[Cliff R]

I've used my 2003 Harley Davidson Road King as an example of a tuneable fuel injection system that I've been working with for several years. I've never been overly happy or impressed with it, and have spent nearly $1000 on two completely different fuel managment systems for it.

Except for instant start-ups, it has never worked as good anyplace as my carbureted 2001. It has always been slightly "anemic" at very low throttle openings, and has not responded well to any setting(s) I've made anyplace to help it.

Anyhow, I was just about ready to amputate the entire system and install a Mikuni CV carb on the bike, as I can get flawless performance from it in all areas in minutes. Right before taking the plunge the bike starts stalling every single time I come to a stop. After checking over the obvious stuff, I'm thinking the POS cam chain tensioners in the Twin Cam engine are taking a dump, so I take it to the local dealer.

The next day they call and say that they found two sizeable holes in the high pressure fuel line inside the tank, and that they have been there for some time as the line was rubbing inside the tank, continuing to make them larger.

So I get the bike back, and guess what, it is FLAWLESS in every area, running equally as good as the 2001 carbureted bike.

Ya, I know I've slammed the fuel injection a few times and used it as an example when making comparisons with Pontiac set-ups, etc. Anyhow, my information was flawed by a fundemental problem with the 2003 Road King. Now it runs as good as my old bike did, and I don't need to choke it on cold starts.

Just wanted to clear this up, as I have slammed fuel injection a few times for not being up to par no matter how much money and time I threw at it......Cliff

[Mr_GTO]

It's easy to slam when you don't know all there is to know about it. I can tell you more about EFI than I can about a carb...just different experience with it.

Glad to hear it's back to normal.

[Cliff R]

I never did "slam" fuel injection, but the complexity/investment of a complete system still doesn't show me enough power or economy anyplace to start fitting them on old Pontiac engines.

Good new with the Road King, is that I didn't amputate the fuel injection system, even though it runs no better anyplace than a well tuned Mikuni CV carb....but at least now it meets my expectations, and my efforts to map the system have now got it up to par in every area.

In comparison, the CV carb in particular, idles flawlessly (when modded correctly) with big cams, and is seamlessly smooth at really low throttle openings and right off idle. No TPS signal to reference attributes to some of that, and they do a very good job of atomizing the fuel with plenty of room/distance down the intake runner(s) to enhance this as well......Cliff

[Mr_GTO]

Originally Posted by Cliff R

I never did "slam" fuel injection, but the complexity/investment of a complete system still doesn't show me enough power or economy anyplace to start fitting them on old Pontiac engines.

Good new with the Road King, is that I didn't amputate the fuel injection system, even though it runs no better anyplace than a well tuned Mikuni CV carb....but at least now it meets my expectations, and my efforts to map the system have now got it up to par in every area.

In comparison, the CV carb in particular, idles flawlessly (when modded correctly) with big cams, and is seamlessly smooth at really low throttle openings and right off idle. No TPS signal to reference attributes to some of that, and they do a very good job of atomizing the fuel with plenty of room/distance down the intake runner(s) to enhance this as well......Cliff

Uh? You never did?

Ya, I know I've slammed the fuel injection a few times and used it as an example when making comparisons with Pontiac set-ups

If you don't think it's worth it, fine. Don't ever buy one for a Pontiac.

[shaker455]

Cliff,
Some of the new EFI stuff for twin cam engines are pretty advanced and my friend has a Road King cop bike that is now stroked with a new mangement system that you can adjust the fuel curve every 100 rpms....pretty cool!

You can start off with a map and adjust from there..

My bike is old and I have a simple CV that I've tweaked and dyno tuned for my drag pipes.

As for EFI on Pontiacs I helped my buddy dial in his Holley Pro-jection 950 on his car as he had been running it on a SBC map and had the rear injectors turned off!

I called Holley and the guy I talked to had made a map for his own Pontiac so he email it to us...

Installed it and changed the fuel curve by 10% and I proceeded to blow the tires off the car....Nice!

[Cliff R]

"If you don't think it's worth it, fine. Don't ever buy one for a Pontiac."

Since I said, and will say it again, thousands of dollars spent to go no faster at any rpm and just add weight, adding complexity and hundreds of potential failure points, to a pretty simple set up, certainly nothing we're going to look at around here. I guess we will call that a "slam".

Besides, I can think of at least 200 other places to spend a couple thousand dollars around here.......Cliff

[Mr_GTO]

Originally Posted by Cliff R

"If you don't think it's worth it, fine. Don't ever buy one for a Pontiac."

Since I said, and will say it again, thousands of dollars spent to go no faster at any rpm and just add weight, adding complexity and hundreds of potential failure points, to a pretty simple set up, certainly nothing we're going to look at around here. I guess we will call that a "slam".

Besides, I can think of at least 200 other places to spend a couple thousand dollars around here.......Cliff

TO YOU. Don't say we unless others agree with you. There are plenty of people here who have used EFI with great results and don't share your sentiments.

[Skip Fix]

Cliff one o m y mechanic buddies has become a dealer for one of the bike EFI controllers that let's you change all kinds of parameters. He feels its really helped fine tune the factory systems easily.

[Z Code 400]

I have actually been thinking about that 950cfm Holley EFI kit for my Pontiac...Robert

[shaker455]

Well Robert,
If you read the manual & set all your parameters & start with a Pontiac map you'll have great results.

[JC455]

Cliff,
Sorry I didn't know about your FI issues... the rubbing-hole-in-line is a common issue on that generation (actually, I think until 06-07) of injected Twinkie.

On another note, I wish for FI when my buddies and I are travelling. I am very near sea level, so when I'm riding at 10,000 ft, the CV doesn't like to run so good- ya know? My buddy's '04 FLH fires right up and adjusts it's fuel mixture. I suppose I could tear the carb apart, but that ain't gonna happen for 1-2 days riding in high country.

Oh well, glad to hear you've got your fuel issues fixed.

[amcmike]

Ease up now, Mr_GTO. He (on his own accord) manned up that the system he was dogging was not properly working, and that it didn't apply when comparing to car EFI systems. No need to light him up with both barrels.

Cliff I'm glad it's finally working for you.

[Cliff R]

Easy there fella's, next someones going ask my opinion on Comp XE flat camshafts!

Correct, I was trying to come clean as my results with the EFI tuning were flawed by an unknown underlying problem

Seems like WAY to many folks these days are all "touchy" about certain topics.

For the record, I'll stick to posting usable and accurate information, and your fuel injection topic is not something I haven't spend CONSIDERABLE time working with over the years.

I have set up intercooled turbo charged Rustang's to run into the 9's in full street trim, and Buick GN turbo cars to run nearly as quick, not to mention boatloads of diesel truck applications, which are all "fuel injected". It has it's place, and THE way to go for anything with "hair drier" or blower pressurizing the intake system, IMHO.

For older musclecars, I have sat back and watched folks dump TONS of money into "fuel injection" systems that ended up working no better than dirt cheap aftermarket carburetor, if as good. The fixed throttle body systems with the "injectors" above the throttle plates just don't offer anything over a well set-up carburetor, anyplace, unless you own a hill climber and like to tip your truck nearly upside down on big rocks on the weekends.

If one is going to move up to a true fuel injection system, the complete systems using O2 sensor(s) would be the way to go, IMHO, over one where you just map in different paramaters, such as the set-up on my HD Road King.

I actually LOVE to read about folks using very basic components, like the recent thread with the modded 301 distributor, etc.

Skip, I had the Daytona Twin Tuner, but with the fuel pressure not up to par, it wasn't working correctly. Currently running the Power Commander system, and it works quite well, although it takes laptop downloads to set it up. The Twin Tuner had enough lead on the wiring harness that I could hang it next to the tank, and make changes 30 percent rich/lean in over half a dozen different areas "on the fly".

The downside to the pre-2007 Delphi systems is that they do not use O2 sensors, and although completely "tuneable", still a fixed curve and don't change or compensate for varying atmospheric conditions, etc. Probably why we can run equally as well everyplace with the CV carbs?

The anology still applies to retrofitting on musclecars, the "throttle body" systems are just an expensive carburetor, and any fixed system is going to have it's limitations. Having a constantly "thinking" system, like is used on modern vehicles, that would be the direction to go (as some have done here), IMHO......Cliff

[carbking]

Cliff - glad you got it fixed. While in general, most hobbyists hate to consult a dealer, sometimes the dealer is aware of issues with a certain model.

I share your opinions of efi. As one growes older, walking along the interstate is a less desirable option.

With carbureted vehicles and point/condensor ignitions, I have walked once (fiber timing gear disintegrated after 200k miles). With efi and electronic ignitions, I have walked 6 times.

Remember the cell phone was invented AFTER efi and electronic ignition became popular.

To each his own.

Jon.

[Cliff R]

Jon, I concur on the "walking" deal, been left stranded by FI about a half a dozen times, requiring that costly new fuel pumps be put into the gas tank of the "modern" vehicle I was driving.

I put nearly 200,000 miles on a 1979 Blazer while I was in the Military. Commuted with it just over 100 miles a day for several years, and it never left me walking once. I did have to put a voltage regulator in the SI alternator once on the beach in Hatteras Island NC, and one fuel pump at a friends house while there visiting (about $14 repair and 20 minutes). Never touched the carb in that entire time (because I had to), one engine, one transmission, couple of dozen u-joints, brakes, hoses, belts, the usual stuff.

All in all, TB and fuel injected vehicles have been good to me, aside from the fuel pumps in the bottom of the tanks taking a "dump", I've only replaced two injectors over the years on vehicles I owned personally.

Anyhow, back to the topic at hand. My purpose for the thread was to let folks know I had compared the FI system on my Road King to a near identical bike I owned that was carbureted. At that time, I gave the advantage to the carbureted bike, winning out or being equal to the FI in all areas but cold starts. Once I got the FI up to par, and re-mapped exactly for my application, they are equal in all areas, with the cold start advantage going to the FI bike. Which is no more than having to reach down and pull on the enrichener on the carbureted bike, then push it back in about 20-30 seconds later......Cliff

[Region Warrior]

Please, no XE opinions! LOL
Would'nt mind try'n one of those 950 setups myself.
But i'm with Cliff on this one also.
Way to much $ vs the benefits.

[65catalina]

Yea, I'll keep my carb and points in my 65 as well.

[mechanic17]

No intent to hijack here, I just figure Cliff has the attention of some of the FI gurus here, and I have what I think may be a simple question for you about stock TBI (of the 1993 vintage).

A mild flat tappet cam 218/224 @ .050, .462 lift should not cause my previously healthy Chevy 305 to idle at 8 inches of vacuum, should it? I'm assuming I need a FI remap or whatever you Buck Rogers types call it, but is there some other check/solution?

Like Cliff said, I'm reluctant to start throwing hundreds of $$ at a problem I could solve with a $300 carburetor. . .

Car actually runs good, sounds good, but not getting enough vac for my brakes and others have reported this combo idling at 14 ". Oh, and I put a Perf RPM intake with TBI adapter and have triple checked, no leaks. So a carb would be easy at this point with a fuel pressure regulator, I believe.

Kudos to Cliff for being a good scientist and reporting skewed data. . .

[Overkillphil]

Same here, EFI is great if already installed from the factory. Easy to modify and tune electronically too. However, there is just no rational thinking in retrofitting it in a non-EFI performance vehicle unless the person doing it is an expert on the system being used.

The mechanics of the system are easy to install, yet the system is incredibly complex from a reliabity assessement standpoint. And our CR Qjets are STILL substantially more responsive than any of our EFI cars. Throw in the occasional EFI pump failures, IAC temper tantrums when the weather changes and MAF reliablity headaches and a properly tuned carb beats it hands down for simplicity, reliablity and cost.

[Zombi]

I'm curious how you guys are figuring an EFI system is so expensive? How much is a typical "good" quadrajet?