Maverck - Our ‘81 SC Build

[PeteKz]

If you haven't replaced the front fuel lines yet, now is the time.

Note to others doing this job: The best way to get the fuel out of the tank is to disconnect the line from the pump to the FI system in the engine compartment, connect a hose to it, which drains into a container. Then run the pump until it sucks air. You will still have several quarts of fuel in the bottom of the tank, but less than any other way I've tried.

[maverck]

Originally Posted by PeteKz

If you haven't replaced the front fuel lines yet, now is the time.

Note to others doing this job: The best way to get the fuel out of the tank is to disconnect the line from the pump to the FI system in the engine compartment, connect a hose to it, which drains into a container. Then run the pump until it sucks air. You will still have several quarts of fuel in the bottom of the tank, but less than any other way I've tried.

All of the lines have been replaced in my ownership so I should be set there.

Although tedious - I assume I should run a few clean gallons through until I get no more sediment.

Gallon in - remove the screen to drain, repeat. Until it drains clear.

Then replace the fuel filter - fill it up - and let er rip!

[maverck]

Tossed the other side on cribs to get it level and started cycling some clean fuel through it. Got a bit more sediment (pretty hard to see in the second pic) however after another gallon drained it started draining clear, not cloudy, with no further sediment. In total I believe I drained 4 to 5 gallons out of it.




Now planning to get some fresh fuel in, replace the fuel filter, and then redo the fuel flow and pressure tests to see if there are any notable changes.

Crossing fingers and toes.Wish me luck!

[maverck]

Back on the road and off to the local station to grab a full tank of non-oxy.



After about 20-30 miles I am planning to toss in the new fuel filter I just received from our host. After this, all fuel tests will be repeated and I will post the results.

[maverck]

Been putting in the miles! The popping at cruising speed is certainly reduced.

Today I got around to putting in the new fuel filter.
The new Mahle unit from our host is quite a bit bigger than the Bosch unit that was in the car.

The paper towels shows the color of the fuel that came out of the bottom of the filter when unhooked. Pretty nasty!

[maverck]

Some mornings just hit different. This past weekend - early am miles as fall hits in MN.

[mooch29]

Originally Posted by maverck

Some mornings just hit different. This past weekend - early am miles as fall hits in MN.

Really like the look of those gauge bezels!

[maverck]

Finally got around to repeating my fuel flow / pressure tests after replacing the fuel screen in the tank and the fuel filter.

The pressures are moving just a bit closer to spec but not there yet and residual pressure looks good. And the flow test actually got a bit worse.

I am wondering if the pump is clogged up / damaged from the debris I found in the tank.

I must say - it is fun learning more and more about the vehicle through all of this!

- 69 degrees- 20 Celsius
- System pressure- 4.45 bar
- Cold control pressure - .45 bar
- Warm control pressure
- 1 min 1.1 bar
- 2 min 1.7 bar
- 3 min 2.7 bar
- 4 min 2.9 bar
- 5 min 2.9 bar
- 6 min 2.9 bar
- 7 min 2.9 bar
- Residual pressure
- 0 min 2.3 bar
- 10 min 1.55 bar
- 30 min 1.5 bar

Fuel flow test. Here is the volume after 30 secs.



To that end I believe the next step in my journey is another new fuel pump. Previous shop will not warranty the one they installed about 1 year back. Any recommendations from the community or helpful tips for install?

[maverck]

New pump and check valve ordered from our host.

In the meantime leaned up the fuel mixture an 8th of a turn to see if it helped with a surging idle when warm. And wouldn’t you know it - it did!

Really crossing my toes that this new pump gets me closer to specs.

One - step - at - a - time!!

[maverck]

Originally Posted by mooch29

Really like the look of those gauge bezels!

Thanks @mooch29! When I bought the vehicle it had some flimsy grey plastic rings and when I removed them some of the black gage bezels were damaged !

I replaced with these and think it turned out pretty well.

[mooch29]

Originally Posted by maverck

Thanks @mooch29! When I bought the vehicle it had some flimsy grey plastic rings and when I removed them some of the black gage bezels were damaged !

I replaced with these and think it turned out pretty well.

Which ones did you get? I'm going to take on the task of redoing my wheels with silver petals, tying in something on the inside would be a nice touch.

[maverck]

Originally Posted by mooch29

Which ones did you get? I'm going to take on the task of redoing my wheels with silver petals, tying in something on the inside would be a nice touch.

They are the Rennline set.

https://www.pelicanparts.com/More_Info/RENI04.htm?pn=REN-I04&bc=c&SVSVSI=0572

[PeteKz]

With 400ml of fuel in 30 seconds, you should only get fuel starvation at full throttle above 5000RPM or so. If it runs well below that, then yeah, probably need a new pump. Since you already ordered the pump, do the full throttle/5000RPM test before you install the new pump and report what happens.

[maverck]

Originally Posted by PeteKz

With 400ml of fuel in 30 seconds, you should only get fuel starvation at full throttle above 5000RPM or so. If it runs well below that, then yeah, probably need a new pump. Since you already ordered the pump, do the full throttle/5000RPM test before you install the new pump and report what happens.

Thanks PeteKz!

At full throttle she is ripping right now! Running so good when you get on it. I will pay keen attention to what happens over 5k tomorrow when I get on it.

Really the only big symptom right now is needing throttle on cold start, and in about 30-45 seconds it will then idle on its own. And between 2-3k when off the gas I am getting some popping.

[PeteKz]

Re needing throttle on cold start: Make sure the CSV and TTS are working correctly, and test the AAR too.

Re popping on decel: Check that the exhaust gaskets are not leaking. You have been adjusting the CO screw--make sure you didn't adjust that too far.

[maverck]

Originally Posted by PeteKz

Re needing throttle on cold start: Make sure the CSV and TTS are working correctly, and test the AAR too.

Re popping on decel: Check that the exhaust gaskets are not leaking. You have been adjusting the CO screw--make sure you didn't adjust that too far.

No noticeable fall off up to 6200 rpm’s this am.

[PeteKz]

Then your fuel pump may not be delivering as much as the spec calls for, but obviously, it's delivering enough! When you get the new pump, swap them and see if that increaes the delivery amount. Keep the old pump as a backup.

Regardless, the pump is not the cause of your cold start issue, nor the decel popping.

[maverck]

Continuing to grind on this. Wanted to double check the pressures with another gauge as I started to get some low numbers with no meaningful changes to the car that would have dropped them.

One of my local air cooled shops borrowed me their tester and I am glad I tried it. My gauge is definitely off!!! E.g. system pressure on my gauge was 4 on my retest and 4.95 on the gauge I borrowed.

CCP still a bit low. WCP within .1 bar and everything else looks great. Tried tapping the pin on the WUR to bring the CCP up but it wasn’t moving. May have been a bit too gentle?!

- 48 degrees- 20 Celsius
- System pressure- 4.95 bar
- Cold control pressure - .8 bar. Tapped the on on the WUR a few times to see if it would change and it didnt
- Warm control pressure
- 1 min 1.5 bar
- 2 min 2.0 bar
- 3 min 2.35 bar
- 4 min 2.65 bar
- 5 min 2.9 bar
- 6 min 3.2 bar
- 7 min 3.3 bar
- 8 min 3.3 bar
- 9 min 3.3 bar
- Residual pressure
- 0 min 2.75 bar
- 10 min 2.05 bar
- 30 min 1.8 bar

[PeteKz]

I’m still thinking it’s something in the cold start system. Pressures look okay.