Tbi swap build thread

[rfmaster]

Originally Posted by dropd80s

Finally got my CCSB pulled out of the shop under its own TBI'd power yesterday! Shes an 86 with a 90 sub TBI 350/700 and complete harness swap. Everything stock. My problem is she seems to be running very rich. I have considerable black smoke at idle. I have let the truck warm up to operting temp, and still have no codes stored. Everything is clear.

I am curious if the higher pressure fuel pump I ran (E2000) is overloading the FPR?
I know I need to check and make sure the 5/16" return line I ran is not kinked.
Also, I have no exhaust on the motor, only a few inches of pipe on the manifolds. Could this be cooling my 02 and not letting it read properly?
I assume this could also be a CTS problem or Vacuum leak?

Any ideas you guys have or how I should go about ruling things out would be a huge help. Thanks in advance

Yes, all of the above can potentially cause rich condition. Make sure that your harness has ALDL connector wired and SES is functional. If your ECM sees open CTS it will set Code 15 (very cold temperature = rich fuel mixture!) Jumper Pin A&B of ALDL and read SES blinks.

I would go through the check list first before jumping to any conclusions.

1) Verify operating fuel pressure by measuring FP at the input port of the TB with a fuel pressure gauge. That should take care of E2000 pump and 5/16" return line. You should see solid 13 to 14 PSI. Stock regulator can handle 40 PSI pump without too much trouble.

2) Non functioning CTS or an open ground lead will cause rich condition.

3) I am going to assume that you have cast iron (CI) exhaust manifolds - these should be adequate to keep your O2 hot (around 600F), but a full length exhaust system should be put in eventually.

//RF

[dropd80s]

The ALDL and SES light are both functional. I have checked for codes and only get the code "12", so I am good there.

I will check the fuel press. and see what it shows.
The CTS is just a switch correct? This should be easy to check.
And yes I have stock exh. manifolds still. Just got to get her to the muffler shop to get the exhaust ran.

Thanks for your help.

[rfmaster]

Originally Posted by dropd80s

The ALDL and SES light are both functional. I have checked for codes and only get the code "12", so I am good there.

I will check the fuel press. and see what it shows.
The CTS is just a switch correct? This should be easy to check.
And yes I have stock exh. manifolds still. Just got to get her to the muffler shop to get the exhaust ran.

Thanks for your help.

CTS is NOT a switch - it is a thermistor. Basically a variable resistor that changes its resistance value with temperature. A typical AC-Delco CTS will be 99.3 kOhm at -40C; 9.25 kOhm at 0C (32F); 2.75 kOhm at 25C; 175 Ohm at 100C. ECM uses ADC to measure voltage drop across CTS to determine corresponding coolant temperature.

//RF

[dropd80s]

Originally Posted by rfmaster

CTS is NOT a switch - it is a thermistor.

Ok now I think you're just making words up as you go along . I understand now. I'll check to make sure the CTS is also working correctly.

Thanks again.

[rfmaster]

Originally Posted by dropd80s

Ok now I think you're just making words up as you go along . I understand now. I'll check to make sure the CTS is also working correctly.

Thanks again.

Occasionally I slip-up, but not this time....

http://en.wikipedia.org/wiki/Thermistor

[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?

[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

[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

[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.

[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?

[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.
Posted via Mobile Device

[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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[critict1gc]

sweet definitely let me know what u find

[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?