Tbi swap build thread

[rfmaster]

Originally Posted by cheepin

So this thread is awesome and I got my 454 TBI running in my Crawler.But it spun a bearing and ate the caps pretty damn good.I have a running SB400 I want to swap in.What do I need to do to for the TBI to run it correctly?The swapped in comp and harness is from an '88 crewcab 1ton.It's a short deck 454 so the dist. should work correct?

Yes, standard deck 454 distributor should drop into your SBC 400. Intake manifold is different, but that's an easy problem to fix. For the most part 454 calibration should work just fine with 400. Injectors are already big enough (80/90 lb-hr) to supply 400 fuel requirements. Do you have any idea about the cam in the 400???? In particular, idle vacuum and idle RPM???

Take a look at your ECM - there should be a service number and BCC code. Based on BCC info SA curves can be looked.

//RF

[cheepin]

Originally Posted by rfmaster

Yes, standard deck 454 distributor should drop into your SBC 400. Intake manifold is different, but that's an easy problem to fix. For the most part 454 calibration should work just fine with 400. Injectors are already big enough (80/90 lb-hr) to supply 400 fuel requirements. Do you have any idea about the cam in the 400???? In particular, idle vacuum and idle RPM???

Take a look at your ECM - there should be a service number and BCC code. Based on BCC info SA curves can be looked.

//RF

As far as I know it is a stock 400.Pulling it out a of 79 Suburban.The 454 had the coolant adapter piece under the throttle body.Do I need to use this or can I just do an after market adapter.I think the metal tube coming out of the adapter is leaking anyway.

[rfmaster]

Originally Posted by cheepin

As far as I know it is a stock 400.Pulling it out a of 79 Suburban.The 454 had the coolant adapter piece under the throttle body.Do I need to use this or can I just do an after market adapter.I think the metal tube coming out of the adapter is leaking anyway.

If the 400 uses Q-Jet or square bore intake get a carb to TB adapter plate from http://www.tbiparts.com/ It is not a cheapo plate you get from other vendors, but a nicely done CNC'd aluminum piece which addresses common vacuum leaks that plague other adapters.

The 454 used a heated cast iron adapter module - GM must have had a warehouse of Q-jet BBC intakes that they did not want to melt down back in the late 80's! I use them for door stops - sorry I am bad...

//RF

[bagged74]

Does anybody have info on swapping to the electric speedo cluster from a 91 model suburban? I picked up a cluster yesterday, but haven't found a pinout to compare to the one in my 89. I'm sure I am going to need to repin my plug at the cluster, I just need to know which ones to move.
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[critict1gc]

couple of questions
i need a layout or something for all the vacuum lines where they all go to and also im am deleting my egr so can i just cap off the lines for it

[critict1gc]

also for the vss im am wondering wich one to get that will work with my th350 and the 208 transfer case. would the painless one work or will this one work
http://www.jegs.com/i/Caspers+Electr...02049/10002/-1

[68 TT]

Originally Posted by critict1gc

also for the vss im am wondering wich one to get that will work with my th350 and the 208 transfer case. would the painless one work or will this one work
http://www.jegs.com/i/Caspers+Electr...02049/10002/-1

What about using an optical VSS & matching speedo out of an 87-89 square body with TBI?

[critict1gc]

has anybody tuned a tbi swap with a big cam in it i was wondering if i could get my cam to work its. heres the specs
Hydraulic Flat Tappet
Duration @ .050'' Lift: 229 Intake / 230 Exhaust
Lift: .480'' Intake / .486'' Exhaust

[rfmaster]

Originally Posted by critict1gc

has anybody tuned a tbi swap with a big cam in it i was wondering if i could get my cam to work its. heres the specs
Hydraulic Flat Tappet
Duration @ .050'' Lift: 229 Intake / 230 Exhaust
Lift: .480'' Intake / .486'' Exhaust

What is the Lobe Separation angle?? LSA???? You need about 112 deg to have a chance. IMHO 230 deg is on high side, getting a stable idle will be a challenge. One option is to have ECM to revert to open loop idle and n-alpha mode which uses RPM, temperature and TPS sensor inputs only and MAP input is ignored. Stock ECM does not support this, but it can be done with EBL.

//RF

[critict1gc]

i think i might just change out the cam i was talking to the guy over at tbichips.com and he recommended this one
Lift .464"/.470"
Duration 262/270

[rfmaster]

Originally Posted by critict1gc

i think i might just change out the cam i was talking to the guy over at tbichips.com and he recommended this one
Lift .464"/.470"
Duration 262/270

Do you mean 12-262-4; Grind Number CS XE262H-14???

Yea - this is a good cam for performance applications - Camaro, but it will work equally well in a truck with lower gear ratio rear end. It has a wide power band 1,500-5,500 and should produce around 14 in-Hg at idle. Some tuning maybe required, but it is within range of stock calibration.

I have similar cam profile in my roller 383 - 08-304-8; Grind Number CS 266H-R14 and it is a stump puller!

//RF

[critict1gc]

wondering bout hooking up my temp guage can i just spice into the wire then send it to the guage

[rfmaster]

Originally Posted by critict1gc

wondering bout hooking up my temp guage can i just spice into the wire then send it to the guage

Absolutely NOT!!


The stock temperature gauge uses a low impedance sending unit

Temp AC-Delco (G1852)
F | Ohms
100 | 410
120 | 300
140 | 187
160 | 150
180 | 123
190 | 112
200 | 94
210 | 83.5

The ECM uses a high impedance sending unit which has the following Temp vs. resistance characteristic:
F | Ohms
100 | 1400
120 | 970
140 | 660
180 | 300
200 | 208
210 | 177

Connecting cluster gauge to ECM CTS will load input ECM circuit - screwing things up royally!! DO NOT DO IT.


There are combination sending units that provide one output for ECM monitoring and the other for the instrument cluster gauge. I have not had a chance to evaluate and verify instrument cluster portion. GM standardized all ECM's (80's and 90's) to work with CTS GM # 12146312 temperature characteristic. Instrument cluster gauges - well, that's a huge unknown.

//RF

[critict1gc]

ok i will just have 2 separate temp senders. so on that note i saw a pic on here where someone had a temp sender on the thermostat housing does anyone know where i can get this

[68 TT]

Pretty common GM part. Look at mid 80's cars like Camaro, Monte Carlo & Impala. Some have one threaded boss in them and some have two. Some are iron and some are aluminum.

[rfmaster]

Originally Posted by critict1gc

ok i will just have 2 separate temp senders. so on that note i saw a pic on here where someone had a temp sender on the thermostat housing does anyone know where i can get this

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The following is HIGHLY experimental (This has NOT been confirmed to work in our trucks!)

I did a bit of searching and digging - there is a three wire coolant sending unit which combines CTS that is need for ECM and instrument cluster sending unit used in mid 90 cars (1996 Grand Prix for example):

10096181 PCM/Gauge sending unit $14.81 (Wells TU178)
12102748 Connector pigtail (incl. terminals) $17.29
I am going to get a hold of it and run it over temperature to determine its response curves (and its suitability)

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[68 TT]

Originally Posted by rfmaster

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The following is HIGHLY experimental (This has NOT been confirmed to work in our trucks!)

I did a bit of searching and digging - there is a three wire coolant sending unit which combines CTS that is need for ECM and instrument cluster sending unit used in mid 90 cars (1996 Grand Prix for example):

10096181 PCM/Gauge sending unit $14.81 (Wells TU178)
12102748 Connector pigtail (incl. terminals) $17.29
I am going to get a hold of it and run it over temperature to determine its response curves (and its suitability)

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Nice find RF. That is a pretty common part. It was used on lots of GM stuff. For some reason they only used it on the C/K/G series vehicles with the 4.3 V-6 but that means the temp gauge range is most likely the same as the other full size trucks.

I would love to know if the output is right for a square body temp gauge. Definitely let us know when you get it tested.

Thanks for the info.

[65Guy]

im still gathering parts for the swap but i plan on using a vss with my th350. but what if i switch to a 5 speed with no speedo cable provisions what then?

[rfmaster]

Originally Posted by 65Guy

im still gathering parts for the swap but i plan on using a vss with my th350. but what if i switch to a 5 speed with no speedo cable provisions what then?

JTR offers differential mounted 40-Tooth Reluctor Ring.



This setup uses a stock vehicle speed sensor (GM part #15547452) which was commonly used on transfer cases of 1989 and newer S-10 truck, AWD Astro Vans, and 1987 and newer full-size 4X4 trucks. The combination of VSS and 40 tooth ring provides 40 pulses per drive shaft rotation signal which would require you to get VSB module to bring it down to 2000 ppm required by TBI ECM. This way you can get around lack of speedometer provision - however I would imagine that these 5 speed tranies would have a built in VSS output which can be coupled into VSB and correct 2000 ppm needed by TBI ECM can be attained. So I would look for a built in VSS and figure out its output characteristics before diving into reluctor ring approach.

As for speedometer - OE gauge will have to be replaced with an electronic unit.

//RF

[rfmaster]

Originally Posted by rfmaster

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The following is HIGHLY experimental (This has NOT been confirmed to work in our trucks!)

I did a bit of searching and digging - there is a three wire coolant sending unit which combines CTS that is need for ECM and instrument cluster sending unit used in mid 90 cars (1996 Grand Prix for example):

10096181 PCM/Gauge sending unit $14.81 (Wells TU178)
12102748 Connector pigtail (incl. terminals) $17.29
I am going to get a hold of it and run it over temperature to determine its response curves (and its suitability)

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Update
Over the Labor Day weekend I was able to score a sending unit and connector from 90 Olds during my JY trip that produced bunch of other parts. Last week I found a block of scrap aluminum which I drilled and tapped to accept 3/8" NPT sensor.

Test Jig



Next week, time permitting, I'll run some temperature curves against J-type thermocouple bolted near sensor (there are two 4-40 holes) using hot plate for temperatures between +25 and 125C and temperature chamber for -40 to +55C. Should be interesting.

Sensor is OE GM - part number ????
Yellow & black are used for ECM
Green and sensor body are used for instrument cluster gauge.

//RF

[critict1gc]

sweet definitely let me know what u find

[rfmaster]

Well, here are the results.

The OE 10096181 PCM/Gauge sending unit was tested from 22 to about 120C while mounted in AL block filled with antifreeze. J type thermocouple was bolted within 1/4" of the temperature sensor and recorded using laboratory grade thermometer. Both ECM sensor (yellow and black wires) and Instrument cluster (green wire and block ground) were measured concurrently and compared against published specifications for 12146312 CTS.



From the plots it is clear that the ECM output tracks GM published 12146312 spec very well.

The instrument cluster output characteristic is slightly different, but not by much.

However, as it stands, it would appear that 10096181 has a different Temp vs Resistance characteristic when compared to AC-Delco G1852 or Standard TS6 common GM gauge sending units used from mid 60's to late 70's trucks and cars:



The question is then can the cluster gauge bridge circuit be adapted to work with 10096181??? Stay tuned.

//RF

[critict1gc]

ok i cant figure this out i have good power and ground to all my sensors and stuff and when i turn it over my fuel pump turns on and it cranks but no fuel comes out except when i shut it off just a tiny bit skirts out and i got no spark but i have 12v going to the coil

[rfmaster]

Originally Posted by critict1gc

ok i cant figure this out i have good power and ground to all my sensors and stuff and when i turn it over my fuel pump turns on and it cranks but no fuel comes out except when i shut it off just a tiny bit skirts out and i got no spark but i have 12v going to the coil

Check and verify the following:

ECM harness connectors

Pin A6 +12Volts during cranking (and in run position)
Pin B1 +12Volts during cranking (and in run position)
Pin C16 +12Volts during cranking (and in run position)

Fuel injectors are getting power during cranking. 12 volts should be present.

It is very common conversion error to connect ECM and injector wires to a fuse box terminals that go off during cranking.

//RF

[critict1gc]

well what wires do i power up from my computer is it on of the adld wires