Cliff459

Hello all-

I am at my wits end here, any good advice would help me somehow return to sanity. I have a 1995 4Runner with the 3.0 3VZ-E in it that absolutely refuses to start up now. The motor was rebuilt about 70,000 miles ago and was running like a watch until recently. It had begun starting very hard, but after cranking over several dozen times it would eventually sputter to life and run rough as heck until it warmed up some. I figured it needed the normal tune-up, and when I had a chance I changed out the spark plugs, wires, distributor cap and rotor. The day after this it was still running as crappy as ever, so I figured that I may have some kind of fuel-related issue, such as a bad cold-start injector. I figured I would have to change that out ASAP. But, when I went out to start it the other day, it cranked over fine, tries to fire but won't catch and start at all. It has spark and fuel pressure to the rail (45 psi), but won't even try to fire any better even when starting fluid is applied. The "check engine" light does not indicate any codes are stored in the ECM, either.

Here's a list of things I've done so far:

Replaced spark plugs (NGK gapped at 0.031 per spec)
Replaced distributor cap and rotor
Replaced spark plug wires
Replaced ignition coil
Replaced "ignitor" for coil
Replaced cold start valve/injector
Checked ignition timing (it's spot on!)

Again, the ignition system is fine, every plug wire makes a brilliant bright blue spark when tested. Starter seems to be cranking well, no drag. The engine seems to fire somewhat, but not enough to take off. The plus seem to have fuel on them when pulled out after extended cranking periods, too.

Seems really strange that I could drive it smoothly home about 36 miles of highway, park it for the night, and the next morning it won't start?

I'm stumped!

Thanks for any good ideas that may give me some new things to test.

TNRabbit

So have you checked the cold start injector yet? Also, there's a cold start switch that can go bad....

Swimmerboy2112

iTrader: (2)

Have you pulled the dipstick and checked the oil? Maybe (hopefully not) you have a blown headgasket.

93toyrunner2

Download the FSM from the link in my signature, and open the manual to the 3VZE engine, MFI System, Cold Start Injector page. Test the injector. Go to the Cold Start Injector Timing Switch page, and test the switch. As TNRabbit said above, the switch is probably the issue.

Cliff459

Thanks for the hints, guys. I already have the FSM and have been using it to check stuff out, honestly can't remember if I checked the cold start injector switch or not. I did replace the cold start injector itself, and that did not improve anything. The new one does seem to be putting out fuel, but maybe not enough.

So, now I will check the switch itself per the FSM procedure and get back to you. From looking at the wiring diagram of it, I think the switch is toggling the ground leg of the circuit to control the injector. Maybe that faked me out because I did try testing the positive side of the circuit at the injector itself and that had juice just fine. The diagram shows that the ignition switch feeds one side of things, too.

Ugh, why did they put the flippin' switch behind the intake cowl, against the firewall? It makes it really difficult to get at...

scope103

If it really won't start with starter fluid (the devil's plaything ...), then it probably is not the cold start injector. All the CSI does is richen the mixture when cold, and you can't get much richer than starting fluid. That said, starting fluid is really easy to mis-use, so back to diagnosis.

Make sure the plug wires are in the right order (if you checked the timing, #1 is probably okay, but you need all 6). Check compression. Be sure that the intake hose is connected to the air cleaner (if you removed it to spray starter fluid, you may have disconnected the air flow sensor, which you need to run the fuel pump).

Fuel, air, spark. It's gotta be one of those three.

89tonkatoy

could have jumped time already had one that done that i threw all kinds of parts and time at it and ended up bein timin

Cliff459

Well, I finally got my answer on this problem. Towed the rig to a local shop with a rep for being truthful and fair with Toyota stuff. Mechanic there did a leakdown test, bad results. Turns out the folks who rebuilt the engine a few years ago didn't get the valvetrain set up properly, too tight on the intake valve clearance. So, I have badly burned intake valves for sure, hence the low compression readings and why the beast won't start!

I passed on the $1,700 quote they gave me for the repair job. I'm just going to pay them for the work they did. Guess I'll get the wife a new rig and put this one on the "back burner" to be tore down and fixed by yours truly when I get some time off of work!

Thanks again for all the good troubleshooting advice given here, that's one reason why this forum is such a great place!

thook

Holy crap. There's several things that can cause hard starting problems. Burned valves seem to be one of the trickier things to track down. Glad you found the problem, atleast. Not that burned valves are to be rejoiced....hehehe....but, glad you found it.

Jed2884

I have a 95 4 runner with an auto transmission. The anyone is bad. However, I have a 91 pickup with a manual transmission. I searched the threads and studied wire diagrams and went along with the conversion. I had to change a few pig tails but got everything hooked up and back together with manual transmission installed. I have swapped dozens of motors and at worts had to have it taken to the dealer to be reprogrammed. I don't think my issue is reprogramming though. I have power everywhere I think I should on the ignition but I'm not getting ˟˟˟˟ to my starting or firing system. All grounds are connected and connected as well. Will someone please give me see ideas as to why I'm not getting power to my starting and firing systems. I did jump the neautral/park safety. I also tried it with the manual trans ECU and nothing

jbtvt

Hard telling without more detailed descriptions of what you cut but if you're not getting spark I guess I'd work back from the plugs to the coil/igniter, check them for power, resistance etc (but mostly power) as described in the FSM and back from there to the plugs at ECU

Also, you may do better with starting your own thread with more detail, diagrams etc than resurrecting someone else's long dead one

Jed2884

I wanted to but I could not figure out how to start my own thread. This website is not the easiest to navigate

jbtvt