dodgethis Posted March 11, 2014 Author Report Posted March 11, 2014 (edited) I would recommend removing the entire fuel rail assembly to make things easier. Yes that metal clip must be removed and a small flat screwdriver or pick works. I want to say a good injector will read about 15 Ohms but I could be wrong, I don't have me book with me ATM. Make sure you replace ALL the O-rings on the injectors as they will more than likely be stiff and could make resealing the injectors a pain if you reuse them, so don't. But they only come 4 to a pack. IIRC a oil pump seal from a older 70's era Impala was the paper one to use and I cannot recall the regular O-ring size. Also get some permatex sealant #2 and put along the bottom of the lip at the top of the shaft once removed. Also put some engine oil on the teeth at the base of the shaft to make re-installation a little better. Hopefully your coolant fitting to your thermostat housing is the threaded kind and not the pressed in kind or you will have all kinds of fun. Coolant fitting? I wouldn't think I would have to deal with that as long as I pull the fuel rail. Really the only coolant hoses I had to deal with was the two from the throttle body. What, do I have to mess with the hoses going to the thermostat in order to get the fuel rail out? Excuse me, I see what your saying. The Hate is coming, while trying to get at the oil drive pump. Edited March 11, 2014 by dodgethis Quote
RobertISaar Posted March 11, 2014 Report Posted March 11, 2014 Thanks Rob, once I pop that clip, I have read how other have ohmn the injectors, and have got confused on doing it. To set me straight, Just simply checking resistance on each injector correct? Found Shurkeys image about the oil drive pump: http://hbassociates.us/Lumina_Oil_Pump_Drive_01.JPG yes, resistance check, depending on if you're using an auto-ranging meter or not, set it to measure ohms(not auto-ranging, set it to the 20ohm scale). Quote
Joshua Shaw Posted March 11, 2014 Report Posted March 11, 2014 The "Spliced" plug wire bothers me.. Any chance you can upload a pic?... I shooting on a limb here, any chance you have changed the fuel filter. last time i had a random miss on my 4.6 mod motor was due to a bad fuel filter.. haha cost me 3 sets of plugs and a set of plug wires tracking that one down. Quote
dodgethis Posted March 11, 2014 Author Report Posted March 11, 2014 The "Spliced" plug wire bothers me.. Any chance you can upload a pic?... I shooting on a limb here, any chance you have changed the fuel filter. last time i had a random miss on my 4.6 mod motor was due to a bad fuel filter.. haha cost me 3 sets of plugs and a set of plug wires tracking that one down. the "spliced" wire they are talking about, I have yet to figure out what they did. There visually is no difference. I think they just made up some "Bullshit". While reading some of the notes, they disconnected and reconnected a plug wire, and magically it ran better. I have ohmned both coil packs, and found they are within tolerance. ICM is fine, Primary is around 5.5kohms. The fuel filter has been changed before, probably 6 months old. I have a new one, just haven't installed it yet. What I'm hoping on, is ohming the injectors without pulling the rail (trying to work up the nerve to actually do it), but really I just want to check to see what the resistance is, and go from there. If I find one out of spec, i will probably pull the rail, and replace all injectors, and new o-rings Quote
Joshua Shaw Posted March 11, 2014 Report Posted March 11, 2014 Well that makes sense. Ive worked in several shops over the years and you wont believe the bullshit they come up with. So, plugs, plugs wires and coil all check out or have been proven good. Im no expert here but this really intrigues me, so im doing the best i can with what knowledge i have. Im sure these other guys know a shit ton more about gm then i do. Shit. i would bench test the injectors myself. Im really interested in what caused you these issues. good luck my friend. On the another note, being a totally different power train, i just fixed a random miss on my buddies truck by replacing a faulty IAT sensor. Quote
dodgethis Posted March 11, 2014 Author Report Posted March 11, 2014 Alright, I couldn't figure out how to pull the connectors off the injector in order to check resistance. As far as pulling the rail, I have the two bolts off that hold it on. I have unscrewed the connector that incoming fuel line goes to. What do you use to disconnect the return fuel line up under the FPR? Damn I'm so close... Quote
dodgethis Posted March 12, 2014 Author Report Posted March 12, 2014 Holy Crap, this is too cool, got the fuel rail lifted! Will report on injector resistance. Quote
dodgethis Posted March 12, 2014 Author Report Posted March 12, 2014 Ok, kinda bummed out. Injectors on the front of the engine are: I2 (12.2 Ohm), I4 (12.4 Ohm), I6 (12.2 Ohm). Back of the motor are: I5 (12.3 ohm) I3 (12.2 Ohm) I1 ( 12.2 Ohm). I found out the best way to disconnect the injector from the connector is Push in the metal clip, and while doing so pull the connector off. I have seen some video where some will pull the clip completely out. Im stumped I don't know, what could cause the misfire on 6 or 3. I will get new O-rings and gaskets to replace. Anyone have any thoughts? Quote
dodgethis Posted March 13, 2014 Author Report Posted March 13, 2014 Pulled the Oil Drive pump, They (Who ever had replaced the LIM Gaskets) used gasket maker around the edge of the pump. Tomorrow, will pick up all the gaskets from a AC Delco warehouse. Depending on the price I will pick up two new OEM injectors and hope for the best when I put it back together. The throttle body and plenum are still sitting in a Solvent bath. I did remove the sensor from the throttle body to prevent future problems. Quote
dodgethis Posted March 14, 2014 Author Report Posted March 14, 2014 Ok, Got the Oil Drive Pump replaced with new OEM O-ring, and a felpro gasket up under it. I also have replaced the injector O-rings. I was going mention, GM has replaced the Black and Brown O-rings with Blue O-rings. I didn't know that. Will pick up new OEM injectors at the tune of $112.00 a pop. Then I start putting her back together. Hope for the best! Or else: Quote
dodgethis Posted March 20, 2014 Author Report Posted March 20, 2014 A little bit of a update, So far this is what i have done. New PCV (AC Delco) Replaced engine rear O2 Sensor (AC Delco) Cleaned and Replaced Oil Drive Pump with new O ring Gasket and a gasket up under the lip of the pump. Cleaned Throttle Body, Throttle Position Sensor, Idle Air Temperature, and EGR Replaced Sparkplugs from NGK TR55GP with AC Delco Rapid Fires Replaced AC Delco Spark plugs wires with New AC Delco Wires Had the Plenum Professionally Cleaned, Grabbed New Gaskets for it Replaced all Injector O-rings, and replaced Injector 3 and 6, with AC Delco Injector Replaced gasket, and rubber hose off of the throttle body Questions: I was trying to find just the plenum gaskets that had the red ring that went around each port, but oreiylls sold it as a kit with the EGR Gaskets, and lower Intake Gaskets at $80.00 dollars, Should I buy the kit, or will Fel Pro MS91481 suffice? Would anyone suggest anything I should look at before I hook everything up today? I don't have any random engine shutdowns, just this random misfire. Have I covered everything? Quote
rich_e777 Posted March 20, 2014 Report Posted March 20, 2014 The kit from Oreilly's is probably a top engine gaskets set. Plenum gaskets are probably the same and Ive never had an issue with the felpro gaskets. If you still have the same issue after this you might start suspecting the thing under the coil packs, which the name currently eludes me. If you had the misfire on opposing cylinders then coils or the module underneath would have been first suspects. Quote
dodgethis Posted March 20, 2014 Author Report Posted March 20, 2014 The kit from Oreilly's is probably a top engine gaskets set. Plenum gaskets are probably the same and Ive never had an issue with the felpro gaskets. If you still have the same issue after this you might start suspecting the thing under the coil packs, which the name currently eludes me. If you had the misfire on opposing cylinders then coils or the module underneath would have been first suspects. The thing under the Coil Pack, oh the ICM? Ignition Control Module, Rich thanks for the input, I definitely take account of that if it happens again. AAAARRRISSSAARR, any thought sir? Quote
RobertISaar Posted March 20, 2014 Report Posted March 20, 2014 not really..... you're following the logical order of things, i can't think of anything else you should be doing along the way yet. Quote
dodgethis Posted March 21, 2014 Author Report Posted March 21, 2014 Interesting, I saw one injector #6, was leaking from the top (connected to fuel rail) fixed that by pressing back into the fuel rail, however noticed Injector 3 was not firing. I was turning the engine over and see residual fuel left in the other injectors, but #3 sill looked dry. I guess its time to look at wiring diagram, and a light check. Fuses in the engine bay were good. Quote
dodgethis Posted March 21, 2014 Author Report Posted March 21, 2014 False alarm, it helps when the injector loom is hooked up accordingly Quote
dodgethis Posted March 22, 2014 Author Report Posted March 22, 2014 Well....... I put everything back together, all connections are accounted for. It ran a alot smoother. The random Misfire went away, however, I now have P0122 TPS/Pedal Posiion Sensor A Low, a Cylinder 1 Misfire, and P0403 EGR Flow Circuit Malfunction..... Oh and I noticed smoke coming from the back of the engine. I immediately shut down the car for fear of a fire. It didn't smell of gasoline burning, or what, but didn't want the house to burn down. Well back to the drawing board..... Quote
dodgethis Posted March 24, 2014 Author Report Posted March 24, 2014 (edited) Alright car is fixed Basically, the penetrating oil used on the old oxygen sensor was burning off. I had mistaken it has a possible fire starting behind the car (I know, sounds crazy, It was late at night). Anyway, Fixed the EGR code, by swapping the Old out with a new EGR. I replaced the TPS, and all is working fine now. Cylinder 1 misfire went away amazingly. The car is running wonderfully now. I remember vaguely that someone on the forum mentioned being careful with opening the throttle too high because one could damage the TPS. I noticed when I pulled the old TPS, it didn't return to its original position, which I ended up replacing. Edited March 24, 2014 by dodgethis Quote
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