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Drzdirtbag Samba Member
Joined: September 27, 2014 Posts: 80 Location: Kamloops bc
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Posted: Tue Jun 06, 2017 8:33 am Post subject: Engine suddenly runs terrible |
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Hay all,
I have a 76 2l fi van, she has been running like a top su i rebuilt her last year.. If put 15k miles on her with no issues.. I pulled into the driveway at home last night, shut it off, then 5 minutes later went to start her up to move her, and she didn't want to start, I could get her to run but very rough and wouldn't idle. Almost like the timing was way off... I haven't had a chance to investigate yet.. Anyone else had this issue?? Any thoughts?? I know it's had to suggest anything without hearing it..
Thanks, randy. |
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williamM Samba Member
Joined: August 07, 2008 Posts: 4333 Location: southwest Arizona
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Posted: Tue Jun 06, 2017 9:28 am Post subject: Re: Engine suddenly runs terrible |
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Well- you can throw parts at it -- or get the free trouble shooting tech manual here and do a "Robbie" style investigation to replace the faulty part.
Because FI is essentially a vacuum controlled fuel pressure system, a cold start system , an air flow control for fuel enrichment n fuel pump safety- not to mention the double relay, then power supply-
You can see why a few readings from components are needed to peak interest here.
your essentialy asking "what pellet hit the duck" _________________ some days I get up and just sit and think. Some days I just sit.
opinion untempered by fact is ignorance.
Don't step in any! |
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AB westy nut Samba Member
Joined: June 01, 2010 Posts: 1124 Location: Calgary, Alberta
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Posted: Tue Jun 06, 2017 9:33 am Post subject: Re: Engine suddenly runs terrible |
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Start with the easy stuff like looking for a massive vacuum leak. Maybe one of the larger hoses split or popped off. The fact you can get to start means it's getting spark and fuel. _________________ 1963 Ruby Red 356 Cabriolet
1976 Sage Green Westfalia Deluxe |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51057 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Tue Jun 06, 2017 9:38 am Post subject: Re: Engine suddenly runs terrible |
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A broken rubbing block on the points often produces a similar symptom.
As already mentioned get systematic with it and don't just start poking things or replacing parts, it was running fine and then it wasn't, what broke or came off suddenly? _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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ROCKOROD71 Samba Member
Joined: January 18, 2012 Posts: 2770 Location: Boston, MA
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Posted: Tue Jun 06, 2017 10:53 am Post subject: Re: Engine suddenly runs terrible |
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My 77 did this on Sunday. Couldn't get it to start. Made all manner of terrible noises, then started and would only stay alive with the pedal floored, eventually came out of it (running like shit for ~ 2 mins)
Then ran fine.
Ran fine today.
Sweet, "reliable" FI
My engine was gone through extensively last year, lots of hoses and clamps and stock tid-bits replaced to specs.
Feel like mine is the temp sensor but do those go intermittent before actually failing or do they just fail? _________________ 1971 STD BEETLE- DD-1st car, 1st love. keepin' it stock! 1600DP, Solex 34-3 Mexi Bosch SVDA Dist NOW w/POINTS
1977 WESTY "KrustyKamper" 2L FI
79SuperVert wrote: |
30 years from now, the next guy may not want your girlfriend, but he may want your classic car, depending on how nice you were to it. |
asiab3 wrote: |
Careful guys, a petulant child can grow up to be president these days. |
**winter drivers: no survivors!**rust warrior**#keepbodyshopsbusy** |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Tue Jun 06, 2017 11:12 am Post subject: Re: Engine suddenly runs terrible |
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Look for any hoses that may have popped off. |
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Drzdirtbag Samba Member
Joined: September 27, 2014 Posts: 80 Location: Kamloops bc
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Posted: Tue Jun 06, 2017 12:49 pm Post subject: Re: Engine suddenly runs terrible |
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Thanks for all the help fellas.. When I get home from work tonight I'm going to have a look.. It's the first time she has given me any problems and she waited till we where home first.. I love my van.. |
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curtp07 Samba Member
Joined: November 28, 2007 Posts: 874 Location: Mass
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Posted: Tue Jun 06, 2017 1:37 pm Post subject: Re: Engine suddenly runs terrible |
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Smoke tester is invaluable.. _________________ Subaru |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12686 Location: on a bike ride somewhere
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Posted: Tue Jun 06, 2017 11:13 pm Post subject: Re: Engine suddenly runs terrible |
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ROCKOROD71 wrote: |
Feel like mine is the temp sensor but do those go intermittent before actually failing or do they just fail? |
TS2 holes and connectors can build corrosion from sitting. Part of the fuel injection troubleshooting manual should say "unplug it and plug it back in." That will let you know if anything is loose or corroded, which can happen intermittently and pass the resistance test but give problems on the road.
Everyone with a FI bug or bus should have this somewhere handy.
https://www.thesamba.com/vw/archives/manuals/afc_fi_training_troubleshooting_manual.php
After a multimeter, I find the sense of smell to be helpful with a fuel injected car. If you smell gas, you have a rich condition or a misfire. If you don't smell gas, you probably have a fuel delivery problem.
Let us know how you do with the multimeter, and if you find any hoses disconnected, or if you just flat out ran out of gas or anything silly. It happens to all of us.
Robbie _________________ Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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ROCKOROD71 Samba Member
Joined: January 18, 2012 Posts: 2770 Location: Boston, MA
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Posted: Wed Jun 07, 2017 5:12 am Post subject: Re: Engine suddenly runs terrible |
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Thanks for the response Robbie. This morning The bus would start and rev up quickly and die, after a long-ish drive last night and being parked. I popped the engine hatch- sure as shit there was a hose just blown off completely disconnected. Must have been coming loose for a while with a slight vacuum leak. Right now I couldn't tell you what hose it is, but it connects up to a plastic T or Y connection where the hose has a metal pipe it clamps to that also goes into the connector with a clamp on it. Can't get it super tight but it is in there, I will have to take a more in depth look at it when I have the Bus at home. At least it is running "ok" for now.
I do have that manual and a multi-meter, I really need to start using them!
I do have a slight gas smell normally, but I think I have a weep (not a leak exactly) at the fuel rail LH side, where that little outlet for a fuel pressure tester goes. There is a bolt with a seal under it that I need to replace.
Thanks for the suggestions everyone, sorry to hi-jack... _________________ 1971 STD BEETLE- DD-1st car, 1st love. keepin' it stock! 1600DP, Solex 34-3 Mexi Bosch SVDA Dist NOW w/POINTS
1977 WESTY "KrustyKamper" 2L FI
79SuperVert wrote: |
30 years from now, the next guy may not want your girlfriend, but he may want your classic car, depending on how nice you were to it. |
asiab3 wrote: |
Careful guys, a petulant child can grow up to be president these days. |
**winter drivers: no survivors!**rust warrior**#keepbodyshopsbusy** |
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Drzdirtbag Samba Member
Joined: September 27, 2014 Posts: 80 Location: Kamloops bc
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Posted: Wed Jun 07, 2017 10:49 am Post subject: Re: Engine suddenly runs terrible |
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Well, it's unfortunately nothing obvious.. It flashes up right away like she is supposed too, but dies a second later.. If I'm on the gas, I could keep her running but it's super rough.. I'll keep looking.. |
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Tumbledown76 Samba Member
Joined: June 16, 2015 Posts: 91 Location: Bussachusetts
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Posted: Wed Jun 07, 2017 11:58 am Post subject: Re: Engine suddenly runs terrible |
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I had this problem a couple of months ago. Started right up, dies right down unless I pump the throttle...a lot. In the end, tt was a combination of vacuum leaks first (found them with smoke), and then realizing my AFM was shot. The Bentley and AFC tests served me very well.
Drzdirtbag, what happens when you unplug your AFM unit? Will your bus idle.
ROCKOROD71, looks like your somewhat local. If you need to borrow a smoke tester or a hand, lemme know. _________________ 'Camel' - '79 Riviera, 2.0L FI, Dakota Beige |
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Drzdirtbag Samba Member
Joined: September 27, 2014 Posts: 80 Location: Kamloops bc
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Posted: Wed Jun 07, 2017 12:31 pm Post subject: Re: Engine suddenly runs terrible |
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Thanks tumbled
When I unplug the aim, it starts right up and keeps running game at a higher rpm...
Randy |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22568 Location: NYC/Upstate/ROW
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Posted: Wed Jun 07, 2017 12:37 pm Post subject: Re: Engine suddenly runs terrible |
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Quote: |
do have a slight gas smell normally, but I think I have a weep (not a leak exactly) at the fuel rail LH side, |
If it will help you park this until you get this fixed, please rename the "weep"......... "flamethrower"
Posted with love - there is no such thing as a small fuel leak. _________________ .ssS! |
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Drzdirtbag Samba Member
Joined: September 27, 2014 Posts: 80 Location: Kamloops bc
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Posted: Wed Jun 07, 2017 12:53 pm Post subject: Re: Engine suddenly runs terrible |
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Well... Crisis averted.. As most of you thought, it was a vacuum hose off.. I just couldn't see it till I removed the cover to inspect the AFM.. Thank you all so much.. Again!! Haha
Cheers to all, and time to go for a drive..
Peace, randy.. |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12686 Location: on a bike ride somewhere
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Posted: Wed Jun 07, 2017 1:54 pm Post subject: Re: Engine suddenly runs terrible |
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Woooo two for two in this thread for disconnected hoses?
Remember that VW didn't use hose clamps on the intake vacuum system anywhere- this allows hoses to pop off in the event of an intake backfire to soften the blow to the AFM flap. Leave the hose clamps in the tool box for emergencies.
(Remember when BigEmma's AFM flap was jammed shut, and it required a tow that ended up destroying their entire brake system? )
Robbie _________________ Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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curtp07 Samba Member
Joined: November 28, 2007 Posts: 874 Location: Mass
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Posted: Wed Jun 07, 2017 7:42 pm Post subject: Re: Engine suddenly runs terrible |
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A poor mans "pop off valve" just like my old 911 with the early CIS that would backfire and blow the air box to bits before the "modification"... _________________ Subaru |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50255
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Posted: Wed Jun 07, 2017 11:12 pm Post subject: Re: Engine suddenly runs terrible |
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Yeap, the engine likely rocked backwards on shut off momentarily pressurizing the intake manifold and a loose hoses blew off. VW originally used hoses that matched the ID of the fittings they went on, i.e. a 12mm ID hose went onto a 12mm ID/13mm OD fitting offering a nice tight fit. However once the rubber of the hoses ages the fit is no longer tight and the hose may blow or even just plain fall off. Replacing all the hoses, elbows, and boots periodically when the rubbers gets hard will save endless headaches. |
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ROCKOROD71 Samba Member
Joined: January 18, 2012 Posts: 2770 Location: Boston, MA
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Posted: Thu Jun 08, 2017 6:04 am Post subject: Re: Engine suddenly runs terrible |
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All my hoses were replaced last year. This particular one that blew off, I will have to get a picture of, seems like the ID is the same on the hose as where it goes, there is a metal "connector" pipe used to join them, hose clamp on the hose end as well as the plastic fitting. Can on;y "tighten" a clamp around the plastic fitting so much before it breaks or cracks, which I do not want. Was wondering if it would be ok to wrap this metal pipe in electric or plumbers tape to get a tighter fit or use a mandrel or something to widen the pipe a hair> I feel like getting it in snug should help with potential vacuum leaks at that spot. Will get a picture as soon as possible. _________________ 1971 STD BEETLE- DD-1st car, 1st love. keepin' it stock! 1600DP, Solex 34-3 Mexi Bosch SVDA Dist NOW w/POINTS
1977 WESTY "KrustyKamper" 2L FI
79SuperVert wrote: |
30 years from now, the next guy may not want your girlfriend, but he may want your classic car, depending on how nice you were to it. |
asiab3 wrote: |
Careful guys, a petulant child can grow up to be president these days. |
**winter drivers: no survivors!**rust warrior**#keepbodyshopsbusy** |
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ROCKOROD71 Samba Member
Joined: January 18, 2012 Posts: 2770 Location: Boston, MA
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Posted: Sat Jun 10, 2017 2:29 pm Post subject: Re: Engine suddenly runs terrible |
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So here are some pics of my hose in question:
Above you can see the braided hose in my hand with a metal pipe in the end, and a hose clamp. This hose goes to my decel valve, and connects to the open plastic T fitting you see in the pic.
Above you see the braided hose and pipe plugged into the T fitting. It goes in and out with not much effort, which leads me to believe air leaks here easily. Note there is a hose clamp on the plastic T fitting as well. I am hesitant to crank down on that because if the plastic cracks, thats a whole other can of worms.
Another shot from the rear hatch of the hose plugged in place. The T fitting goes to the LH side of the plenum and to the LH side of the engine bay, where it exits. I take it this is for the vacuum booster brake servo? It is a hard plastic type line, not rubber.
How can I secure this hose and prevent leaks? Can I use electric tape around the metal pipe junction so I have to really twist it in lace, then tighten the clamp on the plastic T fitting? Should I widen the pipe somehow? It needs to be a more snug fit, for sure.
Thanks for any suggestions... _________________ 1971 STD BEETLE- DD-1st car, 1st love. keepin' it stock! 1600DP, Solex 34-3 Mexi Bosch SVDA Dist NOW w/POINTS
1977 WESTY "KrustyKamper" 2L FI
79SuperVert wrote: |
30 years from now, the next guy may not want your girlfriend, but he may want your classic car, depending on how nice you were to it. |
asiab3 wrote: |
Careful guys, a petulant child can grow up to be president these days. |
**winter drivers: no survivors!**rust warrior**#keepbodyshopsbusy** |
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