FITECH 39001 low idle cannot adjust up
Dubvalman, tell me what the handheld is doing and your fuel pressure when it is running bad. I would try a ground wire directly from the throttle body to the battery and shield your blue wire if not using timing control. This does not sound like a unit problem. Most likely an electrical issue causing the unit to receive bad signals. This will cause the unit to have the symptoms you have.
Every Fitech unit is bench tested before shipping. This isn't bullshit, I have personally seen their testing area. Allthough not impossible, the likelihood you got a bad unit is very slim.
We will figure this out....
Hi Austin
Thanks for the patience with this. I have a battery cable connected to the cylinder head right beside where the manifold bolts up, surely this would be sufficient an earth for the unit? I will run another however if you think that may assist/improve the situation.
As for the shielding, I did check the location and proximity of the ignition wires when rewiring the switched +12v for the white wire, and there must be approximately 1 1/2 to 2" gap between the blue wire and the nearest ignition lead. But again if you feel putting some shielding over the blue wire would help. Upon reflection, I will not wait and have ordered some RF shielding braid and will fit it anyway 🙂
I have bought a new Bosch O2 sensor and will fit that - other forums have contained similar symptoms and the prognosis seemed to be improvement after replacing the 02 sensor with the Bosch one. I am not pinning my hopes on that, just its an easy test and cannot hurt.
I pulled the plugs and cylinders 1 to 4 showed some over fueling - a bit rich, but considerably less than I expected. Cylinders 5 & 6 however - there is probably less soot in my house chimney. Plugs 1 - 4 were brownish with a hint of black, 5 & 6 were literally black. I fitted new plugs but the issues persists and seems to be worsening. The vehicle will not idle when at temperature now and requires throttle to start - hot or cold - that went away when I moved the source for the white wire, but is back now. It did however drive fairly well when cold and up to approximately 170 degrees. After that the silliness returns.
I did get some data logging done - I can identify the elements, but as for interpreting them; I am not proficient with EFI - hence the use of carbs for so long on my vehicle 🙂 🙂 I did notice that the logged temperature is different to the hand held indicated temperature?
And yes I am sure we will figure this out ........ especially now the memory and frustration of the energy expended pushing the car home is fading.
Ok, temp difference is common issue. Go grab a Delco temperature sensor. This will fix that problem as long as both sending units are near each other. I prefer the near the thermostat.
The supplied O2 sensor is a Bosch. Up to you, but I am going to bet that isn't your problem.
When it starts running bad, check for codes. Also look at the RPM indicated on handheld. If the RPM is way off, that tells me it is electrical interference in the blue wire and/or distributor. Are you running a factory distributor with factory module?
As for grounds. I run a ground from the body, chassis and engine on all my installs. Never had a ground issue... Running one from the unit directly to the battery doesn't need to be permanent. Good way to diagnose though.
Your handheld dashboard will tell you a lot. Watch RPM, AFR and AFR trim. If they aren't constantly adjusting then the unit is confused. Usually ground and/or interference.
Hi, not sure what you mean about the Delco temperature sensor. The issue is what is in the data log is different to what was showing on the handheld at the time of logging. Not that there was a difference between the vehicle temperature gauge and the handheld.
The shielding is on it's way, and I will fit it and earth the casing, along with running an earth from the throttle body directly to the battery. When the engine starts the erratic behaviour there hasn't been any codes, none that I have noticed anyway.
Hopefully Saturday will have the adjustment/tweaks done and I will drive the vehicle again and see how it goes.
Good luck. I will be available. I don't have bankers hours like Fitech.😁
Fitted the shielding on the tach (blue) wire. Soldered an earth to the shielding and earthed it through the cylinder head. Fitted an earth to the unit. Renewed all vacuum lines. Checked all connectors, renewed a couple (just to be sure they were as a good as I can make them). Set of new E3 plugs.
Still needs some throttle to start but does idle smoother. The IACs are not in the range given but I ignored them and went for a short drive. Racked up 30+ kms with no silliness from the system. Idle was a bit erratic - sometime sits high 850 to 950, other times sits where it was set - 750 ish. Thankfully not stumbling, stalling, surging, spluttering. Did not need to restart once for the whole drive. The drive was city and motorway mix.
Tomorrow if the weather is good I will do a 100+ miles of mixed driving which should give it opportunity to learn and settle. With luck your suggestions have solved the erratic behaviour and it will get better and better.
Good deal. Enjoy. We can tweak some of the calibration, but for now let it learn.
EPIC FAIL!
Twenty minutes or so into the drive and the same BS starts. RPM wont come back to idle, surging, stumbling, dieing; i didn't even get as far as yesterdays drive! - a complete pig to drive. I had to nurse the thing home AGAIN and push it up the drive as it wouldn't even pull enough for that small hill from a standing start.
I thought perhaps it did not like the emission control set up on the vehicle, so I even changed the plumbing for that, completely blanking the vacuum line which connects to the PCV thinking it may be making the the system think it had a vacuum leak which was upsetting it. Made absolutely no difference. The vehicle has approximately 16" of vacuum at idle - so no leak. I was not able to get it to run well enough to risk going out again.
Now there is a new problem which has manifested. When the vehicle dies, key off then try to start, when it eventually does fire up - try to select dashboard or anything on the handheld and a message "Failed to load" is displayed. I have to unplug the handheld, key off and then fingers crossed the message clears and I get the handheld functioning again. Also several times when I pressed the little control knob to start data logging it indicates it has started with the green band with the message "data logging on" but none of the figures change and the RPM displays something wild like 58999 rpm?
Dispite the claims it is suitable for smaller engines, it appears that it is only compatible with engines producing 200 - 300+ hp. The fuel settings are so rich it is amazing that the vehicle does even start or drive. I may as well have slapped on a 900 CFM carb onto my little 202 cu in engine - I would be having the same issues.
I am so dissapointed with this system. It has been so unreliable and hopeless from the first turn of the key. I have followed the installation instructions to the letter, re- read and rechecked everything to be sure it is not me inducing a problem through poor installation, listened and applied all of your suggestions; but at this stage - I gotta start believing it's this unit.
I have given this thing enough attention, pandered to its idiosyncrasies, and as the only item left to be changed is the O2 sensor - that will go in when it arrives and if it does not settle down and start allowing the vehicle to be drivable for a reasonable period for the thing to learn - it will go in the trash and I will either re-install the old carb or try the Sniper.
I am reasonably patient most times, but this system is erratic, finicky and not showing any thing to suggest its reliable.
That RPM number is the common issue with electrical interference in the blue wire or the distributor. The unit is doing its job, but getting a bad signal. You have an electrical issue. Sorry for your frustration.
Any suggestions what may be causing it now?
- The blue wire has been shieled from just before the eyelet connector at the coil up to the factory connector block
- The white wire is fed more or less directly from the battery - circuit switched through a relay
- Earth fitted between TBI unit and the battery -ve
Where would it be getting the interference now? Would it be possible that interference is being induced by the vehicles wiring harness? The Fitech loom is paralleled with the vehicle loom - could it be that susceptible to interference that laying beside the vehicle loom for a short distance is upsetting it so much?
Again thank you for your input - it is really appreciated