Misfire

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Kristian_Wraae

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May 18, 2007
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I've been having some misfire since I had my engine rebuilt.

I have the BC 264 stage 2 cams set at 3½ advance on the exhaust and 2 retard on the intake.

I have new working plugs and wires.

I have tested for leaks in the intake and found non. I have unplugged the injector one by one and also the ignition wires.

The misfire sounds like this: www.japanerfusk.dk/mis.wav

The misfire is random and not rythmic.

I considering a valve in not closing correctly or a leaking EGR valve.

Any other suggstions?

The engine has been completely rebuilt with new JE pistons and eagle rods. Alle new gaskets and bearings.

Since sunday the car has developed a ticking sound syncronized with the engine rpms when driving (in gear - I have an automatic) but no tick when in park and reving the engine. I'm suspecting an exhaust leak - maybe from the EGR cooler.

I have checke the EGR valve and it does open when I apply vacuum to it but I'm thinking that it might not close completely.
 
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Kristian_Wraae

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May 18, 2007
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I did a compression test:

komp.jpg


I also blocked the EGR and tried out another coil pack.

Still misfire.


So I guess the only thing left is to pull the injectors and have them checked?

Any other things I should consider?
 
eman2289

eman2289

Noob..but not incompetent
Feb 23, 2007
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When I had a random misfire, it turned out to be a clogged injector. I figured id give it a shot and throw in some Lucas injector cleaner. It took about a day of driving, but it went away. Give it a shot, it cant hurt anything.
 
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BLACKCAT

New Member
May 24, 2007
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You are currently running -2 I & +3.5 E cam timing at 119.5 lobe centre & 25 degrees valve overlap.

Have you filed the dizzy slot so you can retard the exhaust cam more & obtain more static advance as the distributor drive on the cam is out of sync?

I have filed mine down to 1mm from the end & can retard my exhaust down to -4 & still obtain 15 degrees timing.

You need to retard the exhaust more to pick up power.

Try altering your cam timing to -3 I & +1.5 E, giving you 118.5 lobe & 27 overlap. You wont loose any torque down low & will pick up power after 4500.
 

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Kristian_Wraae

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I haven't filed anything. Thanks for your suggestion.

I set the timing to 12 with the cams at 0 0. Then I tuned the cams to +3.5E and -2I. I don't know what that makes the timing (I'm a 7mgte novice)

Do you think the cams are the reason for the misfire?

At the moment I'm not trying to make power. I'm just trying to figur out what is causing the misfire. If it's the cams then fine but I don't like it if it's one or two of the injectors that are not flowing correctly.

Any suggestions to which cam positions that could make the engine run as smooth as possible in order to find out if the cams are guilty?
 
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BLACKCAT

New Member
May 24, 2007
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Each time you alter the exhaust cam position you have to readjust your base timing. Altering the intake cam has no affect on the base timing.

If you had it at 12 & then advanced the exhaust 3.5 degrees your timing would be more like 17+ now so check your timing & bring it back to 12 as this may be part of your problem.

The BC cams distributor drive is out of sync with the original Toyota.
That is why you have to dril/file the slot in order to advance it more to obtain the same setting.
 
jdub

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
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Feb 10, 2006
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HUGE difference between a misfire and rod knock :3d_frown:
And this doesn't even sound close to RK.
 
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supra_ed

New Member
May 30, 2006
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im goin through same thing- 40 over cp/pauter, os valves and 272's. been trin to figure it out for weeks- did same things u did, compression test, plugs wires, timing, injectors tested fine. just yesterday i found a sensor (blue one on the thermostat housing by the power steering res) that was broke and loose. put new one in which i had lyin around and the car seems to idle better. it doesnt miss or stutter anymore. at least in the garage. i cant test drive it because the weather is an icy mess. maybe it didnt do anything for me but it does idle and rev easier.......
 
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Kristian_Wraae

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supra_ed;931523 said:
im goin through same thing- 40 over cp/pauter, os valves and 272's. been trin to figure it out for weeks- did same things u did, compression test, plugs wires, timing, injectors tested fine. just yesterday i found a sensor (blue one on the thermostat housing by the power steering res) that was broke and loose. put new one in which i had lyin around and the car seems to idle better. it doesnt miss or stutter anymore. at least in the garage. i cant test drive it because the weather is an icy mess. maybe it didnt do anything for me but it does idle and rev easier.......
Click to expand...

Which sensor is that? The BSVS? I have just replaced that. (Broke it with my arm trying to exchange the plug wires......)
 
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Kristian_Wraae

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Instead of having the injectors checked I was considering a Lexus AFM and some new bigger injectors. I'm going standalone later when I have accumulated some more cash but for now the Lexus AFM would allow me to upgrade the injectors and stille be able to use the factory ECU.

With my cams in mind would it be better to get 680cc injectors? I suspect that the BC cams make the car run slightly leaner and that I would need slightly more fuel than on the stock cams. Or am I completely wrong here?
 
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Kristian_Wraae

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I have set the CAM at -3 I & +1.5 E. The timing is still set at 12 at 0 0 so it'll be something else now (maybe 15 or something like that). I don't have at timing gun here so I can't set the timing until I get hold of one.

I have recorded another sound clip: http://www.japanerfusk.dk/alleefterstart.wav

It's been recorded after the car has been sitting for half an hour but still warm. As you can hear the explosions start after a while and gets worse as the exhaust heats up or an injector puts enough unburnt gas in the exhaust.
 
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Kristian_Wraae

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May 18, 2007
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I have Denso Iridium IQ22 plugs and NGK wires (those blue ones everybody uses).

All brand new. I even bought a new set of IQ22s in case there was a problem with the ones I had.

No change.
 
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Kristian_Wraae

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I didn't test the coil packs. I just borrowed a working set and tested with that one. It didn't change anything at all.

It is grounded alright.
 
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