924Board.org

Mike77 · Joined: 14 Dec 2002 Posts: 103 Location: PA

I FINALLY (after 5 years) got my 77 licensed and insured and took it for it's first real drive. It runs and drives great....as long as I never have to stop and buy gas, or go shopping for less than 2 hours! That hot start problem is a major pain! The car has new injectors, accumulators, fuel hoses (all of the old parts leaked, which I thought was the problem). I even built the hot start button described in the tech section. It works as far as activating the cold start injector (which does not seem to leak), but that doesn't fix my problem. I have a fuel pump off of a parts car, but it has been packed away in a box for a few years so it may not be good (although it looks fairly new). My last hope is to try it, in case my fuel pump check valve is the problem. If that does not fix it, what else could be the problem? That's the only thing I haven't tried, and I'm having my doubts if that will fix it. This seems to be an incurable problem! Has anyone else found their hot start problem to be unfixable? This has got me really frustrated because I have 10 days to get the car inspected (PA) and there's no way it will pass if the mechanic can't get it to start to pull it into the garage, or restart to get it back out. The rest of the car is very nice but it will be unusable if I can't rely on it restarting.
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Mike

64 Volvo 1800s

78porsche924 · Posted: Sun Apr 27, 2003 12:45 pm Post subject:

I had the same problem as you. I would almost drain my battery trying to get the thing started. Replaced the check valve in the pump. You could blow straight through the thing. Starts immediatly now. I would go for the check valve as they are fairly cheap.

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Mike,

It does sound like a classic fuel leak down problem. Did you replace the cold start injector or just install the switch? Typical leak downs are caused by leaking injectors, bad relief valve, leaking accumulator or the fuel distributor leaking internally. It may help to use a good fuel system cleaner? BTW if it is a leak down problem, turning the ignition to on (not crank) then off a few times should reprime the fuel system.

Another area to check is your coil. Sometimes a faulty coil will work OK when cool but fail when heat soaked.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

ltgland · Posted: Sun Apr 27, 2003 7:09 pm Post subject:

I had a bad heat soak problem with my starter motor. could be that

Mike77 · Joined: 14 Dec 2002 Posts: 103 Location: PA

From what I understand, the check valve in an early 77 fuel pump is internal and the whole pump must be replaced. Is that true?
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Mike

64 Volvo 1800s

924 turbo · Posted: Mon Apr 28, 2003 12:28 am Post subject:

My '80 924 has this problem as well. The car will crank fine when warm (so it's not the starter) but it won't start. I installed a switch to run the cold start valve when I need it for hot starting. In my situation, it works to solve the problem.

Here's the bad news. I've replaced everything in the fuel system except the fuel distributor, the pressure reduction solenoid, and the frequency valve (the last of which your car won't have). This includes the fuel pump with internal check valve (it works) and the fuel accumulator. My car passes all CIS pressure tests, including residual pressure.

I think the problem in my car is the fuel distributor (process of elimination, heh). I'm not really willing to fix it at this point, as the car runs and I don't ever get stuck. It runs good enough, warm or cold, for me not to care anymore.

The only other strange behavior it exhibits is a slight hesitation at 2800-3000 rpm (usually at sustained part-throttle cruising) and poor initial cold-start characteristics (the car runs rough unless I stab the throttle and bring the revs up to about 3k momentarily, then the idle smooths out).
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Jon Furst

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

Mike,

An external relief valve can be added if you have the banjo fitting fuel line.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

Mike77 · Joined: 14 Dec 2002 Posts: 103 Location: PA

I've tried turning to the on position (but not before giving up cranking) and it didn't work. I even tried disconnecting that electrical connection on the fuel distributor, which when disconnected allows the fuel pump to run, and that didn't re-pressurize the system either. The only thing that seems to at least give a sputter is to disconnect the rubber boot that attaches to the intake manifold. It then tries to start, but won't run. After the car sits for a while, it starts right up.
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Mike

64 Volvo 1800s

NINEEAGLES · Joined: 25 Apr 2003 Posts: 219 Location: SW PA

I read in the owners manual that if the outside tempature is above 90 something that you should depress the accelerator to the floor before you crank it....this has worked form me in the past but it seems to really load up if you don't let off as soon as it fires....this doesn't always work, though...it's tricky...If I forget to hold the pedal down before I crank, it won't fire at all....at least until I crank for about 10-15 minutes (a few seconds at a time of course)...this is very frustrating and I am going to try to intall may own version of the Dave Russel thing.......

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

dpw928 wrote

Rafael · Joined: 13 Nov 2002 Posts: 11 Location: SPAIN

I´ve resolved the problem some time ago.
First of all, the botton like you have, only works when the engine is cracking after you left the key of the contac in normal position, the power to the cold start valve it´s of, and the engine need more fuel to run.
Try this, take the contats of the cold start valve apart disconect the wires and cut it (THIS IS VERY IMPORTAT because the wires that come from the car are given + or - to the valve) take + from the battery directed and the ground with the botton, so you have all the control to activated the cold start valve, and left it the time that you want and the time that the engine need to run well.
When the engine cold you must push the botton to start because know you have the control of the valve, and in warm starts you push the botton and when the engine start left it some time until you feel the engine is run ok.
If it works to you you can put it a fuse, and some reles like i did for the cold starts.
Try this and tell us.

numbbers · Posted: Tue Apr 29, 2003 10:31 am Post subject:

Check the faqs in the tech section.
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1980 924 Turbo

Mike77 · Joined: 14 Dec 2002 Posts: 103 Location: PA

I tried my parts fuel pump tonight, and the pump is dead, so I still don't know if the check valve is the problem. Today I accidently shut the engine off after a long drive and it wouldn't restart even when I tried immediately after shut off. The hot start button didn't help either. If I pull off the rubber boot, it sputters but won't keep running. After sitting a couple of hours, it started up and ran fine. I'm so fed up with this problem that right now I'm debating whether to sell the car as a complete, very nice car with a severe hot start problem, or part it out since all of the new parts are probably worth more than a nice 924 (that won't restart). I hate to be a quiter and admit that this has beat me, but I"VE HAD IT...I'm tired, fuel soaked, and I refuse to pour any more money into high cost repairs like a fuel pump or fuel distributor). On a more positive note, the times I've spent actually driving this car have been great! It handles super and feels rock solid at hiway speed.....too bad I can't shut it off and count onever getting home for at least 2 hours.
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Mike

64 Volvo 1800s

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

Mike, the first thing to do is pick up the CIS pressure test kit. there's a thread Vaughan posted a while ago with a link to a supplier. if the residual pressure checks out then the warm-up regulator is next to check. it can cause all sorts of mysterious behavior when the injection is setup to compensate for a bad WUR. it sounds likely that you're losing pressure if it's as bad as you describe.

the hot start is a nagging problem with CIS. there was an aftermarket kit a long time ago to help solve the problem. i've got mine in pretty good order (everything checks out) and i still get a little stumble when starting hot sometimes.

the thing not to do is to just replace random components. that gets really expensive really fast! try not get discouraged.

edit: i didn't notice you saying that pulling off the rubber boot gets a sputter. when you do that you're basically cutting of the fuel supply to injectors. that would make me think you're running rich at restart. a leaky cold start valve would be a good place to start. the next time it happens pull a spark plug out and see what it looks like. if it's wet then you're flooding. leaky injectors would be another culprit. this could have the effect of bleeding off fuel into the cylinders which would flood it plus you would loose all the residual pressure in the system. lots of possibilities.

-nick

Mike77 · Joined: 14 Dec 2002 Posts: 103 Location: PA

My warm up regulator is brand new. I found a great deal on a new one on ebay, so I bought it as a spare. My injectors are also new (the old ones did leak). The cold start does not leak and neither do the injectors. What would cause the mixture to be too rich, other than a messed up mixture adjustment, or fuel dist?
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Mike

64 Volvo 1800s