will not start when warm

[don gilbert]

82 3.0, will crank rite up in the morning and run all day, but when it sits for about 15 min will not hit a lick. just put a new wur on it, as per advice, but no change. can lift up on the sensor plate while cranking and it will start, but spits and sputter for a while and then will clear up when i work the throttle for a while, any advice before i spend more money on somthing i dont need?

[Cooper911SC]

Fuel Accumulator? Located in left side of engine compartment next to fuel filter. If the Accumulator is bad the system pressure will bleed off too fast once the car is shut off and create a hot start/vapor lock problem. Lifting up the sensor plate like you are is re-pressurizing the system which is what it needs to start hot.

Good news is...the accumulator is far LE$$ Expen$ive than your WUR! =)

Cooper

[Alan L]

Yes, +1 on accumulator - sits next to fuel filter.
If you had the gear - or someone has - you could check this by watching the pressure bleed away after you shut hot engine down. It is a spring loaded diaphragm. It could be a check valve (non-return) on the pump also.
On cold start you get an extra shot of fuel straight down the throat via cold start valve. This does not happen when warm.
Alan

[GothingNC]

Accumulator for the 82 SC runs about $250.

I would swap out the fuel pump check valve first.

[Ron.G]

I'd do the $22.00 fuel pump check valve before I replaced the accumulator.

Edit: What GothingNC said

[Gunter]

Gothing and Ron.G said it: Check Valve on FP.
Fire Extinguisher!
Open the lines very carefully. You may need new washers.
Clamp the short supply line to prevent the fuel from spilling.
If the short 1/2" line needs replacing, the tank has to be emptied.
If the pump is really old, now is the time to replace it together with a new check valve.

[don gilbert]

ok, ed u cate me a little, my "mysteries of cis book came in today and i've read it cover to cover. so now i understand that the fuel accum. holds " at rest pressure". alan, you said that the cold start valve was the reason it would start the first crank of the day, my reasoning also, but according to the book i got today, the cold start system only operates at temps below 50 degrees, and it hasent been below 50 here in memphis in a while. why will it crank and run so smooth first start of the day if it is losing "rest" pressure during to nite? just trying to figure things out not meaning to sound contrary, I did put a new fuel pump on it when i did the 2.7 to 3.0 swap in jan, and noticed the check valve on the old pump which i had to remove and put on the new pump. i guess i should go ahead and get a new one of these at least, thanks ,don

[Alan L]

Don,
What I would suggest is that you try and measure the system pressures. Particularly the 'at rest' pressure. This will tell you if you are dealing with a pressure leakage problem. If the pressure holds, then obviously you are going to be looking elsewhere. (I made my own gear for not many $'s)
Typically, from all the threads I have read, the pressure leakage seems more a problem with hot start rather than cold start (I've not had this issue - so going by others symptoms). My conclusion would be the cold start valve compensates enough for the deficiency. I guess your temps are deg F. That puts you around 8 deg C. I'd be surprised if your cold start valve was never operating above that temp, in spite of what the book may say. You could probably check that by pulling the plug, and even better - putting a V meter over the pins and get someone to crank your cold engine - see if you get 12V. If you do, it is firing fuel while the 12 V is present.
My 930 I'm working on was a pig to start from cold. After tracking a series of issues I found the cold start valve itself was seized shut - no 'clonking' on applying 12V.
When I freed it, the car started first time. It is summer here.
Regards
Alan