3VZE won't fire after overhaul
#1
3VZE won't fire after overhaul
My son and I pulled the motor on his 95 pickup (3vze, 4wd) to do head gaskets, seals, clutch replacement, and some other work. We've learned tons from this site and are grateful for the knowledge that we've picked up so far.
We are now stuck and I haven't come up with a solution through searching, although my search-fu is admittedly weak.
The motor turns over, but won't fire. My first thought is that I got the crank at TDC on the exhaust stroke, so I pulled the distributor, rotated the crank, and reinstalled the distributor. No joy.
I am getting sparks at the plug, and I have fuel pressure at the cold start injector. Where should I look next?
We are now stuck and I haven't come up with a solution through searching, although my search-fu is admittedly weak.
The motor turns over, but won't fire. My first thought is that I got the crank at TDC on the exhaust stroke, so I pulled the distributor, rotated the crank, and reinstalled the distributor. No joy.
I am getting sparks at the plug, and I have fuel pressure at the cold start injector. Where should I look next?
#2
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I'd check compression. It's easy to do, and no-compression would give no-fire.
Use your timing light to eyeball timing while cranking. It won't pick up the 180° out you've already thought of, but if you're off by one tooth (about 28°) it might not fire.
You DO have the induction piping hooked up, don't you? If air isn't flowing through the VAF the injectors won't open.
Use your timing light to eyeball timing while cranking. It won't pick up the 180° out you've already thought of, but if you're off by one tooth (about 28°) it might not fire.
You DO have the induction piping hooked up, don't you? If air isn't flowing through the VAF the injectors won't open.
#3
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My son and I pulled the motor on his 95 pickup (3vze, 4wd) to do head gaskets, seals, clutch replacement, and some other work. We've learned tons from this site and are grateful for the knowledge that we've picked up so far.
We are now stuck and I haven't come up with a solution through searching, although my search-fu is admittedly weak.
The motor turns over, but won't fire. My first thought is that I got the crank at TDC on the exhaust stroke, so I pulled the distributor, rotated the crank, and reinstalled the distributor. No joy.
I am getting sparks at the plug, and I have fuel pressure at the cold start injector. Where should I look next?
We are now stuck and I haven't come up with a solution through searching, although my search-fu is admittedly weak.
The motor turns over, but won't fire. My first thought is that I got the crank at TDC on the exhaust stroke, so I pulled the distributor, rotated the crank, and reinstalled the distributor. No joy.
I am getting sparks at the plug, and I have fuel pressure at the cold start injector. Where should I look next?
I'd check compression. It's easy to do, and no-compression would give no-fire.
Use your timing light to eyeball timing while cranking. It won't pick up the 180° out you've already thought of, but if you're off by one tooth (about 28°) it might not fire.
You DO have the induction piping hooked up, don't you? If air isn't flowing through the VAF the injectors won't open.
Use your timing light to eyeball timing while cranking. It won't pick up the 180° out you've already thought of, but if you're off by one tooth (about 28°) it might not fire.
You DO have the induction piping hooked up, don't you? If air isn't flowing through the VAF the injectors won't open.
#4
#5
Compression was equal in all cylinders at 120 psi, but I have doubts about the accuracy of the el-cheapo gauge (which was borrowed). They are, at least, equal.
I'm definitely getting fuel in all cylinders, too.
I'm running out of daylight and warm(ish) weather and the battery is getting sluggish too. I'll have to take this up again Thursday when I have some more time.
Thanks for the ideas so far.
I'm definitely getting fuel in all cylinders, too.
I'm running out of daylight and warm(ish) weather and the battery is getting sluggish too. I'll have to take this up again Thursday when I have some more time.
Thanks for the ideas so far.
#6
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Voltage to coil?
Coil wire in place and tight?
Cap and rotor properly seated?
Plug wires going to proper plug?
Timing set properly?
Pull a plug or use an old plug and ground out the threads on a good chassis ground while hooked up to a plug wire and have someone turn the engine over. Hold the rubber boot only. Do you see or hear a good spark when the engine is cranked over?
If you see a good blue and not yellow spark, either the timing is way off ( I have seen in other engines the distributor so far out of time the flash shows no marks what so ever) or for some reason your not getting any gas into the cylinders
Even if the wires were mixed up you would get a back fire or a cylinder firing every now and then if the distributor was sending out a spark voltage.
Check for any blown fuses and make sure the distributor is sending out a spark. Even poor compression will make some noise and a rough idle.
Look for loose or missing plugs that were left off during the overhaul.
Lets hope all the timing belt(s) and cams were installed/timed properly.
Coil wire in place and tight?
Cap and rotor properly seated?
Plug wires going to proper plug?
Timing set properly?
Pull a plug or use an old plug and ground out the threads on a good chassis ground while hooked up to a plug wire and have someone turn the engine over. Hold the rubber boot only. Do you see or hear a good spark when the engine is cranked over?
If you see a good blue and not yellow spark, either the timing is way off ( I have seen in other engines the distributor so far out of time the flash shows no marks what so ever) or for some reason your not getting any gas into the cylinders
Even if the wires were mixed up you would get a back fire or a cylinder firing every now and then if the distributor was sending out a spark voltage.
Check for any blown fuses and make sure the distributor is sending out a spark. Even poor compression will make some noise and a rough idle.
Look for loose or missing plugs that were left off during the overhaul.
Lets hope all the timing belt(s) and cams were installed/timed properly.
Last edited by Rapidrob; 01-05-2016 at 02:26 PM.
#7
Progress!
Thanks for the ideas so far. We now have a running motor. Aside from a belt squeal, it's got a smooth idle.
BUT
The timing was/is definitely off. I've got the distributor cranked all the way over at the end of its adjustment range and I'm about 30 degrees BTDC. From what's been said here, that would be a timing belt off by a tooth. I am also making the assumption that my jumper wire in the diagnostic plug was making good contact. I was improvising, so that's something I'll have to check when I can work on it again.
So how do I tell which cam is off and in which direction? Is there something else I need to check as well?
And thanks for the help everyone. You've helped get us to where we can at least limp the truck to a heated shop to continue our work in relative comfort. It's been a bit nippy out.
Thanks for the ideas so far. We now have a running motor. Aside from a belt squeal, it's got a smooth idle.
BUT
The timing was/is definitely off. I've got the distributor cranked all the way over at the end of its adjustment range and I'm about 30 degrees BTDC. From what's been said here, that would be a timing belt off by a tooth. I am also making the assumption that my jumper wire in the diagnostic plug was making good contact. I was improvising, so that's something I'll have to check when I can work on it again.
So how do I tell which cam is off and in which direction? Is there something else I need to check as well?
And thanks for the help everyone. You've helped get us to where we can at least limp the truck to a heated shop to continue our work in relative comfort. It's been a bit nippy out.
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#8
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More likely the distributor is off one tooth (as stated above, that will give ~28°).
If you're really worried about the cams, just remove the upper timing belt cover and look. At TDC, the marks on the cams point up (or if they're pointing down, just spin the crank one turn).
When you correctly insert the jumper TE1-E1, the CEL flashes steadily about 2x/second. (unless you have a stored code, in which case you want to read that).
If you're really worried about the cams, just remove the upper timing belt cover and look. At TDC, the marks on the cams point up (or if they're pointing down, just spin the crank one turn).
When you correctly insert the jumper TE1-E1, the CEL flashes steadily about 2x/second. (unless you have a stored code, in which case you want to read that).
#9
I misunderstood on the one tooth off. Got the distributor turned and we have a running engine!
Got the belt squeal taken care of too.
Unfortunately I found a coolant leak under the throttle body. We didn't replace the front hose and it's going to need it after all. There's another leak underneath and further back. I'm guessing I have a problem at that connection too. It could be worse.
Thanks all for the help. We were getting a bit frustrated and needed a bit of clear-headed thinking to get this sorted out.
Got the belt squeal taken care of too.
Unfortunately I found a coolant leak under the throttle body. We didn't replace the front hose and it's going to need it after all. There's another leak underneath and further back. I'm guessing I have a problem at that connection too. It could be worse.
Thanks all for the help. We were getting a bit frustrated and needed a bit of clear-headed thinking to get this sorted out.
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