Pelican Parts Forums - CIS hard to start when hot

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- - CIS hard to start when hot (http://forums.pelicanparts.com/porsche-911-technical-forum/199658-cis-hard-start-when-hot.html)

Quote:

Originally Posted by rwest (Post 10060462)

I “joke” that when someone asks troubleshooting questions on a forum, they should have to put down a deposit and they get it back only if they follow up with what fixed the problem.

I like it.

Like an escrow account you pony up when you join the forum.

Maybe $30. $10 per issue. Three issues max at a time. Just enough to make you think.

So many threads in other forums I trudged through looking for the silver bullet. Nuttin.

Many guys are great about closure, though.

I have been having the same issues with my 1973.5T/first CIS. I added a "hot start relay" which helps maintain current to a hot solenoid, but the lack of a check valve creates the same problem (enough fuel to get some of the cylinders going but slowly before all cylinders are up and going).

My fuel pump is in the rear in the drivers side wheel well. My fuel pump has to pull the fuel from the tank not push the fuel as on pumps moved closer to the tank (1974 - on). When the engine is turned off the fuel flows back to the tank, making restart slow going. I NEED A CHECK VALVE in line!! Its not my accumulator or WUR, cold start valve or injectors (they are all new). Its the damn set up for the 1973.5T and one I need to address for this summer. Try the check valve first!

Bob

Usually hot start issues are the fuel accumulator.

I have this exact problem with my '83 SC. Hot starts within a few minutes of shut off are immediate. Wait longer to restart, up to 30 mins or so, and it requires some cranking, followed by a period of rough idle. Beyond 30-40 minutes, it's a bear to start. Every time this comes up, the recommendation is to check the checkvalve on the pump, bad accumulator, leaky injectors or some combination.

Well...

My pump and checkvalve check out good (both are relatively new). Accumulator is relatively new injectors are brand new, all 6 of them. Fuel pressure check shows 20 psi after 90 minutes, which is well within spec. Yet the problem persists.

I am having issues with cold idle and warm idle after warm restart, both smooth out after 5-10 minutes of idling - I cannot figure that one out, but not sure if it's related to the no hot start condition after 30 minutes. This CIS system is driving me nuts, especially without dropping the engine and sorting through that mess on the back on the airbox and intake system.