Motor Age Garage: Phasers on Stun

I got a little too comfy with that pattern, and there came the day I drew a work order on a Taurus that my neat little routine didn’t fix. I got that hook rider in my service bay, didn’t hear the pump, checked the inertia switch and replaced the pump, all to no avail. The new pump didn’t run either, and I felt like a dummy when I discovered a chalked up ground wire at the battery terminal. I’m an honest guy, and as I perused the notion of removing the new pump from the tank and reinstalling the old one, I was hit with the realization that if I did that, the old pump could (and probably would) fail within our service warranty window and then I’d be stuck with having to do the next repair for free. The ground chalk was erased and the new pump remained in the tank. I could have saved a life, who knows?

Navigating Wisely This Lincoln’s driver had driven it bucking and jerking with the Check Engine light on for about three months until her father drove the vehicle one day, felt the problem and told her something needed to be done about it, and so it wound up at my shop. We drove it, felt the jump, snagged some cam sensor codes and scope patterns (verifying cam misalignment issues) and postulated there might be a phaser problem.

The PICO scope pattern we got from the two cam sensors and the crank sensor pointed to a concern on the No. 1 bank’s camshaft. Was it a phaser or not? We removed the sensor, bumped the engine over until the three-prong side of the No. 1 banks’ phaser’s trigger wheel was lined up with the hole and looked to see if the arrowed “L” symbol on that gear was out of line with the center prong. If the phaser was out of phase, the arrowed L and the prong won’t eclipse. 

This one seemed to be a shade off, but not enough to account for the pattern we got, so it was time for exploratory surgery. With the valve covers and the timing cover off (no small feat), we discovered the real problem, which, it turns out, is more common than phasers. The straight fixed slide on the upper stretch of the No. 1 bank chain had disintegrated and that chain had been whipping around in there to make some pretty serious marks on the inside of the cover.  This one would get a couple of phasers after all, along with new timing chains and all the stuff that goes with it.  The guy I had doing the job was (and is) one of the most conscientious and careful second semester students I’ve ever seen, and I kept everybody out of his way while he plowed into that Navigator with one of the computers rolled over to where he was working. This B level job would have been a 14-hour flag for a line guy.

Those Crazy Others
Four more vehicles rolled in while the Navigator was under repair, a 1999 Town Car with a stubbornly steady number four misfire, a 2002 Taurus the owner said had an under-load bite at 45 mph (all too familiar), a 2004 Tahoe with an intermittent no-start problem and a 2001 F150 with electrical gremlins – the instrument cluster was remaining illuminated with the key off, complete with fluttering odometer segments and a dead battery after sitting overnight.

The Town Car’s No. 4 plug well was loaded with coolant, which led us to examine the heater hose fitting right above it. Sure enough that pressed-in hose pipe was leaking coolant into the spark plug cavity. That one got an intake manifold.

The Taurus wasn’t so cut and dried – the only concern the customer had voiced when I wrote that one up was the 45 mph irregular misfire bite, and he said he had already replaced the spark plugs and wires. The next morning, I fired it up to drive it into the service bay for preliminaries only to discover that it was surging dreadfully. It ran so bad it would barely pull off in any gear when it was cold.  There was no need to go for a test drive – all this nonsense would need fixing before anything else was done. 

After some scan tool PID-sifting that didn’t help very much, I unplugged the MAF sensor on a hunch and it ran about 60 percent better, and while cleaning that MAF might be in order, we replaced it with a reman from the parts store. The MAF was dirty due to a used-up air filter wasn’t just clogged, it had been compromised. It was one of those cheap ones that shrink with age, and it had several rotten holes in the pleats. With the air filter in such bad shape, it was no surprise to remove the Motocraft fuel filter and find it was plugged so badly I was concerned that it might have damaged the fuel pump, but afterward, the pressure was fine. After we got all the preliminaries done, we drove it again with the IDS running Power Balance and found the bite that was his original concern. He had cracked the number one spark plug, and after we replaced that, the bite was gone. 

The Tahoe was a frontier that was more interesting than the Taurus and a bit trickier. I had yet to experience the hard start it came in for, but we changed the engine oil and replaced the air and fuel filters. That fuel filter was so old, it was rattling when we shook it. Our DTC scan showed a P0178, which pointed to the Fuel Composition Sensor, but when we chased that one, we were confused by a 56 hz reading we measured with a meter on the signal wire that conflicted with the scan tool PID reading of 43 hz. Should we believe the PCM or the actual measured value? Was the PCM smarter than our meter? The scan tool showed a 37 percent alcohol reading. The simple fact is that the FCS is such an expensive part ($700 list price), it’d be kind of spooky to toss one of those bad boys on a whim or a hunch. I wanted confirmation of some kind. After all, if this was the problem, why wasn’t the no-start concern more consistent? 

The F150 wasn’t a frontier for me, and since I had worked at the Ford dealer, I knew where to look for this electrical gremlin problem. I had a couple of students remove the fuse panel/junction box, pried the cover open on it and found that the laminates were wet and green due to a leaking windshield. Moisture damage to this very important box can cause any number of electrical concerns, and so, a few hundreds of dollars later, this one drove out with a new junction box on its way to the glass doctor to have that water leak fixed.Michelle’s Maxima While the Navigator was undergoing the final stages of its chains-and-phasers surgery, I got a call for a repair from the owner of a 2002 Nissan Maxima that had been diagnosed by her husband, who had decided it needed a starter, because

sometimes the existing one would only click rather than spinning. When I settled into the seat and turned the key, and the Maxima’s V6 spun very aggressively for about 40 seconds before it fired up. The driver’s husband was standing right there, but he hadn’t mentioned this long crank-hard start issue, which was probably at least part of the reason the starter was dying. This wasn’t a frontier for me either.  I had the idea it probably needed a cam sensor on one bank or the other, and I said as much as he was headed out the door.

Amber, one of my newer students, replaced the starter and then bench tested the old one. In spite of the fact that the old starter spun so well on the car, it would only click during the bench test. With the new starter in place, the long crank happened again, and I stabbed the EASE WVI’s green connector into the DLC (which is the quickest way to grab a code) and got the P0340 I expected.  The cam sensor on bank number one would be our next move, but first we had to spray wash away about a pound of accumulated greasy crud from the sensor and its connector. 

When the parts store arrived with the replacement sensor and it was installed, the Maxima fired up so fast the crank barely made a full round on starter power.  With some battery terminal maintenance and a few more simple checks, the Maxima was done.

Tahoe Frontier Conquered
The owner of the Tahoe had called earlier that morning to suggest that I put it outside the shop for the night, which was going to be pretty chilly, and while I had her on the phone, I decided to start it up. All it would do was spin like the Maxima, but with no eventual start. She did say that when it pulled this stunt, you could leave it sitting for several hours and it would start and run just fine.  

O

ne way or another, we were in business, and I shooed her off the phone so I could concentrate, fearful that the Tahoe would decide to start. We had an rpm signal (I scoped it and it looked great). We had fuel pressure, strong spark, and clicking fuel injectors. What about fuel quality? I discarded that as an issue because it started so well most of the time. 

I poked around in Identifix and noticed that a couple of shops had run across problems like this that were caused by the Fuel Composition Sensor, but that sensor was still too expensive to take a chance on, so I opened a hotline call on it and got my verification from the GM guy. The P0178 was a strong indicator (56 hz notwithstanding) that the FCS was indeed the cause of this nonsense. I yanked a spark plug and found it very wet. Could the PCM be over-fueling the Tahoe thinking there was more alcohol in the tank than there actually was? 

A call to the customer confirmed that her son, who drove the Tahoe never used E85 – he only pumped regular into that cavernous gas tank. We ordered the Fuel Composition Sensor when the owner green-lighted it and let the truck sit all night before installing the sensor. A follow up since has verified that the hard starting concern is fixed, albeit at a pretty stiff price.

Navigator Frontier Conquered The student who was working on the Navigator was studiously putting every little part, bracket and wire harness back in place (which is demanding for any student, but this guy is good). He spun the fan back onto the water pump pulley and tightened it with the fan wrench, filled it with coolant, and turned the key. It fired right up, and the new timing chains rattled for about a second until the oil pressure tightened the tensioners.  The air suspension compressor kicked in and raised the Navigator on its bags, and it sat there purring like a kitten.

I’ll be the first to say that, as an instructor, it’s kind of spooky to give a job this complicated to a second semester student. But I as I watched this guy carefully observing virtually everything the shop manual told him to do, I knew early on that this one would go well. And it did. While the job was under way, I told him that he would feel like Superman when he heard that 3-Valve fire up and run right. 

My prediction was correct, but I must confess that, when I heard that Navigator light off, I felt as super as he did. We weren’t stunned by these phasers. We had breached our final frontier, at least for that week.