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Wagoneerlover 02-20-2008 01:58 PM

TBI systems vs DIY vs each other
Hello everyone,

For those of you running tbi systems on your rigs, Post your ideas, thoughts and experiences with the systems and which system you feel you would want on your rig if you could do it over again. (If you are fine with your current system then post that about it. Of course you all should know that I am biased as I never ran any of the other systems on my rig. I have only run a D.I.Y. system and I am in the process of finishing up my article (Sorry everyone lost the charger to my digital cam and without pics I dont have incentive to finish) (Well the charger has been replaced and I am ready to go again and finish!). Below I have listed links for the various out of the box systems and for a DIY write up (Mine of course, if some others out there have done DIY write ups please post too) Hopefully this resource will help some of those who are interested out there in the various systems to make a sound choice based on what they feel will best suit their level of expertise, budget and comfort level. The Links to the various TBI makers out there are listed below (Maybe I missed some but I dont know of all of them)

1. Affordable EFI

2. Custom EFI

3. D.I.Y (Do it yourself)

4. Holley TBI

5. Howell

6. Megasquirt
MegaSquirt 3:

crispyboy 02-20-2008 02:28 PM

I have two FSJ's each with a different system.
First off my vote goes to Howell - they have great customer service and are easy to work with.
1.) My J20 has a Custom EFIS system. I think I was one of his earlier customers. John is a one man show who is extremely smart but has no business sense - too bad. I had to wait for some time to get my system then it took quite awhile to get it tuned properly. Presently I believe he uses chips where the owner can burn the chips after he makes the changes. After all is said and done my truck runs awesome - like a modern day vehicle, the truck should have come from the factory this way. Too bad John couldn't get his act together a little better.

2.) My GW has a Howell system. I bought the system brand new but it was second hand from a board member. I called Howell and had a chip burned for my camshaft. The chip that came with the system was supposedly for a stock engine but this could not be confirmed. It took quite some time to get the GW to run half way decent by trading chips in the mail. I found one good enough to get the GW on the road. I drove to Howell operation in Michigan. The programer spent about 6+ hours with me. I came home partially satisfied. Howell did not charge me anything but I tipped the programmer for his time and help - he was really pretty good. I have a GW that runs pretty good on the road but the idle has a lot to be desired. I blame this on myself and the wrong camshaft selection. I have a Edelbrock cam and should have went with the Crane with 112 lobe centers. I have been told that this lobe seperation can confuse the computer..... Hopefully later this year I hope to tear down the engine and make a change. I even have wild ideas about an Edelbrock system....... just dreaming.

TBI can take some work and patience to get it right but it's worth it.

Chumley360 02-20-2008 03:18 PM

OK I'm going to be all over the place here, so just be aware. I like Megasquirt for my custom cars, I find that it just lets me do more than some of the out-of-the-box systems. I have run an older version of the Holley TBI and had no problems with it. The new Edelbrock MPI system kinda has me drooling to get a Javelin to try it on. I think that the biggest and most important idea with going to any of these systems is personal knowlege. Know what you need vs. what you want and look for what will get your there the easiest. OTB systems may not offer a wide enough range of parameters for some people, while fully programble units might offer too many. I also support building kit from scratch/junk-yards, I just think it's fun.

crispyboy 02-20-2008 03:41 PM

If I could understand the programming I would love to do the DIY - I understand everything else.

PlasticBoob 02-20-2008 03:52 PM

I just got MegaSquirt running on my 401; I did a lot of research over the past few years and MegaSquirt looked like the best option for me.

The only downfall is that you have to know what you're doing, and it takes a long time to understand and tune (plus soldering together the ECM takes time if you opt to go that route). But that's just my kind of system! I love challenges.

So far, MegaSquirt hasn't been nearly as bad as the naysayers have made it out to be; I just think they didn't do their homework first. My installation went smooth as silk and it fired up on the very first click of the key.

budojeepr 02-20-2008 04:10 PM

I did DIY, but cheated - I used the original engine the TBI system came with, and put it on a 1969 truck (no Republik of Kalifornia smog).

With Bill USN's excellent FAQ on Binder Bulletin, I was able to modify the harness to integrate with my Painless Performance wiring loom. My work predated the DIY thread on this site.

I have absolutely no complaints on starting, drivability, and 'wheeling performance. Beats the two different carbs I had before, hands down.

mattmopar440 02-20-2008 04:41 PM

I plan on making my own EFI buy taking 4.0 HO head and swappin on a 4.2 I have been reading about it and it not that hard granted you have and Xj laying around for parts :D

Wagoneerlover 02-21-2008 01:38 AM

I didnt get a chance to post my thoughts on the other systems, as I dont have much experience with them. I did know a guy who installed a holley TBI system and it was crappy. The system was really sensitive and always seemed to give him headaches. It took a lot to get it to tune in right and it was really quirky. (Maybe it was because it was when they first brought the system out.)

Other than that I really promote the DIY route because you have a complete GM setup and no parts from other vendors (A lot of these parts can be changed to GM parts or so I hear) besides that, you actually learn the inner workings of the system yourself, you dont have to send your chip back and fourth to get changed, adapted or burned and if you take the time to learn about chip tuning etc you can do amazing things by yourself and you can really fine tune your rig to your own liking. (It sort of becomes like an aged wine, just takes more work than using a corkscrew)

jaber 02-21-2008 08:57 PM

I am running a CustomEFIS system. It's been on the GW for 6 yrs now and is my wifes DD. I must have fond him before he got busy because it only took 3 chips and I have not touched the system other than basic maintenance to the motor. It was a fresh rebuild, .030 over with a com 260h cam.

I have a friend here that just did a DIY on a '68 327 panel Jeep. He is a wiz with the programing and harnesses and will probably build my own next. I just need to find a doner........ :drivin:

sandals1621 02-28-2008 09:26 AM

I just finished a TBI install using junkyard donor parts.
I was going to go howell, but I got a complete, thottle body, harness, computer sensors from a friend (for $0) who bought a truck for the engine trans.

It really wasn't that difficult to do, and i'm horrible at this sort of thing. hardest part (well most time consuming) was trimming all the un-needed wires out of the harness.

I'm running all stock GM parts, a Holley Blue fuel pump and a DUI dizzy and it starts and run's like a champ

FSJ Guy 02-28-2008 10:37 AM

I'll help revive this thread from the dead. Howell TBI. Excellent product, excellent support. Wife can start the car at any time. NO VAPOR LOCK. I love it.

Woodchomper 02-28-2008 01:15 PM

I'm a fan of DIY EFI. I built my system from junkyard parts but I modified the ECM with a circuit board from Basically this board allows for a great amount of feedback when chip tuning. The board I used was called the EBL Classic. A new board is now available which is called the EBL Flash. The EBL Flash board negates the need for buying an EPROM Programmer since the onboard flash memory is used instead of an EPROM.

Serious Johnson 02-29-2008 09:46 AM

If doing it again, I'd go the DIY route. When I was building my Jeep's motor was one of those rare instances when I had more money than time, so I went with customefis. It wasn't a wonderful buying experience, but the kit has been pretty darn good from the get-go.

It's really helpful to understand the workings of EFI inside-down & crossways, and just slapping on a kit short-circuits that. I still havent got around to learning chip programming, and really need to.

General observations/opinion:
-Any system that doesn't control ignition is little better than a carburetor.

-The more OEM parts the better. It sure is easy to just say "'88Chevy" at the parts counter or junkyard.

-MPFI is cool as all getout, but only a tiny bit better than TBI for Jeep-ish work, at about twice the money.

-Include a knock sensor. My 9.25:1 compression hotrod 360 is happy as a pig in Mecca when running 85 octane swill, and steps up to the plate for heavy summer towing when I feed it 93.

-Hilly country use is a good argument for a speed sensor -- cuts fuel entirely on the downhill, potentially saving filthy lucre.

-Make sure that your charging system & wiring are up to snuff -- these things don't much like inconsistent voltage.

-If you don't do large elevation changes, and the summer-winter temperature in your area varies less than a hundred degrees, and you don't rev to 6,500 like I do, the Motorcraft 2150 is a fine carburetor that deserves consideration before converting to EFI just because it's "neat".


chipotle 03-04-2008 09:58 AM

Mine is sort of a Custom EFI setup. I ended up finding a GMC chip from a stock heavy duty truck with manual transmition, and putting it in. It works pretty good, but has problems with towing at the upper limit of the Wagoneer. Some day when I have time, I'd like to get some of the SW to program it hot, and get it better tuned. Since I no longer tow any heavy loads, it's not a problem.

I would recommend staying away from this cough..."business". This all started about 3 years ago. I got zero support, and none of the promised tuning. He was literally 300% late in providing material; and a complete no-show on setup support. I had parts problems that I and my mechanic had to fix.

gojeepin 03-19-2008 09:49 PM

i just did a howell system and its been a complete nightmare:mad: the tech help from howell was helpfull but after several calls we could not figure my prob.took it to a qualified shop and spent hours testing for probs,discovered both injectors were junk"high ohms resistance and more of a drip than a spray,spent 400.00 on new inj which solved that prob,another call to howell concluded that the prom in the comp was also bad,so far my 1200.00 inj system has cost me an extra 650.00.:banghead: i plan to see if they will make it right with me,if not i'll let everone know.i've had holley projection on my cj for about 10 yrs,no probs

pb 03-20-2008 07:50 AM

AFI sucks. Only good if you want to learn everything about EFI in order to troubleshoot their system and you want to be called a liar when they send you the wrong stuff, and incorrect pin instructions.

Wagoneerlover 03-20-2008 05:07 PM


Originally Posted by pb
AFI sucks. Only good if you want to learn everything about EFI in order to troubleshoot their system and you want to be called a liar when they send you the wrong stuff, and incorrect pin instructions.

This is the same way I felt about one of the companies out there (You know who). I had horrible experiences and I never even purchased the product. No response to e-mails for purchase inquiries. Outrageous lies about why things were backed up and orders could not be processed efficiently etc. Thankfully I didnt order, however a guy up the road did and just as I thought it was a nightmare to get his product and when it did arrive it was not as it should have been.

Joe Guilbeau 03-20-2008 07:14 PM

Holley Pro-Jection
Been running a Holley Pro-Jection Throttle Body since problems except for the Throttle Position Sensor needs to be replaced every several years or so, and don't ever let it get wet!!!

BigRedChief 06-20-2008 12:06 PM

I went the DIY route with lots of help from

If I had it to do over again I would have spent the time to pull the parts myself to know exactly what they came from. I got a "kit" from someone and it turned out it had V-6 sized injectors. I had the hardest time figuring out what was causing it not to run well. A lot of things ended up getting replaced that probably didn't need to be because I couldn't and didn't inspect the parts myself before they were pulled too.

Another thing... Don't expect any magic bullet for fuel economy with EFI. If anything it will get worse since a lot of carbs tend to run a little on the lean side. My mileage actually got worse. What I was after and what EFI accomplished beautifully is great drivability, starting and idling.

Dr.E 10-31-2008 10:14 PM

First Fuel Injection TPI
I used the First Fuel Injection TPI set up.
They basically improved on the GM TPI MPFI system.
The customer support was fantastic!
I live in So.Cal. and the owner of the company came to my house,(He lives in
Wisconsin), to help with the initial start up because he was visiting a relative in the area. Wow! taking time from the family vacation to help a customer!
This is a true story! I buggered up some gaskets...Ken Shuneman sent me some new ones no extra charge! Ken even burned me an extra PROM for my spare ECM no extra charge! The system performs flawlessly!
Great product great price...not much more one can say.

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