70 FI will not stay running

[akokarski]

Hello,

It's been a long while since I've been here, but recently was looking at my fastback sitting there and starting to return back to earth sort of speak.

Decided to start putting at least some time back into it to try to get it to run.

Before I parked it it was having bucking issues which I couldn't sort out and eventually it ended up just cutting out and not restarting. And this is why it ended up getting parked for some time.

So what's happening now is it starts fine, but after warm up, it runs reach and eventually cuts out. It will start again after sitting for a few minutes.

I checked timing, reset dwell, check all cylinders by unplugging injectors, seem to be all firing. Also trying to rev it makes it choke.

Tomorrow I'll go through valve adjustment, what should I start looking at?

Thank you!
Anton

[Tram]

Make sure the manifold pressure sensor is holding vacuum.

Make sure there are no vacuum leaks.
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[akokarski]

Hi Tram!

alright, so i checked MPS and it is holding vacuum, quite well actually. I took it out of the car, connected my vacuum pump and pumped it and left it sitting while I went through valve adjustment and few other things, it did not drop an inch


Link


Pulled distributor, and rechecked my injector trigger points, looked ok. No excessive presence of oil or anything.

readjusted timing and double checked the dwel seems to be ok, ~57 deg and stayed within 1 deg.

One odd thing I noticed is one of the lobes is scored more than others. If I run my finger nail up and down it is really noticeable. Which may explain why my idle is not stable.

I sprayed boots and injectors to see if there are any vacuum leaks, still ok. I did go through it in the past (new boots, and injector seals). But once i got it warmed up, it started running rough and was stalling. I pulled connector on IAT and that appeared to smooth out the idle

Link


Looked through my parts and found another I think later or auto throttle body with the same IAT sensor (same part number) but 1/2 inch shorter:

I swapped the shorty one in and it seemed like it made it better, but I did not see much difference on Ohmmeter.

While I was at it, I cleaned up grounds and few other terminals.

Took it out for a drive, it was still bucking from time to time and when I was done playing, it stalled as I backed it into the drive way.

one thing I've noticed is that my #1 and #3 muffler connections are so rusted out that you can actually see through them:

I do have a spare muffler but it's got 3 pipes cut off.

Should I just start looking for a new muffler before going any further or do I continue to hunt down the gremlins?

What should I look at next?

Thank you,

Anton

[Tram]

Bucking is usually indicative of a maladjusted or defective TPS on a C/D system. You might try adjusting, and even take it off/ apart and see if the tracer has worn a spot in the PC.

Yes, replace the muff but that's not causing this issue.

The other thing that can cause this is a bad breaker plate in the distributor. Check this first, actually. Is your timing mark jumping around?
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[Tram]

Check your charging system output and your fuel pressure too.

If your fuel pressure starts dropping off because the pump is getting hot and trying to seize, the low pressure will mimic running rich because the fuel is not atomizing. Once you shut it down and the pump cools, it runs again.

Likewise, if the charging system isn't up to snuff it can quit running due to low voltage. Then, a good battery will regurgitate itself again after a bit and off you go again.
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[akokarski]

Roger that

I will check
1) charging system, i did have a generator rebuilt twice, maybe it was never done right... and I did put on a new voltage regulator.
2) fuel pressure (although i did replace my fuel pump with brand new E2000 IRC but maybe from sitting around I should get a new fuel filter?).

I have a few spare TPS units.

May have a lead on a local muffler...

I think distributor is ok, I wanted to get new set of points, not sure if scored lobe is to be concerned? Timing and rpm are not steady.


Thank you again,
Anton

[akokarski]

I had some time yesterday and today to mess with the car.


1) checked voltage at the reg (unplugging B+ and putting voltmeter between that terminal and ground) appears to be ok.
Z
2) checked fuel pressure, was ok in the begging but after a few minutes it slowly dropped to below 20. I keep hearing gargling noises from the tank. Added another gallon of fuel and it was running ok after that. It might be just so low on fuel that after a few minutes it just draws down. I should probably pull sender to see if it's a mess in there and replace fuel filter. I have replaced it in the past, since the car was sitting for sometime it is likely to be clogging from the varnish. This is a new E2000 pump.

I tried to adjust my tps perhttp://www.thesamba.com/vw/forum/viewtopic.php?t=340479 (made my head spin a bit) and http://www.thesamba.com/vw/forum/viewtopic.php?t=382055

seems like it was ok to be begin with.

timing is jumping around a bit, i tried to turning roter, it snapped back fine, same thing with the plate doesn't feel gummed up or anything. Is there another test for the breaker plate? Can a worn out lobe on the shaft cause erratic idle?

Thanks,
Anton

[Donnie strickland]

That sounds like a fuel delivery issue, i.e. the tank outlet is stopping up with debris. Pull the sending unit and peek inside, and if necessary remove the tank outlet and check the sock filter.
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71 Elm Green FI A/T Squareback

[akokarski]

pulled fuel sender and it doesn't look too horrible but there are some flakes and bits of rust. Sock looks ok, and I don't remember if I have changed it in the past.

either way I think it will not hurt to replace both sock and filter.

One thing I noticed about timing is that when it's cold, timing is really steady (although it is a bit advanced), but once car warms a bit it, arrhythmia kicks in.

Last time I pulled distributor, don't recall seeing a spring on top of distributor pinion, and if I am not mistaken, that can cause timing issues.

I think maybe I should pull that distributor take it apart and give a cleanup? Maybe breaker plate starts to binds once it's warmed up?

Anton

[Tram]

[akokarski]

Hi Tram,

The low pressure which I observed was a drop within 1 min or so. It was gradually dropping to 20 pounds. When I had more fuel in the tank it stayed steady. I think it was really the fact that fuel level was in low reserve that was causing these huge pressure drops.

None the less I will replace sock and filter. I just placed the order, but it will take a while for them to get here and then me to get to it I also ordered a new set of points. Old ones are still serviceable but with a little burn crater on the contacts.

Would a missing distributor drive spring cause similar timing issues?

Anton

[Tram]

[akokarski]

Alright, finally got sometime to pull the tank. I ordered fuel filter and in tank strainer from CIP1 and I don't believe they are correct. Fuel filter is metal silver canister with fittings way to small I think they are more like 1/4 inch nowhere close to 5/15. Sock was also rather short and plastic. Looks to be a good candidate for creating restriction

Found better sock at bugformance in san jose.

Went to take it apart and now I remember that I did replace the sock in the past and ran into the same issue as today. Sock's washer is fused to the nut, both are aluminium. I have a bug kit, but that pickup tube is to small in diameter and nut is to tall, it will bottom out on the tank body before it seals.

Any suggestions on how to go about this? It looks to be NLA, everywhere I look the year range listed for fuel pickup kit is way too generous which tells me it's for carb not FI.

Fuel filter is another story, local parts store found me microgard 33002 http://www.oreillyauto.com/site/c/detail/MGD0/3300...;ppt=C0262 which is replacement for wix and fram G2. Good 5/16 fittings, but on the body it has arrow with tocarb written inside. Should go ahead and use this or is there a better option?

I've used wix 53398 before, but these do not appear to be made any more.

Here are pictures of the sock and the crap that came out of the tank. Not too bad. I think I need to keep the sock.

Anton

[akokarski]

for fuel filter i am thinking of getting FG-800A

Inlet Size (Inches): 0.3125
P.S.I. Rating: 150
Primary or Secondary: Primary
Outlet Size (Inches): 0.3125
Material: 300 series stainless steel
Inlet Style: Push connect
Fuel Type: Gasoline
Outlet Style: Push connect
Micron Rating: 8
Diameter (Inches): 3
Length (Inches): 5.64
Mounting Style: Various
GPH (Free Flow) Rating: 45


for in tank filter I can probably get AN fitting from aircooled.net, add AN to barb fitting and hackout the top part out of my old pick up.

[Donnie strickland]

I went to the parts house and looked through the metal filters to find one with 5/16 nipples, and not so big and bulky. I don't recall the part number, but here's a picture I just snapped.

(I ran out of FI hose clamps, and had to use a couple of worm clamps, which I have not yet replaced )

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71 Elm Green FI A/T Squareback

[KTPhil]

It looks pretty small. Will it pass enough to not restrict flow?

[akokarski]

that's what I was thinking. I would rather deal with too large of a filter than keep scratching my head with clogged fuel filter. How I came up with FG-800A was looking at the same make/model as where airtex fuel pump.

Unfortunately the only filters that are out on the shelf at flaps now days are air and oil filters and everything else is in the back and looked up through computer which would not have the right stuff for these cars...

Anton

[Donnie strickland]

[Bobnotch]

[KTPhil]