FI Tech Frustration is back again

CopperNick

Royal Smart Person
Supporting Member
Thread starter
Feb 20, 2018
2,092
113
Canada
Okay, then I do have to go back to the AFR again and recheck what I input for the intermediate settings. I may have to add more air to take the readings back the other way. That could explain why it is dropping dead on me. Too rich when warm and it could be choking itself out.

Right now the IAC is showing 4-6 on the programmer screen. As for the the backstory on the IAC, apparently, as sold and delivered, my brand new TBI unit came to me with the throttle plates totally closed and the IAC inoperative. Unadjusted like that, one of the major issues is that the throttle plates are way over centered and it takes a lead loaded shoe to put enough pressure on the acc pedal to get it to move. Fought that problem for years in ignorance until someone posted a video of that neat little screw at the front of the injection body that you can barely see the head of, and what has to be done with it. Turns out, literally, that it came from the factory backed out so far that the screw point had NO contact with the cam on the throttle shaft. i forget how far I had to turn it in to get the IAC to come alive but a full turn and a half is a good guess at this point. Buried as it is, you cannot visually observe any changes that adding or subtracting to how far in or out the screw is sitting have accomplished.

The other thing is, at least for my van, accessing that screw is beyond hard to difficult. Van engines are not situated like car engines, When you open the hood, you discover that they are recessed back under the dash to a major degree. With the doghouse off and the engine exposed, my mill is so close to me that I can put my hand on the timer without taking my eyes off the road. At one point I was actually doing test laps with the motor uncovered. Major noise factor but high on the fun meter if you dig being that close to the action.

That being the case any adjustments to the idle screw have to be done with the engine off. Just too much of everything in the road and all of it HOT when the engine is running.

So it looks like I get to go back at it again tomorrow.



Nick
 

ck80

Comic Book Super Hero
Feb 18, 2014
4,420
113
Okay, then I do have to go back to the AFR again and recheck what I input for the intermediate settings. I may have to add more air to take the readings back the other way. That could explain why it is dropping dead on me. Too rich when warm and it could be choking itself out.

Right now the IAC is showing 4-6 on the programmer screen. As for the the backstory on the IAC, apparently, as sold and delivered, my brand new TBI unit came to me with the throttle plates totally closed and the IAC inoperative. Unadjusted like that, one of the major issues is that the throttle plates are way over centered and it takes a lead loaded shoe to put enough pressure on the acc pedal to get it to move. Fought that problem for years in ignorance until someone posted a video of that neat little screw at the front of the injection body that you can barely see the head of, and what has to be done with it. Turns out, literally, that it came from the factory backed out so far that the screw point had NO contact with the cam on the throttle shaft. i forget how far I had to turn it in to get the IAC to come alive but a full turn and a half is a good guess at this point. Buried as it is, you cannot visually observe any changes that adding or subtracting to how far in or out the screw is sitting have accomplished.

The other thing is, at least for my van, accessing that screw is beyond hard to difficult. Van engines are not situated like car engines, When you open the hood, you discover that they are recessed back under the dash to a major degree. With the doghouse off and the engine exposed, my mill is so close to me that I can put my hand on the timer without taking my eyes off the road. At one point I was actually doing test laps with the motor uncovered. Major noise factor but high on the fun meter if you dig being that close to the action.

That being the case any adjustments to the idle screw have to be done with the engine off. Just too much of everything in the road and all of it HOT when the engine is running.

So it looks like I get to go back at it again tomorrow.



Nick
Now you make me want to find a 250/292 i6 van to drive with the cover off...
 

CopperNick

Royal Smart Person
Supporting Member
Thread starter
Feb 20, 2018
2,092
113
Canada
And my early morning tune and test was a bust. Did revisit the AFR ratios for the various stages of warmup and moved them back over the 13 threshold. My desired AFR is set at 13.25. The IAC at warm idle varies from a low of 4 to a high of 6. It starts and runs okay and the initial engine jitters seem to smooth out as it warms up. BUT.........

Any attempt to accelerate earns an automatic shut down. In a carb it you would think it is almost as if there is no transition going on between the idle circuit and the low speed circuit. So I am thinking that I have a definite problem. I have been able to side step it by being real heavy on the throttle at initial acceleration. Doing that almost seems to force the engine to "jump" over the stall threshold and keep on running, until you have to stop for a light or an idiot and the whole cycle starts all over.

My thinking at this point is that I have a major tip in malfunction and I am not sure if it is something that I can correct using the programmer

A little research may be in order but given the lack of a coherent body of knowledge for tuning the early TBI's, this may also be a case of it just getting old and slowly dying on me. That sucks. Sorry, still no laptop; still no maps, and I would likely need someone to interpret them which equals $$$ and knowledge that I just don't have.

Addendum

it is starting to look like the culprit is the Throttle position sensor. it either needs to be reset, or has failed and needs to be replaced. To set it apparently involves disconnecting the ground cable at the battery and leaving it off for a minimum of five minutes. Guessing here that doing this causes the sensor to "forget" any previous readings and go back into idiot mode so it can relearn all over again. All the hassle with getting the IAC correct may have been the trigger for the TPS problem.

However, if the TPS has failed, then that it is more serious issue because, while their price from FI TECH is reasonable, there is no immediate delivery date listed on the website. This, to me, means that I may be facing a planned obsolescence situation with the mfgr slowly eliminating support for its older products in favor of newer ones.

Next step is to try yanking the ground and seeing if that does the trick.



Nick
 
Last edited:

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
4,861
113
Upstate NY
FiTech smh.

Check the sensor. There should be a 5v and ground. The other wire is the signal. Verify proper power and ground and then check the voltage coming from the signal. Do this via back probing the connector with a hem pin. This will confirm the tow is good or bad and also if you have a grounding issue.
 

CopperNick

Royal Smart Person
Supporting Member
Thread starter
Feb 20, 2018
2,092
113
Canada
So went with the "remove the ground at the battery exercise" and left the battery ground detached for at least 15 minutes even though the default amount of time suggested was only 5. And...................It worked.

Fired the unit up and let it warm up, backed out of the driveway and it started down the road like it had a working choke again. Got it over to the service road for the next door warehouse, took the programmer off the dash and put it in my lap so I could watch the TPS sensor readout on the screen, and it rose from 0 at idle to 6.6 at about 15 miles an hour. Did a couple of laps around the building; it sneezed twice on the first lap but came back in when i briefly eased up on the pedal and then came onto it again. No sneezes at all on the second lap so the sneezes may have been part of the learning curve for both the TPS and the fuel graph. Brought it back to the front drive, parked and turned it off. IAC was doing its usual bouncy-bouncy in the idle reading department going from 4 down to 1 but at this point I can turn the van off almost immediately without getting run-on so the IAC setting is staying right where it is.

The big test will be a short drive this afternoon. if that goes well, then I will call the problem solved for now, BUT

I may still convert back to the AVS simply because with it the only things to set are the idle mixture screws and possibly the idle stop. I can get rid of that goofy fuel pressure booster and just use the basic mechanical fuel system Getting back into KISS mode here could easily be beneficial to my mental health and blood pressure. If the van keeps starting and running okay, it will get left alone until the end of summer at which point it goes back in the shop and it's decision time

Now what was that historical about time...... ? along the line of "everything but time"???

And, ah, 64 Nailhead, what is a "Hem Pin"??


Nick
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
4,861
113
Upstate NY
A pin used for hemming pants. Small diameter and flexible.
 

CopperNick

Royal Smart Person
Supporting Member
Thread starter
Feb 20, 2018
2,092
113
Canada
R.I.P. My FI TECH 400 HP TBI Fuel Injection System. Born ??? Died Saturday at 6 PM. Failed the big test, aka the Saturday short drive.

In its defense it did get me to where I needed to be but the run home was nothing but repetition after repetition of stalls. Any kind of gentle acceleration equaled an instant quit. It would crank and re-fire and move along just on the idle but as soon as any transition from idle to the low speed circuit was attempted............ Bupkus.

For the citation on the headstone, I now paraphrase Monte Python; "What we have here is an ex Fuel Injection system. It has ceased to be."

Today being Sunday, it seemed appropriate that I confer the last rites upon the departed. So I spent part of the morning dissecting out the FI systems from their decade long location and remanding them to a box to be subsequently repacked into its original carton for storage. Because it still has salvage value and potentially could be resurrected for use on another of my motors, I elected to carefully remove all the subsystems and their components intact. Which is not as difficult as it might seem as, when I did the install, I chose to take the time and make the whole thing modular, meaning that it all plugs together and what didn't come that way got modified to be that way. Removal does take a big longer but works a lot better than ripping and rending and the vicious application of a pair of side cutters, aka Dykes Pliers.

In it's place, well more on that once I get the install completed, and maybe even some pictures of the deceased and its successor for the history tales.



Nick
 
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mclellan83

Comic Book Super Hero
Jun 27, 2017
3,085
113
Pgh, PA
season 3 netflix GIF by Gilmore Girls
episode 15 videotape GIF
 

Texas82GP

Just-a-worm
Apr 3, 2015
7,609
113
Spring, Texas
My vote would be for a custom tuned non-CCC quadrajet but you don't have the right intake on it for that so it becomes a big project. Sorry to see the Fitech didn't work out. You're a patient man Nick.
 

Ernest

Master Mechanic
Apr 28, 2016
288
63
Texas
All you really need is a carburator and an AFR guage kit.... both readily available as is the replacement parts, only two tunes needed no matter where you live, one for summer time, the other for winter time. Done

This aftermarket FI system along with unavailablity replacement parts supply issues along with the inflated prices, its for the birds, the quality just isnt there anymore, we're now paying more for lesser quality parts due to greed.
 

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