Re: Tbi swap build thread
 

C-9 Goes to the small terminal on the starter. ( tells the computer when the starter is engaged)

C-2 You can just disregard this wire.
D-1 Is a system ground. I just ran a main ground for the computer system and grounded it at the back of the head. (Pass. side)

You are right there is not an A-7 wire but there is an A-5 and this is your ses light. It is a ground the the cpu turns on when it needs to. I just used my choke light and put a switched 12 volts to one side and then wired in A-5 to the other side. works great.

A-6 as you said is pk/blk. It ties into sevral places in the harnes to give switched 12 volts where needed.

As for the fuse rating I think stock is 10 amp.

For b-1 I used a inline 20 amp fuse.

as for A-4 it is just a ground from the cpu to turn on the egr relay. so a fuse is not needed.

Re: Tbi swap build thread
 

This might help also if you don't have it. It is on the first page of this thread. Again good luck. ;)

Re: Tbi swap build thread
 

Pancake

Looks like you are digging into retrofit - full speed ahead

For P/N switch functionality you'll have to wire a small, simple circuit which requires some wire (12 AWG purple and 16AWG, 1/4" crimp connectors (female and male), BOSCH 30 amp relay, and silicon diode 1N4001 - Radio Shack.

Questions???

//RF

Re: Tbi swap build thread
 

Ok...almost ready to put the tbi on my Blazer.....but have another question. I understand the wiring for P/N switch but do I NEED this for a manual tranny?

again, thanks for all the info and advice.

Re: Tbi swap build thread
 

pancake

To get things going it is not required, but having a neutral position sense switch will improve driveability (i.e. ECM alters idle and timing somewhat (depending on ECM, other parameters as well - EGR operation, AIR) between neutral position and being in gear.

Leave B10 (orange-black) unconnected for now (this way ECM will see that truck is always in gear).

//RF

Re: Tbi swap build thread
 

Sorry if this is a repeat post, The other one did not look like it was posted.

Almost ready to install but had a few more questions:

My Oil Pressure Switch has three wires coming off it: orng, gry, and light tan. I know where the orng and gry wires go but where does the light tan wire go?

To install Dizzy do I need to find TDC on #1 and install dizzy so rotor points at #1 plug wire?

What should I start with for timming for a TBI 5.7L?

I need to disconnect a wire to set timming? D5 lt brn/blk wire?

Any advice on timming or insatlling the Dizzy would be great.

Thanks again for all the help and I hope people are getting some usefull information from this thread!:metal:

Re: Tbi swap build thread
 

Sorry forgot about the ADAL connector wire questions:


A blk/wht is a ground?
B to A9?
C brn wire is for the Air Divirter? What should I do with it?
E to A8?
F Lt brn/Blk....Where does it go?
H whith wire...Where does it go..looks like it attaches to a few more white wires.

Thanks again:chevy:

Re: Tbi swap build thread
 

Orange is battery side of FP supply circuit, gray is the fuel pump (FP) side of the circuit. Tan wire goes to oil pressure gauge (depending on switch part number it can be gauge or oil pressure light)

Yes, you need to find #1 Cylinder TDC and corresponding dizzy post.

0 TDC with EST connector open is a standard for truck TBI.

You should have a single wire weather pack connector - usually it is light brown with white or black stripe. Try to get your engine going first, then set the timing once it warms up. 0 TDC is the number. With EST connector open ECM will set code 42 - this is perfectly normal. Clear it by disconnecting battery after shutting engine.

Before taking original dizzy out remove hat and turn engine by hand until balancer reads 0 TDC and mark and rotor points toward #1 on dizzy. Mark that location before removing dizzy from intake. As you pull dizzy out the rotor will turn counter clockwise. Mark the final position as well. The idea here is to pre-align TBI dizzy so it just drops in place of HEI. Otherwise, turn engine to the 0 TDC and with a help of 12" BFS turn oil shaft as shown in the figure below. The key is to have oil pump shaft slot to line up with #5 Intake rocker (approximately). Turn TBI dizzy counter clockwise so as it drops it will turn clockwise and engage oil pump shaft. Whoa la!

Re: Tbi swap build thread
 

Good question

ALDL Pin - Function - wire color - ECM pin
A - ECM ground - black/white - A12
B - ECM Diagnostic request - white/black - A9
C - Air diverter - brown - C2 (not used in your application)
E - 160 baud data ECM - orange - A8
F - Shift light or TCC - tan/black - A7 (not used in your application)
H - Antilock computer data - not used in your application

//RF

Re: Tbi swap build thread
 

Thanks again for the great info rfmaster. I will be installing the TBI soon (within two weeks). I will posty before and after pictures. Thanks again.

Re: Tbi swap build thread
 

Hace some pictures of the TBI setup before install:



I will get more pictures up as soon as I can figure out how to make the files smaller:lol:

Here are some #'s off the TBI set up:

Intake # 14102182

TBI Body 17090061 2139 KCD

Injector #'s GM5235206 and the small # is 7259GM* on one and 7279GM* on the other..Is this a problem?

EGR #21698 or 2169B (not sure if it is a B or an 8)

ESC #GM 16052401 9161

Number on the Bottom of the Dizzy 1103749 9H 4

Re: Tbi swap build thread
 

Some more pictures:


Picture:

#1 wiring harness after sorting out the wires. I need to soilder the ends back that were cut to seprate the wires ( common ground, and orange wire)

#2 Everything laid out on my garage floor.

#3 Sensors, EGR, ESC< Fuel pump relay ( will get new 4 wire 02 sensor and a VSS)

#4 some shims the machine shop gave me to mate the new intake with the old heads.

#5 The intake fresh from the hot tank.

Re: Tbi swap build thread
 

Pancake

GM5235206 injector is rated 61 lb/hr at 13 PSI and was a standard issue on 350 Trucks and should have orange - black paint (some of it is still there). 7579 and 7279 is a production date code. Makes no difference to have different date codes.

TB 17090061 was used on 1987-1990 350 TBI trucks. Nothing special, but make sure that throttle shaft moves nicely and there is no slop due to worn shaft holes.

ESC 16052401 was used in many different EFI and CCC applications. When used in combination with 10456288 KS it should work just fine with your 350

1227747 ECM with ASDU code - very commonly used in conversion from carb to TBI. Depending on heads and compression timing may need to be augmented.

Intake manifold - just make sure that you can bolt it down.

//RF

Re: Tbi swap build thread
 

Great thread... wish I'd found it a year ago when I did a TBI swap into my C20, which is a "mutt" made up of my restored, but wrecked, '82 Camper Special (never lend trucks to girlfriends!) and an '85 with a straight body and frame, but bad engine, shot front suspension, brakes, and rear axle, butchered wiring harness, etc., etc. After getting the mutt running in late '05, I had the usual drive/tune-ability issues with the q-jet and got a full '87 TBI set-up off of e-bay. It took me a few months to sort through it all in the driveway (yup - I'm a bona fide shade-treer, subject to working in daylight when the weather is good). I have it running (and it runs very well if I do say so myself) - I'll mention some of my "insights" (more like problems I dealt with) later.

I ended up using the dash and rebuilt steering column from the '82 due to the '85's butchered wiring harness, shot steering column, and butchered metal dash sub frame (think hacksaws and ball peen hammers). While I installed a new stalk switch for the turn signals and cruise control, I never hooked up the cruise as I mainly use my truck for hauling stuff around town. I am about to go on a longer trip and want to get the cruise operational, so my questions are:

1) What do y'all recommend for the cruise: using the '82 or getting the parts for the later '85 or '87? I think the '82 would be cheapest since I have all the parts (I have some of the '85 parts too), but am concerned about the speedo cable wind-up I see, which is mostly at low speeds, so may not be an issue.

2) If I go the later model route, can I use the VSS signal from the JTR adapter I installed at the transmission end or do I need to get a later instrument panel too? My guess is no as I presume the later speedo-based VSS provided vehicle speed to both the cruise and ECM, but wanted to confirm with y'all.

3) Any other considerations I need to be aware of to help my decision and/or on getting this to work?

Some of my "insights" on swapping a TBI into an older vehicle:

1) Get manuals (or at least wiring diagrams) for both vehicles.

2) A factory TBI manifold requires modification if older heads are used (mine are mid-70's 333882's). I carefully used a disk grinder on the drivers side of the manifold to alter the angle for the bolts and made angled spacers for the passenger side.

3) If you want to use the TBI ECM's electronic lock-up for the 700R4 transmission, get a 700R4 from a later year. My '82 700R4 was not compatible with the ECM and, since my '82 was showing signs of wear (some slippage and lots of silver in the fluid), I got a used '87 700R4 that is compatible and has been working great.

3) Using the original 5/16" return line can result in excessive back pressure, which keeps the fuel pressure too high and makes the vehicle run real rich. FWIW, I have dual tanks and decided to use a Carter in-line fuel pump I found on Summit Racing "designed for TBI swaps into carburetor applications". I installed a fuel pressure gauge at the regulator and the Carter was running at 22 psi, no matter what regulator spring I installed, or how many coils I cut off the springs. I ended up disconnecting the 5/16" return line in sections to see where the back pressure was and found that even short sections had measurable back pressure compared to 3/8" line. After replacing all the return lines with 3/8, except for a short section of 5/16 for the tank selector solenoid, my pressure was down to 17-18 psi... close, but still running rich with a stock ECM calibration. I then found a vacuum adjusted fuel pressure regulator on e-bay and installed that... 12 psi at idle and up to 18 when WOT.

4) Even after sorting out the fuel pressure, I was still running a little rich and attributed it to the stock ECM calibration combined with the older heads and RV (high torque) cam I have in my engine. Researching my options, I ended up buying an EBL ECM, which replaces the PROM with flash memory and comes with "optimization" software. It wasn't the cheapest route, but after data logging and re-flashing my ECM a few times, my truck is running unbelievably well. Fuel mileage is up some 20-25% too (yippee!).

Anyway, sorry for the longish first post, but I wanted to share some of the problems I had and my solutions. And I would appreciate any insight anyone might have on getting my cruise functioning.

Mark

Re: Tbi swap build thread
 

Hey BrontoTX

Welcome to the board. IMHO, Mutts make best friends for life.

My '75 is as simple as it gets - no cruise control. I am not in a position to make comments regarding cruise controls.

VSS input - this is a tricky one, but you can probably adapt later DRAC unit to drive both ECM VSS input (2000ppm) and cruise control computer. The critical part is re-programming DRAC to match your rear end gear ratio, tire size and spedo gear ratios. In the past I found a page were this was documented, but it escapes my recollection at this time. Try Googling. Otherwise, get JTR 2000ppm VCC unit and DRAC in series with each other.

I am not a column expert - try a focused post instead.

TBI comments.
1) Definite yes, I pick-up B-Body FSM - it was cheap and covered ECM that I was using for my conversion.

2) I used pre -87 specific TBI intake, Holley 300-49. (I did not care for grinding) Alternative is to get Q-jet to TBI adapter plate and keep original manifold.

3) There are about dozen variation in 700R4 internal wiring. Two years later I have not hooked up my TCC function in my 700R4. Yes, I know I am bad.

3a) - Avoided back pressure problem by using 3/8" line everywhere. I also use Carter P5000 inline pump - works great. In addition I use a surge tank and a lift pump - both of my tanks are fully selectable and functional.

4) I run EBL conversion with my ECM - the best thing for tuning. I still have some tune work to do ( I have false knock due resonating exhaust system). Overall gas millage went from HWY 13MPG to about 17MPG (700R4). Original HWY (TH-350) was a dismal 10-11 MPG (I have 4.11 gears and 14 bolt rear)

//RF

Re: Tbi swap build thread
 

This is a great thread guys I am so glad that it was started however I wish I would have stumbled onto it earlier in my conversion process as I am almost done now... So I am sure I will have questions when I finally get ready to fire this baby up...

Re: Tbi swap build thread
 

I have looked at both the '82 and '87 factory service manuals and have come to conclusion that the cruise control and ECM are simply not connected in this era of trucks. There is the obvious exception of the VSS signal being used for by both the ECM and cruise in post-'87 trucks, which I determined through additional web research to both use the 2000 ppm signal. So, IF I went with the later cruise control (which I have decided not to do - see below), the VSS signal I am getting from my JTR 2PRS should feed both the cruise and ECM, just like they do when the VSS signal comes from the speedometer on post-'87 trucks (and cars).

Basically, my '82 cruise set-up uses a transducer and vacuum modulator mounted on top of the driver's side inner fender to understand and manage the speed when cruise is on. In essence, the transducer is a VSS-like signal, but internal to the cruise control. Since I have all but one of the '82 parts (I'm missing the throttle rod), I have decided to simply try and get this system functioning as the TBI and ECM really don't "know" (or care from what I can determine) if the cruise is engaged. Once I get the throttle rod and have a chance to test and diagnose the '82 cruise system, I'll report back how it works (or not) with the '87 TBI set-up - wish me luck.

RF - you are correct about there being about a dozen variations of the 700R4 TCC lock-up circuit. Since I had purchased an '87 TBI set-up from the e-bay seller in Brenham, TX, and since Houston (where I live) is only about 80 miles from Brenham, I contacted him and purchased the used '87 700R4 from the same donor vehicle (an '87 1/2-ton Suburban) as the TBI was pulled from. The used tranny was in good shape (clear, non-burnt fluid) and has been performing well for some 5,000 miles now. Given the heavier duty nature and use of my C20, I also installed an aftermarket auxiliary transmission cooler and an outboard transmission filter mount/kit that included a temperature gauge, which I use to keep an eye on when towing.

Also, my Carter P5000 pump works great too, although my first one was replaced under warranty by Summit since the first pump occasionally "locked up" and I had to "jump start" it by bypassing the relay using 12V+ direct from the battery to the pump. Given the problems with the first pump, I also purchased a spare since the Carter pump is the only part in my TBI conversion that is not available at my local auto parts store.

I also have a weird problem with the pump running for a few seconds after shutdown. I replaced the fuel pump relay and this problem occurs with both the pre-EBL ECM and the EBL ECM, but the pump still runs on, so my guess is that the ECM signal "decays" instead of shutting off instantly, keeping the relay engaged.

I did not install a surge tank or lift pump and both my tanks are selectable and functioning like yours. While I am happy with my set-up, perhaps you could elaborate to me and others on why you felt these were required?

Again, thanks to all for this great thread.

Mark

Re: Tbi swap build thread
 

Can someone tell me really quick what color the wires should be on the starter pink or red?

Re: Tbi swap build thread
 

It is pink on my '82 wiring harness, but may be different for other years.

Re: Tbi swap build thread
 

Looks like I wired it up correct then... sweeeeet

Re: Tbi swap build thread
 

WOW, this thread ROCKS! :metal:

Re: Tbi swap build thread
 

Thanks.

Re: Tbi swap build thread
 

Thanks again

Re: Tbi swap build thread
 

Hi Mark

I went a surge tank setup after reading conversion problems experienced by folks with non EFI tanks. Since our trucks are equipped with long saddle tanks fuel sloshing under low fuel levels can result in fuel sock aeration. When this happen fuel pump may experience instantaneous fuel cavitation resulting in fuel pressure loss and possibly inlet vapor lock. In other words - not good. Jeep guys face this problem all the time, but they have it easy by retrofitting to EFI tanks which incorporate fuel baffles to keep fuel sock covered under extreme angles. Alternatively, a small surge tank with low pressure lift pump is a workable solution. Noted, that this is not cheap nor is it simple to implement. There are couple advantages to surge tank system one being use of low pressure lift pump which can be conveniently mounted which can not be done with high pressure EFI pumps. Typically, low pressure lift pumps are self priming, so that if fuel sock aeration does take place pump re-primes itself while EFI pump keeps on delivering un-interrupted fuel flow to injectors. Low pressure pump fuel delivery can take awhile depending on fuel sloshing which plays into surge tank sizing - mine is about quart.

//RF

Re: Tbi swap build thread
 

Thanks for responding to my inquiry, RF. I don't use my truck off-road and/or operate it at extreme angles, so I don't have concerns about fuel sloshing in the old non-EFI tanks. I usually run each tank down to about an 1/8 full before switching over, but I have to admit to having gone below this level on occasion - I've had no starvation problems at any time with my generally sedate driving.

I mounted my Carter in-line pump on the inside of the frame rail slightly ahead of the transmission cross member. To minimize heat soak from the exhaust and possible vapor lock, I also fabricated an aluminum heat shield that I mounted to the frame rail. When I swapped out the lines trying to resolve the fuel pressure problem, as well as when I had to swap out the first pump that locked up, there were times the fuel in the supply lines gravity drained. Each time, the Carter primed fairly quickly afterward, which I attribute to mounting the pump at a level below the bottom of the tank.

Mark

Re: Tbi swap build thread
 

Ok guys I am having problems getting my set-up to run I have spark and fuel but it will not start with out dumpin gas into the tb I do have power to one side of each injector(should power be on both sides?) Is it possible my fuel pump puts out too much pressure and the tb is by passing it all?

Re: Tbi swap build thread
 

I do have power to one side of the injector while cranking but the other side does not flash?? (for some reason I cannot edit my posts)

Re: Tbi swap build thread
 

With ignition on, you should have 12V+ on both the red and white wires. The injectors do need a solid 12V, so if your battery is weak, they may not fire. The blue and green wires are triggered by the ECM to ground for firing each injector. There are ways to check the injector pulses at the wiring connectors, but require specialized equipment like an oscilloscope or trigger lights.

It is possible the injectors are stuck from having gummed up sitting around -this is what the problem was with mine when I first tried to start it and I was able to get one un-stuck by rapping the injector pod on the side with the handle of a large screwdriver. If you can get one to spray (the truck will run rough on just one injector), a good way to see if they are operational is to use a strobe from a timing gun. I ended up having to buy a new injector for one side.

I doubt that excessive fuel pressure is the problem - I'm pretty sure the bypass regulator is after the point where fuel is pressurized to the injectors. While I'm not sure what harm could be done since I've never tried this, you could try to momentarily connect a ground to the terminal of the injector that doesn't have 12V+ to see if it sprays (to try this, you have to have fuel pressure at the injector). If it sprays, there is either an ECM or wiring problem between teh ECM and the injector, otherwise it is probably the stuck injector I mentioned above.

BTW, I'm no expert on this, I've just been down this road before and I'm trying to give you the benefit of what little I know. Hope this helps and good luck.

Mark

Re: Tbi swap build thread
 

I lightly rapped on the injectors and nothing sooooo I guess I ll wait for a few others to chime in...

Re: Tbi swap build thread
 

While I get the sense that you want to figure this out quickly, these "noid" lights are the cheapest way (available on e-bay for $5-10) to see if all the wires at the injectors are getting the correct signal (i.e., determine if the lack of spray is due to the ECM/wiring or the injectors). Perhaps they are available at your local auto parts store.

BTW, I had to rap on my injectors pretty solidly before the one started spraying.

Good luck,

Mark

Re: Tbi swap build thread
 

Do you here your injectors clicking while you are cranking the motor? If you do they have the right voltage to fire them because that is the clicking noise. If they are clicking that probably means not enuff fuel is getting to the injectors.
I had this same problem and it ended up being a pinched fuel line.

I think the injectors get there signal from the ignition moduel in the distributor. If it is bad you might have spark but the injectors will not fire or vise versa.

keep us posted and good luck,
Jamie

Re: Tbi swap build thread
 

Perform the following check.

Turn ignition key into RUN position (do not crank). With a DVM measure voltage (with respect to engine ground) on both injector terminals - you should have voltage (11.5 to about 12Vdc) on both sides of the connector. Repeat for for both connectors.

If only one side has voltage you have injector with open winding (highly unusual) or injector connector that is not properly seated and engaged with injector pins.

Note the color of wires that have voltage.

When you pour a bit of gas into TB do you get engine firing up???

//RF

Re: Tbi swap build thread
 

Sorry, RF, but I respectfully disagree. Again, I'm no expert (I'm worse - I'm an engineer:lol:), but my understanding is that one side of each injector always has the 12V+ and the ground is switched/pulsed to the other terminal/side of the connectors by the ECM. Thus, testing for voltage across both injector connector terminals as you suggested will not show 12V (I just checked my truck and confirmed the lack of 12V across the injector connector terminals when in RUN).

With the key in RUN position, you should be able to measure 12V from the red wire on one connector (or the white wire on the other connector) to an engine or chassis ground, but not to the other connector terminal.

In regard to pouring gas into the TB, he said it would start in post #186.

cjracing: The relationship between the ignition module in the dizzy and the injectors is that the module tells the ECM that the engine is spinning (and at what RPM). The ECM needs to check that the engine is spinning because it is a potentially very dangerous situation if the ECM allows the injectors to fire (i.e.,release fuel into the TB) when the key is in the RUN or START positions and the engine isn't spinning. Since FB72 said his engine would start when he poured gas into the TB, the ignition module is working fine and it is my belief that his problem is (1) an ECM problem, (2) an open in the wiring between the ECM and the injector connector, or (3) a stuck/defective injector.

Since the injectors are basically solenoids, I reiterate my earlier suggestion to apply a ground to the non-12V+ terminal of the connector to see if the injector will fire. With a confirmed 12V+ on one injector terminal and a ground to the engine or chassis on the other, the solenoid/injector should click and allow fuel to flow. If fuel doesn't flow, either (1) the injector is stuck or defective or (2) there is no fuel pressure in the injector pod. If fuel does flow, then the problem is upstream of the injector connector in the ECM or wiring. While I've never tried this test, I don't see why it wouldn't work, nor do I think it risks harming anything.

That is my $0.02 and please understand that I am not trying to offend anyone or debate their advice - I'm simply trying to help.

Mark

Re: Tbi swap build thread
 

That's what I said. Kindly re-read my post (engine is not turning).

Furthermore, measuring voltage drop across 1.1 Ohm injector with a common DVM is fruitless. However, with a dual trace O-scope and A-B function one can measure voltage drop across operating injector. But that's not an issue here. In TBI system (same technique is used in many other injector systems as well) one pin of injector is tied +12 volt bus, while the second pin is being tied to a switching circuit inside ECM. Typically this switch circuit consists of high power Bipolar or FET transistor. In case of 1227747 ECM GM used a high power NPN transistor with collector tied to floating injector pin, while emitter is shunted to ground with 0.1 Ohm resistor. A custom (Delco) injector transistor driver IC is used to current limit current drawn by injector - by monitoring voltage drop across 0.1 Ohm shunt.

Missed that one, sorry.

OK = 2 cents accepted (in this economy)
//RF

Re: Tbi swap build thread
 

The batt in my voltage meter has decided not to play today so I quickly probed the wires and I have at least some power to one side of the injector connection on both sides injectors the other wire does not have any voltage(at least not that the test light shows) with the key in any position or while cranking the engine... Looks like i'm off to town for a battery for the meter.. Again guys thanks so much for the many good points of view..


Also on a side note I have a friend bringing over his scanner for the diagnostic port will this tell me anything ???

Re: Tbi swap build thread
 

I'll put together a basic measurement diagram later tonight - this should help you to troubleshoot. I hate guessing and once you have check list it will make it simpler to troubleshoot further.

Scanner
The ALDL will not tell you why injectors are not firing. On the other hand 7747 ECM will give you sensor data. Injector functionality is not monitored by early ECM - we are talking '80 high tech here (PC-AT, remember those 8086??)

//RF

Re: Tbi swap build thread
 

rfmaster - those diagrams you post up are great, and a bunch of help for someone who hasn't looked at a TBI since the early 90's! :lol: I take it you are making them?

Re: Tbi swap build thread
 

cjracing: The relationship between the ignition module in the dizzy and the injectors is that the module tells the ECM that the engine is spinning (and at what RPM). The ECM needs to check that the engine is spinning because it is a potentially very dangerous situation if the ECM allows the injectors to fire (i.e.,release fuel into the TB) when the key is in the RUN or START positions and the engine isn't spinning. Since FB72 said his engine would start when he poured gas into the TB, the ignition module is working fine and it is my belief that his problem is (1) an ECM problem, (2) an open in the wiring between the ECM and the injector connector, or (3) a stuck/defective injector.

Ok the way I understand how the cranking sequence works is the cpu gets a signal from the starter (C-9 prpl wire that goes to the selinoid on the starter)to turn on the fuel pump while it is cranking. When the engine has oil pressure the oilpress switch is what tells the cpu to run the pump and I understood that the module is what fired the injectors in time with the engine while it is running.
Am I wrong? If I am I would like the right sequence.

By the way FB-72 you have checked to see that you have 12 volts to the pump right? If you have and I missed it I am sorry I am just trying to help ya out.

Re: Tbi swap build thread
 

Yhea Thanks RF for your work on those diagrams they are awsome.

Re: Tbi swap build thread
 

Cj if your talking about the fuel pump no I have not checked but the return line is filling up the 5 gallon can quickly... I have 12 volts dc to both injectors on one side only...