My TBI adventure...so far

[Mr. Notorious]

Nice work. I love this thread

I just got my TBI donor engine over the weekend...

 

[joeyg1973]

I don't think it matters. Every other setup I've seen on a V8 has it on one side or the other.

That is definitely not what I have seen. You are essentially ignoring the feedback from half of your engine. I would put it further down where the pipes cross over.

 

[cruiserbrett]

That is definitely not what I have seen. You are essentially ignoring the feedback from half of your engine. I would put it further down where the pipes cross over.

my old TPI 350 had a single 02 sensor in one manifold. I think its more common than you think.

 

[cruiser enthuiser]

Emissions? Nah....

At one time I had entertained the idea of running the emissions stuff and, who knows, someday I might. Not for now. I removed the EGR and that other sensor that controls it (I forget the name right now). I installed a block-off plate and gasket. The plate came from Summit, about $12.

 

[cruiser enthuiser]

The Moment Arrives...

I spent the better part of Sunday connecting the GM harness to my 40's wiring. What a rats nest! The PO spliced in a stereo, CB radio, auxillary guages and really hacked it up. My Dad spent a couple hours helping me sort it out - he's much better at this stuff than I am .

Once we got it all connected we tried, unsuccesuffly, to start it. It cranked fine but wouldn't fire. Confirmed we had spark, confirmed we were getting fuel. Later than night I read something on the internet that the distributor connections should point towards the #1 cylinder. When I got home from work the next day I tried it and guess what.........

ITS AAAALLLLLIIIIIVVVVEEEEE!!!!!!

YouTube - TBI Conversion - First Start

 

[Trollhole]

Very nice.

 

[cruiser enthuiser]

For some reason I cannot get the check engine light to function. I bought a couple different 12v lights, connected the hot wire on the light to the brown and white wire coming off the A5 pin on the ECM (for the SES light according to my diagram) and grounded the other wire. Nothing. When I use my tester with the key on I don't detect any voltage going to this wire. What am I doing wrong? Anyone know? I may post a seperate thread, but any help is appreciated.

 

[terrx]

Quite often ecm signals are asserted as gnd/(-). I think this is one of them. Try running 12v to the SES light then back to the ecm.

 

[cruiser enthuiser]

Quite often ecm signals are asserted as gnd/(-). I think this is one of them. Try running 12v to the SES light then back to the ecm.

You were right on the money, Terrx! I connected one of the wires to an "always hot" fuse and connected the other to the SES wire of the ECM and Presto! I had check engine light. Thanks for tip. I owe you a .

Once that was connected it was time to check for my first error code. I learned something helpful while looking up trouble codes. The ECM always throws a "12" three times when in diagnostic mode...who knew? You guys probably did. I spent several minutes scratching my head trying to figure why I couldn't find a 12 error code on any of the lists. Turns out this is just an indicator that the ECM is in diagnostic scan mode.

The next code was a 42. This is an ignition error code and I knew this was because I had disconnected the EST wire. Read about this in an earlier Mud post here: https://forum.ih8mud.com/hardcore-corner/243755-tbi-timing-problems.html There is a brown and black wire going to the distributor with a weather pack disconnect specifically for the purpose of setting timing. One wants to disconnect this when setting base timing so the computer is not trying to adjust at the same time. I reconnected this wire and disconnected the battery for 10+ seconds to clear the ECM's memory.

After that I fired up the engine and let it run for a few. Starts out good for the first several seconds then runs like sh*t, starts to back fire. I'm sure it's my timing. I checked error codes and, incredibly, there were none. It was too damn cold outside for me to mess with timing anymore so I'll give it another go tomorrow.

Here's a pic of check engine light. PO drilled a whole mess of holes and mounted crap all over the dash. This abandoned hole was perfect size. Light was from Radio Shack...two of 'em for $3.

 

[FJFOOL]

Congratulations !!! I've been watching (and learning a lot) with this thread. Looking forward to the driving posts.Alex

 

[alex e]

nice cupholders.

 

[terrx]

Sounds like you're making good progress. Glad that it worked.

I forgot to mention it, but the 12v to SES light should probably be switched 12v (IGN). I've been looking at wiring diagrams tonight since I can't remember for sure. Haven't been able to confirm it. If you have a wiring diagram check to be sure. Constant 12v probably won't hurt anything at this stage in any case.

 

[badass]

It took me months to realize that the reason my truck ran like s*** compared to what it runs like now was because that dam tan and black wire needed to be disconnected.

 

[cruiser enthuiser]

I forgot to mention it, but the 12v to SES light should probably be switched 12v (IGN). I've been looking at wiring diagrams tonight since I can't remember for sure. Haven't been able to confirm it. If you have a wiring diagram check to be sure. Constant 12v probably won't hurt anything at this stage in any case.

I tried it that way first and it wouldn't work. I think it makes sense to have the light going to a constant hot so the light will come on even when it's not running. Now it comes on when I put the key in.

 

[cruiser enthuiser]

nice cupholders.

Yeah, they're kinda cool. The PO was a real innovator . Eventually I want to return the dash to mostly stock condition.

 

[Elbert]

I have given a lot of thought to the wiring harness and whether to go with a Painless or use the stock GM harness. Here's the argument as I see it:

Painless= easier installation with new wires/connectors
GM= great price! PITA installation with old wires/connectors

I have nearly zero experience with automotive wiring until this project, so the idea of tearing into the stock harness is intimidating as hell. $370.00 for the Painless may save me weeks (or months) of cursing and spitting in my driveway.

On the other hand, there is loads of information out there from others who have used the stock harness including wiring diagrams, etc. and I would like to put that $370 towards something a little more sexy (new shocks would be nice!). With that in mind I started looking at the harness.

The connectors are all very self explanatory as to where they are supposed to go. I connected everything I could on the intake manifold and labeled it. There are a few cut wires and I am very concerned that the connectors to the fuel injectors look a bit melted (kinda tough to see in pics). Should I find new ones?

I'm mid-stream in reading your thread about TBI. I've owned a TBI GM pickup for some time (recently sold it). I have a vortec 5.7 in my 60. The advantage of the painless harness is that its a stand alone harness. It does not interface with your vehicle other than getting 12 volts to power it, a signal that ign is on and that's about it. You may have already have a working solutin by the time you read this..

 

[Elbert]

I decided on the Airtex E8153. I read comments on the Pirate 4x4 forum that others who have also done the GM TBI conversion have had good success with this pump. I found it on Amazon.com, of all places, for a mere $54.00. I hope it delivers adequate pressure. it was such a good price I figure if it doesn't I'm not really out much money.

Will post more pics of my progress soon.

walbro is a good brand to look for in eletric fuel pumps.

 

[Elbert]

I don't think it matters. Every other setup I've seen on a V8 has it on one side or the other.

TBI engine is not picky about this. I had true dual exhaust on my 92K1500, never messed with the stock 02 sensor. No trouble codes. Vortecs and newer GM engines require at least 2 working 02 sensors and 4 if you want to run legal exhaust with "cats".

 

[Elbert]

With the tan wire disconnected set base timing to 0 degres. ECM is real picky about this... it needs to be exactly 0 degrees. I did not catch what type transmission you have but I'm sure you'll need to look into a VSS setup (vehicle speed sensor).

 

[cruiser enthuiser]

With the tan wire disconnected set base timing to 0 degres. ECM is real picky about this... it needs to be exactly 0 degrees. I did not catch what type transmission you have but I'm sure you'll need to look into a VSS setup (vehicle speed sensor).

Thanks for the input. I did figure out that the timing had to be set to zero (with that wire disconnected) however I'm still having some issues with it mis-firing and idling too high. I think part of my problem may be a very large vacuum leak that I completely ignored . Will post more on that later.

walbro is a good brand to look for in eletric fuel pumps.

The E8153 was definately a mistake and I am replacing it - totally inadequate pressure. I will post an update on that as soon as the new pump is installed.