip take it from there. I should probably get a timing light. So what does that electrode being shiny metal color mean? I'm too lean right?

What color is the porcelian?



As far as your hard start, we may have covered this before, I don't remember, but have you checked to see how long it takes your fuel pressure to bleed down after you turn the key off?

I'm at work now so I'm trying to visualize. I am about 80% sure that Procelain is black, but will confirm later when I get home. And yes, the pump loses pressure immediately after shutting down. But sometimes when I go to start her, it sounds like it wants to fire right up, but ahead of the fuel delivery. Or maybe the fuel is there but the spark isn't. It sounds like 1 cylinder actually wants to fire, but then dies. Usually it's the next key turn that will get her going. I also noticed that my distributor is cranked to the left so that the module is facing the drivers side headlight...wonder if the timing is off, or too far advanced. The MSD sticker isn't facing the radiator, in other words. What other info can I provide??

Thanks in advance!

Your wife's bra size?

:D

Okay, lets start with the plugs. If the porcelian is black, you are running way too rich, and so far that doesn't sound like the case. I would have expected your porcelain to be glowing white, with the ground electrode so shiny.

As far as your fuel system goes, you have a problem, and you should correct it. I don't care who tells you what, your regulator is supposed to maintain pressure after the car is shut off. If it doesn't, it's not working correctly, which means your real fuel pressure under load at high rpms is probably weak, and your fuel pump is working much harder than it should. It also means harder starts, which your bearings aren't terribly thrilled about.

A fuel injection system cannot work without sufficient pressure, and two seconds, which is all the ECM allows the pumps to prime, isn't enough time to build it up to the right point, so you have to cycle the key a couple times to start it. Not very good.

It's your call, but after all the time and money you put into that puppy, and for that matter, the time I put into it, lol, I'd be more concerned about the fuel system. After all, if your fuel system can't maintain pressure when it needs it, a lean condition will result, and could be the cause of your plugs looking so T2.

As far as your timing, it doesn't matter where any part of the distributor points because I didn't see it when you put it in. :D

Grab a timing light, pull the spout, and set it to 10 degrees advanced. That's usually where the chip makers set up the chips for.

:)

Take care,
~Chris

Ok. Thanks.

Well, I did find out that I had my fuel pressure set WAY too high at 44 psi....should of been down to 39 psi when I put the chip in. You are right about the timing at 10 degrees, I called the chip people and they confirmed it.

Also, I should clarify what I mean by hard starts. The car starts fine (now that I've settled the grounding issue) when hot. It's when I go to start her when cold that it takes 3 cranks. Does this change anything regarding your feelings about the pump?

By the way.....here's the message that the Aeromotive technician sent to me about the pump. Let me know whatcha think.

PS - I didn't know you were into black girls....lol


Here's the email:

Jason,

The gauge situation is pretty amazing, glad for us it’s the gauge, not for you of course. An inexpensive, air filled gauge would be best.

The vacuum in the intake manifold will fluctuate with engine rpm, if the cam is large enough, or air/fuel ratio lean enough, to cause the engine to roll or change rpm slightly at idle, the vacuum will go with that.

As we discussed, there are no check valves in a racing fuel system unless added after the fact, as a result, pressure will not be maintained once the fuel pump stops running. Other than the instructions that come with the fuel pump, there is no other documentation I can provide. Let me know if you need a copy and I’ll e-mail it to you.

Any time the pump is running, you should have pressure, anytime the vacuum line is disconnected, it should be stable and the gauge needle should appear “painted on”. When changes in air pressure are introduced into the regulator cap (via the vacuum/boost port), fuel pressure will rise and fall on a ratio of 1:1 with either positive (boost) or negative (vacuum). The reference measure for the ratio 1:1 is PSI. Most vacuum gauges read in “HG (inches mercury) so you’ll have to convert to PSI to check fuel pressure change with vacuum. The conversion from “HG to PSI is roughly 2:1. In other words, 2” HG equals 1 PSI of negative pressure.

Any more questions, let me know.

Brett Clow
Aeromotive Tech Dept
5400 Merriam Dr.
Merriam, KS 66203
PH: 913-647-7300 ext 109
FX: 913-647-7207

Chris,

I got an update for you. Today I started thinking about the fuel pressure. When I got home I started her up cold (she stumbled, stalled, etc.). So I got her going again and I pulled the vac hose off and quickly set the fuel pressure to 39 psi (which is what the chip people recommended) before she died. As I was dropping the fuel pressure the stumbling, erratic idle, etc. went away and she started idling much better. So I then put the vac hose on and the fp went down to like 33 psi. I then shut her down and she started right up again which is progress. This leads into my question.

When setting the fuel pressure, do you set (for WOT) with vac hose off or (idle) with vac hose on?

Correct me if I'm wrong....the reason for pulling the vac hose off is because at WOT vac is zero, so essentially I'm simulating WOT by removing the vac hose. So if you set fp for WOT, than I've been pig rich this entire time, flooding her real bad. No wonder she loads up on me at the stoplights.

But 33 psi at idle?? Does this sound right for a 393 w/ 30 lb injectors, 70mm TB, and a 75mm MAF?

Or do I set the fp to 39 psi with the vac hose on?? If so, the fp will rise to about 45 at WOT.

If the answer is that I've been rich this entire time what damage, if any have I done?

:eek: Neither did I!

:)

Okay, so many questions to answer. :)

First, your starting problem is text book for a fuel system problem. See, when the engine is warm, there is still some pressure, and the engine needs less to start, since it's already "warmed up". The following morning, or any point after say 8 hours or more, the engine has completely cooled, requiring more fuel to start, and the pressure in the system is absolute zero. Thus, hard cold starts.

The letter you shared only confirms what I'm saying in general, but not specifically to you. The point that he made was that because of no check valve, the system doesn't remain pressurized, but the check valve is in the pump, not the regulator. If fuel is going to the tank via the return line after the key is off, it's because the regulator is bad. If it's going back via the supply line, then it's a problem with the pump/check valve.

He is right that race cars don't usually require a check valve, but you car is driven on the street, for distances longer than 1/4 mile, and hopefully for more than 10 or 20 miles in it's lifetime. If your fuel pump and pickup assembly are all aftermarket, and you're sure they don't have any kind of check valve, then that's the cause of your hard starting problem that is slowly but surely eating up your bearings.

I don't recall if I had you check to see which path the fuel was taking when your pressure dropped, but if we already did this, and you determined that the fuel was going back to the tank through the supply line, then forget about the regulator. But, I'd look into a check valve, or a new pump that has one. "Race" parts are often not very healthy for a street driven vehicle, and for the street, you want the system to maintain pressure after the pump is off.



On to the next post...

Fuel pressure is often referred to by it's WOT pressure, because that is the only constant among engines (vacuum will be zero at WOT). The vacuum can fluctuate at idle, and between different vehicles, so the idle setting needs to be vehicle specific. It is almost always better to set the pressure at WOT. In your case, I would say 33 psi at idle sounds about right. Your injectors are too large, IMO, so you need to run lower than normal pressure to keep from flooding it. As long as you are not fuel starved at WOT, then set it at 39 psi with the vacuum line disconnected. better yet, jump the fuel pump wire in your self test connector to ground, and set the pressure to 39 psi with the engine off.


Sooooo, yes, you've been rich this whole time. The negative effects are clogged cats if you have any, and diluted oil. Change the oil and filter right away, and keep an eye on things.

:)

Take care,
~Chris

OK...that explains way the plug procelain is black, loads up and stoplights, and almost burns out my eyes while I run her in the garage. But I guess rich is better than lean (Mr. Optomistic speaking here)

Two more general question (I know...I never stop).

:D

1) When I'm having starting problems I notice that my oil pressure is present while cranking. Can I damage bearings if I have 20-30 psi oil pressure while cranking for only 3-4 sec's?

2) When trying to hear for "pinging", is it a fairly obvious noise? Do I have to be in the car driving hard to hear it or can I get her to ping in the garage by going WOT under the hood? Basically, can pinging be subtle or is it always the obnoxious marble-in-the-clyinder type noise that I've heard in the past (just not on my car):D

Thanks again for the lessons Chris.....you DA MAN!

Starting is always the hardest time on your engine, and is when the most bearing wear occurs. When your engine is running, the crank and cam don't touch the bearing surfaces. The oil is forced inbetween the bearings and the crank, creating a "wedge" of oil that keeps them from contacting each other. This wedge needs sufficient rpms to work. So even though your pressure may develop when starting, you still have the crank rubbing against the bearings. More so true with the crank than the cam. Cam bearings can last forever. This really only applies to the main and rod bearings. Anyway, when you are starting the engine, the rpms aren't enough to protect the bearings. Once it fires, and the pressure is still up, the bearings are safe, until the next time you try to start it.

:)

Take care,
~Chris

Dammit, I forgot to answer the second question.

Pinging only occurs under load, so the only way to get your engine to ping in your garage is to get the front bumper against the wall, and accelerate the engine, with the tranny in gear, to just before the point where the tires would lose traction (don't touch the brakes either!). If it's gonna ping, that's when it will do it.

***FWIW, that's how guys used to set their timing in the "good 'ol days"! One guy would do this with the car, while his partner would advance the distributor until pinging started, and then back it off until it stopped, and tighten it down.***

You can also put it in 4th gear while driving 10 mph, and punch it, but that will only tell you if you have a timing issue, not a fuel supply issue.

Rather than listening for the popcorn kernal in a coffee can, try listening for maracas.

:)

Take care,
~Chris

OK, thanks a bunch. Looks like I better start looking at how much this is gonna run me. Here goes another bundle of cash out the window :(

And I still need paint...oh well.

Thanks for everything Chris,

Jay

Why? Just pick up a pump next time you go shopping. :)