Intake refresh and now wont run...
12-22-2016, 03:07 AM
#31
Rennlist Member
Usually we go back to what was touched last. But - in this case you were trying to fix a rough running engine to start with.
My best plan is to get rid of the easy stuff first. Rent a compr gauge and pull the plugs test for compression and make notes. leave the plugs out for now.
Next, remove the cap, and check the ignition routing by rotating the engine by hand, and watch where the rotor is on each firing stroke. You can find compression at TDC on #1 by putting your thumb over the plug hole and feel for pressure as the piston moves up. Then insure you follow the firing order and check rotor position and ign wire all the way to the plug well(you touched this last).
Also a good time to check the continuity of your plug wires using an Ohmmeter. inside cap contactor all the way out to the spark plug electrode. Some resistance may be present depending on the type of wires, and plug you have, but they should all be very similar, no outliers. If you get 55 ohms on 5 of the leads, and 950 or 1000 ohms on two, that's a problem.
Now you've verified compression and timed spark, the only thing left is fuel and air mixture. Noid light will help here. Also can measure the resistance of each injector since you washed them. Should all be similar resistance. If that checks out, then maybe find the cold cylinders and start moving injectors around to identify which isn't firing. If it follows an injector, there's the problem. If not, then start looking at the inj wiring, or even back to the ECU.
My best plan is to get rid of the easy stuff first. Rent a compr gauge and pull the plugs test for compression and make notes. leave the plugs out for now.
Next, remove the cap, and check the ignition routing by rotating the engine by hand, and watch where the rotor is on each firing stroke. You can find compression at TDC on #1 by putting your thumb over the plug hole and feel for pressure as the piston moves up. Then insure you follow the firing order and check rotor position and ign wire all the way to the plug well(you touched this last).
Also a good time to check the continuity of your plug wires using an Ohmmeter. inside cap contactor all the way out to the spark plug electrode. Some resistance may be present depending on the type of wires, and plug you have, but they should all be very similar, no outliers. If you get 55 ohms on 5 of the leads, and 950 or 1000 ohms on two, that's a problem.
Now you've verified compression and timed spark, the only thing left is fuel and air mixture. Noid light will help here. Also can measure the resistance of each injector since you washed them. Should all be similar resistance. If that checks out, then maybe find the cold cylinders and start moving injectors around to identify which isn't firing. If it follows an injector, there's the problem. If not, then start looking at the inj wiring, or even back to the ECU.
On a side note, your noticeable miss from before may very well have been injector #5. These injectors will seize from varnished fuel. I've seen 6 out of 8 frozen at one time.
Did you ever do anything related to the two L-jet grounds on the right side cam tower??
01-16-2017, 09:08 PM
#32
Three Wheelin'
Thread Starter
Updates! WooHoo!
Well, when Witchunter tells you only two injectors out of 8 have any flow whatsoever, that explains that! Got them back Friday and we are in business.
Still need to do a little tuning here and there (hunting idle, etc.) but I think I can enjoy driving her for awhile before doing anything else major.
Thanks all for the help as always - could not pull this stuff off without you all!
-scott
Still need to do a little tuning here and there (hunting idle, etc.) but I think I can enjoy driving her for awhile before doing anything else major.
Thanks all for the help as always - could not pull this stuff off without you all!
-scott
01-16-2017, 10:06 PM
#34
Three Wheelin'
Thread Starter
Ooops - forgot the video clip...
Here it is...y'all check my gauges and listen carefully and let me know what I might be missing, please!!
scott
scott
01-17-2017, 11:21 PM
#35
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I always liked the idea of changing only one thing at a time, to make troubleshooting easier. Then I did my intake refresh, changing a hundred things at once. High anxiety. I did have a problem - deep despair. Got it solved - oh, what a relief.
Can't say I enjoyed reliving all this in your thread!
Can't say I enjoyed reliving all this in your thread!
01-18-2017, 09:35 AM
#37
Rennlist Member
I always liked the idea of changing only one thing at a time, to make troubleshooting easier. Then I did my intake refresh, changing a hundred things at once. High anxiety. I did have a problem - deep despair. Got it solved - oh, what a relief.
Can't say I enjoyed reliving all this in your thread!
Can't say I enjoyed reliving all this in your thread!
Congratulations, Scott- we know how you feel!
01-19-2017, 11:41 AM
#40
Shameful Thread Killer
Rennlist Member
Rennlist Member
Nice work. Idle hunting is usually down to vacuum leaks, or sticky idle stabilizer valve. I use a can of carb cleaner to spritz around the top of the engine where there are vac hoses to try finding vac leaks. Use sparingly, and if the idle goes up when you spritz an area, you have found a vac leak. The idle stabilizer valve gets sticky from sitting, also from combustion products sticking to the vane or shutter. Can be removed and carefully cleaned and test the operation with a batt charger. Make sure you don't have a vac leak when replaced.
If the idle hunting is more noticable when starting from a cold engine to warm, then more likely the ISV is the culprit. If the hunting goes on more when fully warm, more likely a vac hose.
If the idle hunting is more noticable when starting from a cold engine to warm, then more likely the ISV is the culprit. If the hunting goes on more when fully warm, more likely a vac hose.