83 Vanagon bucking at 60 mph

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energyturtle
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Re: 83 Vanagon bucking at 60 mph

Post by energyturtle » Thu Mar 24, 2016 5:15 am

The only grounds are a three prong connector bolted to engine case on the left side under the plenum. I'm not a fan of clamps. The EGR needs to be taken off and blocked on the plenum. The temp sensor II should be able to be checked by resistance with the key off.
Scottie

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Randy in Maine
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Re: 83 Vanagon bucking at 60 mph

Post by Randy in Maine » Thu Mar 24, 2016 9:31 am

Suggestion....

Start by actually cleaning and tightening the mechanical connection of the TSII to the head, Then follow by cleaning the electrical connection coming from the sender into the engine wiring harness. I have a little brass brush for just this activity.

I can set my ohm meter up so that it will follow the change in resistance from dead cold until the engine is warmed up. You are looking for the change in the resistance.

from Ratwell...

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Amskeptic
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Re: 83 Vanagon bucking at 60 mph

Post by Amskeptic » Thu Mar 24, 2016 2:05 pm

83AC wrote:I was feeling pretty confused about testing things and then realized I have to have the ignition in "on," correct?
If you ever see "resistance" or "ohms" tests, they are measuring the component's intrinsic resistance to electrical flow. The test uses your tester's battery to determine the resistance. So, no, not only do you not want vehicle electrical flow through the component, you also want to unplug it from the electrical circuit in which it resides.

For the Temp Sensor II ( a RandyInMaine subsidiary ), you unplug it from the injection harness, and put the one lead on the wire leading to the sensor, and the lead to bare metal (like the cylinder head aluminum adjacent to the sensor location. Because this is a resistance check, there is no polarity (plus or minus requirement).
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83AC
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Re: 83 Vanagon bucking at 60 mph

Post by 83AC » Sat Mar 26, 2016 1:36 pm

Alright, with some extra time I got back to the engine after fixing the reverse light/horn issue. Thursday, I checked out the temp II sensor and the resistance is in range, so I don't think its the issue, but I will check the change in resistance, though I don't know how to check engine temperature because there isn't a temp gauge on my van.

Realizing I had a way to measure the RPM, I moved on to that. At idle, with stabilizer connected, RPM is high: 1,142ish. I figured I might as well check out the RPM when the engine starts to buck/miss. It happens at about 8000 RPM and gets worse if I push it. Turned off the van, disconnected idle stabilizer and connected the leads. Checked RPM, still high. I adjusted the idle adjustment screw inward and with it adjusted all the way in I was only able to get idle to about 1,118 at best.

Next I added a drop of oil to the wick under the rotor because I have kept forgetting this since last summer. Now, I still think I probably have air leak(s) and need to test for that. I think I still need to plug the vacuum retard line and see what happens. That being said, I think my vacuum retard line is .5mm too small. Effect of this?

I'm thinking I need to look for air leaks first, and fix any. My AAR elbow looks a little creased at the bend and I need to figure out how to relieve that pressure. I was also thinking if I messed up an injector when I replaced fuel lines and o-rings on the injectors that maybe that is leading to the high idle?

Okay, guys. High idle, things to check? Am I on the right track? This would definitely affect my low gas mileage and engine temps. I'm listening.
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Randy in Maine
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Re: 83 Vanagon bucking at 60 mph

Post by Randy in Maine » Sat Mar 26, 2016 2:21 pm

Your RPM gauge is off.

Redline on this engine is about 4200, Idle speed is about 850 RPMs.

(edit : redline 5,400 rpm - ed )
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Re: 83 Vanagon bucking at 60 mph

Post by 83AC » Sat Mar 26, 2016 3:42 pm

Randy in Maine wrote:Your RPM gauge is off.

Redline on this engine is about 4200, Idle speed is about 850 RPMs.
Hmm, yeah I guess that makes sense. I'll try to figure that out. Maybe I did something wrong in how I hooked it up. I'll check on that.
Say what you mean; do what you say.
1983 AC Vanagon camper - Penny Lane

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Re: 83 Vanagon bucking at 60 mph

Post by 83AC » Sat Mar 26, 2016 7:47 pm

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83AC wrote:
Randy in Maine wrote:Your RPM gauge is off.

Redline on this engine is about 4200, Idle speed is about 850 RPMs.
Hmm, yeah I guess that makes sense. I'll try to figure that out. Maybe I did something wrong in how I hooked it up. I'll check on that.
So a duh moment for me here - Bentley 24.11 to check CA vehicles w/ O2 sensor and electronic ignition, "resistor adaptor must be used in conjunction with commercial tach/dwell meter." That explains my crazy RPM post!

Now, for more info: checked resistance on all injectors - within spec. I haven't yet checked the spray patterns or voltage in the lines there. I am thinking it might also be worth running some injector cleaner through? Would it also be prudent to run some sea foam through to clean out anything that needs cleanings for good measure? Any good engine cleaning recommendations to eliminate any dirt related issues?

Checked resistance on AAR- within spec. I've replaced the vacuum retard and advance lines. If I pull the retard line the idle increases, so assuming that unit is functioning. I need to replace the vacuum line from the fuel pressure regulator - it has a crack in the line at each end, but not sure that is the source of my hiss.

Checked intake air sensor per Bentley - all spec, BUT! When checking terminals 7&8, I find at least one spot on travel of air sensor plate that reads 26ish ohms and Bentley says it should never be outside of 40-500. It reads below at about 2/3 of the way through it's travel. What does this tell me? Dirty or bad spot on AFM? Nothing? Could this be part of the bucking problem? Beyond that point the resistance returns to within spec, and when driving, once the bucking starts, if I try to push through that, it only continues, gets worse, and the van slows down quickly.

I still need to clean the grounds. I will check the O2 sensor, multi-pin connector, double relay, etc. to rule out issues there. I don't have a timing light or the resistor adaptor for the tach - anyone ever built one or know where I can find one? I'd like to do a compression test as well and see if I can track down if one or a couple cylinders aren't up to snuff. All cylinders checked out pretty solid when we bought her - around 140/145 on each if I recall. I also need to do a valve adjustment since I haven't done one since we got the van and there is a ticking that seems to be coming from RF cylinder that doesn't go away once warm. While adjusting valves I will check to see if any adjusting screws need to be replaced since I have new ones and will also check to see if the lifters are okay. I'm wondering if one of them isn't pumping up?

Okay, those are my results and ponderings for the day. Guide me, oh wise ones!
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energyturtle
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Re: 83 Vanagon bucking at 60 mph

Post by energyturtle » Sun Mar 27, 2016 4:55 am

The AAR elbow is probably cracked, very common. How about some pictures of the EGR "crimped lines", and the rest of the engine? I want pictures:)
Scottie

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Randy in Maine
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Re: 83 Vanagon bucking at 60 mph

Post by Randy in Maine » Sun Mar 27, 2016 9:32 am

If it were me (and I was trying to figure this out as cheaply as possible) I would first have a good inspection of all of the vacuum leaks.

That would include taking the S boot off the car and carefully examining it under bright sunlight. They love to crack in the pleats. Use your "mirror on a stick" to inspect the 4 intake runners that attach the intake tubes to the heads. Have a look at the 90º boot that attaches the aux air regulator to the vacuum hose going to the S boot. Leave no hose or seal uninspected. New injector seals are only $5.

I would just replace the Temp Sender II for $20. What is your time worth?

Do a fuel pressure test (with and without the vacuum hose attached) and also a fuel volume test. Rule them out.

A 1 gallon paint can and a a few air fitting can also make a decent "smoke machine" to check for various vacuum leaks under low pressure blowing of smoke.

If your EGR valve is suspect, seal it off well using thin metal and good gasket adhesive. Both ends.

Shove a golf T in the little vacuum line going to the air cleaner. Go for a ride and see if that changes anything.

Keep in mind that if you really are a "CA emission set up" everything really needs to match including the AFM unit, and the double relay and of course the wiring harnesses. Inspect the wiring harness that leaves the distributor and heads to the ignition module as it likes to chafe right at the bottom of the distributor.

Your tachometer (green or red clamp) should be hooked to the "1" or "-" side of the coil and the black clamp to a known good ground (like a screw that hold in the engine tinwork). Dwell angle means nothing with your hall effect ignition. You will still get a reading, but it won't mean anything.

Buy a timing light and learn how to use it.

Keep in mind that your set up is a little different than a 79CA bus . Close but different.

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Re: 83 Vanagon bucking at 60 mph

Post by 83AC » Sun Mar 27, 2016 1:21 pm

energyturtle wrote:The AAR elbow is probably cracked, very common. How about some pictures of the EGR "crimped lines", and the rest of the engine? I want pictures:)
Scottie
I pulled the AAR elbow and though it seems squeezed in there tight, it's not cracked, so that's one things down! I'll get you some photos once I have some things back together. I have the AFM out right now so I could get to injectors and such to inspect.
Randy in Maine wrote: That would include taking the S boot off the car and carefully examining it under bright sunlight. They love to crack in the pleats.

Bingo! You got it, Randy! I took off the S boot and there it is, a big old crack in the pleat! I was ecstatic! Ordered a new one today from the guys at Airhead Parts - might as well get one with all of its life in it! In my search for this part I also discovered the sleeves that connect the runners to the plenum are available and mine look like crud, so I ordered 4 new ones and will install those when they arrive also. I have to tell your I am PUMPED :cheers: :thumbleft: =D> To find these problems and parts! One thing at a time. I was starting to feel a little worried I wasn't cut out for this stuff. Thanks you guys for being my extra brains and motivation. I really want to get good at this stuff, and you're helping me learn so much!

I would just replace the Temp Sender II for $20. What is your time worth?

True . . . It couldn't hurt. I will see what happens once I fix the vacuum leaks. I'd like to rule out things one at a time.

Do a fuel pressure test (with and without the vacuum hose attached) and also a fuel volume test. Rule them out.

. . . Always something to learn :thumbleft:

Keep in mind that if you really are a "CA emission set up" everything really needs to match including the AFM unit, and the double relay and of course the wiring harnesses. Inspect the wiring harness that leaves the distributor and heads to the ignition module as it likes to chafe right at the bottom of the distributor.

. . . I'll have to check this out a little closer as I go on. I wouldn't be surprised if as things were replaced the didn't always pay attention to that, but I don't know. The PO used a reputable shop for all of their repairs from what I can tell.

Buy a timing light and learn how to use
:salute: roger that - will do. Have one to recommend?

I also checked out the multi-pin connector at the ECU and everything looked good, though the resistance to the injectors was about half of what is spec. Thoughts here?
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energyturtle
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Re: 83 Vanagon bucking at 60 mph

Post by energyturtle » Sun Mar 27, 2016 1:59 pm

Save your $$on the S Boot. Take your old and get some dawn dishwashing liquid, and clean it up real good. Let it dry. Make sure there's no oil or grease on it, CLEAN. Go get a can of plasti-dip. 3-4 even coats. Re use any serviceable parts you can. There are only aftermarket S boots. While they work, a properly prepped and plasti-dipped original is just as good or better, debatable depending on who you talk to. Good job finding the problem. NEVER ASSUME, AND NEVER THROW PARTS AT IT. GUESSING IS NOT FIXING. Always start with tune up process, then escalate the search into spark, fuel, vacuum. 9 out of 10 times the problem will make itself known during the process. WE DONT CHANGE PARTS AND HOPE. WE ANALYZE SYSTEMS, REPAIR, AND DRIVE WITH CONFIDENCE.
SCOTTIE

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Re: 83 Vanagon bucking at 60 mph

Post by 83AC » Sun Mar 27, 2016 2:40 pm

energyturtle wrote:Save your $$on the S Boot. Take your old and get some dawn dishwashing liquid, and clean it up real good. Let it dry. Make sure there's no oil or grease on it, CLEAN. Go get a can of plasti-dip. 3-4 even coats. Re use any serviceable parts you can. There are only aftermarket S boots. While they work, a properly prepped and plasti-dipped original is just as good or better, debatable depending on who you talk to. Good job finding the problem. NEVER ASSUME, AND NEVER THROW PARTS AT IT. GUESSING IS NOT FIXING. Always start with tune up process, then escalate the search into spark, fuel, vacuum. 9 out of 10 times the problem will make itself known during the process. WE DONT CHANGE PARTS AND HOPE. WE ANALYZE SYSTEMS, REPAIR, AND DRIVE WITH CONFIDENCE.
SCOTTIE
:bootyshake: I already ordered the new S boot. I guess you're right - I could have saved some money there . . . Newby mistake. I got too excited. Maybe in the meantime while I wait on it to arrive I will clean and repair this one to see what the impact is for kicks. Then I'll have a backup . . . Or can sell one . . . Or maybe even return the new one.

Either way, I'm feeling great about finding this problem and am excited about all of the things I have found that ARE working as they should! I've also learned a lot from this about diagnostics and engines, so I'll keep in mind in the future that the frustrating parts of maintenance are all learning opportunities and allow for things to get addressed before they are of concern.

Now, any ideas on the low resistance spot on my AFM and the low resistance from the ECU connector pin to the injectors?
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energyturtle
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Re: 83 Vanagon bucking at 60 mph

Post by energyturtle » Sun Mar 27, 2016 4:31 pm

Its always good to have spares. As far as the low resistance, I would say consult the Bentley. There's also a fine PDF of the F.I. manual for download over at "The other VW site". It was a great resource to me while learning the system. I give ya a couple more weeks and you will have it all figured out. Good luck greenhorn. We all have been there for sure.
Scottie

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Re: 83 Vanagon bucking at 60 mph

Post by energyturtle » Sun Mar 27, 2016 4:38 pm

83AC wrote:
energyturtle wrote:Excuse me if this has already been mentioned. Are you still running EGR and other emissions devices? Correct me if I'm wrong, but about the time EGR is opened under higher RPM's, isn't that where your power loss is occurring?
Scottie :scratch:
The EGR is no longer on this van. The tubes that connected it are crimped closed - I didn't ever know what those were.

As for the temp sensor I I, I think I finally made sense of where it is and now can move on to test it. I was feeling pretty confused about testing things and then realized I have to have the ignition in "on," correct?

I looked at the spark plugs and checked the distributor cap and rotor. Plugs look like things are lean or too hot. Cap and rotor are in good shape. I looked at grounds - a little confused because I thought there was supposed to be a wide ground strap somewhere in the engine compartment of my 83AC and I can't find one - the grounds are definitely dirty and need cleaning.
Pertaining to the crimped EGR tubes? I would like a pic if you can. Something about "crimped" didn't feel right.
Scottie

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Re: 83 Vanagon bucking at 60 mph

Post by asiab3 » Mon Mar 28, 2016 9:59 am

I've seen those aftermarket s-boots in person and they're actually quite well-made. It's important to balance our stubborn "reuse forever" attitudes with occasional purchases that keep our GOOD aftermarket vendors in business. (VWG, or Ventura Warehouse Group, is the parts manufacturing subsidiary of Airhead Parts, and most of their products have lifetime garnets, no questions asked. I don't know about the s-boots, but every part I've installed of theirs fits and functions just like a VW part should.)

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