95blackToy

There was somewhere I read on here a list of 5 signals the ECM has to get to fire the injectors. But after much searching i cant seem to find it again. Can someone help me out? the only ones i remember were AFM, and Temperature.

The help would be appreciated!

skypilot

iTrader: (1)

I just got mine going.

Ground under the ignitor, left hand side. No ground no pulse. Mine was 2k ohms until I cleaned and scrubbed and used electrical contact cleaner.
Ground on intake manifold & engine block; zero ohms.

+12 B/R to ignitor & coil.

Pin 1, 11, & 12 hot +12 switched.

Hot wire (3 sec tops, CSI) with fuel pressure.

Should go if key is held in start position to run the pump.

Hadmatt54

Are you sure you are talking about injector pulse?
With the key on there is battery voltage in the injector circuit. If your grounds are good and there are no wiring problems the ECU will complete the injector circuit to ground making the injectors pulse as soon as you start cranking the engine.
If you are talking about proper engine management, the the ECU uses data from the temperature sensor (current temperature), crank position sensor (Engine Speed), Throttle Position Sensor, Knock Sensor, Air fuel (AFM or MAF) and the O2 sensor to adjust the ignition timing and the amount of fuel (injector pulse and width)that is allowed to spray into the combustion chamber.

95blackToy

thanks guys, my grounds are good, and it wont run unless i hold the key, witch means the CSI is pumping. I worked on this thing for about a month and could figure it out. So i took it to Toyota and they had it for about two and had 3 techs give up and say they couldnt fix it. Its weird though because sometimes it will start working and run from anywhere between a couple days to a few months but the problem always comes back.

That leads me to believe its a short somewhere of something, I don't think a sensor or ECU would be so intermittent. But Its back in the shop and i want to gather some info like that and go question them about checking it. Such as temperature sensor (current temperature), crank position sensor (Engine Speed), Throttle Position Sensor, Knock Sensor, Air fuel (AFM or MAF) and the O2 sensor.

Thanks to you both, Hadmatt you answered my question exactly!

skypilot

iTrader: (1)

Are you sure the fuel pump is running?
Mine needed a jumper from the AFM to the IH1 connector to hold the fuel pump relay( engine run). until then there was no fuel pressure to keep mine running unless you are holding the key down.

holding the key down does not hold the CSI on, the ECU does that. My ESI is hot wired to a manual P/B.

Mine has no OX, or SPD yet along with some other missing nice to have signals but still runs.

Toyota had a recall for cracked ECU's on the '07 corollas and some other models. not likely but still possible if its that intermittant.

sebastianholmes

oooh oooh, i know this one. you need...


INJECTORS!


*chuckles quietly*

93toyrunner2

X2 - Have you bench tested the injectors as seen in the FSM?

Hadmatt54

This is an intermittent problem, so have you or any of the techs that have worked on the truck tried another EFI main relay? The coil in the relay might be weak and might not always close the contacts.
If it's not that, then are you sure the problem is fuel and not spark?
Your engine is ESA (Electronic Spark Advance) ignition. There are two pickups in the distributor ar signal generator, a 24 tooth Ne pickup and a 4 tooth G pickup. This system needs these two signals to start. The signals are recieved by the ECU conditioned and sent to the microprocessor. The microprocessor drives the trigger circuit (IGT), which causes the igniter to open the primary circuit firing the spark plugs. If the ECU does not receive either the Ne or G signals it will not fire the IGT circuit.
Also there is an IGF circuit from the igniter to the ECU it tells the ECU that a sucessful spark event has occured. In the event of an ignition fault after 8-11 IGT signals sent out by the ECU with no return IGF signals the ECU will go into fail safe mode and shut down the injectors to protect the catylist in your converter.
So any wiring problems in this circuit or a faulty igniter will not allow the vehicle to start.
Hope this helps!

95blackToy

I do not need injectors i had them rebuilt 20,000 miles ago when i did the head gasket. and yes the fuel pump is fine, i know its electrical. I have a whole thread on the problem if you look up "once again my 3.0 wont start"

I have plenty of spark, even replaced the distributor. Believe me when my DD is down for 3 months I checked everything within my ability and have had 2 techs give up. And its intermittent, I don't think an ECM would be this intermittent.

I get spark just fine, and never had a problem with it. As long as the key is in the start position doesnt the CSI fire?

I dont want to start a new thread for this problem so pleas go read though my other one. its long but will be better than me explaining everything ive done and replaced and everthing the techs have said. I talked to them today and they said its electrical (thats old news) and that they were trying to track it down. But it truly shouldn't be that hard. I would do it but dont have the equipment and im not the best with electrical.

davesluggo

I am glad to see we are not the only ones that are still dealing with same problem. New injectors, new circuit relay, new fuel pump, new fuel pump regulator, new alternator, new spark plugs, new set of wires to distributor. We stopped working on it for a while, but now it is making me crazy sharing a car with my daughter... so back at it... the thing that kills me is that it wants to run. I am going to try the sensors in the back of the motor next. I am sure we checked the grounds before, but is there an easy way to check them with the truck not running? Mine is a 92, would they be all in the same places? Also, unplugged the O2 sensor today and it still does the exact same thing with it plugged or unplugged? HELP!!!!

95blackToy

Well the techs decided on replacing the whole engine wiring harness. I would have normally done this myself but they are giving me a 12 month, unlimited mile warranty that i cant turn down. All they said was that there is "problems with the connections". What i get from that is that they couldn't find the exact problem so they decided on that. Everything had been checked, every sensor, every relay, every accessible wire. So thats really all thats left. And it will be ready by Thursday. That in itself makes it worth paying, i wont have to deal with it anymore and the problem will finally after months and months be resolved.

Dave replacing the harness is all i can suggest besides checking EVERYTHING! Because everything on mine was checked and was fine and still had no start. But it will be back in action this coming thursday.

skypilot

iTrader: (1)

I wish them the best, and for you to get a speedy repair.

Somehow; I do not place much faith in this.

Maybe because I too have tossed parts at something and accomplished nothing but wasted time and materials. And in the process got the customer upset.

Yours sounds so much like mine. I bet if you hot wired the CSI it would start. That tells you its the ECU,a temp sensor in the back of the engine, or a VSV on the side.

It can be very frustrating, I beat myself silly for 18 months until I figured mine out. Where you are, I've been.

95blackToy

is the vsv on the back of the motor? If it is i put a new one on due too breaking it while doing the head gaskets. Is it the little thing that has 2 vacuum lines going to it?

Well it runs when the cold start injector is hot wired only because it keeps pumping fuel. But since i have spark and compression, i am somehow loosing fuel. And the cause is the injectors not firing. And both of the temp sensors are new back there so it cant be that. Ive tried 2 separate ECUs

And since its intermittent it seems like it has to be electrical. All im worried about is that i got my hopes up and if it doesn't fix it im out the money and its still not fixed.

skypilot

iTrader: (1)

The vsv is on the side with a couple of vacuum lines. The temp sensors are on the back of the engine.

The injectors fire based on a ground connection inside the ECU. So on both sides of the injectors you should see +12 to ground. Yes; this was a big part of my problem, grounds. The ECU case needs to be grounded so it can "fire" the injectors. It was strange to me but the injectors are operated by switching grounds.

I have been told that the intake manifold ground to the firewall is critical, if its not grounded it will not run. It has a clip connector for easy separation to service the injectors. Obviously the block is grounded. The ground to the fender well under the ignitor / coil needs to be zero ohms, nice clean, and secure. this also will stop the injector pulse.

Do you have a set of NOIDS?

There are two ground lines for the injector pulse on the ECU. Pin #10 & #20 to ground E01. Both should be 9 - 14v The ECU fires in banks of three apparently.

Do you have +12 to batt, +b & +b1 on the ecu and is E01 grounded?

jeetS

The ECM does not control the CSI.

The CSI is grounded by the cold start switch and only gets power while the key is in the "on" position

JamesD

The distributor is basically what fires the injectors. The ignitor has to get a signal from the distributor in order to do anything else.

James

95blackToy

all my parts and grounds are good, i checked/cleaned all grounds originally. Ive replaced distributor, ignitor, AFM, and computer with known good used parts. Maybe a few others i cant think of at the moment. Replaced the two temp sensors in the back with new parts. Checked all my relays, checked for vacuum leaks. diagnosed according to what the FSM says. And couldn't find it. Everything that is checkable has been checked by either me or the tech. (my tech has been working on toyotas for 30+ years, hes like 65) I was told that there was no continuity in parts of the harness, so thats the next thing I think. Only problem is that the part is on back order from Japan and wont be here for two weeks.

Im thinking the wires are just old and broke or maybe heat melted them. Is it normal to feel extra heat in my leg area while driving? i can have the AC on and every part of me is cool accept for my legs, and i can feel the heat radiating from the firewall/floorboard. I know this is caused from the crossover pipe, but is that a normal amount of heat?

95blackToy

But i am gonna talk to the tech tomorrow and see if he checked the VSVs

skypilot

iTrader: (1)

The 3slo runs hot, so yes you are going to feel some extra heat. If it were from wires it would be a smoldering wreck.

It could very well be dry rotted from heat. I'm surprised they found a new one for you. Normally after 10yrs they go NS1.

Having dead wires? I've done a lot of old cars and the wiring is usally pretty good.

I really hope this does it for you.

95blackToy

Yeah when i did the HGs Alot of the connectors were brittle and cracked but not wires. Im hoping so to. Im gonna talk to him about VSVs though asap.

And yeah i was kinda surprised to, but he told me two weeks max so lets hope he's right.

I know it runs warm and all and the crossover dumping into the drivers side is hot, but wasnt sure if it was so hot that my carpet should be warm.

Thanks skypilot and so you dont think any of them could have melted insulation? All i know is that apparently there is no continuity in parts of the harness.