plugs reading lean with 30 lb injectors? why?

mrmustangman357 · Aug 8, 2007

hello,

my buddy has a lincoln lsc race car with the 5.0L. He has a larger TB, cobra intake, heavily worked E7 heads, trick flow .560 cam on the stock rockers (yes, I know. . .)and 30 lb injectors with calibrated mass air sensor. He has 14 degrees in it on 92 octane and he dropped the fuel pressure to 28 to compensate for the injectors, which made the plugs read lean. he richened it up (as i recommended him) to 38 with the vacuum line off, but the plugs still read bone white. what's the deal? I know the setup is nowhere near optimized, but he is low on cash and had to sell his trick set of heads for the worked E7s. He also disconnected the EGR but doesn't get detonation at cruise (as the plugs showed) and the ECM isn't throwing any wierd codes except for soft codes and the EGR. He's trying to get the car dialed in NA for the nitrous later, but I told him not to hit the spray with the plugs still bone white.

As for the trick flow cam, it pulls 16 inches of vacuum at idle and there isn't really any fluctuations on the needle. What should he do (that doesn't involve spending loads of cash)?

mrmustangman357 · Aug 9, 2007

any takers? Does anyone have a clue what could cause this? Does anyone have a similar setup with tips on what to do? It was running good before even with the spray, but off the motor it is just acting funny

mrmustangman357 · Aug 9, 2007

oh yeah in a few months when i get back to town we might tune it with my wideband O2 sensor, but until then, we're still looking at the plugs. ANY IDEAS?

87AODGT · Aug 9, 2007

ever think the fuel filter may be plugging up or maybe the fuel pump is starting to give up on ya, if not then I would just try cranking the fuel pressure up until the plugs are black

vristang · Aug 9, 2007

Pull your codes and post all of them...

You will get help.

Right now, you are making people gues, and there are too many things that can cause lean problems...

Step one is posting the codes...

Other info that may be useful...
What ecu is being used?
What MAF/MAS unit is being used? be specific, part numbers if possible...
How long was the motor run each time the plugs were checked?
Was the ecu 'Keep Alive Memory' reset?

That's all I can think of right now,
jason

mrmustangman357 · Aug 9, 2007

alright the codes were for the EGR no flow, fuel pump ECM secondary fault (my 89 has this too but i heard its not a big deal?). the KOER showed nothing wierd. the computer is an A9L and we used the mass air conversion on it. I wired it as per ford racing's instructions and it ran like a top. good for 12s. The injectors are ford racing 30 lb. and a C&L 70mm TB with the correct sample tube. The only difference is that we swapped his old ported J302 heads (if you don't know those, they are the first aftermarket head ford made in the 80s out of aluminum, and they FLOWED) for the worked E7s. We had his car running in the 12s on a 75 horse dry shot with the J302s and 38 psi on the fuel rail with the line pulled. Now with the ported stockers, he's at the same fuel pressure and all plugs are bone white. He also has a mallory hyfire box, but I wouldn't think that would cause the plugs to read wierd? In fact, I was joking with him that the ign box likely made it run as good as it does because it can prolly make the motor tolerate a bad tune

Sorry I couldn't give any more details before because I only see the guy once a week and figure the forum might give me an idea to call him and have him do. 87, good idea, I told him to go R&R the fuel filter and check the fuel pressure to see if that helps. he told me he bumped the pressure to 44 with the line off and along with the fuel filter, he's going to pull the plugs tomorrow and tell me wats up. thanks for the help thus far guys.

mrmustangman357 · Aug 9, 2007

Oh yes, vristang, the plugs were ran about 15 minutes under his normal hard driving last time we added pressure and checked the plugs before driving. it got throroughly hot and hit WOT many times. what is the keep alive memory? The battery has been hooked up for awhile so we figured we gave the computer a chance to correct it. it has newer o2 sensors, and no code was thrown for that

Mustang5L5 · Aug 9, 2007

mrmustangman357 said:
He also disconnected the EGR but doesn't get detonation at cruise ?

Doesn't matter, even without detonation, running at cruise with the EGR disconnected causes it to run slightly lean

Hook the EGR back up. I have no idea why people disconnect it. It gives you no HP gain and just causes nothing but headaches without proper tuning

5spd GT · Aug 9, 2007

I had my EGR unplugged for well over a year, by accident.

The only thing I noticed was the check engine light went off when I reconnected it...

Didn't notice much else...

urban96 · Aug 9, 2007

you really need a wideband to tell if your rich/lean at WOT

during part throttle the computer is always trying to keep a/f at 14.7 which is why the plugs will look lean

mrmustangman357 · Aug 9, 2007

the egr is past gone. the solenoid was ripped off when he gutted the car and the other smog stuff. I can't even find the wiring connector

vristang · Aug 9, 2007

mrmustangman357 said:
Oh yes, vristang, the plugs were ran about 15 minutes under his normal hard driving last time we added pressure and checked the plugs before driving. it got throroughly hot and hit WOT many times. what is the keep alive memory? The battery has been hooked up for awhile so we figured we gave the computer a chance to correct it. it has newer o2 sensors, and no code was thrown for that

Don't take this as rude, but please post the code numbers. There are some different things that can learned from some of them.
It may help, or it may not. It is the 1st thing to do though...

The C&L
Please verify that the sensor on the MAF unit is marked as an 'F1ZF'

Adaptive Fuel
15 minutes is no where near long enough for the computer to sort out the fuel adjustments. You will need to drive the car for probably 20-40 minutes in Closed Loop operation (not WOT).
This will give the ecu enough time to learn the new hardware and make adjustments to the injector pulsewidths.
Keep Alive Memory (KAM) is the portion of memory where the codes and adaptive multipliers are stored.
If power is cut from KAM (about 15 minutes with the battery disconnected will do it), then the adaptive learning starts over and all the codes are 'reset'

I'll see if I can find an old post that goes into more detail on Adaptive/KAM....
Here is an old post of mine on adaptive... There is more discussion about Adaptive and its impacts on fuel in this thread...
http://forums.stangnet.com/showthread.php?t=711715

vristang said:
The ecu compensates via the 'Adaptive Fuel Strategy'

Basically the O2's will read a non-stoich condition (either too rich or too lean).

When the O2's indicate that the mixture is not stoich for an extended time, the ecu will begin applying a multiplier to the calculated injector pulsewidths.

If the O2's are indicating rich, then a multiplier of less than one will be applied, thereby reducing the injector pulsewidth.

If the O2's are indicating lean, then a multiplier of greater than one will be applied, thereby increasing the injector pulsewidth.

The factory A9* ecu's have a range of +/- 12.5%.

In other words the ecu can increase the injector pulsewidth by 12.5%, or decrease the pulsewidth by 12.5%.

A total range of 25%.

When you change the fuel pressure in order to create a lean condition at WOT, you also change the AFR at part throttle Closed Loop operation.

Eventually the Adaptive Strategy will learn that the mixture is lean (as indicated by the O2's), and apply a multiplier of greater than 1 to the calculated injector pulsewidths.

This multiplier will push the AFR for both WOT and Part Throttle, back toward stoichiometric.

jason

mrmustangman357 · Aug 10, 2007

codes were 96 and 84 if I recall correctly. I'll call him and tell him about the "F1ZF" and have him check it. We didn't reset the computer when I was referring to the 15 minute thing. I just said we bumped the fuel pressure to 38 then drove it for 15 minutes then pulled the plugs to see they were white. Hopefully, I'll have an update later today. thanks to all thus far for the help

BWill

Jaswir · Aug 10, 2007

shouldnt fuel pressure be around 40 to 42lbs? with vacum off?

FastDriver · Aug 10, 2007

Can you shoot a pic of the plugs and post it? Doesn't sound lean to me. A plug with some white on it isn't a big deal. A plug with some extra metal on it is.

Lean is fast, unless you're lean enough to get detonation. Besides, as someone mentioned above, the tune at part throttle differs from full throttle. An old-school way to check the tune at WOT is to hammer it and shut the car down without lifting on the throttle, once the motor dies push the clutch in and stop. Get out and pull the plugs.

It's an old technique and certainly not as effective as a wide-band, but it'll give an idea.

Chris

mrmustangman357 · Aug 10, 2007

the plugs look brand new, even though they've had over 150 miles on them. . . They were light grey before the head swap. We tried lighting the whole plug and looking down into the insulator near the bottom, but it remained white the whole way.

greg251 · Aug 11, 2007

What year are the heads? If they are 1986 they have a different plug with more threads than the others and the plug won't be deep enough in the combustion chamber. That would make it appear that you are running very lean.

mrmustangman357 · Aug 12, 2007

he just told me he dialed in 40 lbs with the vacuum line off and just started to ash up. He said he's using the stock autolite spark plugs for the E7s but he said he's going to step up a range colder for the NOS once things get sorted out

mrmustangman357 · Aug 27, 2007

so, this weekend, we finally got the wideband hooked up and made asome passes. With his combo, he launched hard (ET drag slicks - 1.7 second 60 ft time) on motor but only managed 14.2? The wideband read 13:1 the entire way, so I must think the computer isn't far out of whack because it is getting the proper mixture at WOT. It is hard to imagine with what is done to the motor that he isn't solidly in the 13s

mrmustangman357 · Aug 27, 2007

oh yes, on the dry shot spray the a/f read the same, until he plugged in the 100 hp jet, where she started moving toward 14:1. a litle fuel pressure adjustment and it was back to 13:1. We have timing at 14 base, and the computer does move the timing when the SPOUT is plugged back in, so I must think the computer is doing its job. Sorry but my multimeter was broke so we couldn't pull codes (no MIL)

plugs reading lean with 30 lb injectors? why?

mrmustangman357

Member

mrmustangman357

Member

mrmustangman357

Member

87AODGT

vristang

mrmustangman357

Member

mrmustangman357

Member

Mustang5L5

That is…until I whipped out my Bissell

5spd GT

"the 5.0 owns all"

urban96

bubb rubb says:"woo woooooo"

mrmustangman357

Member

vristang

mrmustangman357

Member

Jaswir

Member

FastDriver

I was uncomfortably high & wearing a helmet

mrmustangman357

Member

greg251

New Member

mrmustangman357

Member

mrmustangman357

Member

mrmustangman357

Member

Similar threads

plugs reading lean with 30 lb injectors? why?

Member

Member

Member

Member

Member

That is…until I whipped out my Bissell

"the 5.0 owns all"

bubb rubb says:"woo woooooo"

Member

Member

Member

I was uncomfortably high & wearing a helmet

Member

New Member

Member

Member

Member

Similar threads

Privacy & Transparency

Privacy & Transparency