1979-1993 & 94 Conv [Subscribe to Daily Digest] |
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Several months ago I posted a series of questions about a warm start issue I was having with my CIS 8 Valve non turbo. Apparently it is not uncommon. Problem occurs after being driven to a fully warmed state and then left to rest for more than 15 minutes. Cranking results in initial rough start until fuel pressure is built. Leaky accumulator was removed some time ago. Opinions here and on the web differed on whether the accumulator or something else was the source of the drop in pressure. Check valve at pump is ok.
So here's my question. Looking at a second functional check valve I found that its thread size is identical to the exit side of the fuel filter canister so it can be placed in line with the fuel lines using a threaded brass cap that goes at the fuel pump connection.
My working hypothesis was that if pressure was being lost down stream then a check valve further upstream would retain pressure at the injectors and the fuel distributor (assuming injectors, WUR and distributor were not leaking which they appear not be to be). So I put the check valve in line. As I said with the appropriate o rings its a perfect fit and doesn't leak. Cars runs as well as before, acceleration is normal and most importantly no more warm start issues.
So what dangers if any are there in doing this? Eg is pressure build up an issue? Is the CIS system really sensitive to pressure changes? Will I blow up my fuel filter? Why didn't saab put a check valve further upstream in the first place?
You might ask why not just replace the accumulator - well they are not cheap and this seemed like a reasonable cure for a car that is old but a daily drver. It also lets me determine if any injectors are leaking etc.
posted by 209.197.138...
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