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4.3 tbi swap to 350 tbi swap

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Old 02-01-2006, 01:54 PM   #1
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4.3 tbi swap to 350 tbi swap

Ok guy heres my problem that im haveing with my swap I did the swap but haveing problems with setting the timing Iv looked for the tan wire that you unhook before you set the timing ( base timing) I can't find it anywhere Iv looked up under the dash and no tan wire anywhere even pulled the carpet back nothing even had the ecm box out from under the dash.Second problem is when I have both injectors hooked up it floods the motor seems to be dumping to much gas down the throttle body it will run if I just use one side of the injectors. Could the ECM be trying to make up the difference in timing while its hooked up is why you have to unhook the tan wire to set base timing? Also is the TBI set worth all the problems ? Almost forgot its a 88 so theres no elec trans crap.

Tim W 48030
Old 02-01-2006, 03:09 PM   #2
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Re: 4.3 tbi swap to 350 tbi swap

Did you keep your 4.3 comp or switch to the 5.7?
Old 02-01-2006, 03:21 PM   #3
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Re: 4.3 tbi swap to 350 tbi swap

Ok heres a few more things yes im useing the 4.3 ecm just to get it running. could this be y the fuel mixer is off plus the timing?
Old 02-01-2006, 07:27 PM   #4
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Re: 4.3 tbi swap to 350 tbi swap

when i tried mine with the 4.3 ecm, it ran horrible. i wouldnt suggest it, not even for a test.

that tan wire youre looking for should be tan with a black stripe and comes out of the wiring harness. youre looking in the right place, but maybe its hidden with some other wires
Old 02-01-2006, 07:30 PM   #5
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Re: 4.3 tbi swap to 350 tbi swap

there were some 4.3 ECM's that shared the same part niumber as the 5.7's did, but they need to be re-flashed. Basically, your o2 is seeing it lean, and running those injectors at max pulse width causing it to run too rich.
Old 02-02-2006, 08:04 AM   #6
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Re: 4.3 tbi swap to 350 tbi swap

that tan wire may also be on the other side of the firewall. look at a wiring diagram to be sure. something as crappy as a chiltons manual should tell you where to look. and as for the 4.3 computer, ive heard of people using them just to get them running. but the timing curve is different. go to the junkyard and pick one up out of an old chevy pickup. but make sure the plugs are the same.
Old 02-02-2006, 08:39 PM   #7
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Re: 4.3 tbi swap to 350 tbi swap

OK still can't find the tan/blk strip wire for the timing Iv got most of the harness untaped and still no conector can I just cut the wire going to the dist and put a conector in ?
Old 02-02-2006, 11:06 PM   #8
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Re: 4.3 tbi swap to 350 tbi swap

Ok guy I found the conector it was at the rubber boot that goes through the firewall the reason I coundn't find it was cause I had to move the wire harness that goes through the firewall cause of the exhaust manifold is right at the old hole where the harness went through putting the conector inside the boot where I couldn't see it
Old 02-04-2006, 07:39 AM   #9
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Re: 4.3 tbi swap to 350 tbi swap

Quote: Originally Posted by timw48030
Ok guy heres my problem that im haveing with my swap I did the swap but haveing problems with setting the timing Iv looked for the tan wire that you unhook before you set the timing ( base timing) I can't find it anywhere Iv looked up under the dash and no tan wire anywhere even pulled the carpet back nothing even had the ecm box out from under the dash.Second problem is when I have both injectors hooked up it floods the motor seems to be dumping to much gas down the throttle body it will run if I just use one side of the injectors. Could the ECM be trying to make up the difference in timing while its hooked up is why you have to unhook the tan wire to set base timing? Also is the TBI set worth all the problems ? Almost forgot its a 88 so theres no elec trans crap.

Tim W 48030
I did mine and used the 4.3 computer(because I didnt know) and it run thats about it....let us know how it come out
Old 02-10-2006, 01:47 PM   #10
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Re: 4.3 tbi swap to 350 tbi swap

Well this TBI crap isn't worth it I think Iam going to switch back over to a carb set up to many problems changed the ECM and the injectors and still can't get it to idel could be cause I don't have a y pipe on the manifolds yet plus theres no coolant running through the motor don't have that hooked up yet plus I though I could run the cam that I took out of my 80 monza that I put a 350 300 h.p the cam might not good for a tbi set up it's not a real big cam but the duration might be to big for a tbi so I think I will go with a carb set up the other problem is the motor is a 95 motor with the canted center intake bolts so its going to be a $ intake to change plus a carb and dist and fif the uel reg should solve the problem still going to be a daily driver still going to keep the ac to
and power brakes, can anybody can help me with any of the parts that I need and to changed over cheap?
Old 02-10-2006, 04:25 PM   #11
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Re: 4.3 tbi swap to 350 tbi swap

Ok just did some more checking on the cam and ecu up grades the cam is a 450 /460 lift 224 int 224 exh @.050 duration with a 114 lobe sep its to big for the stock chip would have to have a custom chip made and thats $$$ plus not to sure on the trans converter and the vaccum for the power brake booster does anybody have any ideas on what I should try ? switch to a tbi cam or go with a carb set up?



Tim W
Old 02-11-2006, 02:22 AM   #12
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Re: 4.3 tbi swap to 350 tbi swap

http://www.tbichips.com

cost me $75 + shipping

Last edited by Cronos; 02-11-2006 at 02:23 AM.
Old 02-11-2006, 06:06 PM   #13
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Re: 4.3 tbi swap to 350 tbi swap

Quote: Originally Posted by timw48030
Well this TBI crap isn't worth it I think Iam going to switch back over to a carb set up to many problems changed the ECM and the injectors and still can't get it to idel could be cause I don't have a y pipe on the manifolds yet plus theres no coolant running through the motor don't have that hooked up yet plus I though I could run the cam that I took out of my 80 monza that I put a 350 300 h.p the cam might not good for a tbi set up it's not a real big cam but the duration might be to big for a tbi so I think I will go with a carb set up the other problem is the motor is a 95 motor with the canted center intake bolts so its going to be a $ intake to change plus a carb and dist and fif the uel reg should solve the problem still going to be a daily driver still going to keep the ac to
and power brakes, can anybody can help me with any of the parts that I need and to changed over cheap?
that cam will never work with the stock computer,that might be why it isnt ideling.leave it tbi,when you get the bugs out,you will be glad you did.
Old 02-12-2006, 01:34 PM   #14
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Re: 4.3 tbi swap to 350 tbi swap

Do you have the O2 sensor installed? If not, it will run very rich. You will most likely need it installed an exhaust manifold or the Y-pipe/head pipe. I don't remember if an '88 uses a heated o2 sensor (3 wire), if not the engine needs to run to heat the sensor until it reads correctly.

Another problem could be that with no water in the motor the temp sensor is reading low and could be causing it to run rich as well.

Once you get the TBI working right you will be happy. I am.
Old 02-18-2006, 06:19 AM   #15
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Re: 4.3 tbi swap to 350 tbi swap

Quote: Originally Posted by timw48030
Ok just did some more checking on the cam and ecu up grades the cam is a 450 /460 lift 224 int 224 exh @.050 duration with a 114 lobe sep its to big for the stock chip would have to have a custom chip made and thats $$$ plus not to sure on the trans converter and the vaccum for the power brake booster does anybody have any ideas on what I should try ? switch to a tbi cam or go with a carb set up?



Tim W
just wondering what you come up with??let us know my man
Old 02-21-2006, 11:12 PM   #16
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Re: 4.3 tbi swap to 350 tbi swap

Ok heres what new on my v-8 swap the TBI stuff will stay for now till I can get it running better, still have to get a y pipe made yet but I did pick up new core surport and fenders and wheel wells need the fenders painted and put back on the truck Iam working on the rad and surport.Got another problem maybe somebody can help Iam trying to keep the a.c and the stock 4.3 rad in the stock possion I have trimed the shroud but it doesnt look like theres enough room for a engine fan, I don't want to cut the rad surport for the vette rad cause I would have to move the A.C core to keep it a A.C truck. I have the JTR book and it shows the 4.3 rad with a flex-a-lite model 210 running the full area of the rad my ? is whats the depth of this unit or is there any other electric fan that will work between the back side of the rad with out hitting the water pump pully?


Thanks Tim W
Old 02-22-2006, 07:06 PM   #17
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Re: 4.3 tbi swap to 350 tbi swap

I do know that on one of my other trucks i moved the condencer about 3/4 inch or so and slid it until it touched the backsideof the core support.I dont remember if I cut the support or not,but i dont think I did.I have always used the vett rad. in all the ones i done.just wondering why you dont want to "notch" the core support?dont know wher you live but the 4.3 rad.with ac probably will not keep it cool enough.I live in Florida and it didnt even act like it wanted to stay cool enough with the 4.3 rad.
Old 03-02-2006, 07:05 AM   #18
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Re: 4.3 tbi swap to 350 tbi swap

come on Tim,whats up with the truck anything done lately.Trying not to let the gogo run out on you....lol
Old 03-02-2006, 07:12 PM   #19
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Re: 4.3 tbi swap to 350 tbi swap

Ok heres the new news on the s-10 project I put the a.c core back in the stock spot and cut the back side of the fan shroud for clearence but won't know if I have enough room till I get the fenders bolted back on the front end I also trying a 1" fan spacer with a flex lite 16" seires 400 engine fan its flat on the front of the fan so its going to be close to the back of the rad I have this same set up on my v-8 monza as you know those cars are the same way with the rad setting so close to the fan I also have a 14" electric fan on the front of the monza rad to help with the cooling it works real good in stop and go traffic but then again that car is a toy car 300 h.p I have pics of the set up that iam trying if you are intrested in it
Old 03-03-2006, 05:03 PM   #20
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Re: 4.3 tbi swap to 350 tbi swap

yea man any info is good to all of us.it may work for some and may not for others...
Old 03-04-2006, 06:59 PM   #21
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Re: 4.3 tbi swap to 350 tbi swap

thats wierd fellas, im running a 350 tbi in my truck and running it under the cop 65# injectors, with the 4.3 under the hood computer, hooked it up to a smog machine and it was within parameters for that year engine/car

wierd if you ask me
Old 03-05-2006, 07:34 AM   #22
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Re: 4.3 tbi swap to 350 tbi swap

how the hell did that happen?did you have the computer reprogramed?
Old 03-05-2006, 11:40 AM   #23
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Re: 4.3 tbi swap to 350 tbi swap

nope, sure didnt and im not bs'in you either. that or his computer if fu(ked...but she runs like a dream
Old 03-05-2006, 11:50 AM   #24
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Re: 4.3 tbi swap to 350 tbi swap

Look up at post #14.

I am still wondering do you have the o2 sensor hooked up? If not, it will run very rich no matter what computer is in it. You also need water in it for the temp sensor to work. Again, if the temp is reading low it could cause the computer to run rich. I had a bad o2 sensor in mine when I did the conversion and it ran horrible. It was just dumping the gas in. With the new o2 it ran great. (Note: My SES light was on when the bad o2 was in.)

I cannot comment on whether the 4.3 computer will work once you have the sensors working correctly since I used a 5.7 from the start.
Old 03-22-2006, 02:09 PM   #25
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Re: 4.3 tbi swap to 350 tbi swap

The latest on the v-8 swap got the new fenders painted so now getting to put it back together but ran into another problem I need to tilt the core surport in for the fenders to bolt up to the fenders ths is where I have a problem it puts the fan right up to the rad Iam useing the stock rad and fan shroud that I cut the back side of the shroud but I need more room It may look like I might have to make the truck a non a.c truck after all I haven't given up yet it's just cold outside to play for to long with the truck.


Tim
Old 03-22-2006, 06:55 PM   #26
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Re: 4.3 tbi swap to 350 tbi swap

Quote: Originally Posted by timw48030
The latest on the v-8 swap got the new fenders painted so now getting to put it back together but ran into another problem I need to tilt the core surport in for the fenders to bolt up to the fenders ths is where I have a problem it puts the fan right up to the rad Iam useing the stock rad and fan shroud that I cut the back side of the shroud but I need more room It may look like I might have to make the truck a non a.c truck after all I haven't given up yet it's just cold outside to play for to long with the truck.


Tim
You should not have to do that my friend.I dont quite understand what you mean tilt the support in???But the support only bolts on to the fenders one way,not that you dont know that but I'm not getting what you mean by tilting the support.It will work with ac,you gotta have ac!!
Old 03-23-2006, 08:35 AM   #27
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Re: 4.3 tbi swap to 350 tbi swap

Ok maybe I explain it better this way Iam putting on a new rad core surport it bolts to the frame and the fenders.The problem is that theres no room to run the stock 4.3 rad useing the fanshroud with holds the rad to the surport I trying to use a flex litthe e fan on the motor but when I psh the surport back to bolt up the fenders theres no room for the engine fan. I did cut the back of the rad shroud but thats not a problem I did check with a rd shop for a custom rad that would fit where the a.c core goes with out cutting the rad surport but that means giving a.c as thats about a 275.00 rad ith a trans coler in this is what Iam leaning towards any input would help

Thanks Tim
Old 03-23-2006, 04:52 PM   #28
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Re: 4.3 tbi swap to 350 tbi swap

Quote: Originally Posted by timw48030
Ok maybe I explain it better this way Iam putting on a new rad core surport it bolts to the frame and the fenders.The problem is that theres no room to run the stock 4.3 rad useing the fanshroud with holds the rad to the surport I trying to use a flex litthe e fan on the motor but when I psh the surport back to bolt up the fenders theres no room for the engine fan. I did cut the back of the rad shroud but thats not a problem I did check with a rd shop for a custom rad that would fit where the a.c core goes with out cutting the rad surport but that means giving a.c as thats about a 275.00 rad ith a trans coler in this is what Iam leaning towards any input would help

Thanks Tim
the corvett rad. fits perfect in there.I slid the ac cond. all the way forward and pushed the vett rad. up to it but not touching and used a fan spacer of about a 1/2 inch with a 18 in fan and had plenty of room well,plenty as far as a s10 goes.but, I did not use a shroud as of yet.what mounts did you use?are you saying you are using a electric fan or?
Old 03-23-2006, 05:05 PM   #29
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Re: 4.3 tbi swap to 350 tbi swap

Ok the set up Iam trying is to use the stock 4.3 rad with the motor and trans in the std spot but theres no room for the engine fan its to close to the back side of the rad I know that the vette rad will work but that means giving up the a.c set up cause the rad needs to go where the a.c core is at in the surport even if I take off the engine fan theres still no room for a electric fan set up on the back of the rad
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