Fuel Injection Question

Good luck...

You may have to adjust the throttle stop so that the vacuum advance line loses it's signal. This could mean the AAV is sticking open or there's another air leak.

Regardless, if the factory setting procedure doesn't work, just adjust the throttle until it works right, i.e. blocks the vacuum port. Could be something is bent or otherwise out of wack.
 
AFM.

I beleive I might have a spare AFM. Will look for it on Saturday when I get back into town..
 
Thanks for checking, Mark!

Dad stopped by Gibson's yard, but all the X's he found were from the carbureted years. If you have an AFM we could swap in to test, that would be a great help. Let me know what you find.

We are planning to bring the car to the Culver's restaurant cruise-in Neenah on Monday night. Perhaps we could meet you there. There's been a lot of progress since you last saw the car.

Brian
 
Reply.

Hi Brian. Sure hope you find the solution.

Is your X totally stock ? Or do you have a cam or headers or heavily shaved head or something ? Has it always done this, or did it just start ?

A couple of posts ago, you asked if it was possible to alter the spring tension in the AFM. YES, this is possible !!! Folks here do it all the time, some with great results.

A while back, Matt from MWB posted a fantastic step by step tutorial on how to do it. I tried to find it but was unable to locate it. My memory says it was about 3 years ago. Perhaps our resident "swami of search" (one of the Jims) could perform his magic and find it and post a link.

Perhaps doing so would only mask the real problem, but more info and help never hurts. Besides, I'd love to see that tutorial again..

Good luck, Doug
 
AFM Spring

Thanks for the reply Doug.

My car is Stock. It has exhibited this symptom to one degree or another all the time we've had it running (which isn't that long). The car sat for many years prior. The last time it was running before that was a few owners ago (probably 1995).

I did a search for "Flap Spring" and came up with this: http://xwebforums.com/forum/index.php?threads/7829/ (among others) with lots of good info.

Sounds like the plan of attack currently would be to:
1. Verify the Throttle Plate position at idle and TPS are adjusted correctly.
2. Swap in another AFM to test, if Mark's is available.
3. Monkey with the spring in my AFM

I'll update with any progress, and appreciate any additional suggestions.

Brian
 
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Sounds good..

Hey again Brian. Your plan of attack sounds sensible and wise.

I also found this thread which may be interesting to you:
http://xwebforums.com/forum/index.php?threads/9045/

I still recall an even more detailed thread from quite a while back (Matt even makes reference to it in the thread you linked to). Maybe someone can find it,or maybe it has disappeared into cyberspace...

In any case, it would be nice to have a link to any relevent threads posted here - for future reference. Just a thought....

Please keep us updated on your findings....and hopefully a successful outcome.
 
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Just a thought -- grounds

Just relaying what is a constant reminder, always check grounds. Probably isn't an issue this time because the problem is only at a specific RPM range, but you never know.
 
Thanks

Thanks for the reminder.
Verifying a good path to ground for whatever you're working on definitely is a "theme" around here, and it seems that it is rightly so.
 
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Update

Here's an update:

Friday evening, we re-set the idle, and verified there is now No Vacuum on the line to the distributor at idle. The AFM and Temp Sensor resistance readings are within the acceptable range. The voltage from the O2 Sensor at idle swings from roughly 300-700 milivolts, with occasional readings slightly outside that range. The car idles smoothly, and runs well throughout the range, with the exception of hesitation/stuttering between 2000-2500 RPM under light load. It smooths out if you open the throttle a bit, but just holding a constant speed on level ground in that RPM range is not smooth. The problem lessens if you open the flap on the AFM a little further when it's exhibiting the symptom. The problem goes away if the vacuum line to the distributor is plugged (as per Jeff's suggestion).

Saturday night, we picked up a "treasure-chest" from Mark Lott, who graciously supplied us with everything he could think of that might be part of this puzzle, to swap in and try to find the problem by the process of elimination. We're looking forward to getting back in it to find the problem. I'll update again when we know more.

Thanks, everyone, for all the suggestions & encouragement, and especially Mark for your generosity.:nod:

Brian
 
Injectors

Thanks for the suggestion, Tony. Another person has suggested the same, by 'private message', and I'm certainly not ruling out.

I probably won't have any more to report until after Friday. Tonight is our regular wrenching night, but we want to take it to a 'cruise-in' at a local restaurant. (We'll go with the vacuum advance disabled, so it'll run fine.)

Brian
 
Resolution

Well, the resolution of the whole thing is kinda anticlimactic. It appears to have been ignition timing related, all along.

We re-checked all the settings at idle (Throttle stop, Air Bleed Screw, TPS, Ignition timing, etc.) Everything looked good, but the problem at circa 2500 RPM persisted. My father didn't like the orientation of the distributor because the housing for the vacuum diaphragm was touching the timing belt guard, so he pulled it, re-indexed it, and re-set the ignition timing again. The problem disappeared. :confuse2: The car is running so smoothly now, I feel like driving to Wyoming, or something. Or at least moving on to addressing some of the other little issues.

Thanks again for all the helpful suggestions.

(Tony, I guess I'll have to call your bet off, as I had declared the ignition timing to be good, so you were betting based on faulty information.)
 
Yep... there goes my chance at supplimenting my...

fixed disability income and retiring...

Oh wait... I'm already retired... and disabled... Hate to think of what's next!

Guess I'll haveta dip into my Mega 401K/IRA for some chump change...

Glad you got it figured out... I would like to point out though it appears that it took another OLD MAN with some OLD SKOOL logic to remedy the problem! Be sure to buy him a drink... no, buy him dinner! Tell 'um I told ya!

HA!
 
the "Old Man"

Make no mistake: the "Old Man" in this project knows more about the workings of internal combustion engines than anyone I've ever met. He's surely forgotten more than I'll ever know. The project wouldn't be happening without him. Without a doubt, XWeb has been helpful, but my father has been indispensable. He spent his career designing engines, and had experiences you'd think I was making up if I told you.

I have a reasonably good reputation for being able to fix things of many descriptions, but I have no problem pointing to my father and saying "He fixed it.":thumbsup:

Brian
 
What's wrong with......??

Black-Tooth said:
......Oh wait... I'm already retired... and disabled... Hate to think of what's next!.......
Click to expand...

.....sitting back in a nice comfy chair, enjoying some of that so-called ALL-DAY California sunshine, with a good book and a chilly-bin full of beers beside you!! :sun:
(Pssst, forgot to tell ya - that's exactly what my friend and I are going to be doing for 2 weeks up in SUNNY Vanuatu (Pacific Islands group), from next week - us retirees DESERVE it, Tony!!)
 
Well... in LA-LA-Land, they think yur homeless!

HA!

Good to hear from you Ian... when ya gonna come to the Land O' Plenty and snack with us?

(I understand all medical care is free now... especially if yur an "alien" of some sort. You oughtta fit right in...)
 
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