very lean at WOT

HotrodHans · Posted: Mon Sep 29, 2008 2:01 am Post subject:

OK, test and tune or tried too.

What I've done

POT -1.5
UAP 7.6

Tried adding 5%, 10%, 22% and 40% at a VE of 85MAP and over.

Map shows 98 on data log at WOT.

Drives, cruises, part throttle is great

52PSI fuel pressure ..all the time.

55# injectors

Est. 680 HP.

It still only goes down to 14 AFR at WOT.

I can get part throtlle blips to a 10 AFR

I changed the crank sensor, map sensor.

I changed the MAP default to 4.98 volts

At around 5500 rpm it's like on a rev limter, it just won't rev any higher but I get out of it as that's too lean to stay in.

Rev limit is set at 7500.

timng is at 30.

Put a carb on it and sings to 8000 grand in a second.

Ia giva up pretty soon.

My PW ON bounces between 5 and 9 ms

TPS is at 4.47 consistently.

Something is making the numbers erratic.

HELP.

Inj Duty cycle varies between 51 and 74

TimZ · Posted: Mon Sep 29, 2008 12:06 pm Post subject:

HotrodHans · Posted: Mon Sep 29, 2008 2:51 pm Post subject:

Map is taken off below the throttle blades about 1/2" at the center rear. Single plane hi rise manifold. No spacer. the 1600 CFM air door mounts directly on the manifold. I can plug the map into the air door nipple if you think that would help.

My Duty Cycle though is way off and all over the place.

The original MAP sensor I sent you the data sheet on had oil in it from sitting with the nipple pointed up.

If it's OK, I'll send you this data log.

Thanks,

John

TimZ · Posted: Mon Sep 29, 2008 3:01 pm Post subject:

HotrodHans · Posted: Mon Sep 29, 2008 3:30 pm Post subject:

TIMZ,

U have a PM

EDIT:

TIMZ, sent to your gmaill addy.

Thanks,

John

PanteraTurbo · Stage 2 Joined: 17 Apr 2008 Posts: 58

Sorry John been away from home for the week. Not trying to ignore you.

HotrodHans · Posted: Tue Sep 30, 2008 1:54 pm Post subject:

Blaine,

Welcome back, I thought I had the wrong deodorant...LOL

It didn't seem to have any effect what i threw into the VE. Maybe a small amount.

I can see it hit 10 AFR when I step on it but a split second later it's at 14 range.

You can see the inj duty cycle is awry at WOT

Fuel pressure stays at 52psi

You have mail.

thanks,

John

PanteraTurbo · Stage 2 Joined: 17 Apr 2008 Posts: 58

John, you say this runs fine with a carb. When you test with the carb are you still using the TEC for ignition or do you swap in a distributor? Have you confirmed with a laser thermometer/wet finger that all cylinders are firing. What do the plugs look like now? Do they all look the same. Your pulsewidths for the size injector you have are way rich. That thing should be close to misfiring on the rich side. That may be why you are losing all power up there. You could try to use a UAP of 5 and a POT of 0 and see if the power comes back as well as check your AFR's. When I did that initial calculation for UAP it was for sequential and 100%VE I just did another for Phased and 90% ve and it only showed a UAP of 5 to get an AFR of 12:1. Is it blowing black smoke at WOT? If so and it is still showing lean there may be a cylinder not firing throwing off the measurement. If thats the case and it runs fine with a carb I would be looking for a dead injector or faulty injector wires. It just doesnt add up. Your current settings would give you a BSFC of like .8 . It can only be 3 things. 1. Your fuel system is not giving enough fuel (which seems to be ruled out) or 2. One or more injectors are not firing enough or at all causing a misfire on one or more cylinders throwing your EGO reading lean. 3. Too much fuel up there causing a rich misfire once again trowing the readings lean. I assume being you are running a V8 that the O2 sensor is measuring only one bank. Try to find a cold cylinder on that bank. Since it is wired for phased a bad driver would cause 2 dead cylinders. You would probably be able to tell if two were misfiring. One would be easy to miss. Let me know how it goes.

Blaine

HotrodHans · Posted: Wed Oct 01, 2008 11:26 pm Post subject:

Blaine,

Carb is with the TEC3, I just pull off the air door and put on the carb (850) and adjust the fuel pressure. Don't change anything else...same plugs everythings the same. Unplug the fuel injectors. I would think if it was an ignition problem it would be with the carb also....but ??

Now with the air door

It goes 10 AFR rich as i open the throttle going thru the MAP from 50 to 100.

It's definitely leans out and the power drops. No misfires as far as I can tell even though the plugs are black from testing. I had a bad plug before and it definitely made a difference on this motor.

Notice the inj duty cycle how it falls off? It should be going up I thought.

I fattened up two more rows in the VE per TIMZ suggestion but it remained the same...won't go fatter than 14 AFR at WOT. Fuel pressure stays at 52 psi. If I install the carb it'll scream like a banshee to 8 grand rev limit...like almost instantly.

Right now in second gear as I accelerate slowly it has a lot of power, goes to 10 rich, go WOT and 14, shift to 3rd, still 14. RPMS stay around 54-5500.

Injectors were tested and bench flowed a month ago..all good.

When I had the VE table at zero and a 0 POT with a 5 and/or 6 UAP it went 17-19 lean at WOT.

Why is my inj duty cycle dropping?

Thanks for your input.

Don't be afraid to say I'm wrong if you feel what I've done so far isn't right. I can be stubborn Laughing

John

HotrodHans · Posted: Thu Oct 02, 2008 5:01 pm Post subject:

MMM..ahhh...maybe a BIG BOOBOO Guys.

and I know better, but in a pinch at the track I got a set of AR3932 Autolite plugs from a friend because THEY FIT..and I was hot to race. They looked nice too. Copper core..helloooo..ding...ding....no response from the memory banks. Rolling Eyes

I went to get some more today and I noticed they said NON RESISTOR...OOPS Shocked

(and I'm being nice with the words)

I hope these are the cause to my problems...maybe that's why all the funny lines showed up on the datalog.

going back to the NGK's.

Sorry, my apologies for wasting your time on such a stupid oversight.

Report later.

TimZ · Posted: Thu Oct 02, 2008 9:44 pm Post subject:

PanteraTurbo · Stage 2 Joined: 17 Apr 2008 Posts: 58

We will be anxiously awaiting results. Hope it does it.

Blaine

HotrodHans · Posted: Fri Oct 03, 2008 2:07 am Post subject:

RESISTOR PLUGS DIDN'T HELP.

WHY ME! 120 miles to go get 'em in Indiana. Crying or Very sad

Yes, I'm desperate.

Blaine

I changed plugs, no difference so i went back and zeroed out the VE table and put in a -1.8 IOT and a 7.8 UAP.

Engine was a little fat but ran better but WOT still sets at 14. At least the RPMS got up to 6600 so were in the right direction.

The old plugs were lean (no soot on the electrode at least)so I don't think it was overly rich.

When I shut the motor off, key on and did a little programming the electric water pump started it's thing again. On the monitor screen I had a 99.3 MAP and all of a sudden it went to 55 MAP with a 783 rpm. Engines off. SO maybe the RFI or electrical noise from the pump is doing a number on me.

Guess the only way to find out is put the old manual pump back on.

Ohhh I'm having a ball

TIMZ...you've got mail.

PanteraTurbo · Stage 2 Joined: 17 Apr 2008 Posts: 58

Well you know what they say. When EFI works it works great. When it doesnt.......... I will try to put some more thought into it. Cant say I have been much help anyway. Smile

Hang in there.

Blaine

HotrodHans · Posted: Sat Oct 04, 2008 3:58 am Post subject:

Well, not much to report today but the car ran better. It cranked a 10.20@128 which is about a half a second slow.
but, couldn't keep the front end down...comes up really easy... Smile

but drops quickly in second as the fuel just isn't there as it leans out.

WOT is still 14.

Used a -1.5 /7.8

added 4,5,and 6% in the upper Map ...reads in the 14 range.

Car runs and start, cruises great and up to about 2/3rd's-3/4 throttle, even drops to 10 aFR momentarily.

After that it is 14

I am presently hooking up my garden sprayer to the air inlet.