My TBI 350 runs like hell...........should I give up and get a carb?

[nat]

I converted my 350 to a TBI with an kit from Affordable Fuel Injection. They have not been helpful at all.

My idle is too fast, the timing never seems right, it runs rich, not very good throttle response........it sometimes runs perfect when it is cold, but not very often.

I have taken apart and resealed my setup 4 times............never any change, so I don't think it is a vacuum leak.

What can I do? I have Winaldl, does anybody know how to read the data?

Should I put a carb back on?

 

[inkpot]

Howdy! Not familiar with this kit. Does it require a knock sensor for the timing adjustments? The Idle air bleed solinoid is adjustabe on some years/models. It is about the size of a spark plug, located near the base of the TBI, and it is aimed towards #6 or #8 cylinder. Just remember that it is an air flow, not fuel flow, controller. Does this kit still use a regular Delco Remy dizzy with vacuum advance? Have you replaced the throttle position sensor? What computer are you running? John

 

[brokenparts]

what sensors are you running?

 

[nat]

Sensors:

O2
temp
IAC
TPS
did I miss one?

NO Knock sensor

Fully computer controlled distributor

I am using a 2" bore throttle body.

Any insight is greatly appreciated!

 

[FJBen]

VSS...speed sensor?

is your idle lopey?

A bad temp sender will create issues.

Where is your temp sender located at?

 

[nat]

The temp sensor is located at the front of the intake manifold, you can see it facing us in the pic. The temp sensor for the gauges is the one located next to the goosneck for the radiator.

I don't have a speed sensor. I went with minimal sensors as part of the kit.

 

[Isotel]

tbi can be a pain when its not working right, but its worth it to figure it out!

i put an affordable fuel injection kit on a friends bronco and it runs like a champ!

did you get the entire kit from them, or just the basic harness? you could have a bad sensor or ground.. maybe a bad computer.. I ended up pulling an entire duplicate setup from the junkyard, so i have a backup Computer, Distributor, and all the sensors. then you can start to replace them and figure out what is going on..

Is it Giving you any Codes??

dont give up, Carbs suck

BTW your Serp Setup is BLING!

 

[FJBen]

How did you set the timing? If it's a computer controlled dizzy, did you make sure to disconnect it and set the timing to zero?

Have you checked the actual chip in the ECM to make sure it's seated correctly and no bent or broken legs?

 

[nat]

tbi can be a pain when its not working right, but its worth it to figure it out!

i put an affordable fuel injection kit on a friends bronco and it runs like a champ!

did you get the entire kit from them, or just the basic harness? you could have a bad sensor or ground.. maybe a bad computer.. I ended up pulling an entire duplicate setup from the junkyard, so i have a backup Computer, Distributor, and all the sensors. then you can start to replace them and figure out what is going on..

Is it Giving you any Codes??

dont give up, Carbs suck

BTW your Serp Setup is BLING!

Thanks, the serpentine setup is really nice

No codes.

The whole kit came from Affordable Fuel Injection. I have been becoming more suspicious of the computer or chip. I wish I new somebody with one, we could swap chips.

 

[nat]

How did you set the timing? If it's a computer controlled dizzy, did you make sure to disconnect it and set the timing to zero?

Have you checked the actual chip in the ECM to make sure it's seated correctly and no bent or broken legs?

I set the timing by fist disconnecting that lead, the I set it to 0. Since then, I have tried 0-7 degrees BTDC. Basically always runs the same.

I have pulled the chip. I even bought another computer, but when I hooked it up, it made electrical shorting noises, so I put the old computer back in and plopped the chip back into it.



I am leaning towards a bad computer, or a poorly programmed chip, or a bad IAC or TPS.

 

[Trollhole]

Couple of things.

Did you get the computer/TBI from them? I didn't and sent it to them so they could check it out and install the chip.

Electrcal shorting is not good.

Have you gone through the steps on resetting the IAC?

You have this on the 55 right. Are you using the stock fuel return line?

Have you put a fuel pressure gauge on it? What does it read?

If not take the fuel return line from the TBI and run it in a bucket start the vehicle up and see if it runs any better. What I have found is the return line going back can be somewhat restrictive. 5/16 is the smallest it can be and with all the line on the 55 back to the tank it can become retricted. Not a problem with a carb but with a TBI it really flows out. Really flows. You will see how full it can get that bucket if left to long running.

If this is the case what I would suggest is running a T fitting for the fuel oveflow hose at the back and running it into that. Just got to remember no restrictions. Fuel return pressure should not be over 3-4 psi.


Also where did you mount the o2 sensor?

What plug gap are you using?

Where did you mount your MAP sensor?

I'm assuming your getting at least one code? Code 12 right?

AFI are good guys I have one of their systems. Thought they did a good job.

Give me a buzz if you need help.

864-414-0563

 

[sixty]

I don't know why they don't integrate a knock sensor, its a VERY important part of the system.

You can Email me a copy of the log & maybe I can see something. (I'll pm my Email address)

Sounds like it might be running in Limp mode, which should be caused by a code.

A vac leak will generally not raise the idle on TBI unless its huge, cause the ECM will adjust the IAC to compensate.

I would NEVER pull TBI for a carb.

I would think that AFI would have much better support for thier systems, what do they say to look at?

Swapping ECM wont work, as you should have a custom program. Do you have a ESC module (square, flat module with 4 or 5 pins?

If it was me, I ditch the AFI ECM and buy an EBL & install all of the proper sensors. Learn to tune & your engine will run like a Raped ape and function like a fine watch.

 

[brokenparts]

all the suggestions so far are good... I'll offer another one. Not running a knock sensor can retard your timing quite a bit and run the motor rich. That would also effect your throttle response as the computer is probably running it fat to protect it from knocking since it cant see the knock sensor.

Just another thought.

 

[brokenparts]

Looks like sixty beat me to the punch on the knock sensor... I also am running an EBL ecm vs. the AFI. I'm really happy with the "tuneablity" it has. Great product and really good support.

 

[TBIFJ40]

On O2 sensors: How close is it to the manifold? Nees to be as close to the engine as possible. DONT cut the wire to shorten it, lenghten it etc. Its set up with a certain amount of resistance in it. Messing with it will screw things up. I agree, gotta have the knock sensor. Theres no reason to eliminate ANY of the sensors on TBI, they are there for a reason...yes, even the EGR. Do run a VSS, you can get one from the Jaguar place, goes on the speedo cable, it does make a difference.
TBI is way better than Carburation. Cold and off angle starts are kinda nice.
I think youve tried to change too many things at once. You might be best off getting a completely stock donor system, (run the donor vehcile if you can) putting the whole system on, then changing one piece out a t time until you get your blingy system transfered over. I know it sounds like a lot of work...but..Its hard to beat the stock system.
Remember also, 10psi fuel pressure, pump in the tank is best, need a return line.

 

[Trollhole]

Maybe AFI is filling me with a bunch of crap. I just got off the phone with them and they say 95% of all the systems they install don't need VSS or Knock. He said if you live in a place where you get crappy gas then maybe. Said he has never had an issue. He also stated if you were running a real high performance system or high emissions system then you could use one. He said not having them would not make any loss in economy noticable. These guys build a lot of systems. I find it hard to believe they don't know what they are doing.

I've not had an issue thus far as far as knocking.

 

[Isotel]

mine runs fine without a vss.. same with the AFI System i installed on a friends rig!
Any way you could hook up the old school Distributor to see if its the timing thats making it run like that..

 

[sixty]

The VSS is not always used by the ECM. There are a few benefits to running one (lean cruiser mode for much better mileage) and it can also fix stalling problems when coming to a stop.

The KS is used at all times by the ECM and if the chip is not tuned to ignore the missing KS then it can cause all kinds of trouble. In a perfect world a KS (most other sensors also) is not needed. One batch of bad gas, a slightly clogged injector or some carbon build up and you could run into problems that the ECM could fix (or pull timing to save pistons) with no input. GM put them on stock engines for a reason. I see no reason to remove them as the benefits far outweight the effort of running an additional wire and mounting a $40 sensor somewhere on the block.

When installing a TBI system it is best to use all of the sensors that came with the system & even add an Intake Air Temp sensor if the system did not have one. It makes a HUGE difference in the economy and overall performance. With a VSS installed at highway speeds and light load the ECM will command the AFR to go from 14.7 to well over 16 with a big increase in economy. Without the KS this could be dangerous.

TBI systems are like springovers.... there are tons of shorcuts & some can operate fine, but there are alot of benefits by doing the extra work to make and do it right.

 

[brokenparts]

Mine doesnt use a VSS but I plan to add it and a IAT once I swap over my topend. There is a complete stock tbi system including sensor for sale right now on Pirate for a good price... might want to look into it and add the ebl?

 

[nat]

OK, I have 3 data logs from winaldl and also some video of the motor running. I will try and post this evening.