Does a 1993 3.0 Aerostar have a knock sensor? I've been told it doesn't have an egr valve, now I read no knock sensor....trying to eliminate spark knock here. thanks, Judy

 

The van starts great, runs fine, is a bit sluggish when accelerating though...and tons of spark knock. No smoking from anywhere. Tried cleaning maf, new thermostat (it was stuck closed), cleaned out air intake, adjusted timing....it doesn't appear to have egr valve or knock sensor, not sure what to do next? Just fyi, not sure it matters, but it is leaking oil from somewhere. Otherwise, no major issues.

 

How do the spark plugs look? One of mine was knocking pretty badly, and I found one of the plugs caked with carbon build-up. The other plugs weren't as bad, but also carbon fouled. It was caused by a failed oxygen sensor, making the engine run too rich.

 

can also be a vacuum leak. usually a vac. hose in the 3.0L, less likely but don't overlook leaking intake manifold gaskets. don't miss the hoses on the gas fume purge system under the air cleaner box, long vac. hose back to throttle body.


check the vacuum line to the vacuum modulator on the passenger side of the transmission. pull line off and look for any signs of leaking ATF=s shot leaking vac. mod. =s replace. also carbon loads engine combustion chambers.

was the thermostat stuck closed or open? usually they stick open, engine runs cold. deep deposits of carbon build up in combustion chambers and intake valves from cold rich injector fuel spray. engine ECM never goes into operating temp. closed loop leaner mix mode.

any codes?

how much oil is it using/leaking?

got the right heat range plugs? kids in auto parts stores will pull and sell anything. critical to have the correct plug in these. Copper core Autolites are good in these, no need for expensive platinum. if no AL's avail locally, NGKs and Champion work well in these standard HV distributor ign. system Fords. doesn't require anything special, just correct heat range.

list of plugs by manuf.
Sparkplugs.com - Application Search Results

Autolite - Application Look-up

ChampionSparkplugs.com - Application Search Results

to clean the engine combustion chambers and intake valves, use a 12 oz can of Berryman B12 or just straight acetone from hardware store and a 1/8" neoprene tube. can use Seafoam but it's expensive for just common ingredients, overpriced and not any more effective.
put another 12 oz can of cleaner in the gas tank.

run the warm engine at 2000 rpm with the intake hose disconnected from the front of the throttle body. put neop. tube in can of cleaner and other end at gap at bottom of throttle body plate. allow the engine to suck up all the cleaner slowly. may kill engine. restart and finish.

let engine set and soak for 1> 2 hours and then take out on freeway for 15 > 30 minutes and run hard with several full throttle accelerations from 0 rpm.

 

My husband doesn't think he needs to check the plugs since he put new ones in last year (I disagree). He was wondering if the oxygen sensor could be an issue though.

The thermostat was stuck closed, the van was running hot for a few months (about halfway on the temp gauge). The oil looks ok, not milky, no smoke, not suspecting manifold gaskets just yet. I just read about the vacuum mod this afternoon, so he will be checking that. Haven't checked codes, Autozone only checks 1996 and newer vehicles for free.

It is using a lot of oil....I have been adding a quart about every 10-14 days. I used Seafoam a few weeks back, it didn't seem to help. Hubby played some more with timing, and says the knock is better, I'll find out tomorrow when I drive it if he is correct, but I suspect it will be back.

I really appreciate all your tips, I will have my husband look at all of these things this week. He was living 1400 miles away the last 10 months, and I did what I could while he was gone, which were the simple things like thermostat and top cleaner. He gets to do the hard work : )
Thanks! Judy

 

hi Judy,
here's the DIY procedure for self testing for codes in pre '96
Ford Fuel Injection » How To Run a Self-Test

can try premium high octane 91 or 93 to see if it helps temporarily until he has time to find the problem.
engine knock ping can easily damage these engines.

old worn out O2 sensor usually makes these run lean which causes a ping knock condition. should be replaced every 60k>80k miles.

engine should use no more than 1 quart every 750 miles or the carbon build up in the combustion chambers from burning oil will cause pre ignition pinging knock.

Cliff
tell your husband hello for us and make him a big roast dinner for all the work he's doing on your rig, he deserves it for working on an Aero. my hate rig was wife's old Buick Skylark with transverse V6 engine, almost bled to death changing the spark plugs.

 

Hi Cliff. I did try the higher octane gas as the very first thing, it didn't help. I must say though, that after driving the van this morning, the spark knock is gone, plus it is accelerating much better...can fixing the timing fix sluggishness too? The overall driving experience was improved. How does timing get so messed up anyway?

btw, since he's been back, I've made him homemade soup, lasagne, steak, and many of his faves, lol. He's probably already gained a few pounds ; )

 

The timing can drift from lots of causes. The distributor has a fair amount of rotational mass, which can allow the whole thing to twist slightly over time. It has only one hold down bolt.

Just have him make sure the timing is being set with the SPOUT removed and that the SPOUT gets replaced when he is done. If the SPOUT is not removed, the timing will be way off.

Anything that causes a lean condition can cause pinging.

 

If the engine is knocking, it will not be generating all the power it can, so will feel sluggish. If you can stop the knocking by retarding the timing, it will feel stronger. On the other hand, retarding the timing from "normal" will also make the engine lose power; some of the energy generated from burning the fuel will go to heating up the coolant and exhaust (wasted). That in turn can also cause knocking because all the parts are now much hotter. So the engine has an optimal timing setting that provides the best performance (and efficiency).

 

Judy,
looks like husband has earned pie and ice cream with an afternoon stretched out in the recliner watching football.

enjoy your Aero.

 

Hi, I have a 2010 F150 54 and the knock sensor wire was severed. I posted an inquiry on this forum but haven't rec'd a response. Two independent garages (actual owner) inspected the wire, as well as a local residential exterminator. All have stated it appears to be a slice, there are no rodent markings on this wire or any other wire, insulation, plastic, etc. The Ford dealer alleged pack rat damage caused the wire to be severed and declined warranty. The truck has 6,500 miles and is immaculate. Fords estimate was $600-650. Two independent estimates are in the $350 range including the sensor (OEM) and possibly gaskets ($80). I appealed the Ford dealers decision to Ford warranty and they did not respond so I called them. They said the issue the dealer responded that it was a non warranty matter and case closed. Ford said they do accept any repair facility's opinion or findings. I have some mechanical skills but have some limitations on tools at our seasonal home where I'm at now. I'm almost 70. One owner of a repair shop implied the work was time consuming but not difficult. The estimated hours of labor are 3. I can afford to repair the truck. Sadly this has left a very poor feeling between Ford and myself and I'm considering selling the truck. It's a 3rd vehicle and not being used as we had originally intended when purchased. (health issues). Anyway...........perhaps I'll do a small claims court and see what happens. For now I'm more or less curious if this issue can be tackled by a home body. If special tools are necessary I'm toast. Thanks cj

 

CJ: I think Ford-trucks.com has a F150 forum, but this covers generic information.

Ford's warranties will cover certain failures in normal operations, but not damage, unless you can prove that it was their fault. If the wires were cut, you need to prove that it was done by a Ford technician while working on your car. Has someone worked in that area recently? When did you notice that the wires were cut?

I once had a problem with my engine where it started to run funny. Since it was still under warranty, I took it to the Ford dealer to check it out. They called back to tell me that rodents had eaten through the TPS wires. Since that was not covered, they would charge me a minimum of $50 for looking at it, and $200 to fix it. The part cost about $30, and takes 5 minutes to replace, but they said they would run a full diagnostic afterward. It turned they were all things I could have done myself.

When I looked at the old TPS, it was amazing what the rodents did. There were a couple of segments of wires that were cut out cleanly. If it wasn't for the chewed up black plastic flexible tube that went around the wires, you would swear that someone snipped out those sections of wires with a cutter.