"A few more CIS questions"[Or a 20 year sleep].

[donlan]

Well here goes. i have been doing a lot of watching and using the good advice given here but will need to ask a few ( probably quite a few ) questions. the story ( condensed) so far. Car has been sitting for a while, well almost 20 years. ( My fault) recently i have been trying to start it. Removed fuel tank and had "acid" dipped and REDI-COAT (yes i NOW know about that ) new fuel lines, new fuel pump ( 5 bar pressure) new filter, rebuilt "WUR"( not original 001 but 129) rebuilt fuel distributor, tested and cleaned injector, new intake rubbers , ( full gasket set + from our host) rebuilt throttle operated CPR new vacuum lines, new spark plugs, new air and oil filters ( K &N).

Now as per Tim's ( Tirwin) list.
911T 2/1973
Bought in California in 1994.
Engine No 911/51 * 6124238*. ( I've been told)
Standard ( I think)
Will fire but won't run for more than 5 or 6 seconds and can make a great backfire ( I fitted one of those " pop off valves" ! car had been going without it for over 40 years).
WUR No 0438 140 129
sea level, 20c
WUR resistance, 51.5
System pressure, 295 KPA
Cold control pressure. 200 KPA
Warm control pressure 295 KPA
Time delta......... ???
Residual pressure 30 sec. 195 KPA
5 mins. 165
(sorry)23 mins 120
30 mins 110
60 mins 70
The gauge is in KPA

I had the air box out to replace various parts and it looked OK then but i may have to pull it out again for another check now.

[manbridge 74]

Just worked 11 days straight but at first glance your system pressure is to low. What kind of fuel pump and part number? Have you smoke tested your intake system?

Love the vintage pics.

[boyt911sc]

Don,

It would help other readers to follow your information about the fuel pressures if you could convert them to bar or psi. Was the WUR resistance in Ohms? How did you measure the control fuel pressures? Were the TPR (throttle pressure regulator) and WUR (warm up regulator) tested individually? Thanks.

Tony

[ossiblue]

Originally Posted by donlan

Well here goes. i have been doing a lot of watching and using the good advice given here but will need to ask a few ( probably quite a few ) questions. the story ( condensed) so far. Car has been sitting for a while, well almost 20 years. ( My fault) recently i have been trying to start it. Removed fuel tank and had "acid" dipped and REDI-COAT (yes i NOW know about that ) new fuel lines, new fuel pump ( 5 bar pressure) new filter, rebuilt "WUR"( not original 001 but 129) rebuilt fuel distributor, tested and cleaned injector, new intake rubbers , ( full gasket set + from our host) rebuilt throttle operated CPR new vacuum lines, new spark plugs, new air and oil filters ( K &N).

Now as per Tim's ( Tirwin) list.
911T 2/1973
Bought in California in 1994.
Engine No 911/51 * 6124238*. ( I've been told)
Standard ( I think)
Will fire but won't run for more than 5 or 6 seconds and can make a great backfire ( I fitted one of those " pop off valves" ! car had been going without it for over 40 years).
WUR No 0438 140 129
sea level, 20c
WUR resistance, 51.5
System pressure, 295 KPA=2.95 bars
Cold control pressure. 200 KPA=2 bars
Warm control pressure 295 KPA=2.95 bars
Time delta......... ???
Residual pressure 30 sec. 195 KPA=1.95 bars
5 mins. 165=1.65 bars
(sorry)23 mins 120=1/20 bars
30 mins 110=1.10 bars
60 mins 70=.70 bars
The gauge is in KPA(1 KPA=.01 bar)

I had the air box out to replace various parts and it looked OK then but i may have to pull it out again for another check now.

As posted, your pressures are way too low, at least according to the pressures you posted. You said the new fuel pump had 5 bars pressure but is producing only 2.95 after the fuel distributor (assuming you connected the gauge correctly and the gauge is accurate.) Looks like an adjustment to the fuel distributor is in order once you confirm the accuracy of the gauge and the connections. However, that may not be the problem.

The 73.5 CIS has a throttle positioning valve that taps off of the fuel distributor. You must make sure the fuel gauge is connected directly to the outlet of the fuel distributor and the connection to the throttle valve needs to be attached to the outlet side of the gauge--between the wur and the gauge set. The throttle valve bleeds off fuel pressure so to get an accurate reading, you need to have that bleed-off connected after the shut-off valve of the gauge set otherwise, all your pressure readings will be influenced by the bleed-off.

[E Sully]

Interesting thing is the engine number is for a 1972. 1973 would start with 613xxxx. Engine type 911/51 is a 911E, MFI. CIS would be 911/91.
There is a good chance you have a leak in the air box from the backfires.
System pressure is low, should be 4.5 bar, 850 cc volume in 30 seconds from the return line. Make sure test connections are correct, if control pressure is same as system pressure it may not be hooked up properly. Throttle position valve varies the control pressure in conjunction with the WUR depending on throttle plate position.
Try this link for 1973 CIS info.
http://jimsbasementworkshop.com/CIS/page_images/73%20911T%20CIS%20Print.pdf

[donlan]

manbridge 74. Jeff,fuel pump is a copy of Bosch Motorsport Pump 0580 254 044.[ 72.5 psi/5bar.] 80gph/300lph [way high]. How to do a smoke test [torch the car?] Sorry about the "vintage pics." they are the only ones I have at the moment.First one is the first view I had of the car,[Fishermans Wharf '94] and the next one is taking it to the shipping terminal. Michael.

[donlan]

boyt911sc, Tony, Ossiblue seems to have converted the kpa to bar and here they are in psi: sp 42.5, ccp 27.5, wcp 42.5, rp 28, 24, 18, 16, 10. wur is in ohms [had just been rebuilt before you were due to come to Sydney].The pressures were tested per "Jims basement workshop". The tpr and wur havn't been tested individually. Michael.

[donlan]

Ossiblue, Will check gauge connections.Fuel distributor has just been re-built [as per my original post].Iwill check the connections as per your directions and report results. Many thanks..Michael.

[donlan]

E Sully, Ed, Yes I am a bit confused about motor.I will have to look "deeper" into air box,but the backfires only happened after a lot of trying to start and does not seem to be consistant. What do I disconnect to measure the 850cc volume? Will check connections. Tpv will need adjustment checking as it was sent away to be re-built and my marks dissapeared in the process. I have a printed out copy of "Jim's Basement Workshop".Thank you,will keep YOU ALL posted.Michael.

[donlan]

Ossiblue, Will check gauge connections.Fuel distributor has just been re-built [as per my original post].Iwill check the connections as per your directions and report results. Many thanks..Michael.

[spuggy]

Originally Posted by donlan

fuel pump is a copy of Bosch Motorsport Pump 0580 254 044.[ 72.5 psi/5bar.] 80gph/300lph [way high]

COPY of a Bosch 044? The only copies of Bosch 044's I've ever heard of are the Chinese pirate knocks-offs that were all over the place a few years ago - and they're complete garbage. Google for it/them.

If it didn't come in a Bosch box with "Made In Czechoslavakia" on it, it's NOT the real thing. ANY mention of GERMANY (West or otherwise) on the box/pump is a HUGE red flag, as they haven't been made there in a very long time. At least 10 years. Globalization.

Ditto if the original electrical leads fitted (an 044 is 1mm larger on both terminals), the original hoses fitted (044 needs adapters/fittings) and if it's not 2-3" (50-75mm) longer than the original pump.

If you've got one of those, good luck. It'll probably work as well as the $50 "Garrett" turbos you used to see on Ebay...

A real 044 is cheaper than the original factory part (thanks to volume discounting) - and outperforms it by a very large margin.

But a crapola copy? That'd be the first thing on my list to swap out.

[ossiblue]

Looking over your OP again, I suspect an overly lean mixture due to either a faulty fuel pump, faulty fuel distributor pressure relief valve, or out of spec fuel distributor flow setting. The fuel pressure readings are suspect mainly because the system and warm readings are the same, and the overall readings are so low.

Ordinarily, low pressure readings indicate an overly rich mixture being delivered to the engine but in your case the indications--continued backfire and brief running times--point toward lean conditions. This makes me think there is not adequate fuel flowing to the injectors and the low pressure is being caused by lack of basic system pressure.

If this was my issue, I'd begin with a confirmation of the pressures as measured between the WUR and FD, making sure the connection to the throttle valve was connected to the correct location. If the pressures were still low, I'd move to a test of just the pump pressure somewhere upstream of the FD--say at the connection to the fuel accumulator. If you cannot get upwards of 5+ bar at that point, the pump is faulty.

If you do get adequate pressure directly from the pump, then your issue is at the FD since this is where the drop in system pressure occurs. Most likely suspect is the pressure relief valve.

[donlan]

Ossiblue, Will check my fittings and follow your suggestions in the morning [I didn't get a chance today].Thanks,Michael.

[donlan]

Spuggy,As I said it is a copy.The original part is Bosch 0580 254 985 and a friend pulled it apart and now it won't pump enough pressure [it only has 4 screws to pull it apart] and I am suspicious of the copy and it will be checked to-morrow.Thanks for your input.regards,Michael.

[donlan]

Hello,I got to do a little bit yesterday. Hooked the pressure gauge to accumulator and the time from turning on ignition to looking at gauge it read 3 bar [3secs.] 2 more secs.5bar 1more sec. 7bar /102psi and now 18 hours later it reads 3 bar/44psi. The gauge set up for the pressure tests is installed as per " CIS primer for the Porsche 911". The gauge set up that I have the use of doesn't have a bleed valve. [It belongs to a professional mechanic]. I had to get some fittings turned up on a lathe,even one for my new fuel filter.Made the adjuster block on the hand throttle myself out of aluminium as our host was out of stock [still needs checking for adjustment when the car starts] .Michael.

[boyt911sc]

Originally Posted by donlan

Hello,I got to do a little bit yesterday. Hooked the pressure gauge to accumulator and the time from turning on ignition to looking at gauge it read 3 bar [3secs.] 2 more secs.5bar 1more sec. 7bar /102psi and now 18 hours later it reads 3 bar/44psi. The gauge set up for the pressure tests is installed as per " CIS primer for the Porsche 911". The gauge set up that I have the use of doesn't have a bleed valve. [It belongs to a professional mechanic]. I had to get some fittings turned up on a lathe,even one for my new fuel filter.Made the adjuster block on the hand throttle myself out of aluminium as our host was out of stock [still needs checking for adjustment when the car starts] .Michael.

Michael,

Are you testing the fuel accumulator and the FP? The test shows that the system could hold residual pressure over a period of time. And that means the FA and the FP are good too. How come your system fuel pressure is too low? Have you checked the FD's primary valve? Keep us posted.

Tony

[donlan]

Ossiblue, In your reply no.12 above is the throttle valve "the control pressure regulator w/throttle position compensation" [that's a mouthful] and if so,standing at the back of the car looking forward the line on the left goes to the connection on the FD that goes to the WUR and the one on the right goes to the 'T' piece on fuel return.I posted the results of the fuel pump test in no.15 above.Tkanks,Michael.

[donlan]

boyt911sc, Tony. Yes I tested those as suggested by Ossiblue and I have done another pressure test and the results are confusing so will re-do them in the morning. All the CIS components have been rebuilt before I started to re-wake the car!!! Regards,Michael. p.s. Did you get to Sydney? The results this time [18 may] Temp.15.5c WUR 51.7 ohms. system pressure. 42psi/2.95 bar. cold pressure. 33psi/2.30 bar. warm pressure. 42psi/2.90 bar. after 1 min30 secs. 3 39psi/2.70 bar. after 3 min 30 secs. residual pressure. 22psi/1.50 bar after 30 secs. ' 4psi/0.30 bar after 5 mins. . What did I do wrong!!!! will try again in the morning.

[boyt911sc]

Originally Posted by donlan

boyt911sc, Tony. Yes I tested those as suggested by Ossiblue and I have done another pressure test and the results are confusing so will re-do them in the morning. All the CIS components have been rebuilt before I started to re-wake the car!!! Regards,Michael. p.s. Did you get to Sydney? The results this time [18 may] Temp.15.5c WUR 51.7 ohms. system pressure. 42psi/2.95 bar. cold pressure. 33psi/2.30 bar. warm pressure. 42psi/2.90 bar. after 1 min30 secs. 3 39psi/2.70 bar. after 3 min 30 secs. residual pressure. 22psi/1.50 bar after 30 secs. ' 4psi/0.30 bar after 5 mins. . What did I do wrong!!!! will try again in the morning.

Michael,

The system fuel pressure should be greater than the WCP. That's problem #1. Second, the WCP (warm control fuel pressure) should go up and up until it stabilized. In your case it would be 42 psi. (example) and stay there. It should not go down when the engine is running. Do you have the control fuel pressure chart for your motor?

Yes. I was in Sydney in February and March 2015. Going back again next year. My wife likes to visit Melbourne next time. Keep us posted.

Tony

[Sunroof]

Did you say REDI-KOTE for your CIS tank? If that's the same as RED KOTE your going to have issues: trust me on this one. As you know the CIS fuel tank has the "bakelite" swirl-pot. That's the same material as the distributor and as such, will not let many coatings adhere to it forever! It was suggested that I use it rather then the POR tank coating treatment when I pulled my tank to have it boiled and coated. It was BAD advice for this tank. Well, the coating has dissolved off the plastic pieces and messed up my internal mesh tank filter (screws into the tank from the bottom) and that's like choking a chicken! I pulled the fuel level, looked into the tank with a flashlight and saw ribbons of red in the fuel! Damn! The car will start then stall, start then backfire, start then go a few blocks then stall, etc, etc. CIS has to have CLEAN fuel and this mesh tank filter can be the culprit here. Many overlook this item, which now I realize that for CIS tanks is a first look item when having fuel issues.

So by chance did you replace it when you had the tank cleaned and re-coated? If not, I would say its loaded with paint flakes, reduces flow and there you have it.

You have to drain the gas to remove. Folks fabricate this nut and bolt removal tool to get it out. Its on the board somewhere in the achieves. Simple R&R. By the way it will cost you about 56 dollars. Do not forget the gasket.

Good luck

Bob
1973.5T