Thanks, asavage. Yes, my Dad remembers you well and very much appreciates your detailed reply. Okay, so by holding the gas pedal down you can put the system into 'flooded' mode and possibly start the engine hot much like you can start a flooded carburated engine. I seem to recall having that occur on a 16V VW project I did. I had forgotten that.

The TFI on this van is on the passenger side fender well rather than the distributor. Thank you for your kind offer; I wouldn't tend to look at that module at this point since we had spark even when the engine wouldn't start. I spent some time on the vacuum lines/caps at the tree on the manifold; I replaced a somewhat loose cap and confirmed that the other ones were solid.

Re: MAF, does your comment hold true if the unit is suspected to be incorrect for this application? 96 4wdr made it clear in another post that these MAFs are precisely calibrated for each application, and it appears the unit on the van came from something else. Then again, $100 is $100. I'll try disconnecting it. Also I finished my test; terminal D has 1.3 volts at idle, increases in a smooth and stable manner as I rev the engine, then returns smoothly to the 1.3 when I taper off the throttle.

I do have a fuel pressure tester and I suspect I could perform the test. My Dad had pulled the thermostat last year so I installed the highest temp unit they had, 192. Once I solve an apparent leak, possibly the water pump, I will add coolant and get that squared away.

There has been a development since I posted earlier today that may be very significant; after confirming that the engine would now start, I added a couple of gallons of fresh gas and re-tightened the clamps that hold the air ducting to the MAF and the throttle, then restarted the engine. As before, it idled quite roughly and high; the engine shook visibly. However, this time, approx. 30-40 seconds after starting, it smoothed out considerably, and idle seemed to drop slightly as well. I shut down the engine and restarted it 2-3 more times, and each time this improvement took place. Dad observed this as well. Within a few minutes of shutting the engine off, while it was quite warm, it would restart.

At that point Dad ran the KOEO test and got only codes 111, 10, 111. I'm a bit confused about whether 10 is nothing at all, or cylinder 1 not passing balance test; any help on that? He then recommended we let it sit more like 30 minutes, to let the engine 'heat soak'. Good idea. And sure enough, it would not start. He just now mailed me that he restarted the engine, ran KOER, and got only '4' as a code.

So, what is it that would change at approx. 30-40 seconds after starting? I think this is close to being squared away. Then it's off to the smog shop. Thanks so much.

92

 

I knew that! That's one problem with owning so many Aeros.

Yes. Even if it's the wrong MAF, if it's disconnected then the engine started, it should run smoothly cold. Hot, that's a different story.

He's correct, and they are each special to the application, and $100 will only buy you a Delphi or equivalent, not a Motorcraft (the Delphi I bought was bad out-of-the-box). You're going to want to know that it's bad before you commit to a new MAF, or play junkyard roulette (which is what I like to do). The U-Pull-It type JYs up here are starting to get mercenary on MAF pricing, though.

It's an hour past my bedtime (I now get up at 3:45am), so I'm going to have to try to think about this tomorrow.

 

does the engine miss both hot and cold? not certain reading thru the thread.

here's the Ford ECM computer strategies.
lists the sensors and engine acuators involved in each.

different between each.
cold start is pretty dumb and KISS principle. just ECT, TPS and the computer program plus enough air in the throttle body plate gap and the IAC leakage

http://oldfuelinjection.com/?p=64

 

Thanks, 96 4wdr. It stumbles noticeably when you first fire it, hot or cold. It then smooths out. This morning I will test both the ECT and the ACT; that seems super simple. I'll just compare voltage at startup with voltage when it smooths out. Normally we would expect changes to be correlated with temperature, but perhaps something is off. I'll take this one step at a time; there's only so many things that go awry, as you say.

92

 

Progess today; tested the ECT and the ACT.

ECT:

Startup, 4.3V. Engine running better than previous startups; don't know why.

Approx 5 min running, 3.05V.

Approx. 15 min, 2.80V.

Approx. 20 min, 2.65V.

Now it gets interesting. After having settled around 2.6/2.7/2.8V, steady, it would periodically spike as high as 3.6 or 3.7 briefly, and the engine would stumble noticeably. Then it would settle at approx. 2.6/2.7 and run well again.

ACT:

In the am, when the engine ran better at startup than previous times, 1.78V

Later in the afternoon, when the outside temperature had come up, it showed 2.32V, then within a few minutes settled at 2.14/2.15V and stayed there, very stable.

Faulty ECT? Should I remove it and test resistance at different temperatures in water? BTW, I noticed today that the throttle lever is resting on the stop screw, so the high idle is probably at least partly due to this. Obviously the previous owner had a reason for cranking it up, probably when the engine started running poorly. I know I have to follow the factory procedure for letting the computer set the idle and having space between the lever and the stop screw, but I suppose I might as well wait until I have corrected the primary problem. Thoughts? Thanks,

92

 

Code 111 indicates that all relays and actuators (and their related circuits) are OK, and no faults were found.

Code 10 is not a fault code, but a "separation" code used to separate the groups of codes during a KOEO self test. However, during a Cylinder Balance Test, Code 10 indicates a problem with Cylinder 1 (i.e. it is not contributing at the same level as the other cylinders).

In your KOEO case, a 111, 10, 111 indicates no problems detected between those two tests.

 

That's awesome. Thanks, formeat,

92

 

You should set the idle screw to where it just pushes the throttle plate away from the throttle bore. Its purpose is to prevent the plate from jamming in the bore, now that the idle is controlled by the EEC. If the plate jams, what usually happens is you can't open it when you first step on the gas pedal, so you push a little harder, and then it snaps open, causing the engine to surge, and maybe your vehicle will lunge forward. Then you take your foot off of the pedal, allowing the plate to snap back against the bore, jamming again, so you start over doing the same thing.

 

Thanks, xlt4wd90. I'll check that out further. Another eventful and fun-filled day; attempted to follow the Chilton online troubleshooting for the ECT with it removed from vehicle, with water and an ohm meter. Must have been doing something wrong; couldn't get any resistance readings. Felt like the voltage results I got are strong evidence that it's bad, so Dad sprung for the $16 unit at Kragen. Along with the idle correction (I don't have a tach, but I suspect it is idling something like 250-300 rpm less now), ran much better, and re-ran my voltage numbers on the new ECT. Much lower numbers; once it got warm I was at like 1.20 or something, then it kept going down and hit like .86. Referring to the numbers at oldfuelinjection.com, I see now that these are much more in line with specs than those from the unit I removed, and there is no more intermittent spike in the number and a coinciding stumble/surge in the engine. So it would appear that I correctly diagnosed/repaired that fault. Chalk one up for the shadetree idiot (me).

Oh; I pulled the wiring plug from the IAC with engine running, abruptly died. Good. Also checked for increasing and stable voltage out of the TPS as I opened the throttle with engine off, steadily increased, good. Still haven't tried to run it with the MAF disconnected. Guess I should do that.

But it's clearly not good enough; still some minor roughness, exhaust is nasty (though no smoke). Seems a bit better at higher revs. Then, as I had the heater cranked up all the way after refilling the cooling system, I turned the heater all the way to off with engine idling and it abruptly died. Fired it back up, moved it from on or high, whatever, to floor, and it again died. Hmm...what's THAT all about? This ain't boring, for sure.

As this project is all about seeing if it can run well enough to possibly pass smog, then sell it, without spending money to get there, I think the next thing I better do is run a compression check on all 6 holes. If that checks out, I may need to look at things like plugs/wires/timing. Don't know if I need a certain special tool for timing. Read something about SPOUT connector, not clear on that. Any help is appreciated here,

92

 

The engine dying with operation of the heater sounds like a vacuum leak. The air doors are all vacuum actuated, and they use a vacuum reservoir to supply the pressure during high engine loads. Those lines are very thin plastic, and are prone to cracking with age, and may not be easy to see. Look for all those little plastic vacuum lines under the hood around the heater box and follow them to where ever they go, and make sure none of them are cracked.

 

All the vacuum lines on an Aerostar suck

almost every engine and powertrain system has at least one.
heater system
PCV
brake booster
A4LD tranny
FPR
gasoline fumes tank purge.
cruise control

must be more but I'm old and ya know what goes after all those damn vacuum hoses?

I've replaced some of mine 3 times.

anyone ever have a rig with vacuum wipers? had to let off the gas going up a mountain for the wipers to start again and clean the windshield..
now they really suck in a rainy climate such as the Pac. NW here

 

Not on '95-97; they're all-electric.
Not on '96-97, they're all-electric.

I had to tow with a truck with a vacuum wiper motor. 1953 Chev 3100. I can still remember towing from downtown Seattle one rainy night, up I5, across west to Deception Pass and down to South Whidbey, and having to let off the accel pedal every ten seconds to get the wipers to swipe once. It was a long, dark, rainy drive until 2am.

That was 30+ years ago, though. I haven't had to fool with a Trico vacuum wiper motor since . . . hmmm . . . my 1957 Fairlane 500 in 1983, I suppose. I kept a box of Trico wiper motors & parts for several years, but I think I gave them away a decade or two ago.

 

I remember riding in an old Jeep that had vacuum wipers. They were mounted on the top edge of the windshield and had levers on the inside so you can turn them by hand when the engine wasn't generating enough vacuum.

 

IIRC, Ford Model As had optional vacuum wipers. Of course, being a Model A, I might be thinking of one of the hundreds of aftermarket companies providing add-ons for that car, including a heater. The Model A, again IIRC, did not have one.

(Like Corvairs sold in South America, but this is getting pretty far away from Ray Mac's Aero problem(s).)

 

Actually the advice I'm getting here is awesome, for example, xlt4wd90's comments about the thin plastic vacuum lines. I know I had seen that mentioned in other posts as well. Anyway, that same day I did the ECT and idle stuff, indeed I did see one of those plastic lines cracked wide open and sucking vacuum. Of course that same line disappers into the heater box and his comment about each door being vacuum actuated means it's likely that other leaks exist in the guts of that heater system. I figure tomorrow I will temporarily just cap off that line to bypass any potential leaks further downstream, then turn the heater from high to off and see if the engine still dies (let me know if there's any reason I shouldn't do that). I will do this before spinning my wheels with a compression check.

All considered, I think there is a good chance this thing winds up running really well. The only issue after that is smog...good news there is I have a guy here in N.Cal who is as good as anybody in the business and I've known him for over 25 years, so he'll give me the straight scoop and I can make an informed decision at that point. My hope is that in the process of running through these steps, some of which are new for me, some of what I share can be useful to others. Thanks for all the help folks,

92