86 bogging down

well hey there, new member here. Let's jump right in. I have a prob with my 86 2wd auto. trans.van
It completely bogs down with anymore than idle speed you can slowly rev it up in park, but under a load it will barely move. I've checked everything I can think of, cleaned the throttle control, new o2 sensor, new plugs wires, checked for vacuum leaks, new air cleaner seems to have good fuel pressure, no codes other than 10 for bad starter relay but I bypassed it last year with a secondary starter button, The problem has come and gone for the last month. when it goes away there doesn't seem to be a reason, when I change the o2 sen. a couple of days ago it ran normally ( it threw a o2 code, it was a bad wire) then..... it'ssssss back ! I've got some carbon build up in the tail pipe but other than that nothing. the plugs looked good just worn out. I also replaced the ecm when this problem started with a used one, all was good for awhile. so any thoughts ?

What you're describing could be a few different things. These type problems are usually diagnosed using the process of elimination. This could be fuel related, but doesn't really sound like it. Still, being able to monitor fuel pressure while testing can help narrow things down. Here's a thread that shows one way to do that: http://www.toyotavantech.com/forum/s...sure-regulator.

The next few things that come to mind are the coil, igniter, ECU, and AFM (Air Flow Meter). You've already swapped the ECU, so we can rule this out. You should pull the distributor cap and visually inspect the coil. Sometimes when coils fail they show obvious outward signs. If you see any cracks or burn marks, then it's a no brainer (replace). If it looks good, it's still one of the more likely parts. It's also one of the more inexpensive and easily available parts, so might be worth replacing anyhow. If that doesn't do the job, then I'd go for the igniter next. These are a bit harder to find and new ones are expensive. Purchasing used from a salvage yard or from eBay is usually the best. Here is a link to one on eBay: http://www.ebay.com/itm/TOYOTA-VAN-I...1bca97&vxp=mtr. The eBay one is high priced, but it's easy to get. If you can find one at a Pick-n-Pull salvage yard, they'll likely let you have it for $20. If all this fails, then I'd probably swap out the AFM. Here's one on eBay for $50: http://www.ebay.com/itm/84-85-86-87-...f4c9cf&vxp=mtr.

Sorry I can't help you narrow it down further without the need to purchase parts. If the offending part had failed completely it would likely be throwing a code. Sometimes things get weak though and performance gets compromised before codes are thrown. When chasing problems like this it's always a good idea to make sure it's not scheduled for a tune-up. If it's been over 30k miles since the last one or if you don't know when that was, then it just pays to take care of that stuff. You may inadvertently solve the bigger problem. Things like plugs, plug wires, distributor cap, fuel filter, air filter, etc can & do make a big difference in performance. Please let us know how it goes. Good luck. Tim

Aside from what Tim said, two things jump to mind for me: timing and exhaust restriction. I'd put a timing light on it to ensure that the base timing is correct and that it's advancing with throttle.

Beyond that- severely plugged catalytic converter or crushed exhaust pipe?

Good luck!

Good points! Especially exhaust (that had slipped my mind). Of course his problem comes and goes (or at least came & went) which is not characteristic of an exhaust restriction or a timing issue. Although it's possible there's a big chunk of something in the exhaust that may occasionally shift positions. Tim

not acting like a converter , runs great .....when it runs. Same with the timing , It wouldn't shift back and fourth so quickly. I did find a bad secondary coil though, just got the new one, and the rotor button was iffy So tomorrow A.M.

I did forget to mention pick-up coil. So far I haven't seen one of these fail............but there's a 1st time for everything. Good luck, hope that's it. Tim

Totally missed the part about it being intermittent- good luck!

well the coil change had no effect. although the 2edary coil tested bad. my air tube ( from the afm to throttle body is hard as a rock, and was / is falling apart. I epoxied all of the bad spots, but getting that bad thing back on was such a P.I.T.A. that I might have done further damage. so is it important to have absalute 100% on the tube ? could it be throwing off the afm ? where do I get a new one, can't seem to locate one on line.

OH, and how do I test the igniter ? my book doesn't say.

The air tube needs to be flexible to do it's job. Trying to repair an old brittle/cracked one IMO is a complete waste of time (won't last if it can't flex). Here's a post from another thread:

Quote:

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Originally Posted by timsrv

I ordered one from Toyota less than a year ago and they were still available. It is Toyota part #17881-73020 and sells for about $75 on most of the discount internet Toyota parts sites (expect to pay over $100 at a Toyota dealer).

http://i8.photobucket.com/albums/a23...lebodyhose.jpg

Some people have repaired with silicone, duct tape, and other such things. Personally I consider anything that requires such a repair a complete waste of time. I have found good ones in the salvage yards before and always grab them as spares (for when Toyota quits selling them). Tim

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As for the igniter, the factory service manual says "try another igniter" (that's as close as they get to testing them). Tim

I'm been pretty burned out on this problem for a couple of days. But now back at it, should there be resistance in the distributor cap between the coil pick up and the center post ?

Yes, but these are carbon contacts (to reduce radio noise), so there's quite a bit of resistance here. Something like 15k ohm would be in order.........maybe more.

Yea, I was afraid of that, thought I might have found the ever elusive "simple''' problem.

Things like distributor cap, rotor, etc should be some of the 1st parts you replace.............unless you know history and they're fairly new. Even if they're "newish" it's still good to remove those variables. If it turns out to be something else, you'll have some spares. Tim

Did the simple stuff, I;m going to go through all test to see if I missed anything. I haven't tested the diagnostic system yet. i do have a factory dealership shop manual , so I have all of the testing info, not that I understand it, but "check this " , "it should be" , I can do. I did not take the AFM apart, or the TPS. so removing the throttle body and AFM ....again and wrapping the air hose in plastic, ( to see if that's the problem) will follow. What about the fuel pressure reg. is there a way to test it without a pressure gauge ?
I saw a similar thread, but lost it, don't know if his problem was resolved, but he was doing everything I'm doing.

I would ignore the TPS & the throttle body until this problem is resolved (to my knowledge neither of these can cause a problem like this). Just to rule out the TPS, you could unplug it from the harness for testing (van should still run good with it completely disconnected). For the fuel pressure test I already linked you to a thread for that (my 1st post in this thread). Nothing to take apart on the AFM, just swap it out with another used one. If you haven't already swapped the igniter, this should be next. With cheap used parts on eBay and/or the local salvage yards I would take advantage of that. Having used components around can be valuable trouble shooting tools. I know you've already changed the coil & the pick-up coil.........right? If not, having a good used distributor around can be very helpful too. I got an entire distributor off eBay recently for $20. Tim

PS: A bad throttle body tube will cause rough idle when in drive with the brake applied. It will also cause hesitation on initial take-off. Not likely to be causing the problem you're describing. Tim

"?" coil = the large coil on the back side of the distb. sends power to the rotor. pick up coil = the small coil mounted on the distb base, close to the left front corner ?

Yes. although if the pick-up coil fails you'll need to replace the distributor (I don't think you can get these by themselves). Tim

Quote:

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Originally Posted by timsrv

Yes. although if the pick-up coil fails you'll need to replace the distributor (I don't think you can get these by themselves). Tim

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The Saints of all things Toyota be praised ! After checking everything there was to check.....I HAVE BEAT THE MACHINE, AGAIN !:dance2: It was the Igniter.

And believe me when I say, an angel drove by just at the right moment, when my exasperation was about to turn into despair. I was standing there looking at my van, on a side street in urban Charleston, knowing not to do when....A man drove up and said, "I don't know if you're interested, but I know where a van just like that is, and their going to scrap it". And I thought to myself, "a van just like this ? right' I mean realistically it looks like a lot of other vans to the un-knowing. But it was only 3 MI away, so I jumped on the moped, and found a 85 Toyota van 'just like mine' same color ! I called the # for the biz. that had moved, and the guy said he was just filling it with scrap to send to the yard, and that I could have anything I wanted off of it, FREE ! So I got my igniter , and everything else I could get off that day, Including the ECU, and a nice radio / cd player !
So yes Virgina, there IS a Santa Clause !

What a great ending to that story! Those wacky ignitors. When mine crapped out on my '87 cargo it would start intermittently and run just fine---then not start at all. Now I don't drive anywhere without a spare one in my onboard parts box.