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Registered
Join Date: Jul 2002
Posts: 2
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Bosch distributor question
I am having a problem getting my 2.7 ltr to idle. I have Weber carbs 40IDA P 3C (145 main jet, 180 air correction, 34 venturi, 55 idle, F3 emulsion). I also have an MSD 6AL ignition system. I had been chasing an electrical problem with some spark plugs not firing (it would vary from run to run). I replaced the points and that problem seems fixed. But I still can not get the engine to idle without some pressure on the accel pedal.
In trying to narrow down possibilities, I have two questions about the distributor. 1. Should the vaccum pot on the distributor be capped or connected somewhere (the carbs?). 2. Should there be a ground wire connected to the distributor? Any help or other suggestions greatly appreciated! |
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07-27-2002, 02:16 PM
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Registered
Join Date: May 2001
Location: Peoples Republic of Long Beach, NY
Posts: 21,140
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I can't give you any hard answers..but w/carbs you should be able to immediately figure out if it's fuel or ignition..if ignition then the coil and MSD are easy to check out, along with wiring..the dizzy/initial timing is also simple to figure out...maybe you can pull a spark plug and see if it's wet..someone familiar w/carbs may be able to offer advice just by listening to it..sorry I can't be of more help ......Ron
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Ronin LB '77 911s 2.7 PMO E 8.5 SSI Monty MSD JPI w x6 |
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07-27-2002, 02:52 PM
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Registered
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
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Rick,
What cams are you running in that engine? 1. The vacuum retard module doesn't have to be hooked up .. it's only function was emmissions compliance at idle, but that brings up the question ... what is your ignition timing currently set at? You can find all of the distributor information, assuming it is a CIS 2.7 distributor (same as 2.4 'T' distributor) ... just use the 2.4 timing data. If it is a Bosch 0.231.184.004 RS 2.7 distributor that Richard Parr used to sell with the PMO conversions ... you will find that data too, here: distributor lube... 2. A braided ground cable was included in your OEM wiring harness between the CDI-unit and distributor, and coil ... so, I happen to think it is reasonably important and required.
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' Last edited by Early_S_Man; 07-27-2002 at 03:02 PM.. |
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07-27-2002, 02:59 PM
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Registered
Join Date: Jul 2002
Posts: 2
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Warren,
I'm using cams 901.105.109.01 (left) and 901.105.110.01 (right) set to 4.3 mm at 0.1 mm valve clearance. I have the idle timing set at 5 BTDC, and have tried 5 ATDC and TDC. Above 1500 rpm, the engine seems to accelerate smoothly (sitting in my driveway under no load), but under 1500 rpm, I can't get it to idle without feathering the accelerator pedal. -Rick '73 2.7 weber carbs, 8.5:1 euro p/c's |
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07-28-2002, 05:33 AM
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Moderator
Join Date: Dec 2001
Posts: 9,569
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Ground
When I got my car it had both the Bosch CDI and an MSD 6AL installed. The CDI was not hooked up so I removed it, and its associated ground cable, from the car. Whoops! The engine then ran on three cylinders and dumped raw fuel from the exhaust. I reinstalled a ground strap between one of the motor mount bolts and the chain cover, and amazingly, got all my cylinders back.
I would give this a try before the cams.
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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07-28-2002, 06:22 AM
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