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Should I just replace all the CIS components?
I'm getting my 76 Targa sorted out before starting her up next week. The car has been sitting in a heated garage for 20 years and only started a few times. The fuel tank and fuel pump were a mess and are being replaced today. What else should I do to the fuel system? Should I replace all the injection lines, injectors, WUR, accumulator, relay and should I send the fuel distributor out to be rebuilt. I'm constantly reading about CIS problems on this forum and think I should just bite the bullet and rebuild/ replace these items considering the amount of time the car has been sitting. Or should I simply see how it runs first and replace as needed?
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Crotchety Old Bastard
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The least you should do is drop and clean the fuel tank which it looks like is being done. Optimally I would rebuild the fuel head and WUR, replace the injectors with new, and flush the entire fuel system. At minimum I would remove, flush and test each component.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds '78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8 |
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Almost Banned Once
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If you're going to do all that it would soon ad up to more than a brand new after market EFI system.
ITBs and everything. ![]() ![]()
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- Peter |
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Peter what is an aftermarket EFI system and who sells them?
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Registered
Join Date: May 2002
Location: Portland, Oregon
Posts: 12,650
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Quote:
Just remember their are basically 3 types of CIS Owners in the world: 1) The guys with working CIS systems are probably out driving their cars so they won't reply. 2) The guys that tinker with their CIS systems and have them royally screwed up will keep you running in circles with suggestions. 3) The guys that have spent a fortune on Webers/Aftermarket EFI will tell you they're great to justify their expenditure to themselves. Best of luck!
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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Hey Matt,
I seem to belong to group 1 of the 3 mentioned above. And that after resurecting my 50,000 mile 79 SC from 16 year hybernation. Even the engine was never turned over since then. Up until 1995 it was a more or less a regular driver though second car for fun rides mostof the time. But it was kept in a garage under a blanket. The one issue I had to deal with before getting it going was the fuel tank and the fuel pump. Everything else seemed to be OK. The bottom of the tank was gunked up with thick, almost solid brown wachsy stuff. It clogged up the tank outlet and return ducts and the fuel pump. I did not take the tank out or or go through any washing/cleaning procedures. All I did was to thoroughly clean out the tank borttom around the inside where the mesh tank filter sits. That can be done with the car on a hoist and with rags, carburator cleaning fluid, fingers and small screw drivers or a coat hanger wire bent to an L. After that I used a 2 foot long drain cleaning spiral used for cleaning sink drains from OSH to clean out the tank inlet and outlet tubes. I did replace the fuel pump, and the the tank mesh filter. Then, of course, I replaced the fuel filter in the engine bay. For the fuel pump I got a cheap $50,00 Walbro pump. That one, I thought could catch any junk that came form the tank. Later I could replace it with a Bosch pump. With these relatively easy, but reasonably thorough cleaning actions I felt I could risk starting the engine. I did that after it had been prepped with new engine and transmission oils, and first turned carefully by hand and with the stater without ignition first. That reawakening procedure in my case was all that was needed. Right after that I took the car for a 200 mile ride with absolotely no problems. That was 8 months ago and the car still runs like new with not a single stutter and no starting problems. Of course it goes without saying new tires, new brake fluid were also part of the picture. Knock on wood! (Wooden floor boards?)
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79 SC Targa 72 T Targa Sold 68 T Coupe Sold 65 912 Coupe Sold 62 356B Coupe Sold Last edited by porwolf; 02-09-2012 at 10:47 PM.. |
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Join Date: Nov 2011
Location: georgia/canada
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I agree with HarryD, I had a '77 w/CIS, once I got things adjusted, I left it alone, it ran like a scalded dog! I think too many people 'tinker' with them too much when they have other problems, mainly igniion. I did have module in dist. and MSD. I think shops just do everything to cover themselves which I totaly understand, I think porwolf had the correct plan.
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Fleabit peanut monkey
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Don't get discouraged that there will be no one to help you. There are a several folks here that help with CIS problems all the time that are real good. The biggest problems here related to CIS issues and "running in circles" has to do with the original poster: 1. providing poor problem description 2. not taking action (including not springing for test equipment) 3. taking "extra" steps without vetting the procedure with the thread participants 4. providing poor feedback Just communicate what is going on as best you can and keep your thread updated and you will get what you give. Last edited by Bob Kontak; 02-10-2012 at 04:49 AM.. |
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Exactly! When you do have a CIS Problem, you need to be very systematic to solve the problem. The list you give is what is needed to diagnose the problem via BBS. In fact most of the "good" advice I see is having the person verify first that everything but the CIS is ok (fuel delivery, ignition, air leaks etc) before messing with the CIS (or carbs or MFI or EFI) components. Many so called fuel metering problems are actuall ignition or fuel system delivery problems in disguise.
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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Location: Portland, Oregon
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Matt,
Like the above posters noted, cleanup what you can and get the car started. Once it is running, make sure everything is ok, fix/replace what is needed and go have fun.
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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Registered
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Clean it all up, check your pressures with the correct cis gages. Do a test with the injectors pulled and spraying in separate jars to check for even flow of each injector, and to see if they give a nice conical spray pattern. This will give you an idea of what to start replacing.
I personaly have a complete second cis system for my 1973.5 for back up parts. It was assembled over time from reasonbly priced parts sold in the Used Parts forum. A lot of the parts looked like they were past their prime, but often they just needed cleaning and adjusting.
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Ed 1973.5 T |
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Oh, one more thing, just in case, when you get it started first time have second person with a good fire extinguisher ready to spray the engine! On rare occasions strange thing happen. On some thread someone had a backfire that blew out the fuel injectors that continued to spary gasoline! Even the installed pop-off valve did not help. You will install the pop-off valve, right?
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79 SC Targa 72 T Targa Sold 68 T Coupe Sold 65 912 Coupe Sold 62 356B Coupe Sold |
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CIS troubleshooting.......
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Matt, The decision to replace good working CIS parts is up to you. If downtime is more critical to you than spending unnecessarily, then I would go along with your decision to replace everything at your heart's content. I'm cheap and frugal, so I only replace parts that could not be fixed or repaired. On the other hand, if the mechanic working on your car is not very familiar with CIS (911) it would cost you more in terms of man-hour (labor) to sort out the problem/s. I'm no CIS expert, but I have not encountered a CIS problem that could not be diagnosed correctly by DIY'ers like you or me. So installing new parts in your engine is not a bad course of action. It makes the job less difficult for the mechanic but would cost you more in return. If it makes you more comfortable having these parts replaced now, go ahead. Only time would tell if you did a good decision or not. It is only money!!!!! Ask your mechanic to purge the fuel circulation system with fresh gasoline mixed with injector cleaner solvent for atleast 15 mins. run or more. Then inspect the spray patterns of each injectors including CSV. The injectors should not drip when not in used. ![]() Tony Last edited by boyt911sc; 02-10-2012 at 05:08 PM.. |
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Registered User
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Thanks everyone for the great advice, it's exactly what I wanted to hear!
The last thing I want to do is to dump more $$ into the car than I have to (2 daughters in College) I"m sure the brakes and other systems will need attention and $$ as well. I'm definitely nervous before turning the key because I don't really know what I have yet and may be looking too far ahead. I bought the car for $7,500 which was all I could afford and if it takes me a few years to get it right it's fine with me. I didn't buy the car as an investment and if I get underwater with it that's fine too. I Just turned 59 and I simply want a nice old P car that I can drive into my golden years. I owned two 356's and a 912 in the 70's and have always regretted selling them, I won't be making the same mistake again! If things don't go well with the start-up next week I'll definitely be back looking for more advice, thanks again! and yes I did install a pop-off valve and new fuel lines and will have a fire extinguisher ready. ![]() |
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I have a little different take
DONT SCREW WITH IT!
If it starts, FANTASTIC! Point is, I would clean your gas tank, and CHANGE THOSE OLD FUEL LINES! ALL OF THEM... Do the Fuel Injector test, However I would also run some type of fuel system cleaner thru the tank and such. Overseas we would double and triple the amount because of the crap we would get in the tank. But what ever you do, DO NOT MESS WITH THE FUEL DISTRIBUTOR. With power on the car, lift up the sensor plate with your fingers two or three times, if you feel resistance and hear the injectors scream, then all is good with the distributor...DONT MESS IT! Have I stressed this enough? Lets Recap... 1. Clean your gas tank 2. Run a good fuel system cleaner in the tank 3. Check your injector spray pattern, clean and replace as needed. 4. REPLACE THOSE OLD FUEL LINES....! 5. Do your sensor plate check.... 6. DONT SCREW WITH THE DISTRIBUTOR I speak from lessons learned, and experience on this. By the way, my 74 CIS ran like a scalded dog!
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Signature Phrase " CATCH ME IF YOU CAN" 1988 Porsche 930 "Squerly" Built by "Porsche Doc" -------------------------- 1974 Porsche 911 (2003 - 2012) 2000 Boxster S (2006 - 2008) |
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Get it running ............
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Matt, Ask your mechanic to pressurize the fuel circulating system by running the FP for several minutes and look for any sign of fuel leak. Check the oil level. With fresh supply of gasoline in the tank and a fully charged battery........fire the engine. He should also check the control and system fuel pressure before running the car. There is a 50/50 chance it would start. If it would start and die..........you know you have ignition (sparks). The previous test I suggested would verify fuel delivery. Keep us posted. Tony Last edited by boyt911sc; 02-10-2012 at 05:27 PM.. |
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