YotaRick27

what voltage do you need to see at the ECU?
The yellow plug under the bed to the fuel pump, is that where you want me to test the fuel pump voltage or at the jump connector behind the AFM?
What is a FPU again?

wallytoo

iTrader: (1)

how do you figure this? according to my 87 toyota fsm, the idle spec with vacuum connected is 27-31 psi. 31 is precisely within the factory specs for fuel pressure at idle. if the vacuum hose is disconnected from the FPR, the spec at idle is 33-38 psi. now, his statement that pressure is back "between 31-35 psi" does indicate pressure too high at idle, unless it is 31.

Co_94_PU

iTrader: (-1)

Lucy is an 86, someone kindly post up the fuel pressure test page or stats.

88, says 35 low 40 high
87, says 30 low 35 high

​​​​​​(Those are the midpoints of the specs)

..
Rick looking for the voltage check that failed earlier, 9.5~ volts on the primary power wires, pretty sure it was the very first test in the chart (b+, bat and one other that I'm not recalling).

Not sure on the fuelpump wire colors, when you probe them it should be obvious which is ground and which is positive. With the pump running one side will show battery voltage and the other will show ground, without the pumo running one shows ground and the other will show a higher resistance which includes the pump windings and brushes.

wallytoo

iTrader: (1)

ah, the detail lost because it isn't in his sig.

interestingly, the 87 fsm does not show different fuel pressure specs for the 22re vs 22re-t; in fact, the later year 22re-t pressure specs are the same as the 87 specs for both engines.

but, going by the numbers above, i'd guess that the 86 has specs either the same as 87 or lower overall, rather than higher like the 88 and later versions.

YotaRick27

Co_94_PU

iTrader: (-1)

you have near battery voltage at the ECU and nonsignificant voltage drop in the grounds, in spec fuel pressure.

Now why does the vafm unplug make it start needs answering. Is the voltage reference circuit dropping out during crank (probe VC voltage, cold vs nonstart)? Is it the fuel pressure up, what is the fpu vsv state open (low fuel pressure) or closed (high) and does this change in the nonstart condition when the air meter is unplugged?

You can measure efi relay voltage and voltage drop by back probing it (tpin the wire connector), voltage on each side measured to battery ground and voltage drop from the input to the output.

YotaRick27

Co_94_PU

iTrader: (-1)

Number six and eleven voltage tests.

You might as well do one, two, and three again while you are there. Post those results along with voltage readings directly on the battery post as well on the battery cable ends.

I'm not working tomorrow, so might get the urge to drive the 80 miles and go run these tests also, but don't count on it is sub zero here also and it is stored outside..

Worth noting I think there is a typo error, can some one with the printed manuals confirm VC voltage. I was pretty sure that was a five volt reference (should read 4-6 for the VC?) I know we have 86 and 87 FSM owners reading this thread they have posted FSM data..

RAD4Runner

My 1986 Print FSM says VC-E2 : 4-9 volts

Co_94_PU

iTrader: (-1)

Thanks. I was just looking at the diagram of the vafm internal circuit and it is a voltage divider from battery voltage so that higher voltage fits what I would expect

YotaRick27

YotaRick27

It’s stored in my garage and I have a garage heater(diesel). Yes I will retest voltage on 1,2,3,6 and 11 once I get home from work. Lucky me I have a friend out of town for a week I can borrow his car. So your thinking it might be a bad afm?
I'm going to try and do another test of the afm this evening. I have and stop by a friends and borrow his AFM to test the difference. http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml
I will keep you updated. You work weekends too? Might just want to plan a trip to see all the sights like rushmore and falling rock. But in 0 degree weather it's not so fun. You should come out to the classic though when it's warm in July.

wallytoo

iTrader: (1)

rick,

you need to stop with the guessing, and stop jumping all over the place in terms of testing. co_94 isn't "thinking it's the afm", he's trying to help you diagnose the problem systematically and thoroughly so that you can avoid randomly throwing money away by replacing perfectly good parts. the aim isn't to guess what part has failed, but rather to use the tests to eliminate components as the source of the problem by verifying that the component works correctly. some of these tests are about determining whether a problem is in the wiring, and some are about the components. by verifying that the wiring or component is functioning properly, you can eliminate it from suspicion. it takes time and thoroughness to do this correctly; eliminating some of the tests/steps might implicate a failure in a part/wiring that in reality is working correctly.

YotaRick27

Copy, I understand. I am not just getting input from this thread but other research and advice from techs on possible issues to help diagnose the real issue. I'm not throwing money at it. I would not have picked up a new pump if i didn't have multiple red flags leading in that direction. For example: low fuel pressure, low voltage to ECU and no start after heat soak. Was it the fix, no but it was good insurance to know it is now eliminated from being the issue and needed to be replaced after what I found. Trust me I'm with you when it comes to trying everything first to save money.

YotaRick27

Last night I tested the EFI relay by supplying power to hear the "click" then measured the resistance between the other two pins. My meter read: 0.03 then quickly dropped to 0.01 each time I tested both cold and warm. So It is a good relay from what I'm seeing. Right?

Co_94_PU

iTrader: (-1)

No. Not a bad anything, yet, I can't make that call when you don't report the test results or answer questions!

As frustrating the issue is for you, imagine it from my end!
CO says, "Rick does your truck not stay running now?"
Rick says, "my battery voltage is 14 volts now."


So we do this again..
On a cold start what is the fuel pressure?
When it won't start hot what is the fuel pressure?

Co_94_PU

iTrader: (-1)

not a valid test, not for what we need, it only tells you that it does in fact close the switch (we already knew that from the voltage at the ECU).

When you pass current resistance cause things to heat up, when it heats up its resistance to current (ohm value) goes up. More current (amps) more resistance.. More resistance less voltage..

YotaRick27

ok ok I will get your answers today for both fuel pressure and voltage tests...

Co_94_PU

iTrader: (-1)

Here, watch this video.. Hopefully it will make more sense with the visuals.

​​​​​

Co_94_PU

iTrader: (-1)

And one more..

Order one of these.

It seems at some point they changed the switching temp on the original part number, even if that is not the case you don't have this switch you have something else in the thermostat housing.