Help! Serious 97 Aerostar woes...
 

My family owns a 97 Aerostar 3.0 2WD, it's got about 175K miles on it. A few months back there started to be a issue where if it was sitting in park the idle would drop suddenly and then come back up, especially when you first start it, then about 2 weeks ago the van was started and it began shuddering badly, there was no backfiring, but there was definite constant vibration/shuddering, with very little power during acceleration, after taking it to Autozone and having the code reader put on it, it showed a code for the camshaft position sensor and a code p0171. So I removed the camshaft sensor and found the magnet had fallen out, and stripped the vane right off the shafts and polished the top of it in the process. I ordered a Dorman camshaft synchroniser and sensor and installed it per instructions on this site, lining up the crankshaft TDC using the missing tooth in the gear. After that the shuddering wasn't as bad, but still much worse than the day before this occuring, I decided to check the sparkplugs, front driverside was worn down, so I installed new plugs, there is was something odd about how the plugs looked tho, on bank 2 all the bottom electrodes were heavily worn, and the rear one smelled of gas, on bank 2 all the bottom electrodes looked great and not wore down at all, but the middle and rear plugs reaked of gas, while the number 1 plug looked and smelled fine. Well, after doing this, the shaking was still there, mind you there was never any engine noise like the lifters had gone bad or something rattling in the engine. So I remembered a trick to test the sparkplug wires and sprayed some soapy water on them, sure enough I could see them sparking to each other in the dark, so after replacing them as well, this plug fiasco taking about 2 days to complete, I really didn't see any improvement, so now I was very perplexed, I was still getting code p0171, I sprayed around the intake heavily with carb cleaning and didn't notice any RPM increases, so I think I ruled out vacuum leaks, I then took it to a buddy who owns a shop and they quickly ran it thro some tests, cleaned the throttle body, and even tested the o2 sensors, he said the sensors were a little worn but still working and wouldn't be causing this, he said to replace the coil pack and see if that fixes it, and after that check the engine compression which sounds like a major issue. We bought this car used and never replaced the coil pack, and this was the first time we replaced the wires. Does anyone think this could be the coil pack doing all this? And what about the odd condition of the plugs? one bank being heavily worn with one plug smelling of gas and the other not very worn but but two of the plugs reaking of gas? The only other odd thing I noticed was, after driving the van for about 30 miles and going back to check the camshaft synchroniser, it was out of alignment with the crankshaft according to the alignment tool, ie I brought it back to TDC and the tool would no longer fit into the synchroniser housing, I realigned everything but that didn't fix the issue. I'm very perplexed about all this, any advice would be much appreciated!

Ok, it looks like some things are on the right track, but there are several things, which have been posted in a sticky on this site because they are so important.

Lets start with the plugs and wires. The reason you so excessive wear on the driver side plugs is because the previous set were not the required double platinum plugs. Many Fords are very particular about ignition components, the replacement parts have to be at least as good as OEM. This means Motorcraft or Autolite double platinum or iridium plugs, and Motorcraft or Magnacore wires.

Using a flammable spray to check for vacuum leaks is not only dangerous, but very ineffective. I know lots of people who have "ruled out" vacuum leaks based on this method, then had to go back to square one and repair a vacuum leak. The method only works on painfully obvious leaks in my experience.

The gas soaked plug could be due to it not firing or it could be caused by an injector on that cylinder that leaks down when the engine is turned off. To determine this, you need to do a fuel pressure leakdown test. If the pressure doesn't hold when the engine is turned off, then the fuel is leaking out somewhere, good chance it is one of the injectors, though it could be other sources too.

Your friend is right that the O2 sensors wouldn't cause this issue, but once you get the misfire corrected, you need to replace the sensor. They are designed to be replaced about every 80,000 miles.

On the camshaft sensor, pull that Dorman part back out and get a Motorcraft part. Other people have mentioned problems with the Dorman units.

On the coil pack, it could be bad, but you should have a misfire code if that is the case. I'll assume you have a misfire anyway. Assuming it is the coil pack, don't waste your time with an aftermarket one. Get a Motorcraft or AC Delco coil pack.

I like to get many of my parts at RockAuto Auto Parts in part because the prices are good, but also because they carry the Motorcraft parts.

Hi Khan, thanks for the advice, but one thing is about the old spark plugs is they were all double platinum plugs, and the new ones are iridium. So what's your take on that? Oh, on the possible leaking injectors, would that be causing this problem? Like i said it was sudden, there was that problem with the idle, but the vibration/shaking suddenly came up, the night before this it was running fine. On the coil pack, according to the printout from autozone one of the reason for a P0171 code is ignition misfire?

My son had a broken wire on one of his injectors which cause a dead miss obviously. We found it after replacing spark plugs and wires. check them out.

code p0171 is a common Aero engine fault code.
engine running lean, too much air, not enough fuel

usually one of 2 culprits
1. broken pulled off vacuum line on vac. line christmas tree distribution tee located on driver side valve cover rear top or fuel vapor canister purge system under air cleaner. or air leak after the MAF, large tube, throttle body gaskets, IAC gasket, leaking intake manifold gaskets.

2. dirty coated MAF. search aero forum for MAF cleaning, worth a try. usually have to replace because the deposits become baked on.

the cam position sensor on OBDII systems only sets the fuel injection timing point.

are the O2 sensor OEM original with 175k on them? if so, replace the front one, the only one that sets air/fuel mix. you'll pick up some mileage especially on that 97 OBDII system.

check out our site sponsor, Rock Auto dot com, great prices, selection and fast shipping. far smarter than you're average parts store counter kid these days, they know their business

these EDIS waste spark ignitions like your 97 3l have to have wear prevention tips such as plat. or iridium on both the center electrode and the ground strap due to the series paired plugs

Hi 96_4wdr, I'll see about checking around the intake again for leaks, I can't get down to where the intake manifold connects to the block, I assume I should take it to a engine diagnostics place to get them to look at it? My MAF sensor is clean looked at the sensors and tried running it with it plugged, idle was far worse, revved up then down and almost cut off, stalls when being given any gas. And the plugs that were on there and wore so strange on one side were Double Platinums, I replaced them with Iridiums. We're extremely limited on money, should I just replace the coilpack or take it to a engine shop?

Does anyone know where I can get a a layout or diagram of all the vacuum lines under the hood of the 97 3.0? Also, the only way I was able to tell if I had the crankshaft at TDC was by using the position of the crankshaft sensor and the missing tooth on the crankshaft gear, on other cars the notch for TDC is very small, if I didn't get the crankshaft at exactly TDC and it was off by a degree or two when I installed the new camshaft synchronizer and sensor, would that cause this problem?:-huh

What is your first code? The first code in the list is the one you focus one. You need to address the lean condition, lean problems if ignored can cause physical engine damage on the '95 and newer 4.0L.

The first code is the P0171 code, and the only other one now is a evap code cause the gas cap has gone bad, that code has been there for over a year. So focus on the lean code correct? I guess I need to hunt for a vacuum leak.

Guess what, vacuum leaks in the evap line will cause evap codes.

Ok, I'm giving a update here now cause I've done alot of work, after my last reply I went out to get codes again and it gave a IAC code, so I replaced that and the code went away. I then finally found the vacuum leak that was causing the p0171 code, It was underneath some hoses, the line going from the thermisistor to the throttle body, it was split wide open, so I went ahead and replaced all the lines from the canistor, to purge valve and thermisistor too. That improved things, the idle wasn't all over the place and acting like it was gonna cut off, but the vibration is still there, and then the O2 sensor threw a code so I replaced that. Now all I have is that p1443 code that has been there for over a year. But the engine still vibrates, especially at a 100 or so RPMs higher than idle rpm in park. So far in the past 3 weeks I've replaced the camshaft sensor and synchronizer (which had been busted for months from the look of the damage that was inside of it) sparkplugs, spark plug wires, IAC valve, PCV valve and hose, vacuum hoses, radiator, oil pressure switch, O2 sensor, fuel filter. Now that troublesome vibration is still there and it still doesn't have as much power as it used to. This vibration was sudden, it wasn't there the night before then bam. So anyone have a clue what could be causing this?

Time to do a cylinder balance test and determine which cylinder is not performing as well as it should. Running a compression test might be a good idea at this point to determine the health of the engine.

As I mentioned, I learned from hard experience that lean conditions can cause physical damage to the engine. On my brothers van he drove it with an intermittent lean condition for about three weeks before he got a misfire. The heat from the upper intake gasket leaking into cylinders 4 and 6 had caused the valves to warp on those two cylinders. Expensive and time consuming repair, certainly would have been less involved to have replaced the intake gaskets to begin with.

Can the standard scanner advance and autozone lets you borrow do a cylinder balance test?

The OBD2 system is actually measuring crankshaft acceleration constantly, it will probably detect a poor cylinder performance as a misfire. If your bored though....... a compression test should set your mind at rest (even better a leakdown test).

The worn spark plugs on one bank is normal for the edis systems, the firing stroke on one bank is reversed polarity which burns away the centre electrode more quickly. Motorcraft plugs will last about 100,000 miles on a good engine though!

Did you set the Synchroniser with the engine on the POWER stroke ? (with compression in the cylinder), if not then your injector timing will be 180* out of synch & will cause power loss & lumpy idle etc. check this ASAP. This is MOST likely your problem if it is set wrong. Both valves in cyl #1 should be OFF the cam at TDC.

If coil pack was NFG you would get a problem on 2 cylinders simultaniously, which would give out PO3XX codes.

Check for a cracked plug or loose plug ,this can give you nightmares & should set a code too. IS the CEL now off?

When did you last change the fuel/ air filters , now would be a good time!

Aeroman.

How did you determine that the old plugs were double platinum? What is the part number. The wear pattern suggests they were single platinum plugs.