Dilomski

Hello all,

I recently got myself my dream truck - the 4runner and although is is in very good shape overall, it has its issues. It is a 1991 5speed with 3vze engine.Problem is the other day I couldnt start it at all, cranking but not starting, even on a downhill street.Recently it had its rough starting problems, I suspected the cold start injector, because it was disconnected from its plug when I bought the car. Then in the mornings when engine was cold it was a 5-6 tries with cranking to get it started. Plugged in the CSI and then when engine was warm and trying to start it after some 15-30 min it was the same struggle. To this day, when it was just cranking.

What I did so far:
- checked the fuses and relays in the engine block - everything ok.
- checked the COR according to the manual - 2 out of 3 combinations werent getting continuity.
- jumped fp to b+ to check for sound, I heard a single click.Tryed to start the engine this was, no success.
- tryed spraying to start it - still not starting.
- sparkplugs and cables are good.

What I think to do tomorrow:
- check the plug for the fuel pump under the back seat.

Any advice? Mechanics in my town are not familiar with cars like this and looks like I am on my own at the moment. Its fun working on you car, but am a beginner, specially at the electrical stuff.

scope103

Yes, most of any vehicle made in the last 50 years is "electrical." You must have a multimeter to work on one. No excuse not to have one. https://www.harborfreight.com/7-func...ter-63604.html

Jumping B+ to FP does require key-on. With key-on, confirm you have battery voltage (about 12.6v) to ground on B+. If you do, jumpering B+ to FP bypasses the COR and the pump should run. In a quiet garage I can hear it from the diagnostic connector; out on the street, maybe not. If the pump isn't running, you need to work your way to the pump. Before you pull the pump, of course, you'll check for voltage on the connector to the pump.

Dilomski

Thanks scope103, I do have a multimeter, will double check the b+ to fp tomorrow again, after checking the voltage on the battery.After that, the connector to the pump.Hope that gets it closer to finding the problem.

87-4runner

If you tried starter fluid and still got no start... I'd be thinking fire not fuel....

Dilomski

Can you add more detail, I honestly have no clue what you mean with "fire".

scope103

Generally, you squirt in some starting fluid to "test" the fuel supply. If it runs with starting fluid then quits, you don't have fuel. If it won't run with starting fluid, then you may not have ignition ("fire").

So far, you're a little light on detail, and some things are contradictory. Whenever anyone says "all the fuses" are good, I have to chuckle. You don't even KNOW where all the fuses are! But only a handful matter; so tell us which ones you checked. And how you checked. (Multimeter? remove and examine? checked that something was in the socket? And just how did you check a relay?)

If it really is a "fire" problem, a quick way to make progress on that is to put the inductive pickup of your timing light on each plug wire; if the light flashes, you're getting spark. (You may not be getting it at the right TIME, but having any spark narrows your focus a lot.)

Dilomski

Thanks, this makes sence indeed.

I checked the fuses in the engine block - passenger side on my truck - namely radio, wiper, engine, cig, gauge, ign, efi relay, head(lights) relay. Used a multimeter. Fuses I pulled each one, checked by eye to see if the metal connection is broken or not, and then checked with continuity with the specific setting of the multimeter to hear the beep signal that there is continuity. Relays - plugged out, checked with aligator clips attached to the battery ( around 12,25V at the time) and second set of normal probes attached to the multimeter set on ohms.This read 0.000 on both relays. I did not checked the 30A relay or the 80A next to it (dont have a picture of this now, can make tomorrow).

Dilomski

Still nothing, me and a friend checked couple of things on friday, it has spark, but wont start.Fuel pump gets 12 volts when cranking.Jumping Fp to B+ still doesnt do a thing, neither combining it with disconnecting the connector for the air flow meter (which we tested and it is in the range for resistance).Ignition coil is okay, my friend tested it with multimeter.He thinks its the distributor cap, but aint sure.Engine is turning over, not starting, even when spraying starting fluid.

Co_94_PU

iTrader: (-1)

Have you done the spark test mentioned above yet..?

Dilomski

I did checked for spark today, took out cilynder 1 spark plug and tested all the spark plug wires with it. All 6 wires produced spark. Reason I did not check the other 5 spark plugs was that I could find a spark plug tester with a lamp. Sorry about that, but the car is going to be checked on monday and the guy has this tester. Anyway, was about to check inside of the VAFM, but messed up with the removal and took out the connector plug - a bit of beginner mistake.Anyway the whole inside of the VAFM looks too bad anyway, I doubt it was working like it should anyway.

Check out the pics and what should I do? Clean and try to solder the 3 wires, that are disconnected, but where exactly? Junk the whole thing and look for a used one?






these 3 wires were probably cut off when I pulled out the outer part

Co_94_PU

iTrader: (-1)

This is corrosion due to water seeping past the poorly executed silicone job. It can be cleaned up and resoldered..

It doesn't necessarily explain the no start, the fuel pump jumper would of bypassed this. You also shouldn't of heard a click but a hum from the fuel pump, the COR isn't involved if you're using the jump on the diagnostics port.

You tried starting fluid, which it should run on with the vafm not connected.

You verified there is spark, but not the spark quality (voltage).

Have you done a compression check?

Dilomski

The yota is currently at a place where will be looked at. Today saw the compression test, it was okay. The guy wasnt sure whats the problem might be, thinks either fuel pump, crankshaft position sensor or slippage of the time belt.

Getting desparate, two weeks and nothing yet.

Co_94_PU

iTrader: (-1)

If the valve timing is off it should/will show up in the compression test due to the valve opening and closing late or early..

You have spark, this means the distributor is working.

You don't have a crank sensor from what I recall.. It uses a pickup coil in the distributor. Again the ignition is firing..

You could have the spark plugs out of order. Maybe a failing ignitor
​​​​​​

Dilomski

I guess will try to test the ignitor according to FSM, the distributor too. The guy is not really an electritian, so gotta check it myself. Will keep updating the thread, thanks for every opinion, it really helps a lot and once again sorry about my stupidity, I am really new to all this

At least I resoldered the VAFM and will reinstall it in place tomorrow.

Dilomski

Tried to measure resistance on the ignition coil, but my probes were too thick for the power cable connector. Gotta get thinner probes to measure.

Couldnt take off the connector for the distributor, kinda stuck while getting dark outside, will try tomorrow.

Any ideas how to troubleshoot the ignitor?

Dilomski

I was just thinking, I never saw a check engine light coming on the dash at any time before the truck stopped. Neither after that. Never. Now I see it, but its not a icon with an engine and the letters "check", its just the engine icon. I am pretty sure its normal to have it on while the key is in "on" position, but the engine is not running, right? As soon as the engine starts it would go away.

That being said, should I assume there is no problem according to the ECM? Or my truck check engine icon is without the word "check" in it? Checked for codes, nothing comes up (blinking fast forever) If the light hasnt come prior to the total stop, should I assume is the ECM that is faulty, thus controlling the fuel pump not to start?

Dilomski

Well, the dude didnt do a thing to help, almost nothing. Measured the compression on one of the cylinders, 130 psi. That is without a VAFM at all, it wasnt installed at that time. Anyway, I bought a pressure gauge myself and will measure every cylinder and post the info here.

Dilomski

Measured the #1 cylinder , cold engine (not really a choise here), CSI off, igniter connector off, air hose on - around 120-125 psi. Didnt do the other cylinders, was a pita to put the compression gauge inside.
Measured every cylinder for spark with a spark plug test lamp, got a spark in every cylinder.
VAFM working fine after resoldering the connector,opening and closing when cranking. Measured it according the FSM; checked out fine in every category,including E2-VS 557 ohms (200-600 FSM) and E2-VS 118 ohms (20-1200 FSM).
Read in another thread that I should get continuity between E1 and FC when cranking, I did not get continuity.Also checked for battery voltage in FP connector in diagnostics while cranking, but got only 8,7 V. Have no clue if is relevant or "not starting" important.

Not sure how to test the distributor though, this gray connector is suppose to split in two right? Having trouble doing this.

Dilomski

Did a paper sheet test on cylinder #1 and it got a gasoline spray mark on it when I cranked for around 10 sec. So, pretty much that should write off fuel, I guess. Thinking about checking engine coolant sensor, heard that it can cause the ECM to think that the car is too cold or hot and not start the engine if faulty sensor.Really more thinking the problem is either distributor pickup coil or timing belt issue. Unfortunately dont have the tools or knowledge for the job so gotta wait another guy to check it out Those torque wrenches are not cheep.

Dilomski

UPDATE:

Went to a guy, checked all the cylinders compression - guess what?

ZERO compression on the 2,4,6 cylinder.. All three on the drivers side.Plus the distributor was aimed at number 6. Switched it to 1 and the car tried to start, but still nothing. Plus I saw the coolant level was critical low, I saw it a week ago, that means way after the car stopped running. Havent got a temp problem when I drove it, never.

Any ideas on this compression issue, valves maybe?