1969-1984 [Subscribe to Daily Digest] |
 | [Main Saab Model 99 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Warm-up regulator for hot start problem Posted by Gary Stottler [Email]  (#1463) [Profile/Gallery]
(more from Gary Stottler) on Tue, 12 May 2015 06:43:48
In Reply to: Re: fuel quality is very important, high ethanol levels, Stephen, Fri, 8 May 2015 21:16:03 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Hi Stephen,
As discussed previously, the warm-up regulator is a possible culprit in that if the regulator leaks after the engine is shut off, the "resting pressure" will bleed off through the warm-up regulator return line and back to the main return line to the tank. This loss of "resting pressure" will allow the fuel in the 4 injector lines to boil causing the hot restart problem. As I mentioned in my last post though, I can't guarantee that replacing the warm-up regulator will fix the problem unless everything else is perfect.
It turns out that in 1978 a number of changes were made to the system to improve this problem including modifying the warm-up regulator return so that it's blocked in the fuel distributor when the pump is off. Also, 1978 got a larger capacity accumulator and a separately replaceable check valve in the fuel pump. Unfortunately the replacement valve is no longer available unless you buy a whole new pump. The 1978 and later system could still have problems with leaky injectors or if the line pressure regulator in the fuel distributor leaks. Although that last item seems to be rare, it is possible in all years which is one reason I hesitate to promise that a new pump, new injectors, and a new warm-up regulator is a 100% fix.
If you have the Saab Service Manual for 1975-1980 there is a good picture on page 240-2 of the whole system.
More to follow on the electrical system....
Best,
Gary
_______________________________________ Gary Stottler
, Wed, 6 May 2015 17:50:08, Thu, 7 May 2015 07:32:50, Tue, 12 May 2015 07:08:16, Tue, 12 May 2015 07:15:58, Tue, 12 May 2015 06:43:48 <-- Viewing This Message, Wed, 13 May 2015 05:35:24, Mon, 18 May 2015 16:17:53, Wed, 17 Jun 2015 05:47:23
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
