Likely injector issue discussuion | Ford Explorer Forums - Serious Explorations

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Likely injector issue discussuion


July 23, 2007
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City, State
Year, Model & Trim Level
93 XLT, 03, 2 wheel drive
This is not about an Explorer but rather a 99 E150 with a 4.2 V6, but what I am experiencing could easily apply to other models of the era. The vehicle is a low use vehicle since about 2002. It became a specialized vehicle at that point and probably has 10-20k on it since then. It has a history of not passing smog checks until 1000 miles ago when it passed easily after receiving new cats a year or two before I bought it.

During the first 1000 mile I had it I noticed what I would describe as a minor miss very occasionally. After looking at plugs I noticed the passenger front plug appears to have significant fuel/carbon fouling over time, it does not look like oil related. I also noticed the filler hose to the tank is leaking. Before dropping the tank I decided to run it out of holds 35 gallons. Getting near empty I parked it nose up in a driveway. When I attempted to start it two days later it would not start at all. After adding 5 gallons or so of fuel it would hard start cold then stumble on acceleration. I got my first misfire code for the passenger front during one of those first rough cold idles. I have not seen it since, though the problem remains When warm the drivability issues improve and it is capable of a smooth idle. I changed plugs and wires just to start down the process of elimination path.

On hard cold starts it would now blow some unburned white smoke from fuel and blow raw fuel from the tailpipe. This goes away shortly after starting to warm up. It is now low on power in general and I hear pinging develop even at low engine temps while climbing. It was more or less the same before and after new plugs and wires, though the new plugs especially the carbon fouled one seem to help it start more easily now cold...which makes sense to me.

I checked fuel pressure today and got 32 psi key on engine off early on. This later made its way to 40-42 ready to start. After start it will idle at 32 and with load I can get to 42 psi...all of this seems normal. Unplug fuel pressure regulator it goes to 40-42, plug in it goes back to 32. I thought I had somehow hurt the fuel pump when I ran it out. Now I don't think I have.

Now my hypothesis is I have a bad passenger front injector since the beginning. I think it is either mechanical or electric issue, possibly dirty, though it seems plenty of fuel is getting in as opposed to a lean problem. I think when I ran it out and some of the no fuel cranking injector operation somehow made the condition of that injector worse. It is capable of idling too smoothly warm for there to be a bunch of issues with multiple injectors. Fuel pressure leakdown measured at the Schrader valve on the rail is from 32 psi down to 18 in 2.5 hours when I checked within the last hour. Every time I turn the key on once before cranking, not multiple cycles, it goes right to 40 psi every time...more seeming evidence the fuel pump is ok.

Anyone had this abrupt worsening of drivability after running out of fuel? Already troubled injector further 'hurt' by overheat due to lack of fuel? Some sort of mechanical degradation due to no fuel? Lack of cushion effect? I assume this is not a pintle injector, rather a ball or disc. Can anyone give me some details on what this injector is from the factory?

I am planning to have the heavy detergent treatment done in case there is some stuff in there due to sitting for long periods fuel varnish deposits etc. I have never done this to any of many vehicles to this date. I am reluctant but given what I am seeing as an injector specific issue, and vehicle history, I am curious. If this does not clear up the issues I want to change that one injector and just test the others (the resistance at the terminals test) just to make sure.

Anyone experience known mechanical electrical failures from Motorcraft or other injectors of this era?

On edit, hooked up to an analyzer today, after fuel system clean and fuel filter change (which did nothing as expected, just one simple thing to cross off) some backfiring on accelerator input in neutral seemed to come from random cylinders, of which one was not one. That could be because it is rich due to injector defect and others are being leaned in general and randomly lean misfiring in response. I am not sure how the motor sends that individual cylinder backfire or afterfire message, but was told the engine can lean and richen left or right bank of cylinders but not individually. The history long and short of cylinder bank leaning/richening looked pretty even, though I thought I saw some extra tendency towards right bank richness, which is where #1 cylinder is. They were unable, to continue work which was disappointing, truth be told I can tell they don't want to do injector work on it...disappointing when shop gives quotes, accepts the easy money but leads one on in the end...which I can tell happened. Second time at this shop...probably wont be another. ...heck I may do the work myself.