TBI Conversion Success Story

[Beaverseagle]

Hey Everyone,

I've been working on getting my TBI conversion working correctly for sometime now. I think I finally got it dialed in. I've done a couple of 500 mile trips and a lot of Chicago rush hour traffic daily commuting. The Cubs are going all the way this year!  Since then, it's been great.  I've wanted to write something up as a lessons learned. I've read so many conflicting things over this TBI conversion. Some people hate it other's love it.  I have to say once I got it setup, it's been great. 

No more hard cold starts and pumping the gas pedal.  Good gas mileage (as good as it can be. 2 inch lift with 235 tires).  Great Power.  I highly recommend it.

Sorry I didn' t include any pictures for this write up.  This is more informational than a step by step.

My Ride

82 258 SX4 Automatic

The Kit I used:

Kit: http://www.ebay.com/itm/Complete-TBI-Fuel-Injection-Conversion-Jeep-Fuel-Injection-4-2L-258-CI-/221894894279?hash=item33a9f762c7

Kevin White is the guy who makes these kits. He has several videos online and some very general TBI conversion instructions that seem to be boiler plate from what I found on the web.   He was very supportive with my annoying emails.  But please be aware, he cannot hold your hand. If you do this, you need to be able to figure out why is not working with your engine.  There are so many different applications, he cannot possibly know all the different issues that you might have.  While this is for a 258 engine, there are no instructions specific for this application. The best video he has is for a standard GMC truck.  Over all the kit is very well made and thought out.  The wiring harness was very easy to figure out and everything is clearly labeled and connections were very well done. All the senors were high grade.  My default answer for everything was this thing is defective and the chip you put in it was wrong.  He's reply and rightfully so was that it's you not me in our relationship.  I've been on his side of these types of things before and I figured he was right.  But I still wanted it to be him!

Plug and Play Upgrade

I can only speak for my make and model but this is pretty much a bolt on upgrade. All the sensor and ports were already part of the stock fuel system. All I had to do was to remove the old sensors (most of them were even hooked up) and put in the new ones. I had a friend try and upgrade an 86 cj7 and had a hard time.  I'm not sure if it was his kit (not the same as mine), but he had to mod his engine and exhaust.

There was one Mod. I take that back. For Autos only !

So the only real Mod I had to make was the tranny kick down lever. This does not apply to manual birds.  In hindsight, I could have tried swapped out the throttle adapter with my stock piece. I'm not sure if you can do this or not. If you don't want to mod your kickdown setup, you may want to try. I just tossed all the stock stuff out and almost ruined my transmission in the process.  I had no idea that the throttle position works together with the transmission.  I just thought it kicked down the tranny for passing. These two things need to be linked always!.  So what I did was use a piece of steel brake line.  I drilled a hole in the end that hooks to the throttle body and slipped it over the nipple on the throttle plate and made a hook in the other end.  This connects to the tranny.  The lever on the tranny needs to provide the correct amount of tranny fluid pressure as the throttle opens a closes.  So far so good. However, she will not downshift to second gear.  The spec says under 70 mphs she should kick down to second gear.  My belief is that the  brake line is bending and doesn't provide enough force when the tranny fluid is at a higher pressure.  I'm going to use my steel brake line as mode and go to the hardware store to find something stronger. I'll update once I do this.

Emissions

Remove all you emissions crap.  The emissions will not work with this kit, so just get rid of it.  If you are concerned with the environmentally impact, more than likely the emissions is not working correctly anyway and it's doing more harm then good.  A new TBI system has to have less than an environmental impact.  That air injection system is probably worthless by now.  I had a huge vacuum leak around the exhaust hoses that connect to the head.  And your engine looks cleaner!  I removed my CAT because it was plugging my exhaust causing a not start issue. Be aware, you will need to replace or remove your cat once you remove the air injection system.  If you choose to buy another cat, make sure it doesn't require it to be hooked up to the air injection system.  Probably a captain obvious statement, but hey I wish someone would have written this for me.

First Start

Once I hooked this thing up and followed the instruction, this baby fired right up. I was very proud of myself.  It actually worked!  I gave myself a big pat on the back. I figured it was all down hill from there. Was I wrong!  It was then a month of troubleshooting. I was having all kinds of issues and I couldn't figure it out.

It Was the MAP Sensor!
So I finally figured out that there was no vacuum going to my map sensor.  I tested everything before figuring this out.  Because ALL of the of the information I could find was that I had the vacuum lines correctly hooked up.  One constant was that the port on the throttle body between the fuel inlet and outlet ports is supposed to a manifold vacuum port and the MAP sensor needs to go to the port.  I didn't question it.  Well, I don't know if this was just my issue, but my buddy who tried to do a conversion and failed on his 86 Jeep said he had the same issues. But he never checked his MAP sensor! And threw away a 1200 dollar kit. This thing was throwing too lean or too rich codes at me. But it was also throwing low voltage to the MAP sensor.  So I hooked up a vacuum pump to it and bam.  It instantly ran better and i no longer was blow black smoke.  That port was giving me a very low pressure and not nearly what the MAP sensor needed.  So i ran the MAP sensor vacuum hose to the port on the fuel intake manifold towards the rear of the engine and I was in business. I haven't had an issue since. 

Timing

Timing should be set to Zero.  I believe in the video where Kevin installs this on a GMC truck, he sets the timing to 8 degrees BTDC.  He doesn't say if this is compensating  for something, etc.  But the written directions say zero.  Once I set it to zero she performed better.  I know a lot of guys do this by ear. If you have that skill set you don't need to be listening to me.  This is my experience.


Where to Mount the Computer and Wire Harness?

This is a no brainer  but took me a while to figure out.  Just remove the old computer and mount the new computer there. Duh!   You can completely remove the old computer. I just followed the wires to my engine wire harness and cut everything out that lead to the computer.  I pushed my new wire hardness through the firewall.

I think that is all.  If I think of anything else, I'll update.

Thanks for everyone that responded to my stupid questions while I did this conversion. It was all very helpful.  I hope this write up can be just as helpful to someone doing this conversion.   Forgive all the spelling and grammar mistakes. 

[vangremlin]

Thanks for the great write up and the things to be aware of!  Glad its working so well, I've thought about going this route, primarily for better performance in the mountains out here in Colorado!

One question, do you have emissions testing where you live?  Parts of the emissions testing here is a visual inspection to make sure all the right pieces and parts are still installed.  With an upgrade like this, I believe a person can still pass the test without all the original emissions equipment but there are extra steps involved.  I think it helps if the kit that is installed has been certified as CAFE (?) approved, meaning that California has approved the kit.

Thanks again!

[Beaverseagle]

Thanks for the great write up and the things to be aware of!  Glad its working so well, I've thought about going this route, primarily for better performance in the mountains out here in Colorado!

One question, do you have emissions testing where you live?  Parts of the emissions testing here is a visual inspection to make sure all the right pieces and parts are still installed.  With an upgrade like this, I believe a person can still pass the test without all the original emissions equipment but there are extra steps involved.  I think it helps if the kit that is installed has been certified as CAFE (?) approved, meaning that California has approved the kit.

Thanks again!

Illinois has a grandfather emissions law.  Vehicles of model year 1995 or before that were in compliance with the Illinois Vehicle Emissions Inspection Law on February 1, 2007.  So it does, but my bird is exempt.   

I have to say that there should be some kind of exemption for fuel injection upgrades for older vehicles. Where they just simple test your emissions and not the stock setup from out dated tech.  That air injection system could not possibly hold the test of time. They put that thing on there to get the EPA off there backs and not to last the life of the car.   I bet if I put a CAT on my bird with the TBI, it would have better emissions than it did in 1982.

But that doesn't solver your problem.  Contact Kevin and see if he as a Certified Kit.  He might be able to point you to a good source if not.

[Beaverseagle]

This is a carb certified kit http://www.4wheelparts.com/Performance-Parts/TBI-KIT-Emission-Legal-Version-CARB-EO-D452-1981-86-CJ-42L-Emissions-Legal.aspx?t_c=74&t_s=368&t_pt=3776&t_pn=HOWCA/JP25881-86&utm_source=google&utm_medium=cpc&utm_campaign=shopping&emlprox=out&ppcfon=1&gp=1&gclid=CjwKEAjwgo6_BRC32q6_5s2R-R8SJAB7hTG-9LhdpKXpNW_p_BGNlFGiWe1KvRVTfwHcpVXbbvfQaRoCyVjw_wcB

[vangremlin]

Thanks for the link.  I think I'll also check with Kevin and see what he has to say about his kit. 

[rmick]

Did run a new larger return line or just use the original return line.

[Beaverseagle]

Yes i did. When i was troubleshooting, i was worried about fuel pressure and vaccum leaks. I put new hard lines in when i first put her back in service. But it was a hack job. I had several places that i connected from hard line to rubber lines. So i bought like 12 feet of FI rubber fuel line. I have 2 connections. One from the throttle body to the fuel pump. Then fuel pump to gas tank. I get 13 psi. Not sure of the size but it is larger. I'll take a look tomorrow what size I'm running.

[Beaverseagle]

Oh sorry. You asked about the return line. Yes i also ran a new return line for the same reasons.  It is larger. I used regular fuel line and i ran it directly to the the tank.  Ill check out the diameter and update.

[mudkicker715]

The original retun fuel line hhad a restricter built into you would normally miss, as its not visible.

[rmick]

Thanks

[Beaverseagle]

I used 3/8 fuel injection line for the main line and 5/16 for of regular fuel line for the return line.

I hope this helps.