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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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 Posted: Sat Aug 31, 2013 10:59 am Post subject: MAP Sensor issues? |
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ok, so it looks like tha map sensor in my 71 square is giong bad. 
- engine runs full on rich. so rich it burn your eyes. 
- won't idle (idles down, sputters and dies) 
- slow\studders on rev up 
- engine WILL run if throttle is kept open. soon as you let off though, idles down and dies
- i am pretty sure i have the right MAP Sensor (311 906 051 c) for my stock F\I system.
- can't find any broken\loose\frayed\shorted wires in the F\I harness 
i have searched high and low for a new MAP Sensor, only to find there seems to be none available. ok, so if there are no new ones available, then what about rebuild kit? has anybody heard of rebuilding these? i mean it's just a simple copper diaphram, can't be rocket science! i just want my baby to run right. any suggestions? thanx as usual!
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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KTPhil 
Samba Member
Joined: April 06, 2006
Posts: 33991
Location: Conejo Valley, CA
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| Posted: Sat Aug 31, 2013 11:05 am Post subject: |
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| Check all your vacuum hoses. You have symptoms of a large vacuum leak, which will make it run rich. You can also check if the MPD is holding vacuum with a mity-vac or similar vacuum tester. |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Sat Aug 31, 2013 11:43 am Post subject: |
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ALL HOSES are properly fitting, German, and new. when i rebuilt the top end of this engine, I replaced all fuel & vacuume hoses with all new German lines. I was thinking vacuume leake too, and even though they are all new lines, i looked anyways. everything seems to be fitting fine, can't find any leaks...
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Sat Aug 31, 2013 12:16 pm Post subject: |
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PM me if you need a good MAP for testing. Also, make sure your charging system is at full capacity and, as stated above, you have NO vacuum leaks.
The 914 guys carry a kit:
http://www.tangerineracing.com/whats_new.htm
"MPS diaphragm kit" in the right column about midway down.
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Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 33991
Location: Conejo Valley, CA
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| Posted: Sat Aug 31, 2013 1:19 pm Post subject: |
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| How do your injector tip seals fit? Using the proper Bakelite spacers? |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Sat Aug 31, 2013 5:08 pm Post subject: |
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| Tram wrote: |
PM me if you need a good MAP for testing. Also, make sure your charging system is at full capacity and, as stated above, you have NO vacuum leaks.
The 914 guys carry a kit:
http://www.tangerineracing.com/whats_new.htm
"MPS diaphragm kit" in the right column about midway down. |
thanx tram. here's what i have done so far\recently:
- installed a "hard start relay". works fine
- replaced the MAP sensor with the old one. (it used to surge just a little bit, but holds a GREAT vacuume)
- looked at the F\I wiring harness for breaks\shorts. none detected so far.
- changed out the generator for one that works properly.
- replaced all fuel & vacuume lines with new german lines
- spark plugs were replaced about 1 month ago.
it would seem that i am not firing on all 4...
- when rev'd up:
- enging shakes badly from side to side
- produces minimal power
- backfires or misses
- studders on throttle
known issue i am going to fix:
- about to splice# 4 Fuel injector wires\electrical with a know good one. as this is being typed. the current #4 fuel injector is connected (barely) as the wire broke off from the spade connector in the plug, and i had to spread the back of the spade and kinda "crimp" some exposed wire back on, just to make a "band-aid" connection. i don't THINK that this is my issue, but repairing it propperly couldn't hurt...
ok, all that said, ideas?
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Sat Aug 31, 2013 5:22 pm Post subject: |
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ok, so i am not going to be able to splice in the connector today. gotta cook. but i'll get to it tommorow...
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- 1968 Squareback (Scarlett)
- 1969 Westy |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Sat Aug 31, 2013 5:37 pm Post subject: |
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| KTPhil wrote: |
| How do your injector tip seals fit? Using the proper Bakelite spacers? |
when i rebuilt the top end a month ago, we used all new seals injector seals. the bake-lites wer cleaned up, and reused after inspected for cracks ect.
* NOTE: the engine was running GREAT for about a week, but developed this stumbling issue over a coupple days. on OCASSION, i can start the engine, it'll idle fine, but it seems like whenever the engine WARMS UP is when it gets an attitude with me. maybe this will help in the diagnosis. lastly, the thermostat accordian thing is disconnected, and the cooling flaps set to full open all the time...
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Mon Sep 09, 2013 6:59 am Post subject: |
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ok, so i finall got my baby into the shop and here's what we have found SO FAR:
- all 4 spark plugs were fouled. just black as pitch.
* replaced a 4 spark plugs
- both heads were actually LOOSE AS HELL! only had 5 foot pounds of torque on some studs!
* torqued down the BOTTOM head studs. will torqure down the tops once i can get the time to take off the engine tin and get to the properly.
- found a VERY SLOW vaccume leak in the MAP sensor. basically it looses about 1 lb of vacuume per 30 seconds or so.
* i'll look into getting a rebuild kit soon and call it a day
well that's the latest and greatest update! thanx to you guys for the advice!
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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Mike Fisher
Samba Member
Joined: January 30, 2006
Posts: 17969
Location: Eugene, OR
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| Posted: Mon Sep 09, 2013 7:23 am Post subject: |
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Are you adjusting your MAP with a tiny screwdriver? Tram adjusts my MAP/AFR with his sniffer hooked to the tailpipe.
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69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
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'68 Karmann Ghia sold
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Mon Sep 09, 2013 11:12 am Post subject: |
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| Mike Fisher wrote: |
| Are you adjusting your MAP with a tiny screwdriver? Tram adjusts my MAP/AFR with his sniffer hooked to the tailpipe. |
Different MAP. This is the sealed C map, yours is the A/B.
OP, I think you'll find that loose heads were your issue. Make sure the studs aren't pulling out of the case.
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| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
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73sports
Samba Member
Joined: September 26, 2004
Posts: 2107
Location: Warrington, PA
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| Posted: Mon Sep 09, 2013 2:58 pm Post subject: |
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What's the system voltage with the car running? I chased a problem for a while on my car, and the FI system was fine, but the voltage regulator wasn't.
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Mon Sep 09, 2013 6:55 pm Post subject: |
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| Mike Fisher wrote: |
| Are you adjusting your MAP with a tiny screwdriver? Tram adjusts my MAP/AFR with his sniffer hooked to the tailpipe. |
Adjustment screw? there's an ADJUSTMENT SCREW? i did not know that! exactaly WHAT does it adjust?
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
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| Posted: Mon Sep 09, 2013 7:01 pm Post subject: |
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| vwkombi1966 wrote: |
| Mike Fisher wrote: |
| Are you adjusting your MAP with a tiny screwdriver? Tram adjusts my MAP/AFR with his sniffer hooked to the tailpipe. |
Adjustment screw? there's an ADJUSTMENT SCREW? i did not know that! exactaly WHAT does it adjust? |
No. You have a different system than Mike does.
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Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Mon Sep 09, 2013 7:01 pm Post subject: |
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| Tram wrote: |
Different MAP. This is the sealed C map, yours is the A/B.
OP, I think you'll find that loose heads were your issue. Make sure the studs aren't pulling out of the case. |
thanx tram. yeah, once the lower head nuts were tightened, things improved DRASTICALLY!! however, i will end up pulling off the tin and ensuring that All head nuts are tightened properly. since only the bottoms were torqued down properly, i consider what has been done as a "band-aid". i also have plans to look at the fuel injectors. the enging STILL seems to only fire off on all 4 intermittantly, and the engine is still running WAY too RICH... but what the hell, at least it RUNS! lol!
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Mon Sep 09, 2013 7:03 pm Post subject: |
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| 73sports wrote: |
| What's the system voltage with the car running? I chased a problem for a while on my car, and the FI system was fine, but the voltage regulator wasn't. |
actually, i just replaced the Voltage regulator and generator. the system is putting out about 14 volts. good to go!
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- 1968 Squareback (Scarlett)
- 1969 Westy |
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Sun Sep 15, 2013 12:59 pm Post subject: |
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so ive been busy!
i pulled off each of the fuel injector wires, and discovered that all 4 are firing off just fine. i took it one step farther, and observed the injectors firing off into a coffee can, so i am sure that they aren't plugged up or something. so then i started looking at the spark plug wires. all 4 are firing off just fine, and seem to have a healthy spark. but i am still firing on 2 and 3 ONLY. so i am thinking of tearing down all the engine tin and looking at re-torquing ALL the head studs, since we only torqued the bottom ones. maybe there's an air leak or something around the heads? as it is, it sounds like a midget with a hammer beating around back there. we JUST adjusted the valves, so i am wondering if somehow the heads have work themselves loose and now the heads are leaking or something? thoughts?
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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JSMskater
Samba Grease Gorilla
Joined: February 01, 2006
Posts: 5362
Location: Murrieta California
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| Posted: Sun Sep 15, 2013 6:48 pm Post subject: |
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| vwkombi1966 wrote: |
so ive been busy!
i pulled off each of the fuel injector wires, and discovered that all 4 are firing off just fine. i took it one step farther, and observed the injectors firing off into a coffee can, so i am sure that they aren't plugged up or something. so then i started looking at the spark plug wires. all 4 are firing off just fine, and seem to have a healthy spark. but i am still firing on 2 and 3 ONLY. so i am thinking of tearing down all the engine tin and looking at re-torquing ALL the head studs, since we only torqued the bottom ones. maybe there's an air leak or something around the heads? as it is, it sounds like a midget with a hammer beating around back there. we JUST adjusted the valves, so i am wondering if somehow the heads have work themselves loose and now the heads are leaking or something? thoughts? |
only firing on 2 and 3? sounds like trigger contacts to me! check the 3 wires and plug and contacts themselves -- they are in the distributor.
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vwkombi1966
Padawon Learner
Joined: August 11, 2002
Posts: 604
Location: Oak Harbor WA
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| Posted: Mon Sep 16, 2013 12:14 pm Post subject: |
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| JSMskater wrote: |
| only firing on 2 and 3? sounds like trigger contacts to me! check the 3 wires and plug and contacts themselves -- they are in the distributor. |
i checked the contacts. they are showing great continuity... 
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Aircooled VW: more expensive than CRACK!
- 1968 Squareback (Scarlett)
- 1969 Westy |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21510
Location: Oklahoma City
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| Posted: Thu Sep 19, 2013 2:42 pm Post subject: |
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| vwkombi1966 wrote: |
| JSMskater wrote: |
| only firing on 2 and 3? sounds like trigger contacts to me! check the 3 wires and plug and contacts themselves -- they are in the distributor. |
i checked the contacts. they are showing great continuity... |
Continuity is not the only critical issue with the trigger contacts.
You need to make sure as you are spinning the distributor around by hand that the trigger contacts are actually being operated by the cam.
Also...resistance is very important with the trigger contacts. the maximum Resistance is 1.2 ohms for each trigger....with no more difference between each side than .2 ohms.
For instance: one trigger reading 1.1 ohms and one reading .8 ohms...is not great.
One trigger reading 1.2 ohms and one reading 1.0 ohms is high...but preferable.
Ideally they are much better if all read under 1.0 ohms...and within .2 ohms of each other.
Why?...because when resistance gets high, the signal is slow. At speed....it can make for short or incomplete injections.
Typically...IIRC though....triggers control 1 and 3 and 2 and 4 as pairs.
If you have one cylinder in each pair not getting enough fuel...though you say they are all injecting.....then perhaps they are not injecting enough on 2 and 3.
This could be a ground issue.
If you had head leaks...it could simply be poor compression on those two. Ray |
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