Need some input -> Problem with 3.2 transplant going lean and misfiring after two min

[Wayne 962]

Originally Posted by cabmando

A thought on the fuel, if you're worried about contamination from the tank, couldn't you place an inline filter at the tank temporarily along with the one back in the engine bay? I'd think that double filtration would rule out contamination from the tank. I'd think that draining and filling several times like you have would dilute whatever contaminant might be in the tank. I'm assuming the 914 has the bung in the bottom of the tank that everything tapers to like the 911 does so I'd think unless it's a gelled mass that is in the tank, you'd have it cleared by now.

Normally, I would agree 100% with you, and that's pretty much what I've done so far. But my cost on a new tank from Dansk is a whopping $160, so I got one and I'm going to just stick it in there and eliminate that as an issue. If the tank were much more expensive (like $800-$1000) then I would think twice, but it's so cheap, that it's not worth really mucking around and maybe leaving something odd trapped in there.

-Wayne

[cabmandone]

Originally Posted by Wayne 962

Normally, I would agree 100% with you, and that's pretty much what I've done so far. But my cost on a new tank from Dansk is a whopping $160, so I got one and I'm going to just stick it in there and eliminate that as an issue. If the tank were much more expensive (like $800-$1000) then I would think twice, but it's so cheap, that it's not worth really mucking around and maybe leaving something odd trapped in there.

-Wayne

IOW it ain't worth the time to try it! Good call. I was thinking a tank would get a little out of hand.

[Wayne 962]

Originally Posted by Steve W

I had all mine rebuilt by Mesa Hose in Costa Mesa.

Just spoke with Brooks Brown, our rep there at Mesa Hose. He said they just had a set of these done that went out the door today. He said remove them from the car and send them in. I am going to try to get the tank and the lines out today. Jacking the car up and dumping gas on my face is not something that I'm looking forward to at this moment.

-Wayne

[cabmandone]

Smoke a cigar and make it interesting Wayne!... no sense of adventure man!

[Wayne 962]

Okay, got it out. Wasn't too bad. I installed a high volume flow fan into the garage a year or so ago, and that has helped tremendously with the cars being in there. I typically just leave it on all the time.

Discovery: there's rust in the tank for sure. I've seen better, and I've seen worse. This one doesn't look too bad to me actually, but maybe there was a *lot* more in there before and it may have not gotten all flushed out. The tank is out in the sun, evaporating the fuel out right now, I will take a look later on to see if that is just surface rust or actual sediment. Not a super-hot smoking gun, but a very close suspect here. As everyone else mentioned as well, it's a good idea / good time to replace all the fuel lines.

Question: The 914 has a supply line and a return like for its fuel injection system, just like the 911 CIS and Motronic, etc. On the 914, the tank return line input is very tiny compared to the supply line. I'm not sure of the answer and I haven't done any research either, but perhaps someone here knows off the top of their head what the side of the one on the bottom of the 911 3.2 tank looks like? I want to make sure they are the same (it looks like it would be very easy to drill this out slightly larger if needed).



Thanks!


Here are some photos:


Connections under the tank:


Fuel pump:



Brand new tank - looks great!



Original fuel sender, dated 1973. I thought I replaced this like 25 years ago, but maybe not:



Connections on the bottom of the tank:



Here's that fan I mentioned, very useful:



Nice to have a skinny wrist to be able to stick it inside the tank (just barely):



Fittings look to be in poor condition:

[mysocal911]

Originally Posted by Wayne 962

On the 914, the tank return line input is very tiny compared to the supply line. I'm not sure of the answer and I haven't done any research either, but perhaps someone here knows off the top of their head what the side of the one on the bottom of the 911 3.2 tank looks like? I want to make sure they are the same (it looks like it would be very easy to drill this out slightly larger if needed).

If the size of the fuel return line were inadequate, the system fuel pressure would be too high.
Given the number of times the fuel pressure has been checked, a restricted return line is not one of your problems.

[Wayne 962]

Originally Posted by mysocal911

If the size of the fuel return line were inadequate, the system fuel pressure would be too high.
Given the number of times the fuel pressure has been checked, a restricted return line is not one of your problems.

The pressure was a little higher than the spec, like 2.7-2.8 bar when it should have been 2.5. I'm going to compare the pump flow rates from the 914 fuel injection to the 911 fuel injection to see if they are similar / comparable. If yes, then it's probably not a problem.

Thanks!

-Wayne

[Wayne 962]

Always finding more issues - the filter screen is completely worn away / dissolved. I guess this wasn't looked at when the new fuel lines were added. The remnants of the filter screen are still slightly attached.

-Wayne

[Wayne 962]

Update / plan:

- Have the new gas tank, it's the wrong one of course, and the correct one won't be in until about August. Still, this one might work - I just need to make / modify a bracket to hold the expansion tank. Should work, but it's just yet another thing.

- Took all the gas lines (eight total) to Mesa Hose, and they are going to be remaking them out of teflon, as per Steve W.'s suggestion. Those are due back on Tuesday. The only lines that remain in the car are the center tunnel lines, which are steel, I believe (I replaced them with steel 25 years ago, but when the conversion was done, the builder took the supply line out and replaced it with a larger diameter line, which I still believe is steel). I will blow those lines out, and I'll also run some isopropyl alcohol through them. The car is in my garage at home, and I don't really have the capacity to do much more than that.

- The engine has a bit of carbon buildup which I will be picking away at over the next few days.

- The injectors and fuel rails are out being cleaned and tested.

- The new air flow meters arrived this week. I also ordered a new adapter for the KN filter that eliminates that extra 90-degree bend. I'll have to fabricate some brackets for that.


That's it for now...

-Wayne

[cabmandone]

Break out a bore scope and have a good look around in the tank. If it doesn't look too bad, do a good rinse and put the thing back in. Get that puppy crankin!!

[Wayne 962]

Brief update:

- Ordered new parts to re-orient the air filter / air flow

- Installed new plugs, routed the BERU wires properly

- Sent the injectors back to RC to have them take a look. One was completely non-functional! We'll have to see if this one continues to give problems. I tagged each injector with a different color zip tie so that I would not get them confused. I looked at the mini filters that are integrated into the injectors - I didn't see any filters that looked super clogged. This is both good and bad. Hopefully the injector will not act up - if it does, I will probably go ahead and replace all of them.

- Got the new AFM from Autobahn here in San Diego. This is a take-off unit from one of the Singer 964s. I tested it using the oscilloscope - works fine. Also drilled out the plug (never did that before). The plug is interesting, it's aluminum with a steel bottom to it, so that you can't damage the unit. I've never quite seen something like that before.

- Waiting to get the fuel lines back from Mesa Hose (hopefully tomorrow). Then the reinstall of all of this stuff will happen. It will probably take a day or two, depending upon how much I get distracted.

Photos:

Fitting up the air flow meter with the new brackets:



Here's my new filter, elbow, and mount (that I still need to modify slightly to make it fit). Spectre Performance made the elbow, the mount, and the connector (clamps not shown). Seems like okay quality stuff - all bought on Amazon.



Newish AFM from the 964:



Testing the new AFM -> Looks good!



AFM test - power in, ground, and the signal to the scope:



Wiring diagram for the AFM:



Another big, long test on the AFM (slowly moving the flapper):



Another shot of the new Air Flow Meter (AFM):



Injectors back from RC. I thought my idea of using colored zip ties was pretty easy and clever. So, I didn't have to make labels 1-6:



The internal filters inside the injectors (did you know there's an internal filter inside each injector?) - these looked okay, not completely gummed up:

[Wayne 962]

Injector report showing a bad #1 injector!



Cleaning up the engine bay and the ignition wires, reattached the air guide carefully to avoid contacting the wires:



Other side, cleaning up the wires:



I'm going to replace this while it's out of the car too:



Organizing:



More organizing:

[Solamar]

I know this isn't your first rodeo, but hat's off to you for perseverence!

Fingers crossed it was a fuel contamination issue.

[Wayne 962]

Originally Posted by Solamar

I know this isn't your first rodeo, but hat's off to you for perseverence!

Nope, not the first rodeo, but I'm gettin' old, and this bull is kicking hard!

-Wayne

[scarceller]

Wayne,

The AFM mount up is much better now, nice job. Is that a S&B Air Cleaner? If so those are top notch! They also have a version called Power Stack that has intake element even of the top of the filter.

The flow numbers for the injectors also look good now, I bet your AFR numbers will be far better at warm idle.

[scarceller]

This is a power stack S&B air cleaner, they are custom made to spec, you chose dimensions from a catalog. I've used these for years:

[Wayne 962]

That is pretty neat. No, mine is not as Gucci as those, but this time I did size everything correctly and I fabricated some nice custom brackets to hold / suspend the filter using the stock mounts - used an old muffler clamp that I found - drilled a hole in it, and mounted it using a rubber grommet and an existing S-shaped bracket. I also tied the AFM into an existing boss on the manifold. I was surprised that this seemed to work fairly well on the first try, but of course, it's not in the car quite yet!

-Wayne

(VEX Robotics table in the background, if anyone is trying to figure that out...)

[cabmandone]

Were there angels singing when that pic was taken? There should have been.

[allenone20]

You may have already checked this but make sure the fuel line is not touching or near a heat source.
It may be that the fuel is being heated to causing vapor to form in the line.
As a precaution you should heat shield or insulate any exposed fuel lines.

[FFOURIE]

Hi Wayne,

I had a similar problem on my Boxster 2.5 flat six. It turned out to be a faulty vario cam solenoid on bank 1. I replaced the solenoid and the engine has since been performing perfectly