'83 SC Warm Restart Problem and Questions

Mike Stanko · 07:26 PM

I'm a noobie owner of an '83 SC. Stock except for B&B headers and 2 in 2 out muffler. Except for the situation I'll describe below, the car drives and runs fantastic.

I experienced a warm restart problem a couple days ago. Car sat for perhaps 30-40 minutes after a 1 hr fun drive with a fellow Pelicanite. Thanks Wil

. Car was up to it's usual stable warm temp for the fun run...190 deg F. Went to restart it and it wouldn't fire up...just turned over. Tried it half dozen times over the next 5 minutes....nothing. Mild, but not strong gas smell afterward.

Spent the next 20 minutes looking for loose wires and vacuum hoses and made a couple restart attempts...nothing.

Another 10 minutes passed while the following 3 things were done...green wire at the distributor cap was giggled, all fuses in the front were rotated to make sue they were good contact, and all relays were pulled and put back (in case of a bad/corroded contact).

Car then fires right up. I seem to recall the thermostat reading a little higher than 120 deg F. So an hour to an hour + passed by from turning off after the fun run until I get a successful restart. Suffice it so say, I was

and happy.

Question #1...could 1 of those 3 last things done have been responsible for allowing the successful restart or did the temperature simply drop to the point where the cold start circuit was operating.

Question #2...if the answer to question #1 is "you likely just waited around long enough for everything to cool down and the cold start circuit went into effect", is there anything I can do to easily and safely to trick an up to temp car to use the cold start circuit logic.

I've read some past CIS warm start posts and let's say that I now know enough to be really dangerous

My first thought is to start by investigating if my pressure vs. time is per spec and to also see if fuel drips out of the accumulator. Is this the right first move?

I have only driven the car perhaps 8-10X and 400 miles since buying it. Never had a cold start problem. Initially idles at around 600 rpm and after perhaps 1/2 to 2 minutes, it settles in at about 1000 rpm.

No problem with a warm restart when I made a few brief stops for gas when the car was definitely up to temperature.

But....I do remember one time where upon a start, the car loafed at only 200 rpm for about 2-3 sec, I gave it some gas, and after a delay of 2-4 sec, it became happy and idled normally. But I can't remember if this was a cold start of a warm restart. Darn...getting old stinks.

Mike

ianc · 08-07-2007, 08:05 PM

Hi Mike,

Welcome to 911 ownership. As an SC owner, one of your first purchases is going to need to be the CIS pressure gauges. Typical warm start culprits are a leaky\faulty fuel accumulator, and\or fuel pump check valve. Search on these items for procedures for testing both. Good luck with it!

ianc

Mike Stanko · 08-08-2007, 06:23 AM

ianc,

Thanks for the welcome. I'll take your advice and get the CIS pressure gauges. I see Pelican offers this Bosch unit:

Bosch CIS Tester
Use the same equipment that the factory techs use to dial in the fuel injection system. Comes complete with all the fittings, schematics and detailed instructions.

PEL-PP910450 Bosch CIS Tester $218.95

A little pricey. But is this the gauge apparatus I'll need?

Mike

ianc · 08-08-2007, 08:16 AM

Hi Mike,

Yes, that's the unit. It is a little pricey being a Bosch, but there are cheaper units to be had. I believe I bought mine from NAPA for around $60 some years back...

ianc

rallyracer · 08-08-2007, 09:13 AM

I bought this one. It works as intended.

http://www.sjdiscounttools.com/ta33865.html

David

JK-81SC · 08-08-2007, 12:22 PM

I had the same hot start problem with my '81. I had to readjust the fuel pressure, replace the fuel accumulator, and readjust the mixture. The mixture adjust screw is very sensitive, BTW.

I bought my fuel pressure gauge from JC Whitney for about $60.

When everything is adjusted correctly, the car should start without touching anything but the key. If you have to press the accelerator pedal, then something still isn't right.

Mike Stanko · 08-08-2007, 06:10 PM

David...thanks for the link to a cheaper alternative.

Jeff...thanks! So it sounds like the diaphragm in your fuel accumulator was leaking and you weren't holding fuel pressure for a warm restart. Is this correct? Did you verify that fuel leaked out of the fitting on the spring chamber end of the accumulator? Did you measure the system pressure vs. time before and after replacing this item? What did you find?

Sorry for all the (likely dumb) questions.

Mike

Mike Stanko · 08-08-2007, 06:26 PM

In case anyone is interested, a search allowed me to find this very nice site with CIS info...

http://members.rennlist.com/jimwms/CIS/CIShome.html

Mike

JK-81SC · 08-09-2007, 07:37 AM

Quote:

Originally Posted by Mike Stanko

So it sounds like the diaphragm in your fuel accumulator was leaking and you weren't holding fuel pressure for a warm restart. Did you verify that fuel leaked out of the fitting on the spring chamber end of the accumulator?

Yes. I took the fitting off the bottom of the accumulator, and a lot of fuel poured out. A clear sign of a diaphragm that had a hole in it.

Did you measure the system pressure vs. time before and after replacing this item? What did you find?

I measured the fuel pressure after replacing the diaphragm, and the pressure held according to the specs in the Bentley manual. I didn't measure the pressure before I replaced the accumulator, but I'm sure the pressure would have dropped to zero very quickly.

My fuel pressure was out of range on the temp vs. pressure graph. I ended up pulling the WUR and doing a modification to allow me to adjust the pressure with a screw and a nut. If you decide to do this it's easy. Here's a sketch some else posted from years ago. I used a socket head cap screw instead a set screw.

The pressure is adjusted by driving the pin down with a hammer, or pulling it up with the nut. I had to whack pretty hard on the pin to get it to move, and it's hard to get it to move a tiny bit. With the mod, you can dial in the exact pressure. Just hold the screw in place with a hex wrench and turn the nut to pull the pin up.

Mike Stanko · 08-09-2007, 06:08 PM

Fabulous info Jeff. I owe you one. My buddy, also a Pelicanite, told me about a WUR mod he saw in Pano some years ago to allow a pressure adjustment. And wa la, you post it. Fantastic.

Mike

JK-81SC · 08-10-2007, 06:43 AM

Glad to help Mike. Let us know if you get your car fixed.