Ford 3.0L starting issues - high idle @ start-up

[Beast of Busco]

I have had quite a time in the last couple months with my '95 Aerostar w/ 183,000 miles on it. In January it would intermitantly turn over fine but not start (it ran fine when it did start). I took it to a local NAPA garage and they did a tune up with new plugs, dist cap and rotor. After that,it would start but not run right.

The garage did a compression check (all cylinders were around 140 psi except #1 which was 130 psi) and also checked the catalytic converter (it has a few pounds of backpressure). He told me to basically get rid of it since the engine is worn out and it needs a new catalytic converter.

It was missing and everything when I picked it up (had NO power and I couldn't go over 30 mph without it shaking). When I got home I called them back asking them if they were SURE they checked everything...and I felt like they didn't want to work on it anymore.

A week ago I opened it up (which isn't an easy task with all the "room" in these vans!) and found that they had put the plug wires on incorrectly! Not only was the firing order wrong, but #1 wasn't in the right spot!

It now runs okay... but the idle is high for the first 2-3 seconds or so and then it goes back to normal. We've had this van since 1996 and it is definitely higher than normal. Is there something else I need to check that would cause this?

BTW...I will not be doing business with this NAPA garage any longer.

 

[punisher]

Most obvious cause for the idle speed increase is the PCM raised the idle RPM to compensate for the firing order problem and it now needs to relearn correct idle speed.

Warm engine to operating temp. Disconnect battery, or pull PCM fuse. Have a cup of coffee, wait 15 minutes to reconnect power. Start engine with gear selector in "park", and AC off. With foot on brake, cycle the gear selector through all the gears pausing about 15 seconds in each gear until idle stabilizes, cycle selector back to park. Repeat procedure with AC compressor on.

It is normal for the idle to "flare" a bit after startup when the engine is cold this time of year. It is also possible the shop messed with your base idle speed when they realized it didn't idle correctly/right speed. It is very very rare to ever reset the hard idle on a fuel injected Ford. I did lots of cleanup work after independants. With the engine warm, disconnect the IAC (with AC off) and verify base idle is to spec, usually 600-650 RPM (check emissions sticker). You can also check the throttle body and IAC and clean if neccessary, reset learned idle afterward. The shop did your cat converter no favors by getting the firing order wrong.

 

[Beast of Busco]

Thanks for the help!

I did what you recommended and it still revs at start-up. I think I will check the throttle body and Idle Air Control next...I am familar with cleaning these on my '01 Saturn SL1.

I was surprised my mpg was almost 20 when I filled it up this morning. I have let it idle a lot in the past week and thought it would be lower.

I have done business with that shop since around 1995 or so. There have been a couple other times where they gave me bad advice and I should have realized it then. The mechanic is more of a "replacer" than a troubleshooter. I am in industrial maintenance, and have seen a number of these in my industry through the years. They won't be getting my business any longer, even if I have to pay more.

I really don't want to put a lot of $$ in this van, but would it be worth replacing the cat. converter?

 

[unDummy]

If you have emissions testing and it passes, leave the converter as is. If no emissions testing and you like destroying the environment, hollow it out. But, you can get generic replacement catalytic converters that aren't too expensive. '95 is pre OBDII, right?

Run a few bottles of quality FI cleaners.

With 20mpg, your van is running pretty good. Just stick with maintenance intervals and keep on driving.

Do another compression test. Then, I'm voting that this vehicle become a Auto-rx test candidate.

Its tough to find competent shops. Sometimes, you'll just have to buy some tools, a factory service manual, and spend your free time on the vehicle!

 

[Beast of Busco]

I'll run a couple bottles of the Techron FI cleaner.

I have thought about the Auto-Rx....I've done it on my Saturn but not this vehicle.

As for working on it, I just wish I had more room!

 

[mazduh30]

Normal for engines to have high idle 1200-1500rpm for a few seconds and drop slowly to idle speed (my high idle is 1200). This is for to lower the emissions by heating up engine quickly, hotter the egine the lower the emissions. But if the high idle doesn't drop in a few seconds or really high, might be that your MAF sensor might be out of range.