Rough idle, backfire hesitation
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Rough idle, backfire hesitation
Hi so I bought a great little es 300 92 blown hg, took off to shop they rebuilt heads. It ran fine before just blew white smoke and a shutter to the motor. When I have put everything back on it does not run right. First i tried sparying starter fluid around no change . Traked downthe #4 injector was bad replaced it. Runs better but still hessitates and idels real rough. Any suggestions? New plugs wires cap and rotor timing if at 10 but fluctuates a little with the engine. It smoothes out when I pull the dash pot va hose off and leave it dangle but ides at 1500 ?
#2
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Assuming your camshaft timing is correct, I would look for vacuum leaks.
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In regards to timing the mark on the pully is lined up to the o mark then the top cams are lined up the the niches on timing cover is that correct? Also it seems like the left( 246 cyl) is off a 1/4 inch or so is that off or within tolerance?
#4
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Every 3VZ-FE timing belt job I've done, the right hand cam (front of car) was slightly out, the other mark was bang on. Either way the marks never seem to be exact, what doesn't help is the tilt of the engine makes eye balling more difficult. But if you have the crank at zero, and the cams appear to line up to the marks on the back plate, then you probably have the cam timing right. Even if it was off 1 notch the engine will still idle fine it just won't have good power.
If you don't have one, get a hold of a vacuum gauge. At idle it should stay perfectly steady, or maybe a slight bit of jitter on the needle. A spray bottle with soapy water is a nice way to find vacuum leaks, spray around various parts of the engine, if you have a leak the engine will stumble or even stall out.
Another simple procedure is a load test. Pull the spark plug leads out one cylinder at a time and listen for a change in the engine. If you pull one and nothing changes, that cylinder is not burning fuel properly. It's hard to do with the bank bank of course.
To check for cam timing, line up the firewall side cam exactly, the front mark for me was always out just a bit, like I would have to rotate the cam counter clockwise to make it be 100%. Also the crank mark should show exactly zero.
...one thing I forgot to mention. Were the camshafts installed on the heads properly? The gears need to mesh with the marks lined up. If not, you can set the timing belt 100% and the cam timing will still be off.
If you don't have one, get a hold of a vacuum gauge. At idle it should stay perfectly steady, or maybe a slight bit of jitter on the needle. A spray bottle with soapy water is a nice way to find vacuum leaks, spray around various parts of the engine, if you have a leak the engine will stumble or even stall out.
Another simple procedure is a load test. Pull the spark plug leads out one cylinder at a time and listen for a change in the engine. If you pull one and nothing changes, that cylinder is not burning fuel properly. It's hard to do with the bank bank of course.
To check for cam timing, line up the firewall side cam exactly, the front mark for me was always out just a bit, like I would have to rotate the cam counter clockwise to make it be 100%. Also the crank mark should show exactly zero.
...one thing I forgot to mention. Were the camshafts installed on the heads properly? The gears need to mesh with the marks lined up. If not, you can set the timing belt 100% and the cam timing will still be off.
Last edited by LeX2K; 10-08-13 at 03:13 PM.
#6
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The brake booster line is perfect, but you will probably need a couple of hoses of different sizes to adapt. Make sure you put the gauge before the one way check valve. It doesn't have to be the booster line, any line that goes straight into the air chamber is fine.
You could also do a compression check of at least the front bank. Bad cam timing and you won't get consistent readings.
You could also do a compression check of at least the front bank. Bad cam timing and you won't get consistent readings.
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#9
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Like I mentioned previously, I find a spray bottle with soapy water works well.
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ok so figured it out. no leak, just dumb lol. i had put the rh cams in, lined them up with one having 1 don't and the other 2 (180 deg from where it should have been) should have worn my glasses lol but fixed that and boom runs great!! nothing like a purring motor. now to fix the cracked wood grain and climate control blacked out lcd
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