stroker393

This is my values for the TPS:

FSM values are:

Resistance
closed / VTA-E2 0.47-6.1K actual 1.12K

0.020 in / IDL-E2 2.3K or less actual- infinity
(closed is .062K and any movement goes to infinity)

throttle valve fully open VTA-E2 3.1 - 12.1K actual-infinity

closed VC-E2 3.9 - 9.0K actual 6.2K

The current values are within limits at the TPS plug and at the ECM.

stroker393

Trying to adjust the TPS on vehicle is giving very erratic ohm values on the IDL-E2 pins from closed to setting feeler gauge and stop screw at .077MM to fully open. I'm going to probably install a new unit this week; if it doesn't cure my "no start" problem maybe it will correct my RPM-speed issue. I did spray starter fluid into valve body and it started right up but you could tell it was only running on that and the throttle body cleaner residue. Am I overlooking something with a fuel issue. The plugs are surely firing to even burn the starter fluid.

ChefYota4x4

iTrader: (5)

You can run that motor without the TPS even plugged in(IIRC, start it, too?)

Sounds more like the ignitor is not relaying "all is fine, fire away". Have you pulled those plugs to verify fuel is soaking them? I would doubt it, since you're starting with fluid... Could be a combination of things between 'really off' timing(dizzy/timing components) and refusal to send injector pulse... Could be compromise in the No.10 and No.20 Pins in the harness.. Many possibilities. Not sure the TPS is your issue. The erratic thing is interesting..... But not sure it would prevent starting. Try starting it with the TPS unplugged(Or look into whether it will start with it unplugged on your rig, etc.... I just can't remember on the starting thing).

Seeing 12V at the #10 #20 pins with the key on/STA does not mean it will continue to fire once the ignitor is supposed to come in and send signal to fire/when to fire. I know you've tested lots, don't give up... I bet the gremlin lies somewhere in the 'semantics' of something you've already tested(but haven't tested while running?)

Did you do a noid light test?

Sorry, can't make time just now to read back, ..... and I'm on MANY threads chiming in. Could you do a good summary, nice and neat like you HAVE done above, with "Start to Finish Details of everything you've noticed/ruled out/conditions you have".....???? Just one more time?

ChefYota4x4

iTrader: (5)

OK, now I see you tested the #10 and 20 pins with key on... BUT, I believe there is a test while turning it over/or just to STA position/ for the #10 and 20 pins. CAN'T promise that... but I seem to remember there being one. If you can get this to verify you're getting continuous voltage to the injectors(and find fuel soaked on the plugs) then you can probably conclude something pretty substantial there. IF NOT, and you DON'T see voltage heading back TO the injectors after the ignitor signals the ECU to fire them... Then I would GUESS that would be just as telling. That's why noids work so well... They can tell if VOLTAGE IS ACTUALLY GETTING to the connector. (SOrry if I missed that, Stroker.... I'm just trying to chime in with help on the run, lol. You can just correct me if you've ruled all that out )

stroker393

The two wires between the igniter and ECM (IGT & IGF) send current to the ECM or send current to the igniter from the ECM? With key on and start I have no voltage on these two pin points (ECM plugs connected) at the ECM or igniter. It really trys to fire up when I have the test light probe in the IGF pin for some reason. I have tried (3) used igniters and get the same results. I want to say "I have found my problem" or have I ? What voltage should I be getting at these two pins?

ChefYota4x4

iTrader: (5)

Hey man, ... I TOTALLY FEEL YA! lol. Unfortunately, I can't say, off hand. I'm kinda mobile, and can't look anything up. I also don't remember cuz I'M OVERWHELMED AND MY BRAIN IS LIKE BOILED CABBAGE RIGHT NOW! hahahaha. I remember having trouble reading that at the ECU for some reason... It was explained to me, but I just can't remember. I was testing and could read a 'FLASH' of voltage when engaging "STA" ..... But when I'd let it turn over, I couldn't seem to get any consistent reading. I know one time I had it on 2V setting on the meter... This, OBVIOUSLY, will not give me an accurate reading..... Well, cuz it's more like 5V pulse to the Injectors..... which is more than 2V, DERRR! lol.

Thing is, mine was starting at the time... I just had this horrible miss(It ended up being the CAM, but that's besides the point for this thread).

And you're SURE you're maintaining adequate fuel pressure to the rail, etc., ...enough to get 'go go' if something wonky wasn't going on in there?

I've seen several different things cause this problem, man... It's so hard to say, and I'm BY NO MEANS a Guru(especially over the computer, lol).... It's usually between;

1. Injectors not getting or having the ability to maintain voltage
2. Ignitor
3. Pick Up Coil
4. REALLY off timing
5. Y-Connections for Injectors in Harness have bad corrosion/possibly even separated.
6. AFM - Fuel Pump relationship wonky
7. C.O.R. starting to fail and or having too much corrosion/getting too hot/ thus, failing to allow the Fuel Pump to kick on and stay on(Usually more of a 'INITIAL' start up at hot engine conditions). Mine did that for a while, then just gave up. Replaced it, never had a hard start since. (leaking windshield caused bad corrosion/and or/or both, SHORT and Corrosion.

Seems like you've said you have HOT WHITE SPARK... So IGN, at least related to spark getting there, is not the problem. More often, it seems the spark will still be delivered, but by misreading something, the ECU just shuts off the injectors.

Is there testing for the 'FUEL CUT' .... I think there is in the FSM, IIRC.

Sorry I can't give you more answers... I wish more would chime in(the Guru's! lol)... Maybe Sunday being part of it is the problem there... Not much traffic on sundays.

ChefYota4x4

iTrader: (5)

Have you really inspected those pins to see if something(a connector pin) has backed out and is possible not making decent enough contact? It's happened. It's actually A LOT more likely than an Ignitor or ECU going bad. lol.

stroker393

quote from a old post:

IGT is your ignition trigger signal, it tells the coil when to fire. the IGF signal is a feedback signal that says that ignition took place.


I'm trying to understand this ignition because I have "spark" at the coil, dist and plugs because the IG2 wire coming from the switch (black-red) goes to the + side of the coil which is split and goes to the igniter. The black-white wire comes out of the igniter to the - side of the coil. Is this for the intial startup with the key at STA. When you release the key that is where the IGT and IGF come into play creating the trigger and feedback signal. I did see in the FSM that to check voltage at the ECM in regard to IGT (IGF is not referenced) is at idling and is a "pulse generation". What voltage readings at IGT and IGF should I be seeing when cranking the engine; still trying to research that.

ChefYota4x4

iTrader: (5)

Ahhh. Yeah, that's right... Like I said,...."boiled cabbage" in my head lately, lol.

I don't know, plain and simple. I do know that people have had wiring issues where the signal ends up not getting BACK to the ECU and then, therefore, the ECU does not allow 'GO-GO' lol. Like, when you hit the breaks, with RPM over 1000 and you're in motion? ECU shuts off the injectors for a moment, as it KNOWS that one should not hold the brake while 'needing' gas, lol. My idle was stuck at 1200rpm one time(think it was my TPS out of adjustment).... and anyway, as I came to a stop light, the rpms would drop, back to 750, quickly..... then, it would surge up and down from 750 to 1200.... I thought it was possessed.... Turns out, it's just a simple, rudimentary signal relationship between the ECU and Brake Light and Injectors... RIGHT? lol

Man,..I just have this FEELING that this is something SO STUPID! lol. Sneaky, but something that you laugh hysterically as you figure it out! lol. I HOPE YOU FIGURE IT OUT SOON, SIR! Tell the boy "I'm WORKING AS FAST AS i can, CAPTAIN! I'm a _ _ _ _ _ _ not an engineer, daamut!" hehe. JK, .... I know what it's like!

stroker393

http://www.autoshop101.com/forms/h39.pdf

I think I have found the info I need / page 6 quotes:

"The IGF signal is used by the ECM to determine if the ignition system is working. Based on IGF, the ECM will keep power supplied to the fuel pump and injectors on most ignition systems. Without IGF, the vehicle will start momentarily, then stall."

Sounds like what I've got going on. IGF is signal from igniter to ECM and IGT is signal from ECM back to igniter. I'm going to run more tests but yesterday I think IGF maybe flashed .02V on the multimeter but I was looking for 12V so I ignored it.

stroker393

I am close to giving up on this truck. I have never had a vehicle that I couldn't get back running but this one is pocessed. I have replaced from a running truck the:

ECU
igniter/coil
VAFM
CO relay

and have installed new:

EFI main relay
fuel pump
ignition switch

and I get the same reaction every time I try to start. The cold start injector sprays and it runs for about 2 seconds and then nothing.
I checked fuel pressure and it is OK (45-55 psi) and it will run on ether (starting fluid).
I have checked and cleaned all ground connections and all fuses are OK.

This truck was running great one minute and then it does not fire up again. I have run so many tests on this thing and have read post after post.

ChefYota4x4

iTrader: (5)

Wish I knew someone in NC that could stop by and take a look, man I know you're probably losin it, been there/done that/seen that movie! haha.

Pretty sure I was told this rig does NOT have in injector solenoid/resistor.... But it's seeming pretty clear(possibly) that SOMETHING is telling the injectors not to fire. Think you said the dizzy pick up coil was spec'ing out fine... And along with the things you're replacing/swapping in from donor rigs... REALLY seems like it would have to be a break in some wiring to/from something. Maybe it's just gonna have to take a Guru getting his hands on it, if even for a second set of eyes(Cuz I know you've tested everything 3 times). That's how I felt with my horrible miss... Ended up being multiple mechanical things, including a tore up CAM and too many loose valves. And yet, I STILL have that lil miss that no one yet can figure out. Crazy!

I know you said you tested the BK pins in the ECU.... I'm just curious if there is something in that safety feature that can cause injector shut down(like a short, etc.)... Clutch start neutral cancel thingymadoer? :>/ ---Feels like I've read so many posts on "tries to start but then dies/runs on ether"..... But unfortunately, most of those guys give up or never post back! I sure wish I had a solid idea for ya man! <<<< I agree!

stroker393

My truck is fixed and I found the problem by pure luck. Picked up a NOID light and without pulling the intake to check 1-3-5 cylinders I started at #2 and noid light didn't flash when cranking. With #2 wiring plug not installed I put noid light on #6 and the truck fired right up with #6 flashing the light. I removed noid light from #6 and placed on #2 and it went to flashing. I pulled the noid light out and installed wiring plug back on #2 and the engine smoothed out some (running on 5 injectors verus 4). Injector #6 is bad and grounding the entire circuit out to #10 and #20 pins.
:b ounce::bou nce:

ChefYota4x4

iTrader: (5)

WOW, holy crapoli! That's great news, man! i thought you'd been through ECU/Injector and otherwise related testing.... no? What a WELCOME fluke, eh?

stroker393

I did run injector tests but only in the "on" position. 2-4-6 all had current on both wires to the injectors and the #10 and #20 pins at ECU had 12V. It never accured to me that the "start" position would give no voltage with all injectors plugged up but pulling one wiring plug off (#6) would have 12V in the "start" position at #10 and #20. My next step with the noid light test was to see if the injectors were getting the pulse signal to fire them and when #2 didn't flash I was going to swap distributors because the NE signal wasn't getting to the ECU. The NE ohmed out on the low side at .169 when the FSM gives a range of .190-.290. If I can help anyone in the future with the same problem with this thread I started is that if you don't get an error code from doing the tests then don't start swapping parts because it isn't going to help. I just got lucky when I pulled #6 when #2 was still unplugged and did what I did. When it fired up it took a second to register in my brain that this SOB is running!

ChefYota4x4

iTrader: (5)

WOW! Just fantastic happenstance, man! Very happy for ya