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Here's a brain teaser for you guys

(Click here to view the original thread with full colors/images)

Posted by: Frogman

This question is more for the guys who have done more than "RimZ" so please bear with me.

We still can't get my Mark to tune for crap. If we change on setting, another setting in a totally unrelated part of the tune gets automatically changed by the computer. Something that should not happen.

Right now, we can get the car to start. It's a rich start though. The injector pulsewith on startup is damned near turned off. The car will idle like junk until the computer sees the O2 sensors warm, and switches to the closed loop tables.

Even then, it likes to hunt quite a bit. The lowest RPM we can get the car to run is at 800RPM. 790RPM, the car does not like. Once the car is in closed loop it drives like a bat out of hell though.

The dashpot seems to work fine. On deceleration, it brings the RPM down to commanded RPM. Most of the time... A few times, it just didn't respond quickly enough, and let the motor die.

There is a tune for just about every state the car can be in. Cold idle, warm idle, cold and warm drive, cold and warm neutral, and we also found out on friday there might be a damned table for Reverse as well.

The main problem we're running into is the computer changing values as it desires. Whether it's supposed to or not.

Any ideas I could pass onto my Dyno guy? Yes, the guy is good. He tuned the fastest... contour? escort? hell, I don't remember no more. So he does know his stuff.

We're going to swap the computers and see if that will change anything. For the guys with the Cobra manifolds, did you use the Lincoln IAC or the Cobra IAC?

My dyno guy just doesn't understand WTF is going on.

75Lb/hr injectors.
SCT maf (the biggest one they sell)
98 Cobra manifold (no holes in it like the 96, and it has the correct plastic with rubber insert gaskets)
No vacuum leaks.

Again, thoughts or ideas would be welcome.

Thanks.

Posted by: MonsterMark

Quote:

Originally Posted by Frogman

75Lb/hr injectors.

Is my guess. (Which doesn't mean much I'll tell you).

Those monsters must be urinating into the cylinder.

Posted by: NYC LS8

I keyed in on the 75 pounders, too. Why so big?

Posted by: Frogman

The injectors are under control. We thought it was them at first, but no dice.

Why sp big? 800+ motor horses need lots and lots of fuel. And since I don't want to run say, 60# injectors at 100% duty cycle, I got the 75 pounders.

Posted by: NYC LS8

I guess we're to assume that it's an 800hp motor. Gotcha.

No idea why the tune keeps changing, obviously it's not from the injectors. Was just curious why the 75 #ers when there was no other mods mentioned.

Do you get any codes? Or can you monitor the IAC and ECT sensors? The car runs off the ECT until it goes closed loop, I believe, so maybe it's sending out wacky signals..?

Posted by: Jibit

Quote:

Originally Posted by Frogman

The car will idle like junk until the computer sees the O2 sensors warm, and switches to the closed loop tables.

Maybe I'm wrong but I didn't think this had to happen anymore? I thought the newer cars didn't need to warm up the 02's, hence why no one has problems with high flow cats anymore.

Quote:

Originally Posted by Frogman

The main problem we're running into is the computer changing values as it desires. Whether it's supposed to or not.

That's extremely odd. Any way to track what is changing it? I'm thinking there's a sensor(s) that are trying to correct parameters based upon what its reading. The computer is constantly altering things to get the best drivability. I assumed this was turned off when someone added a chip or went it and altered things?

Quote:

Originally Posted by Frogman

We're going to swap the computers and see if that will change anything. For the guys with the Cobra manifolds, did you use the Lincoln IAC or the Cobra IAC?

I would think the Cobra IAC has different parameters but again, nothing you shouldn't be able to fix with tuning.

Posted by: Stack

Sounds like you flux capacitor is going out... you might want to get that checked

Posted by: mespock

I'd suggest use the @#$%ing Search Function...

Then add a set of 20's on her... That should solve the problem..

Sorry just had to do it....

Posted by: Jibit

Quote:

Originally Posted by mespock

Then add a set of 20's on her... That should solve the problem..

yeah rimz always solve the problem! Well, sometimes a fuel pump always solves the problem

Posted by: Frogman

Quote:

Originally Posted by mespock

I'd suggest use the @#$%ing Search Function...

Oh yeah, yeah, you're right! I forgot about the search function. I mean, I'm sure this topic has come up a ton of times seeing how all of my fellow Mark VIII owners on here are running stroked, forged and force inducted motors in their cars. I shall try the search funtion.

Quote:

Originally Posted by mespock

Then add a set of 20's on her... That should solve the problem..

20's? Screw that. I'm going to 26" RimZ, y0!

Quote:

Originally Posted by mespock

Sorry just had to do it....

I understand, me being a n00b and all that just signed up a couple of days ago to ask this question..

Quote:

Originally Posted by Jibit

Well, sometimes a fuel pump always solves the problem

Walbro 255LPH HP with less than 30 hours on it.

Pump's keeping up with demand... at least according to the fuel pressure gauge mounted on the FPR.

Posted by: driller

Quote:

Right now, we can get the car to start. It's a rich start though. The injector pulsewith on startup is damned near turned off. The car will idle like junk until the computer sees the O2 sensors warm, and switches to the closed loop tables.

Hmmm... I wonder if it's related to my issue with the dynotune the other day. My oxygen sensors apparently aren't functioning at idle??? This causes a rich condition. I've been told it can be due to the O2 sensors' position in the headers and can be accounted for in the SCT tune.

Bear in mind I have no stroked, forged and force inducted motor in my '93.

Posted by: Frogman

My dyno guy touched on that very same issue last time I saw him. I can't remember if he said he compensated for it or not.

However, that still doesn't explain why the car idles badly once it's warmed up though...

We'll see how the spare computer behaves. If the same thing happens with the new computer, then we'll know it's something else.

I really doubt its the injectors. I mean, hell, the High HP 4 cyl crowds are running 100+ lb/hr injectors just fine.

Posted by: driller

Quote:

Originally Posted by Frogman

My dyno guy touched on that very same issue last time I saw him. I can't remember if he said he compensated for it or not.

However, that still doesn't explain why the car idles badly once it's warmed up though...

Warm or not - mine was still rich at idle with no O2 feedback.

Posted by: Roadboss

I would suspect the MAF feed back or leak/short from what I am reading. I am running the SCT 2400

Posted by: Frogman

MAF Feedback? Pardon my ignorance, would you please expound on this?

The MAF graph was fairly smooth. I would think if the MAF was bad, the graph would look like a porcupine. Either way, please enlighten me, RB. Thanks.

Posted by: 98LSC32V

You are running a return style Walbro pump in a hybrid return/returnless variable voltage fuel system. Even though your fuel pressure seems fine it could be causing problems. You need to get a Lincoln Aviator fuel pump or modify a Ford GT fuel pump to fit. I'm not sure this is what's causing your problems but if it's not the Walbro can cause new problems down the road.

Posted by: Frogman

No I'm not. I'm running a return style fuel system, just like the OEM setup. The fuel system past the fuel filter is an aeromotive setup. 98 Cobra rails and Aeromotive regulator. Return Style, not 98 1/2+ Cobra returnless.
Note the Fuel return block on the upper right hand corner of the package.

There is nothing hybrid about it. The fuel pump is the same pump most Mark owners use... The upgraded 255LPH HP pump. Well.. to a degree, it's actually a 255LPH HP Walbro designed to fit a cobra canister, but I've already modified the canister. It ran just fine before the motor was pulled.

As I said earlier, the fuel pump is keeping up with the demand just fine, according to the fuel pressure gauge I have on the Regulator.

Posted by: Jibit

I was being sarcastic when I said a fuel pump, didn't think anyone would take me seriously

Posted by: Frogman

This is a serious thread, man! The eff were you thinking!?!?!

Hahaha. It's all good. That's how you solve such issues. One thing at a time.

Posted by: Redwingvksm

As in the reprogrammed computer changes the values all by itself?

For something like that, i dbout it would be mechanical. I'd seriously take a 2nd look at that computer, and maybe even spring for a megasquirt...

Posted by: Frogman

I've sent off a spare computer I have. We'll see what the results are in a couple of weeks.

Posted by: 98LSC32V

OK well I wasn't aware of what fuel system setup you had going... I would go to a different tuner who deals with lots of 4.6 DOHC setups if possible. Your guy might be good with tuning but a person who has seen lots of modular forced induction applications would be better.

Posted by: Frogman

I would... But most of the cars in his shop are modular Rustangs. Mostly Cobra Flavors. The guy drives an 06 GT.

And I think you misunderstand. It's not boosted yet. I want to break in the motor a bit before boosting it. A thousand miles or so ought to be good enough.

Posted by: Darrin

A 255lph Walbro isn't enough pump to keep up with 800hp. That isn't your real problem, but just something you need to know.

Also, with injectors that large you will likely have idle issues. Log the injector stuff at idle and you will see what I mean.

It will be rich.

Just for S&G, swap in a smaller set of injectors for idle only testing. It might surprise you what you find.

Darrin

Posted by: Frogman

The fuel pump is FINE! As I have mentioned in my previous post, it's NOT YET BOOSTED.

I had thought about swapping the injectors to a smaller set, and see how that works out. But my question still remains. How is it that the 4 cylinder crowd can run 110+ Lb HR injectors just fine then?

Posted by: Stack

I run 120 Lbs on my 4cyl SVO and it runs fine!

I don't know how I do it LOL!

Posted by: Darrin

THANKS FOR YELLING AT ME!!!!

God luck.

Darrin

Posted by: Frogman

I'm nsorry Darrin. I wasn't trying to yell at you, man. I was trying to emphasize the pump is fine with the current setup. I know, CAPS means yelling on the web and all. I should have bolded the words "fine" and "not yet boosted".

Inserting all those [ b ] and [ /b ] tags is such work, you know... :|

I know a 255LPH pump won't feed 800BHP. I've got a nifty relay setup that a fellow LvC Member has made for me that will take the voltage reference from the OEM fuel pump voltage line and activate three relays which will run three 255LPH intank pumps. Pumps that will be massaged into the tank by a custom tank shop in TX. Another LvC member who knows Fuel delivery designed the Fuel System on this car as well. It's not fully implememted yet because I still need to drop the tank, send it off, etc. But believe me, fuel delivery to this motor has been well thought out.

Posted by: phreakness

post up your log or link it to a site. if your using livelink and SCT

log your STFT and your MAF AD count's

with that big of a MAF and your injectors that huge I bet the value files your using are either wrong or WAAAY the F off.

Posted by: Roadboss

This is old stuff and he never answered any Q's waste of time.

Posted by: Frogman

Gee, thanks Roadboss.

Posted by: Dacket

You can hit CTRL + B to make it bold.

It works for me at least.

Posted by: Frogman

Huh....?

Posted by: ground_zero298

Did you ever get this fixed frogman? I could get you lidio's number. A fresh prespective might help you get it figured out.

Posted by: Frogman

I think we've gotten it licked.

I've been at the dyno shop all day.

Thanks for all who contributed with input.

Posted by: MediumD

Quote:

Originally Posted by Frogman

Huh....?

If you hit the Control key and then the B key, when typing in the reply box, it inserts the UBB tags for you and moves the cursor between them.

Posted by: Frogman

And you can also QUOTE WTF you're referring to, did you know that? It makes it easier for people to follow what you're talking about especailly if the post in reference is several replies back

Thanks for the Ctrl B "lesson". Alas, I think it's safe to say I know a bit about vB, UBB and the like, since I run a couple of vB forums.

Posted by: mmtphoto

maybe it's karma, skippy (oh, sorry, that's me)-I meant 'toadboy'

-
try 'search'..'lol''

Posted by: Frogman

Maybe it is Karma... but you're still an idiot, so I'll take my Karma and I'll leave you to be an idiot.

Posted by: mmtphoto

Quote:

Originally Posted by Frogman

Maybe it is Karma... but you're still an idiot, so I'll take my Karma and I'll leave you to be an idiot.

doesn't take you long, does it? we all sat here, waiting for a response-I had the under. I won-thanks for that, and the laughs too-oh, by the way, on a scale of clever retorts, yours garnered a 3 out of 10-'LOL"

Posted by: glanga

What was the problem? The injectors?

Posted by: Frogman

Quote:

Originally Posted by mmtphoto

Yawn. There you go again with the "we" thing. You're still an idiot.

Quote:

Originally Posted by glanga

What was the problem? The injectors?

No, it was the dashpot function. Cleared itself after fiddling with the spare computer I had. The motor still has a bit of a lope to it, but we've attribuited that to the cams.