1989 4Runner 3.0 3VZ-E 235,000 miles
Passed down from my brother in CO to my son in TX
A year before it was passed down, my brother had the engine rebuilt, so to speak. And had a brake job done. Tons of maintenance; have receipts for almost everything.

I have searched these forums for weeks and used many solutions offered here to fix problems, but now I am stumped. I need to get this vehicle running for my college kid.

Recent background on 4Runner:
After Christmas break, the day he was heading back to college, the vehicle would turn over, but not fire. I found a loner car and shipped him back to college. The Texas weather was mild during this break; not getting very cold.
But I did have him go out most days during the break and start the 4Runner to keep it 'primed' - as it has had a couple of past issues with sitting and not starting. I jacked with it a few days and I'm certain I killed the starter.

So I replaced:
Starter / Starter Solenoid
Battery
Battery Cables and Terminal Connections
Spark Plugs
Changed the Air Filter
Coil Wire (because I broke it)
Rotor / Cap
Fuel Filter
Main Relay (round relay below the EFI fuse on driver side kick panel)
The spark plug wires are about 1.5 years old and look good.

Tested the engine and it turned over and started and ran for 1 second. Checked the forums further and bought a multi-meter and broke out the FSM and more youtube videos.
Tested the VAF (or MAF as some refer to it) and didn't get the expected readings. Same with the TPS.
Also, never heard the fuel pump running. And I took the coil pack to another guys house, where his 88 4Runner mostly sits. He let me swap coil packs and it started his 88 without issue. Relief.

So I replaced:
VAF (technically, I broke this by NOT slowing down to read the exact words in a prior post where a guy said he broke his by removing the screws instead of the clip). Tried to solder back together, but readings were still no good.
(VAF replaced 2x, because the first replacement from auto parts store did not work)
TPS
Fuel Pump
Inspected all vacuum lines - no issues
Inspected Air Intake Hose - no issues
Inspected the fuel in tank - no issues
Cold Start Injector still seemed to work

In addition, I removed the throttle body and cleaned it. Cleaned the stopped up port to the Intake Air Temperature sensor and confirmed the plunger was working fine. Replaced those hoses.
Cranked it, and it ran like it was brand new. It ran perfect during a 40 mile test drive. It ran perfect the next day for 2 hours of a 3 hour trip back to the university. And then it stopped running. Stranded on the side of the highway, pulled off fuel pump hatch and confirmed the FP was not running. Towed it back home and tested the fuel pump several times - it works using the test methods I found here. Removed the COR and it tested good. Checked all other fuses - they are good. I did not test the COR while plugged in because I didn't understand how to on some other forum - I guess it wasn't dumbed-down enough for me.

Note: I didn't replace all these parts at one time. I only replaced a part after I diagnosed it as bad, or I broke it. I did spend a lot of money those 3 weeks that I worked on it, I know.
Also, I checked the codes many times and eliminated codes with replaced parts throughout these 3 weeks.

Where it stands now is that it starts and runs for 1 second. I have cleared the codes many times, but the current codes I get are:

14 Ignition Reference Signal - I read about some of this on the forums, but I must have missed the solution to this code.
51 Switch signal -A/C switch ON during diagnosis - THIS WAS OFF
51 Switch signal -closed throttle position (CTP) switch OFF during diagnosis - I NEVER TOUCHED THE GAS PEDAL
51 Switch signal -park/neutral position (PNP) switch not in P or N during diagnosis - IT WAS IN PARK

Thanks for any help. There are not really any good Toyota mechanics left in this county. The mechanics I have talked to find Toyota's quirky to repair and stay away from them.
Sorry if the post is too long, but I wanted to give all the relevant information I could.

 

Check voltage at pump. I had a broken wire that didn't supply sufficient volts to fuel pump. Felt like an idiot. I tested if I had power not how much. Replaced several parts before I discovered the $0.50 fix. You can hot wire pump to battery to test if not running. But checking exact voltage is gold standard.

 

Assuming you have good grounds (clean bright metal to clean bright metal, firm mounted). Your primary issue is the Igf signal, verify continuity and low resistance between the ignitor and ECU, and plugs firmly seated. If you have a good connection between them you have either a bad ignitor, or a damaged ECU.

The 51 is similar, bad grounds, loose plugs, broken wires, a damaged TPS or ECU.

Edit/ps: I forgot a few issues, primarily the fuel pump. Use the fuel pump test jumper at the diagnostic port.


Common denominator here is the grounds specifically E1.

 

So I jumped the Fp in the diagnostic port, turned on key, and checked voltage at the Fp. It was 10.76.
While the jumper was in place, I also tested the voltage of the Fp terminal at of the COR. It was 11.
Checked the EFI Relay (since it felt hot) and checked for good grounds and loose plugs and loose spark plug wires. Those items checked out fine.

How do I verify continuity and low resistance between the ignitor and ECU?
Keep in mind, I removed my Coil / Igniter Pack and placed it on an 88 4Runner, and it started.

 

that last question hints you didn't test the resistance between the E1 and battery negative terminal.. cause it's the same test.

​​​​​Set your meter to 2k/200 ohm, place one lead on the ECU connector Igf pin, take the other lead into the engine bay and probe the ignitor plug(I don't remember what color or pin, it'll be in there somewhere.)

Same for the ground, locate E1 at the ECU, probe the battery terminal.

Your looking for a reading close to zero.

 

PS, you might have misunderstood "plugs" as spark plugs I mean the wiring connections/plugs

 

Co_94_PU,

How do I determine which pins on the ECU are for what; i.e. the IGF pin and the E1 pin?
Or maybe I am misunderstanding. Just spent the last several days working on the other vehicles in the household, so my mind is probably mush.
Also, if I understand correctly, I will need some long leads to go from the ECU to the battery terminal, right?

Thanks in advance for the clarification.

 

Go to this link, page EG2-184
http://htftp.offroadsz.com/marinhake...86troubles.pdf

That shows the ECU pinouts. IGF is a black wire with yellow stripe. E1 is a brown wire.

 

Now wait a minute. Are those voltages where they need to be? That is rhetorical. 11 volts is not enough, especially when you are dealing with an electronically controlled fuel injection system. Troubleshoot your battery/charging system. Put some jumper cables on it and see what it does. Check those voltages again with the cables on it. A bad battery can give you every one of the symptoms you have described. Forgive me if I missed where you changed the battery but you have a low voltage problem regardless.

 

COR or circuit opening relay. The air flow meter kicks the relay on when it senses air moving and its basically the fuel pump relay. It also is triggered by the starter to give fuel when cranking. Its tucked up behind glove box on passenger side. In 1st gen runners they get water on them and fail. Seen it a few times. You should be able to take a piece of wire and bridge b+ and Fp at the diagnostic connector under the hood and it should power the fuel pump. Try running it with the wire jumped like that.

 

He has a reoccurring IGF code....

 

You should be able to take a piece of wire and bridge b+ and Fp at the diagnostic connector under the hood and it should power the fuel pump. Try running it with the wire jumped like that.

I did this the other day. The result was the fuel pump running continually, and it sounded like fuel was spraying somewhere in the engine, maybe the cold start injector. The engine would not start. It turned over just fine, but I had the feeling it was being flooded.

I also did this, but I never got a reading:

Go to this link, page EG2-184
http://htftp.offroadsz.com/marinhake...86troubles.pdf
That shows the ECU pinouts. IGF is a black wire with yellow stripe. E1 is a brown wire.

My IGF wire was blue. The wire in the slot to the left of the IGF slot was black with a yellow stripe, but I tested both anyway and got a blank screen. Not sure if I am doing something wrong.

 

The only way to get a "blank screen" (with a digital multimeter) is to turn the multimeter off. You can get 0.000 or 12.65 or 0L ("overload," for when you've exceeded range on ohms), but not "blank."

I really don't think your code 14 has anything to do with run-for-one-second. Yes, the ECU shuts off the injectors after missing IGF for 6 ignitions, but I would expect it to start and run for more than one second. Instead, I think your VAF-COR circuit is not working correctly, so let's check that.

I assume you can hear the fuel pump running with the jumper. The "spraying" sound could just be a little fuel vapor going through the FPR, so get your stethoscope (rubber hose, paper towel tube, wooden dowel, http://www.harborfreight.com/mechani...ope-69913.html) and localize the sound. The FPR isn't near the CSI, so these won't be confused. You might want to do an easy test for fuel flow: disconnect the fuel return from the FPR, replace with 6mm (1/4") clear vinyl to a suitable container. Look for about 1/2 liter/min with the pump jumpered. (This is all low-pressure tubing, so you can hook it up with just the hose clamps provided. If you disconnect on the high-pressure side, you MUST replace the crush washers.)

IF you're flooding out the engine (with a stuck-open CSI or other injector), you should be able to pull the plugs and find one or all of them wet with fuel (you have to work quickly; the fuel can evaporate if you take an hour getting the plugs out).

 

I dont think he means a full "one mississippi" count after releasing the key, but that is a bit beside the point..

you must have an igf signal at the ecu, no if and or but..

if it misses the igf signal for one full firing sequence(4-6 pulses) it shuts off the injectors. 600rpm ÷ 60 seconds = 10rev. On a four cylinder four stroke engine that means 10 pulses per second (too lazy todo the math for a six but its more than ten). Crank, fires, runs for a moment, dies.

By no means am I ruling out issues with the startup system but until it has a Igf signal its pointless to try and diagnose the cor because its just going to die once you let off the starter regardless.

anyways..
if the cold start injector is leaking you can see it with a flashlight with the throttle plate opened (fuel pump running off a jumper pre startup). You can rule out if its leaking due to wiring issues by unpluging the signal/driver.

 

you meant to say about a half a liter in thirty seconds?

The pump should be supplying more than a liter a minute (189×6=1134cc/minute at about 88-89% duty cycle its 1000cc/min)

 

I'm going to disagree with the ORDER of your diagnosis. Determining whether the fuel pump is running, and even determining if you have adequate fuel flow, just isn't that hard (as described above). On the other hand, detecting the IGF signal is (IMO) quite difficult. https://www.yotatech.com/forums/f116...gniter-287857/ Just checking for continuity on the IGF line (Black-Yellow, by the way) doesn't really tell you much at all.

So you need fuel flow, and at some point, IGF. But check the easier stuff first.

Well, on my fine-running truck, I get 1/2 liter/min on the fuel return (engine off, pump on). I don't know where you get the 88% duty cycle; 1000cc/min at even 30 m/h would be < 2 mpg. I don't think I've ever seen a number lower than 9 on my mpg gauge.

But I can make mistakes; when you've got nothing better to do, why don't you try it out on your truck?

 

I tried jumping off the 4Runner with another vehicle with a new battery. Same results; cranks, but fires, run for a second and dies.
I jumped the FP and the spraying noise is not coming from the Cold Start Injector, but rather the other side of the engine below the throttle body. Not sure if that helps.
I bought a new COR and it did not fix the problem. I will be taking that back.

If this is a fuel supply issue, wouldn't the fuel pump jumper that makes the fuel pump run continually have enable the vehicle to start?

I think someone in an earlier post suggested taking something off the fuel rail to test for fuel, right???

 

Yep..

 

I got about 1/2 liter in about a minute. Does this mean the fuel pressure regulator is good?
What if I just replaced the FPR; is it difficult to replace the FPR?
It seems like a simple job, but looks can be deceiving with this Toyota.

 

Correction on last post. That was posted by accident.
When I conducted the test with Fuel Pump jumper and fuel line in a container, it filled up 1/2 liter in about 5 or 6 seconds. Seems like it is pouring out way too fast.
Any chance I did something wrong?