ErickBaker Posted October 7, 2006 Share Posted October 7, 2006 We have a 2000 Ranger that has been in the shop about five times for a misfire on cylinder number 4. One of our gravy techs did a tune up on it the first time and has put a plug in it the other four times. After the plug is changed the truck will make it about 4,000 to 6,000 miles before it comes back missing. The plug looks good (i.e. no oil fouling, porcelain not cracked). I was wondering if you guys have seen anything like this before. I'm guessing something like headgaskets with a small leak killing it over time? /forums/images/%%GRAEMLIN_URL%%/shrug.gif Kind of grasping at straws. The only thing abnormal on that cylinder is relative compression is down about 4%. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 8, 2006 Share Posted October 8, 2006 Is this a 4 cyl or a V6? Quote Link to comment Share on other sites More sharing options...
ktmlew Posted October 8, 2006 Share Posted October 8, 2006 If it's a 3.0 they had some valve seat recession problems on those I believe? I would do a real comp test... Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 8, 2006 Author Share Posted October 8, 2006 Sorry I neglected to mention that is is the 4.0L. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 8, 2006 Share Posted October 8, 2006 I'm gonna go out on a limb and suggest that there is the chance that nobody has actually experienced the miss???? The 4.0 had a lot of intake sealing concens when cold.. this would usually set mixture codes but I suppose anything is possible.... including cylinder codes.... You can verify this by getting the motor as cold as possible and using the smoke tester on it Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 8, 2006 Author Share Posted October 8, 2006 It misses terribly. When it came in this Saturday I pulled the powerbalance up and cylinder 4 is a dead miss. Not like a normal ignition miss though in the way that it's not load dependent. It's just a dead miss and it goes away when I replace the spark plug.( at least for a few thousand miles) Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 9, 2006 Share Posted October 9, 2006 I'm thinking ignition secondary.... a fresh plug is going to fire pretty easy.... round off the corners and load it up a little and required voltage is going to go up.... Look for lightning strikes along the plug wire (wouldn't hurt to inspect the running mate, too) or carbon tracks inside the boot.... also on the coil tower and inside the coil boot as well. I have a Radio Shack 30X magnifier that I use on the toy cars that can reveal any manner of concerns (sometimes, simply putting on my reading glasses does that, though). Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 9, 2006 Author Share Posted October 9, 2006 Now that you mention it I did notice some very light carbon tracking on the plug. I'll have to check it out better Monday. Saturdays don't lend themselves to very involved diagnostics. I'll let you know what I find and thanks for the help. /forums/images/%%GRAEMLIN_URL%%/notworthy.gif Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 9, 2006 Share Posted October 9, 2006 Ahhhh, Monday.... It's Thanksgiving in Canader... Monday is a paid holiday.... /forums/images/%%GRAEMLIN_URL%%/cheers.gif Quote Link to comment Share on other sites More sharing options...
pcassidy111 Posted October 9, 2006 Share Posted October 9, 2006 A few suggestions. Check the inside of the boot for a carbon track. Current ramp the 3/4 coil, I have had weird misses that I traced back to a shorted coil-may be intermittent. Is the injector firing when the miss occurs, bad injector driver? Put dye in the coolant, run the engine for a while to circulate it then put the radiator pressure tester on it and pressurize it overnight. In the am pull the plug and look for dye in the cylinder, then reinstall the plug and crank it over with a remote starter (do not allow it to start) then pull the plug and look for dye on the plug-I have found cracked heads on 4.0L that will not show up with a block check. Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 9, 2006 Author Share Posted October 9, 2006 Thanks. Called hotline this morning looking for some words of wisdom. After checking all the basics.(Manual compression, injector flow, coil output, fuel psi, etc.) They told me to try copper plugs instead of the platinum. That doesn't cut it with me so I put the coolant pressure tester on it and am currently letting it sit. I did notice that the plug in cylinder four had kind of an amber tint to it while the other plugs were all clean and white. I think the coil out put is ok because I put a gap of about a half an inch on my spark tester and it still fired every time. One thing I neglected to mention is that when it first came in I put my combustion gas tester on it and it turned up negative. /forums/images/%%GRAEMLIN_URL%%/shrug.gif I'll see if it's leaked down in the morning. Thanks again. Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 10, 2006 Author Share Posted October 10, 2006 Well no signs of coolant dye in the cylinder or on the plug this morning. I guess I'll try hotline's flakey idea about the copper plugs. /forums/images/%%GRAEMLIN_URL%%/shrug.gif I appreciate all your help. I'm sure I'll be seeing this truck again in about 3,000 miles. Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 11, 2006 Author Share Posted October 11, 2006 Well I got concrete evidence today that the truck has a blown head gasket. I put a cylinder leak down tester on cylinder four and it began pushing coolant out of the radiator. /forums/images/%%GRAEMLIN_URL%%/shrug.gif For information purposes, I put the copper plugs in and the engine idled rough as hell and they caused a random misfire. This is one of the few cases where hotline was a bust. Now we'll see how this gets paid for. This gentleman's ESP expired while our other tech repeatedly "mis-diagnosed" the vehicle. Can you say P05? Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 11, 2006 Share Posted October 11, 2006 No dye in the chamber because a radiator pressure test (I don't use this for suspected combustion leaks) can only give about 16 or so PSI... Leaking the cylinder delivers shop air to the chamber (150PSI in our store)... the extra pressure can make all the difference in the world... Quote Link to comment Share on other sites More sharing options...
pcassidy111 Posted October 11, 2006 Share Posted October 11, 2006 No dye in the chamber because a radiator pressure test (I don't use this for suspected combustion leaks) can only give about 16 or so PSI... Leaking the cylinder delivers shop air to the chamber (150PSI in our store)... the extra pressure can make all the difference in the world... In my shop I am seeing Jeep V8 and a few Ford 4.0L with cylinder head cracks that are causing intermittent cold start misses. Block checks usually come up negative but pressure testing them overnight usually shows coolant on the plug. I'll try using the leakdown checker on a cold engine, it might speed up the diagnostic process, though on my problem vehicles only cooling system pressure is present prior to the problem occuring (because the engine is off and has to sit overnight or cool to ambient temp), maybe it was intermittent because the offending cylinder is on the compression stroke. No explainaton for why the leak shows up at 16 psi but not at compression/combustion pressure other than the leak is temperature sensitive. Quote Link to comment Share on other sites More sharing options...
CERTIFIEDFORDTEC Posted October 14, 2006 Share Posted October 14, 2006 Its a crack cylinder head guaranteed! #3 and #4 always crack between the seats. A new plug cures it for a limited time until until the plug goes bad again. I've seen it a few hundred times here. recommend both heads! Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted October 14, 2006 Share Posted October 14, 2006 It has been a while since I worked on cars and gas engines in general but I do remember those 4.0L heads having that problem with cracked heads. I think you are onto something here. Unfortunately it requires tear-down to validate this suspicion. Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 15, 2006 Author Share Posted October 15, 2006 I feel pretty confident that it is the head. Now I'm just waiting for it to go through all the red tape. Nobody wants to pay for repair. Customer feels we dropped the ball on diagnostics which allowed his ESP to expire. Just for the record I agree with him. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 16, 2006 Share Posted October 16, 2006 Eric, is there any chance that he can produce documentation to show that this has been an ongoing concern? I'm not sure how AWA works with extended warranty but I do believe that part of our job is to advise our customers as best we can. Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 17, 2006 Author Share Posted October 17, 2006 He may have the bills from his previous three or four visits. He paid for the first tune-up but after that they SPW the plug on cylinder 4. This being the first time I've looked at the truck I'm not positive about all the details of the past visits. I agree with your statement about keeping the customer informed, but as I'm sure you know, sometimes the powers that be aren't on the same page as us. Bottom line is that the shop dropped the ball and we should goodwill this job to make the customer happy. Today when I left the were talking about getting one of the hourly guys to do the job. It looks like I'll be out the next three days due to a foot injury at work, so it will probably be gone when I get back. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 17, 2006 Share Posted October 17, 2006 The only foot injury I ever sustain at work is when I stick one in my mouth /forums/images/%%GRAEMLIN_URL%%/laugh.gif Even if the plugs have been given SPW, I would think that this would show up somewhere in vehicle history... if not in OASIS, it should be in local records.... Disclaimer... we recently switched to some different RO software.... and I hate it, absolutely hate it. Still, we can use a VIN or customer name to see what's been going on... The old ROs had indication of outstanding FSAs... that was good since I can't seem to get many guys to run a friggin' OASIS when they know they should... Good luck... Quote Link to comment Share on other sites More sharing options...
ErickBaker Posted October 17, 2006 Author Share Posted October 17, 2006 We have a work history and OASIS attached to every ticket. I suppose he could use the work history to show that this has been ongoing. I agree the OASIS with FSA's on them are nice but most techs in our shop tend to ignore them. It all comes down to taking pride in your job. Techs ignore things that they don't want to do (i.e. 4.0L headgaskets and recalls) and only accept gravy tickets. It really burns my ass when techs want to do driveabilty work as long as they can make 4 or 5 hours off the ticket in about 30 minutes. Meanwhile you have a handful of techs in the shop doing heavy line work, other tech's comebacks, and diesels while struggling to get 40 hours a week. /forums/images/%%GRAEMLIN_URL%%/mad.gif Sorry just venting. Quote Link to comment Share on other sites More sharing options...
CERTIFIEDFORDTEC Posted October 18, 2006 Share Posted October 18, 2006 In my old shop we would use the borescope on every 4.0 ohv that we suspected had a cracked head. The old rotunda one with the 90 degree end showed the crack everytime....for future help i guess :-) Quote Link to comment Share on other sites More sharing options...
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