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This will be my third and final attempt to post this.  I just replaced the engine in my 90 Warrior V-6 AT with a long block from Champion engines. I finally got it running after multiple setbacks, fuel, coolant and AT fluid leaks. And it only runs on 5 cyls. I can't determine which one the miss is in pulling the plug wires individually at the cap while running, #4 does not change the miss or idle speed, but neither does #5 wire either.   The compression is good enough, 150 lbs in all but # 4 which is 140. I took it to my local mechanic and he could not get the timing right, so he suspected that the timing was off a tooth on one of the cam sprockets (most likely drivers side)  I pulled the upper cover again to check and the marks were all perfect still.  I took the valve cover off on drivers side to check valve clearances and they were all within limits (some too loose, none exceptionally tight.)  During the rebuild I replaced the distributor with an aftermarket, the injectors with 4 hole aftermarket, plugs and wires and of course timing belt and all the components.  The engine starts fine and idles smoothly except the consistent miss, but has no power at all, could not climb any grade of a hill and only revs to 2500 in gear.  I don't know how to determine if the injectors are all functioning, can't imagine getting a stethoscope in there to hear them. I wondered if the replacement distributor could be the culprit also. I ascertained that the timing mark on the balancer when at 0 , the #1 piston is at TDC, so the shaft key must be in place. I am flummoxed and would appreciate any suggestions / ideas from all you seasoned wrenchers.    Thanks in advance   Desperate Dan

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I am NOT enough of a gearhead to have much to offer, but 3 small ideas pop to mind.   These might be pretty useless & others will have better input.

- Determining injector function - there are cheap stethoscopes which have a solid metal rod as the "pickup", I see them in the big bins of cheap discount tools sometimes at a Napa, more frequently at an Ace hardware store.   Put that rod directly against each injector (hopefully you can access them), and listen carefully - should be able to learn the "normal" clicking sound of a working injector vs anything else, especially no discernible  sound would be suspicious.  Expect challenges in learning which noise is from the injector vs other noises coming thru the injector from the engine.  Autozone sometimes has those parts bins - any chain part store should have ability to find & order a stethoscope.  Alternative - people who know how to use the engine electrical diagnostic devices possibly can hook up to all injectors or spark plug wires & the tool can tell which injectors give acceptable electric signals - and which plugs are igniting something.  Find someone with old diagnostic devices leftover from the old days (if you're in Denver, I got something, but won't be home this weekend to dig it out - nor do I know how to use it).

- Carefully check the distributor shaft's alignment...  Having that off, by tooth or 180 degrees, can sometimes get an engine running although very poorly...  I learned that on an old Toyota Corona with an 8RC engine.  It's possible to get the camshaft 180 degrees out of sync with the crankshaft - I don't remember details well enough to describe, others will.

- A small thing to try - assuming your engine has plain old fashioned distributor & you rotate it to change timing. when it's running albeit poorly, try manually advancing & retarding on the distributor, see what happens.  If it seems to get better when advancing in particular, could be a sign that timing is messed up (which is crankshaft-to-camshaft-to-distributor relationships).

Ouch, I am feeling some of your pain as I recall trial & tribulation from my past.   Good luck.

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If the valve timing was off the entire bank compression would be low. Pulling a plug wire should produce a definite miss fire. Have you connected a vacuum gauge to it? If the vacuum is low I would try disconnecting the catalytic converter. Number 1 cylinder is on the right side and Toyota V6 has an interesting firing order 1-2-3-4-5-6.

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Thank you both for your insight, things to consider in my quest.  I think the mis-fire and the low power are two separate problems. In reading through more posts yesterday, I ran across one that had a heat related power problem, similar to my lack of power, and a couple of the suggestions to him were to check the fuel pressure.  And that brought back to mind that I had to replace my fuel regulator at the intake rail, due to a huge fuel leak when ignition was on. I found a used part on Ebay and fixed the leak, but now I have ordered a new replacement to eliminate the possibility of the used part being defective.  Since I will have to remove the intake plenum (once again) I can check the resistance of each injector then too.  Still can't find the mis-fire though.  Like I said, Pulling the plug wire on #4 doesn't change the miss, but neither does pulling #5 wire.  I'll ask around for a shop that could do a diagnostic to determine the firing/mis-firing.   Any other thoughts?  DD

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Is it possible that both #4 & #5 are out?  If you pull both & nothing's different, that'd be quite revealing.  Switched wires, maybe at the distributor?  My first rebuild was a Toyota 8RC engine, and seemed a failure until I discovered I put the distributor cap on slightly crooked, and it ran like a champ after straightening it out.     BTW 4 cylinders out of 6 firiing would likely give you low power, and that one condition would turn your 2 problems into 1.

On a different note, you'd hope a long block would have full compression on each cylinder, 10 pounds difference on that #4 is "within tolerance" on a used engine but not a reman or new.   Many autopart stores also will slap the diagnosis machine on all plug wires & that might reveal something. 

I've also heard of coincidences like a bad plug wire in a new kit, showing up exactly when someone's just done major maintenance & confusing the diagnosis - bad plug, bad wires, bad distributor parts, etc.   

...if you find out & fix the issue, please do post the resolution!   I always find it sad when we never find out the end of the story. 

Edited by tstockma
clarity
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Old school technique. If you have an inductive pickup timing light attach to each plug wire in any order. Observe the flash with each wire. A miss will show up in the flash sequence. Once you find the bad cylinder(s) start your trouble shooting from there. It’s a poor mans oscilloscope.

Edited by fred heath
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Right on Fred!  Yep I've done that plenty too.

BTW Dan, 4 cylinders out of 6 firing would likely give you low power, and that one condition would turn your 2 problems into 1.

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