- Thread starter
- #21
That one looks good. Let me fiddle with mine this week and i'll let you know. A trip up to Dublin might be in order.
My first 80 (1 Viewer)
- Thread starter sogafarm
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- Thread starter
- #22
Pulled the cover off the maf sensor so far. I adjusted the little tabs resting inbetween the three horizontal prongs(plugs #3,4,5) and the circuit board coming from the plug end. Looks like I had pulled the factory solder away from the circuit board when I originally pulled the plug out by mistake.
Next will attempt to solder the tabs to the circuit board.
Question....Do I solder just the tabs to the board and the prongs float on top or do I solder the prongs through the tabs to the board? In other words should the prongs coming from the plug just sit on top of the soldered tabs or should they be permanently soldered all together and to the board? I'm not sure what these three prongs are designed to do, but I do know they must be crucial to the fuel injection system somehow.
Also, do I need to reset the ECU by unplugging the battery or another method?
Next will attempt to solder the tabs to the circuit board.
Question....Do I solder just the tabs to the board and the prongs float on top or do I solder the prongs through the tabs to the board? In other words should the prongs coming from the plug just sit on top of the soldered tabs or should they be permanently soldered all together and to the board? I'm not sure what these three prongs are designed to do, but I do know they must be crucial to the fuel injection system somehow.
Also, do I need to reset the ECU by unplugging the battery or another method?
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- Thread starter
- #24
I tried a few times to get the soldering right, testing in the cruiser after each attempt.
First solder attempt, it did the same thing it has been doing and started right up, then dying after a couple of seconds.
Second time, it turned over but didn't crank. I had too much solder that ran from the first tab and joined the middle tab.
Third time I put solder on underside of tab and soldered to the board, cranking then dying after a couple of seconds as before.
So I'm back to square one. I'm still not sure what the tabs actually do?
A Dublin trip is looking more and more likely.
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well if you want to come up and hang out i am sure we will be at the shop tinkering on something all weekend. be ready for my wife to throw some terrible pics of you (she only cares how she looks in them) on her instagram account 
send me a message if you are coming up and i will give you my cell number. most people here have it already but i still hate to post it in the open and get more spam calls then i already do.
send me a message if you are coming up and i will give you my cell number. most people here have it already but i still hate to post it in the open and get more spam calls then i already do.
ppc
M Go Blue
You may have multiple problems inside the connections of the VAF. With what you have described with the engine dying after a few seconds is related to the fuel pump cutoff switch is pins 1 & 2 of the VAF connector. The fuel cutoff switch cuts power to the circuit opening relay so that when/if the engine shuts off the fuel pump will be turned off. It is a safety feature for several reasons one of which would be to stop fuel flowing in the event of an accident.
The circuit opening relay that controls the fuel pump activation/control circuit in two ways. First the way, the ECM at startup supplies the control for a few seconds enable to supply fuel to crank/start the engine. Once the engine is started then that portion of the control circuit is deactivated and the fuel cutoff comes into play. With the engine running the vane/door inside of the VAF opens due to incoming air flow and closes the fuel cutoff switch. In your test the fuel cutoff is not functioning shutting down the engine.
A bench test, off the truck, test continuity with a meter between pins 1 and 2. With the vane closed there should be no connection. Opening the vane with you finger a connection should be present between the pins. If this is not the case pin 1 and/or 2 is not soldered properly.
A on vehicle test you can ground pin 2 bypassing the fuel cutoff switch and start the engine. It should continue to run. If it does not stay running you most likely have problems with other pins. Bypassing the fuel cutoff is for testing only and is not a permanent or proper fix.
The circuit opening relay that controls the fuel pump activation/control circuit in two ways. First the way, the ECM at startup supplies the control for a few seconds enable to supply fuel to crank/start the engine. Once the engine is started then that portion of the control circuit is deactivated and the fuel cutoff comes into play. With the engine running the vane/door inside of the VAF opens due to incoming air flow and closes the fuel cutoff switch. In your test the fuel cutoff is not functioning shutting down the engine.
A bench test, off the truck, test continuity with a meter between pins 1 and 2. With the vane closed there should be no connection. Opening the vane with you finger a connection should be present between the pins. If this is not the case pin 1 and/or 2 is not soldered properly.
A on vehicle test you can ground pin 2 bypassing the fuel cutoff switch and start the engine. It should continue to run. If it does not stay running you most likely have problems with other pins. Bypassing the fuel cutoff is for testing only and is not a permanent or proper fix.
Can someone explain this to me in stupid? Thanks
ppc
M Go Blue
That was the stupid version. Maybe you need the assistance of a friend to go over this and help you test/repair.
- Thread starter
- #29
Thanks for the explaination ppc, that sounds like what might be the problem. I will test with a multimeter and post results. PS I admit I had to reread your post a few times before it made sense to me, but that's why I want to learn more.
Connected to the first pin(from bottom of pic) is a long flat vertical bar that rests on the wound up spring loaded "sprocket" arm when flap is closed. When the flap opens and the big round spring winds counter clockwise, the first pin loses contact and comes close to touching the second pin. It just misses contact by 1/16" or less. Is this supposed to make contact when the flap is open or just be very close? If it is supposed to make contact, then there is the problem to adjust. I need to bend the second pin until it makes contact with the first pin when flap is open.
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ppc
M Go Blue
Before bending anything first post your results of testing with a multimeter. I might have this backwards. If the two pins have connection when the flap is closed then there should be no connection with the flap open or vice versa.
- Thread starter
- #31
Ok, good news, that was the issue. The first and second pin appendages were not making contact when the flap closed or open, no continuity. I must have bent the #2 pin when I pulled the plug originally. The two appendages are supposed to make contact when the air flap is open and not make contact when closed, this is the continuity circuit that ppc was referring to before. After bending the #2 pin appendage to where it just made contact with the #1 appendage when the flap is in open position and not touching when flap is closed. Continuity reading between #1 and #2 pin when flap is open was .005 to .010 depending on where I held the meter leads. It read 0 when flap was closed.
After reassembling everything in the cruiser, it cranked up and held idle. After a short test drive, throttle response was better than before, and Idles at just above 800 rpm steady. So big thanks to ppc, slow squirrel and slow95z for all your help on the matter.
The CEL is on though, I will have to do some forum searches on how to reset.
On another note, the reason I was even messing with the engine compartment to begin with was to address a charging issue. The last time I drove the cruiser into town, I almost didn't make it back. Several random dash lights(cel, at temp, brake, and voltage light) came on when I first cranked it up, but went away when I revved the throttle. Watching the voltage guage on the way back it was dropping fast all the dash lights came on and the guages stopped working. I only had 10% charge left when I got home. So there is a charging issue that I now have to work out. After looking around saw the neg battery terminal clamp had a broken bolt so replaced and recharged. About then I got bored waiting and decided to do the VAF cleaning. So now that is back running, I will test the alternator to see if that's the issue or maybe the voltage regulator. The saga continues.....
After reassembling everything in the cruiser, it cranked up and held idle. After a short test drive, throttle response was better than before, and Idles at just above 800 rpm steady. So big thanks to ppc, slow squirrel and slow95z for all your help on the matter.
The CEL is on though, I will have to do some forum searches on how to reset.
On another note, the reason I was even messing with the engine compartment to begin with was to address a charging issue. The last time I drove the cruiser into town, I almost didn't make it back. Several random dash lights(cel, at temp, brake, and voltage light) came on when I first cranked it up, but went away when I revved the throttle. Watching the voltage guage on the way back it was dropping fast all the dash lights came on and the guages stopped working. I only had 10% charge left when I got home. So there is a charging issue that I now have to work out. After looking around saw the neg battery terminal clamp had a broken bolt so replaced and recharged. About then I got bored waiting and decided to do the VAF cleaning. So now that is back running, I will test the alternator to see if that's the issue or maybe the voltage regulator. The saga continues.....
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guess i can stop riding around with a VFM in my truck ready to ship out lol. glad you got it and if you ever have questions send me a message. i am not an expert on the trucks but i damn sure know more than anyone at the part store (or even your local dealer) about the 1FZ powered cruisers.
- Thread starter
- #33
I appreciate all your help slow95z. If you are ever down my way, give me a shout. I've got plenty of room for camping on our tree farm. Can do some hog hunting, fishing, or just shooting targets if your into that.
ppc
M Go Blue
I thought I would make one more post to clarify the functions of the VAF that may still be an issue for you and others.
The VAF provides three functions:
1) Fuel cutoff switch - documented post #26 above
2) Temperature sensor - input into the ECM used to calculate air density and proper fueling parameters, possibly idle RPM
3) A variable voltage output signal based upon flap/vane position, input into the ECM to calculate actual air input. The voltage fluctuates primarily due to engine RPM and load. If that voltage ramp up/down is not smooth (dropouts) as the flap/vane position changes then the engine may not accelerate smoothly or have what are perceived as misfires and poor performance.
The VAF provides three functions:
1) Fuel cutoff switch - documented post #26 above
2) Temperature sensor - input into the ECM used to calculate air density and proper fueling parameters, possibly idle RPM
3) A variable voltage output signal based upon flap/vane position, input into the ECM to calculate actual air input. The voltage fluctuates primarily due to engine RPM and load. If that voltage ramp up/down is not smooth (dropouts) as the flap/vane position changes then the engine may not accelerate smoothly or have what are perceived as misfires and poor performance.
I've added this to my bookmarks. Thanks for the great information everyone!
- Thread starter
- #37
You established that plugs #1 and #2 (from left to right) are the fuel cut off switch. What exactly do plugs #3, #4, and #5 control? These were the ones that I had to solder to the board. Looking at the circuit board, it looks like 3 and 5 are continuous and #4 is isolated. I wasn't quite sure when I was soldering them to the board along with the little thin tabs that were soldered further up those same plugs.
The cruiser runs great now (minus the charging issue) with a smooth idle and smooth acceleration, but the engine light stays on when running. All the other warning lights that are on at idle go out when revved above 1200 rpm( original problem before VAF) . I'm wondering if those plugs being solidly soldered to the board might be the cause of the check engine light staying on now.
In reference to the charging issue, I tested the battery at idle and its at 12.5 volts. I tested the alternator positive terminal while idling and it reads 12.37 volts( may be the issue). Does the alternator only charge when above 1200 rpm or should it be charging at idle(800 rpm) Is this a sign of worn brushes? While doing the inspection, I noticed cracks in the fusible link wire sheath, so will replace that since it is the easiest and cheapest to replace first.
ppc
M Go Blue
A good alternator should output 13.5+ volts at idle (650 RPM). As the alternator begins to fail it takes higher RPMs to get that level of voltage. That all is relevant to what lights, accessories are loading the electrical system and initial battery charge condition.
The other connections to the VAF are documented in the FSM with tables for resistance and voltages on pages EG240 and EG290 and the wiring schematics on foldout #18 in the rear of the FSM.
If you don't have a copy of the FSM it can be downloaded here: For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.
The other connections to the VAF are documented in the FSM with tables for resistance and voltages on pages EG240 and EG290 and the wiring schematics on foldout #18 in the rear of the FSM.
If you don't have a copy of the FSM it can be downloaded here: For Sale - 40, 50, 60, and 80 series FSM for a hell of a price.
