Fuel Injection Fix

Well after working with my Stack Injection for 2 months, I have finally fixed it. I S*** Canned the unit and installed a set of Webers! No more back firing, running hot, uncontrollable idle and lazy acceleration. I guess I just wasn't meant to run the unit with my limited computor knowledge, and out here in nowhere ville there was no one to turn to for help. The engine even sounds better and starts instantly like a good carburated engine should.

Vic

 

Glad to hear it's up and running, Vic! Just in time for summer. As you know I am using the same fuel injection manifold that you were using, but with the electromotive computer. I had some help with the programming which led to my success. I was able to get it running on my own but like you was not satisfied. Having the factory rep a half hour away from my house was pure luck. I was able to talk him into driving over to my house to help me. Hope to see you at Monterey Historics this year.

 

[Robert Logan]

Vic,

Sorry to here of your problems with the injection system. I do not know which inlet manifold and Management system you used but there are a few things that need to be looked out for particularly with the manifold:

There must be good control from one butterfly to its adjacent butterfly. This includes the adjustment between the conjoined pair.

I fitted my first injection system to a GT40 over a decade ago and had a multitude of problems with various inlet manifolds from air leaks around throttle shaft bearings to total lack of control between throttles to poor TPS position.

Vic , please do not get disheartened as I have been told that "Rouse Engineering" were having problems with an injection manifold also.

Control is the key.

Best wishes,

Robert

 

[Dan W]

What system were you running and what ecm were you using before you yanked it and did you go to IDAs or IDFs ?

 

[Dave Wharran]

Robert's comments are right on. I had mixture problems even idling when I first started my engine. 4 cylinders were really rich due to minute variations in throttle plate settings (mechanical). Balancing all 8 throttle bodies for air flow is the first step.
IMHO, setting the maps is best done on a dyno. Mine was set up in two hours of dyno time by someone used to setting up the brand of ECU I had. Very hard to do on the street with that much HP and that light of a car.

I had a steep frustration curve with the HALL switch for the direct fired ignition. Like you with the carbs, I was ready to put a standard old distributor in just to get the thing to run without backfiring and barely running.

Technology is unbeatable when it works. When it doesn't work, it's a royal pain ITA.

In the end, I'm glad I stuck with and sorted out the EFI. Fuel mileage is decent. Throttle response and drivability exccellent.

Keep the EFI hardware and maybe go back to it some winter when you can't drive the car anyway.

 

The throtle were all balanced perfectly with a unisyn, timing was spot on, fuel pressure 52 lbs, battery voltage 13+, water temp Ok. What I couldn't understand is why the idle would change from one day to the next, also adding more fuel to the acceleration didn't help. Like I said before, thank God for the Webers.

Vic

 

[Robert Logan]

Vic,

This is known as "cold start". This is an area we have great difficulty with as we do not get many cold days in Australia (get cold and suffer you poor people). We use various sneeky methods to get over this such as injecting extra fuel on start-up, running for a pre determined time slightly rich and paying particular attention to air temperature and water temperature control to increase both injection and ignition maps. Just let me say that there has been many THOUSANDS of man hours in the "standard" maps that we 'give away' with our MoTeC systems.

The injection is the way to go, we have a car in our shop that has a six speed box that at 65 MPH gives us better than 30 MPG on the open road. The same car has blistering acceleration (ask Hershal about the blue car) and with the injection is tuned to drive like a pussey in traffic. The injection is like having a set of Webbers with an adjustable set of jets that you change at will.

Injection is worth sticking with but it is trickey to get right but when it is , it is just GREAT !!!!!

Best wishes,

Robert

 

[James]

Robert,

Looks like we have something we agree on! /ubbthreads/images/graemlins/grin.gif

I'm with you 100% on this one. I looked at both IDA and FI and was persued to go with the FI.

It is the ultimate way. The Motec M48 is just plain brilliance.

Fraser mapped my engine on a dyno(maps engines for Pagani and the like at Le Mans). Bloody awesome! It amazes me what you can do once it is set. I like the fact that you can actually tweeks the settings inside the car.

You also retain the looks of the IDA's

What more could you want? /ubbthreads/images/graemlins/wink.gif

Regards,

J.P

 

Robert, I couldn't agree with you more. I had a 5.0 Mustang that was injected and I made many changes, bigger throttle body, headers, larger Mass Air and a Vortec Supercharger. It ran great and was easy to work on. I am a believer in Fuel Injection (that is why I spent the Big Bucks to put it on), but I am not going to fight this thing all summer as the driving season for this type of car is too short where I live. The plan now, is to retain the mechanicals and get another more user friendly operating system and maybe try it on my 65 Mustang or a Street Rod. Thanks for all your input.
Vic

 

[Robert Logan]

JP,

I am sure we have a lot more to agree on.

Please pass on my kindest regards to Fraser when you next see him. When he was the manager of MoTeC UK , he visited the MoTeC HQ here in Australia and Richard Bendell the MD of MoTeC paid a visit in my old factory. This was before he purchased his own KVA. He is a very knowledgeable man with a HUGE experience in all things motor racing and MoTeC and I could only VERY STRONGLY recommend anyone with injection problems in the UK to seek him out. Richard Bendell has always told me just how good he is in this area.

Best wishes,

Robert

 

Im no expert, but fwiw, have to say 52 psi seems a little high to me. Another problem people have, especially when idle is concerned is injectors that are way too big, what is your estmated bhp and injector flow rate? Just for curiosity sake.

 

The injectors were sized to the spec recommended by the injection manual. I have built a few engines with the same components as mine and the HP was 400-425 with a Speed Demon 650 carb on an Edelbrock manifold. The injectors used were Motorsport 30lb.

Vic

 

[Bo Eliasson]

Was the fuel pressure fixed or were you using a vacuum controlled fuel pressure regulator?
The ECU normally requires a fixed fuel pressure relative to the manifold vacuum i.e. the difference in the manifold (pressure) vacuum and the atmospheric pressure should always be fixed.

 

[Ian Clark]

Hang in there Vic Once you get it set the EFI will deliver better fuel economy and cold starts than the Webers.

The challenge seems to be "mapping" all the different combinations of displacement, cam, heads, manifolds, timing, injectors, fuel pressure, throttle bodies, etc to get it running right.

I beleive Robert when he says thousands of hours have gone into the mapping of the MoTec system.

We spent a ton of time and money attempting to tune our first EFI system with all the frustrations explicated by others before us... with no luck.

The answer was bringing in the big guns. Wayne Presley of VeryCoolParts.com supplys our systems and was very helpfull on the phone, however we needed it fixed with no further delays.

We flew Wayne to our customers shop (ten hours flying each way, plus hotel) to tune the system. Within a couple of hours it was done. Wayne called my cell and said "this car is a rocket ship!" The customer is also very happy.

So call in the big guns and get it fixed, you'll love it afterwards. We've settled on the 347 Ford Racing Crate Motor with EFI and Weber computer through VeryCoolParts as our "standard" system thus eliminates further mapping (P.S. I thought your fuel presure was high too).

 

[Fran Hall RCR]

I suppose my thoughts would be "why " do you have to call in the big guns ......surely the seller of the fuel system and their recommended software should be able to help any consumer in a timely manner,and achieve a sucessful and usable map without 1000 hours of tuning.
Obviously the seller/manufacturer has belief in his products in the first instance..?
After all these systems are not inexpensive and are sold as a "better more user efficient" solution to carbs...of any size shape and configuration.
I have a hard time believing that all of the retailers of these systems have a truly useful database for tuning and as such should not be peddling their wares to the public until they do......
OOPS..just fell off my soapbox

 

[James]

I think the point is this:

When a professional, like Fraser MacKellar, maps an engine he is able to use his vast experience to quickly see whats need changing. I videod Fraser mapping my engine from scratch.

Even for a pro like Fraser it still took a whole day.

I simnply cannot imagine Fraser trying to relay that information over the phone. It would take days.

In my opinion if you are to go down the fuel injection route you need to budget for a professional to map your engine on a dyno to get the best from your engine. Unless you are very experienced, and have mapped engines before, you'll no doubt end up somewhat dissapointed.

Regards,

J.P

 

I have received some interesting private E-Mail since my post concerning my Fuel injection woes. A few were from owners of a system like I was using, wanting to know from whom I purchased my Weber carbs. Very interesting!

Vic

 

[Mark Worthington]

Very interesting, indeed, Vic! I have the RF 8-stack EFI setup with the Motec M48 and have to confess I don't know diddly squat about how to set up an engine with it, and my eyes glaze over when I read technical discussions about EFI tuning. That said, I didn't know diddly squat about hydraulic system plumbing, body prep, or transaxles before I started this project yet have managed to learn enough to get by, and I intend to do the same with EFI. The people I know who use EFI say that once you grasp a basic understanding of it it really is easy to tune. Also, a naturally aspirated engine should only take a couple of hours of dyno time by an "expert" to get dialed in. Yes, the Ferrari F1 team spends measures their EFI tuning time in man years, but once you have your fuel and ignition maps set up properly, you're not going to realize much more by further tweaking.

I look forward to playing around with my EFI setup.

 

[Bill Bayard]

Mark,

Just be glad that you don't have the same ECU that Vic and

I have/had! After 2 months+ of BS, I am tearing mine out

too. I won't name names, but the manufacturer's moniker is

still in my signature(not for long!) I have yet to hear of

an engine that ran well with one of these systems(Or ran at

all in my case). Months and months of tuning seem to be

typical. /ubbthreads/images/graemlins/mad.gif

Unlike Vic, I am sticking with EFI, and getting a different

ECU system (Accel Gen 7). I will be installing it myself,

then taking it to a seasoned pro(Second Streeet Speed)for

tuning on a chassis dyno. The owner told me to bring the

car in at 9AM, and I'll be driving it home, fully tuned,

after lunch! This guy doesn't screw around!

You can check them out at www.secondstreetspeed.com

They turn out some GIGA-horsepower figures!

It'll be a relief to finally make some headway!

This thing has been driving me nuts!


Bill

 

[Mark Worthington]

Good choice on Second Street Speed for the tuninf, Bill. I was in line for a twin-turbo kit for my 99 Cobra, and my research led me to believe they were the only shop in the northeast that I would've trusted for the task. Good luck getting your car set up and running perfectly!