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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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 Posted: Fri Nov 29, 2019 10:20 am Post subject: Hot, low power backfiring |
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This car.... I finally figured out the running rich wanting to die at idle problems (temp sensor), the car ran great for 2-3 days and now a new problem. The car is running a little rich still and when I pull the plug wires it doesn't miss as bad as I think it should. When I adjust the idle screw it will not get very high but it will bog down even further if I screw it in. The car does not have enough power to make it up a hill but if I get some speed it will eventually drive somewhat okay but starts to smell hot.
I thought it was sparkplugs as it had been running really rich, I swapped them (they were not the plugs I expected but I swapped them with almost the same plug but a 6 heat range). This didn't change how it is running. I looked for vacuum leaks and the hose running to the center of the engine under where the air filter connects was pretty bad, I replaced it and also saw no change.
Things that have been done in the last 6 months:
New points, rotor, distributor cap, plug wires, plugs
Rebuilt alternator
New Coil
fuel pressure tested, MPS vacuum tested, valves adjusted, fuel filter replaced (inline not sock), compression test (110 on all)
replaced temp sensor
Timing and dwell set
My thoughts on what could be causing it:
Could it have jumped timing?
Feel like a vacuum leak but I don't see or hear any issues. Also sprayed brake cleaner and couldn't find anywhere.
fuel pump is giving out? (I think this would be lean not rich) |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Nov 29, 2019 10:27 am Post subject: Re: Hot, low power backfiring |
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D-Jet running rich...excessively rich.....when ignition has already been worked through. means you either have high fuel pressure or a vaccum leak....or both.
You need to test every hose connection, joint and sealing segment of the intake manifold and anything connected to it. It must be 100% vacuum tight.
One quick place to start is to test the fuel pressure at idle first. Then test that the MPS holds vacuum. Ray |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22431
Location: Kimball, Mi
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| Posted: Fri Nov 29, 2019 11:41 am Post subject: Re: Hot, low power backfiring |
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| raygreenwood wrote: |
D-Jet running rich...excessively rich.....when ignition has already been worked through. means you either have high fuel pressure or a vaccum leak....or both.
You need to test every hose connection, joint and sealing segment of the intake manifold and anything connected to it. It must be 100% vacuum tight.
One quick place to start is to test the fuel pressure at idle first. Then test that the MPS holds vacuum. Ray |
Also double check the voltage, as low voltage on type 3s with D-jet will run rich.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Fri Nov 29, 2019 11:42 am Post subject: Re: Hot, low power backfiring |
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I think vacuum might be a right but I have no idea how to test it. I just sprayed ether straight into an intake vacuum line that I could feel strong suction and it didn't change how it ran at all.
Should I take it and have it smoke tested? Or is there a better way to do this? |
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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Fri Nov 29, 2019 11:44 am Post subject: Re: Hot, low power backfiring |
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| Bobnotch wrote: |
Also double check the voltage, as low voltage on type 3s with D-jet will run rich. |
Just the battery voltage or should I be testing this new coil and off the alternator? What should I be getting at each of these points? |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22431
Location: Kimball, Mi
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| Posted: Fri Nov 29, 2019 11:45 am Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
I think vacuum might be a right but I have no idea how to test it. I just sprayed ether straight into an intake vacuum line that I could feel strong suction and it didn't change how it ran at all.
Should I take it and have it smoke tested? Or is there a better way to do this? |
You can. Or you can use a shop vac and pressurize it like Mr Duncan did.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Fri Nov 29, 2019 11:50 am Post subject: Re: Hot, low power backfiring |
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| Do you have a link where he discussed the shop vac method? I tried searching and I think I found the thread but I cannot find the spot where he talks about it. |
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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Fri Nov 29, 2019 12:22 pm Post subject: Re: Hot, low power backfiring |
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| I found the thread. Hooked a shopvac blowing on the intake and sprayed soapy water on every hose connection, I did not find any leaks blowing bubbles. |
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Mr.Duncan
Samba Member
Joined: May 12, 2012
Posts: 3542
Location: Houston, TX
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| Posted: Fri Nov 29, 2019 7:05 pm Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
| I found the thread. Hooked a shopvac blowing on the intake and sprayed soapy water on every hose connection, I did not find any leaks blowing bubbles. |
Some leaks only show up with the engine hot. Just FYI.
_________________
(Owner) www.vintagecarleds.com
Red 1971 Squareback Thread
Red 1966 Beetle Thread
---------------------------------------------------
1971 Green Super Beetle (sold)
1966 Ghia (sold)
1971 Blue Super Beetle (sold)
1966 Java Green Std Beetle (sold)
1971 Red Squareback (sold)
1966 Red Beetle |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Fri Nov 29, 2019 10:27 pm Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
| Bobnotch wrote: |
Also double check the voltage, as low voltage on type 3s with D-jet will run rich. |
Just the battery voltage or should I be testing this new coil and off the alternator? What should I be getting at each of these points? |
Battery voltage at the battery engine running around fast idle or at min 1500RPM you should have 13.7 volts or higher. |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 22431
Location: Kimball, Mi
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| Posted: Sat Nov 30, 2019 2:34 pm Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
| Bobnotch wrote: |
Also double check the voltage, as low voltage on type 3s with D-jet will run rich. |
Just the battery voltage or should I be testing this new coil and off the alternator? What should I be getting at each of these points? |
With FI, you want 14.4-14.5 volts. Anything less than 13.7 will cause it to run rich. At least this is what I've found. You can check it at the battery, the VR output leg, and input at the fuse box. Just so you know, when the voltage drops to around 13.7-13.8 you'll get a miss, which is the start of the system running rich.
I spent literally 2 straight months (after work and on weekends) chasing a missing issue, only to find the voltage dropping. In my case I'd start out with 14.6 volts, and with in 1 mile I'd be down to 14.4 volts. At 3.5 miles, it would be down to 14.1 volts. At 5 miles, I'd be down to 13.9 volts. At 7 miles, I'd be at 13.7 volts and the miss would be present. At 8 miles (pulling into my driveway) I'd be at 13.3 volts and the engine struggling to run clean. I set up an 8 mile test run that included both 45mph, and 55 mph zones, so that I was actually no more than 3.5 miles from my house at any time (didn't want to have to walk any further than necessary). At one point I even put a set of Weber carbs on it to make sure it wasn't a mechanical issue (it wasn't) trying to solve the problem (before I did my running voltage test above at Jim Adney's request).
Ray doesn't normally think about a loss of voltage, as the type 4 (411-412) uses an alternator versus a generator, that most type 3s have/use.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Sat Nov 30, 2019 5:59 pm Post subject: Re: Hot, low power backfiring |
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| Bobnotch wrote: |
| JoMoSqBk wrote: |
| Bobnotch wrote: |
Also double check the voltage, as low voltage on type 3s with D-jet will run rich. |
Just the battery voltage or should I be testing this new coil and off the alternator? What should I be getting at each of these points? |
With FI, you want 14.4-14.5 volts. Anything less than 13.7 will cause it to run rich. At least this is what I've found. You can check it at the battery, the VR output leg, and input at the fuse box. Just so you know, when the voltage drops to around 13.7-13.8 you'll get a miss, which is the start of the system running rich.
I spent literally 2 straight months (after work and on weekends) chasing a missing issue, only to find the voltage dropping. In my case I'd start out with 14.6 volts, and with in 1 mile I'd be down to 14.4 volts. At 3.5 miles, it would be down to 14.1 volts. At 5 miles, I'd be down to 13.9 volts. At 7 miles, I'd be at 13.7 volts and the miss would be present. At 8 miles (pulling into my driveway) I'd be at 13.3 volts and the engine struggling to run clean. I set up an 8 mile test run that included both 45mph, and 55 mph zones, so that I was actually no more than 3.5 miles from my house at any time (didn't want to have to walk any further than necessary). At one point I even put a set of Weber carbs on it to make sure it wasn't a mechanical issue (it wasn't) trying to solve the problem (before I did my running voltage test above at Jim Adney's request).
Ray doesn't normally think about a loss of voltage, as the type 4 (411-412) uses an alternator versus a generator, that most type 3s have/use. |
This is why I said 13.7 as the lowest. I don't get a miss and when at idle speed long enough it will be below 13 volt's. Turn on the headlamps and wipers and at idle it will be about the same about 12.5 volts. Mine runs at 14.1 volts at 1,000 RPM and around 14.5 at 2,500 rpm. For some odd reason each new Bosch electronic VR is a bit different my old one had 5Ma draw yet charged higher the new one has a .4mA draw and puts out a few 10th's of a volt less.
The Bentley on page 20 electrical system has a chart no load voltage test 2000 RPM 13.5 to 14.5 volts. A lot depends on the accuracy of your volt meter. I doubt I'd disconnect the B+ at the regulator as the Bentley states because the lead disconnected powers everything running off the fuse box and most DVOM's leads are are not heavy enough to carry the current. I just read off the battery.
I can't say if it depends on what year of FI one has that might make a difference |
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raygreenwood
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Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Sat Nov 30, 2019 8:54 pm Post subject: Re: Hot, low power backfiring |
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You know......this voltage tging is critical.....not just to the EFI system in general....but to the fuel pump.....the ignition coil.....gas furnaces......and stereos.
About 10 years back....I was asking on the STF.....if any of the electronic gurus had an affordable, simple "rectifier"system to keep voltage stabilized.
I got a couple of how to build examples but at that point in time it was kind of at the fringes of my abilities to pull off.
Cut to now. Lots and lots and lots of high end cheap electronics on the market. I found a while back.....a whole range of small, compact, well heat sinked 12 volt, voltage stabilizers. They were in the $40-$60 range.
I was looking at them for stereo voltage stabilization for the most part.....but was also thinking of ignition.
If anyone is interested I will dig it back up. Ray |
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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Wed Dec 04, 2019 3:20 pm Post subject: Re: Hot, low power backfiring |
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So I tested this at 14.4V and took it to the local shop to have timing and smoke test done. The timing was way off, IDK how it jumped timing but it is adjusted and is running about 80% better.
The smoke test, however, was disheartening as smoke basically came out of every place it possibly could. I need to replace the intake boots and replace the line or add hose clamps to all my vacuum lines.
The other thing he did was put a noid light on all the injectors. 1,2, and 4 all pulsed at a nice steady rate. #3 was going crazy what might cause this bad ground? Is this something I need to worry about or just fix the vacuum first and see how it runs? |
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blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
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| Posted: Wed Dec 04, 2019 4:41 pm Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
So I tested this at 14.4V and took it to the local shop to have timing and smoke test done. The timing was way off, IDK how it jumped timing but it is adjusted and is running about 80% better.
The smoke test, however, was disheartening as smoke basically came out of every place it possibly could. I need to replace the intake boots and replace the line or add hose clamps to all my vacuum lines.
The other thing he did was put a noid light on all the injectors. 1,2, and 4 all pulsed at a nice steady rate. #3 was going crazy what might cause this bad ground? Is this something I need to worry about or just fix the vacuum first and see how it runs? |
If you have so many vacuum leaks then you really need to replace the hoses clamps just won't cut it.
The injector ground on # 3 can be either a loose connection at the injector plug you need to remove the actual metal end from the plastic connector and using small flat nosed pliers crimp the rolled ends down a bit then test the fit on the injector before inserting it back in the plastic plug or it can be the ground on the brass trees on the case center line because each injector has it's own ground and they are crimped into 1/4" female connectors.
If you don't check it all you will never find the issues plus replacing the runner hoses and vacuum lines. It's not easy and yet not to difficult. Some slide the runner boots back and remove the throttle body or IAD and then replace the 4 boots onto the runners slide then flush to the pipe ends and while the IAD is off replace the vacuum lines under the IAD it's easier with it off. If you have the PCV system then getting the IAD off is much more difficult and in your photo I can't tell what you have if you have it there will be a pipe on the right side of the IAD off the metal back cover. Post a larger photo showing the case vent and air filter and one of the entire engine top. |
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JoMoSqBk
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Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Thu Dec 05, 2019 11:35 am Post subject: Re: Hot, low power backfiring |
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Here are some pics of everything going on. I assume the beige wires are the Injector grounds. Two of them were fairly loose so I crimped them up tight (there is some bare exposed wire should I add a little electrical tape?).
How should I go about removing the boots to replace them?
Also, I am not sure how to remove the injector side wires from the plastic clip do I just push them out with a small screwdriver?
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Mr.Duncan
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Joined: May 12, 2012
Posts: 3542
Location: Houston, TX
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| Posted: Thu Dec 05, 2019 11:46 am Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
Here are some pics of everything going on. I assume the beige wires are the Injector grounds. Two of them were fairly loose so I crimped them up tight (there is some bare exposed wire should I add a little electrical tape?).
How should I go about removing the boots to replace them?
Also, I am not sure how to remove the injector side wires from the plastic clip do I just push them out with a small screwdriver?
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Ouch. You will want to replace those 4 intake manifold boots. Cut them off with a razor.
To install, you can remove the intake "throttle body" (two bolts to the engine case. Slide on the new boots with some WD-40 as lube onto the intake runners, then reinstall the throttle body and slide the boots back on towards it. Double check your intake throttle body vacuum hose on the left side to the pressure sensor. I found the gates rubber hose you have will leak even when new. I used this size silicone hose to replace it: 6mm https://www.amazon.com/gp/product/B07PPJ8D6M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
And to replace the hose from the IAD (throttle body) to the AAR:
Your current hose looks to be collapsed on itself.
8mm https://www.amazon.com/gp/product/B07PQMHMYR/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The silicone hose fits NICE and snug.
However, giving the condition of your intake boots, your injector tip seals probably need replacement too. Keep that in mind.
As for the 6 wires that terminate to 3 terminals on the ground block, you may want to crimp on new OEM style ends. They look a bit trashed. They are injector grounds, and computer / Throttle position sensor grounds. One connector seems to not be connected at all?
Should look like the below photo.
To remove injector terminals out of the plastic connector, I could make a video tonight showing that.
_________________
(Owner) www.vintagecarleds.com
Red 1971 Squareback Thread
Red 1966 Beetle Thread
---------------------------------------------------
1971 Green Super Beetle (sold)
1966 Ghia (sold)
1971 Blue Super Beetle (sold)
1966 Java Green Std Beetle (sold)
1971 Red Squareback (sold)
1966 Red Beetle |
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Mr.Duncan
Samba Member
Joined: May 12, 2012
Posts: 3542
Location: Houston, TX
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| Posted: Thu Dec 05, 2019 12:01 pm Post subject: Re: Hot, low power backfiring |
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Also, looks like your air idle speed screw is screwed IN all the way.
Seems like you are having some vacuum leaks if you have this screwed in all the way you would hardly get a normal engine to run UNLESS you had a large vacuum leak.
_________________
(Owner) www.vintagecarleds.com
Red 1971 Squareback Thread
Red 1966 Beetle Thread
---------------------------------------------------
1971 Green Super Beetle (sold)
1966 Ghia (sold)
1971 Blue Super Beetle (sold)
1966 Java Green Std Beetle (sold)
1971 Red Squareback (sold)
1966 Red Beetle |
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JoMoSqBk
Samba Member
Joined: February 07, 2019
Posts: 43
Location: MO
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| Posted: Thu Dec 05, 2019 12:08 pm Post subject: Re: Hot, low power backfiring |
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Thanks for the fast reply!
New boots and the two recommended hoses are on order. I'll go ahead and replace ever vacuum hose with these.
The not connected wire was the loose one, I took it off and crimped it to get a better connection.
Do you have a link to the correct injector tip seals? I don't mind replacing everything all at once as opposed to trying this then still being frustrated.
If you don't mind making that video I would be very grateful!
One more question, in the smoke test there was smoke coming out where the TVS mounts to the intake. Should there be a gasket between these two? |
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Mr.Duncan
Samba Member
Joined: May 12, 2012
Posts: 3542
Location: Houston, TX
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| Posted: Thu Dec 05, 2019 12:23 pm Post subject: Re: Hot, low power backfiring |
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| JoMoSqBk wrote: |
Thanks for the fast reply!
New boots and the two recommended hoses are on order. I'll go ahead and replace ever vacuum hose with these.
The not connected wire was the loose one, I took it off and crimped it to get a better connection.
Do you have a link to the correct injector tip seals? I don't mind replacing everything all at once as opposed to trying this then still being frustrated.
If you don't mind making that video I would be very grateful!
One more question, in the smoke test there was smoke coming out where the TVS mounts to the intake. Should there be a gasket between these two? |
Good call on the silicone hose.
When fitting that 6mm hose from the IAD to pressure sensor it "will feel tight" but trust me, it'll fit fine.
These are the brand and type of injector seals you want found at napa.
Part #: CRB 212312
Line: Echlin Fuel System
Smoke test wise, you said the smoke leaked out between the throttle shaft bushings and TPS right? That is "kinda normal" as mine leaks to. Those bushings develop wear. No gasket is used there.
AFTER we get all these vacuum leaks fixed, we can further diagnose your engine.
_________________
(Owner) www.vintagecarleds.com
Red 1971 Squareback Thread
Red 1966 Beetle Thread
---------------------------------------------------
1971 Green Super Beetle (sold)
1966 Ghia (sold)
1971 Blue Super Beetle (sold)
1966 Java Green Std Beetle (sold)
1971 Red Squareback (sold)
1966 Red Beetle |
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