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The hugest TBI conversion write up, EVER

Mastiff

Mastiff

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I don't know why I did this write up... I just had so many pictures. This is the full chronicle of my carb to TBI conversion using a kit from customefis.com.

We're talking 50+ pictures. /forums/images/graemlins/deal.gif

http://www.taildragger.info/K5/TBI/

Let me know if something doesn't look right or is technically incorrect, or whatever.
 
I'll use this thread to talk about something I've been wondering about. Losing EGR. Whats the advantage or disadvantages of it? I lost it on my 85s carb motor but that was just to clean things up I had no alterior motives on that one. I'm thinking it will simplify things in the intake area and maybe wiring but hurt me on emissions. Am I correct in these thoughts?
 
"I don't know why I did this write up... I just had so many pictures. This is the full chronicle of my carb to TBI conversion using a kit from customefis.com.

We're talking 50+ pictures. /forums/images/graemlins/deal.gif..."


/forums/images/graemlins/waytogo.gifExcellent write up, IMHO you were clear & concise as to problems encountered and solutions for same.

Also, appreciate very much your compiling the required components & sources for same if choosing to go the non-kit route.
 
zero gains on a FI engine to loose it. EGR closes at full throttle and it closes at idle. only times it is on is cruise and part throttle.

If it's not installed and functioning then a custom chip will have to be burned. The ECM knows when it supose to be open and it is expecting to see a mixture change at the O2 sensor. So it may actually cause more epense to loose it then to keep it.
 
/forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif Great article, I have been waiting for a good TBI swap article to come along and finally it is here /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
 
In theory EGR should gain you some hwy mileage since it basically decreases the displacement of the engine. No one I've ever talked to about it lost hwy mileage by disconnecting it. I suspect that lacking it the PCM will hard code an EGR fault of some sort. That might screw you if you have emissions testing to deal with since it will turn on the Check Engine light.
 
[ QUOTE ]
zero gains on a FI engine to loose it. EGR closes at full throttle and it closes at idle. only times it is on is cruise and part throttle.

If it's not installed and functioning then a custom chip will have to be burned. The ECM knows when it supose to be open and it is expecting to see a mixture change at the O2 sensor. So it may actually cause more epense to loose it then to keep it.

[/ QUOTE ]

Going from a carb engine, you'd need a computer controlled EGR, I think. I'm not certain of that. If that's the case, then you can either make a non-EGR prom or get the correct EGR. I got rid of mine just to clean things up, and I figured there's no way it can make things run better. It's always on the list of things to check out when the motor isn't working right.
 
[ QUOTE ]
[ QUOTE ]
zero gains on a FI engine to loose it. EGR closes at full throttle and it closes at idle. only times it is on is cruise and part throttle.

If it's not installed and functioning then a custom chip will have to be burned. The ECM knows when it supose to be open and it is expecting to see a mixture change at the O2 sensor. So it may actually cause more epense to loose it then to keep it.

[/ QUOTE ]

Going from a carb engine, you'd need a computer controlled EGR, I think. I'm not certain of that. If that's the case, then you can either make a non-EGR prom or get the correct EGR. I got rid of mine just to clean things up, and I figured there's no way it can make things run better. It's always on the list of things to check out when the motor isn't working right.

[/ QUOTE ]

Nope. THe early EGRs pre OBDII are just regular old EGR's. They have a Solonoid inline on the vacuum. No problem to add it.

Here is a little tip on hunting that will save you a ton of frustration. Find a TBI off a 87-89 454 with the adaptor. It's spreadbore pattern and will bolt right onto your Quad intake.

74TBItop.jpg

74TBIbot.jpg
 
That's cool. I didn't realize the 454 TBI's bolted to the spread bore intake. What is that giant hose coming from the adapter?
 
On the 350's like used inthe story there is a preheat passege in the intake. It prevents freeze up when it's cold. On the 454 since it uses the stock intake there is a gap betweent the throttle body and the intake. That hose is plumbed into the heater hose to heat that adaptor to prevent freeze up.

I have this bypassed on my 88 Burb because the other hose is a factory only $70 heater hose. I didn't bother to get a barbed adaptor and the winters are mild here. didn't have any problems.

That is the one I bought to convert my 75 Jimmy. It came off a 89 454 Sub. In 90 they went to a new intake like the 350's. So this is a little bit of a rare part. /forums/images/graemlins/ooo.gif
I'm selling the 75 and this FI is destined to end up on my 1970 Pontiac LeMans now. /forums/images/graemlins/grin.gif
 
You did a great job on the write-up. Good wording, advice, descriptions, thoughts, and good photos too. I hope soemeone does something similar for big blocks, I would like to move away from carburetion myself. Looks like the rest of the rig is pretty sharp too! Good luck with the final details!
 
I wonder if I'll have problems in the cold then... My Edelbrock manifold doesn't have the coolant passage I don't think. Are you talking about icing on the butterflies mostly? I had this some with my carb since I have the open element air cleaner without the heated air ducting. If nothing else, I hope the computer will open up the IAC and keep me from stalling until the engine warms up.
 
[ QUOTE ]
You did a great job on the write-up. Good wording, advice, descriptions, thoughts, and good photos too. I hope soemeone does something similar for big blocks, I would like to move away from carburetion myself. Looks like the rest of the rig is pretty sharp too! Good luck with the final details!

[/ QUOTE ]

Thanks. /forums/images/graemlins/thumb.gif
 
Mastiff, what experimentation did you use to determine what gas line was feed, return, & vapor?
 
On my TBI senders, only the pickup is submerged under about 1/2 tank. Pump might block trying this, but if you could force air back through to an almost empty tank, you would hear the pickup (feed) line when it started bubbling.

The return line dumps about midway down, and vapor doesn't extend into the tank at all.
 
Problem for me is that both lines are the same diameter, both lines come into the tank very near each other, both smell like gas, etc. It's basically impossible to tell them apart by eye. There must be some test that will give me a definitive answer. Guess I'll probably end up dropping the tank to be on the safe side. /forums/images/graemlins/crazy.gif
 
I counted 49........jk Awesome job on the swap. Personally I had tbi and it sucked so I swaped to a late model fuel injected motor. But I am sure its loads better than the old rochester carbs, plus mine had a bunch of mangled egr tubing and quite a few sensors that had gone bad, needed a tune up, had 180k miles on it, and only got about 9 or 10 mpg. I am also positive that yours runs alot smoother and gets a little better mpg than I did. /forums/images/graemlins/waytogo.gif

Remington
 
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Problem for me is that both lines are the same diameter, both lines come into the tank very near each other, both smell like gas, etc. It's basically impossible to tell them apart by eye. There must be some test that will give me a definitive answer. Guess I'll probably end up dropping the tank to be on the safe side. /forums/images/graemlins/crazy.gif

[/ QUOTE ]

Just find the line that feeds into the TBI and trace it back to the tank
 
[ QUOTE ]
Just find the line that feeds into the TBI and trace it back to the tank

[/ QUOTE ]

You misunderstand. This is a carbed truck that I'm converting to TBI. The fuel lines are both "dangling" at the tank. There is nothing to trace back to the engine.
 
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