924Board.org

924RACR · Posted: Tue Apr 29, 2003 9:43 pm Post subject:

I think it's actually Paragon that sells the bolt-in check valve for the fuel pump.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

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

Mike 77 Read my post and Try it.

It works.

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

The fact that it tries to start with the boot disconnected makes me wonder if my hot start problem is not typical of the "normal" hot start problem experienced by others. I think that if I could quickly reconnect the boot when it tries to start, it would run since the sensor plate would then be able to lift. I need to figure this out soon because my patience (and money) has run out.
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Mike

64 Volvo 1800s

Roger · Joined: 06 Jan 2003 Posts: 1235 Location: Cordova, TN

I have rebuilt my fuel distributor (PITA) and after looking inside it. I cant think of anything that would be affected by a warm or hot condition. Also wasn't Porsches answer to the hot start problem to use a single 40 cc fuel accumulator? I have read that installing the check valve will help.

Could this be vapor lock

I would start by checking the injector spray pattern cold then hot. You could also check the thermo time switch and the auxilary air valve. I dont think the 77 came with a temp sensor for the CIS but check it, if there is one.
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1981 924 NA

Some people are like Slinkies. Not really good for anything, but you
still can't help but smile when you see one tumble down the stairs.

Roger · Joined: 06 Jan 2003 Posts: 1235 Location: Cordova, TN

By the way I have a fuel distriibutor and AMFU of a 77. If you are interested. It cost me $45. I am not looking to make a proffit you could have it for $45. I bought it used when I was having problems with mine. However the 77 is not the same as the 81.
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1981 924 NA

Some people are like Slinkies. Not really good for anything, but you
still can't help but smile when you see one tumble down the stairs.

kabok · Joined: 25 Jan 2003 Posts: 179 Location: Ft. Collins, CO

Hey Mike,
If you have the cold start injector connection to the hot start button done wrong then you will have the hot start problem. There's one way to check this. Start the car and let it idle for about two or three minutes. Shut it off and try to start it again with the cold start conected. My guess will be that you will experience the same problem. Not two minutes is not long enough for the engine to warm up. So it's not really a hot start problem. What you have is the case where the cold start is getting activated even when it's not needed and at the same time shutting off the fuel to the injectors.
Instead of using the existing cold start connection for your hot start button, I suggest disconecting that and using a different one that connects directly to the battery. (you can get one of these connections from the junk yard for a buck)

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

It definetly has to warm up before I have the problem.
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Mike

64 Volvo 1800s

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

ok, here's the latest. I noticed a strong gas smell (like when flooded), the longer I cranked which leads me to believe there is fuel pumping. When I actually had it running I turned the mixture screw to a bit more lean, which also meant turning the idle air screw out to get the idle speed back up (was that the right thing to do?). I immediately noticed that it reved smoother at low rpm. I then got busy doing other things and didn't try to restart for about 45 minutes. Before trying to restart I checked the connector plug on the warm up regulator and found that it was very loose due to broken clips on the side. It connects but it feels like vibration might make the connection poor. Does anyone have a spare of that connector plug? I made sure it was pushed on and tried a start. It started after cranking a couple of times. I'm not if it started because it cooled down, or because of the mixture adjustment or that connection. Time will tell. I've noticed that it seems to really guzzle gas. As I said before I just started driving this car a few days ago, so I don't know how accurate the fuel guage is if only filled to about a quarter tank. ALso, even after my adjustment, the exhaust smells very rich. I sure hope I'm on the right track with this, but I suppose that would be too easy.
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Mike

64 Volvo 1800s

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

Mike,

Your system pressure could be too high but you need the CIS pressure test set to check it. It is adjusted by adding or removing spacers on the pressure relief valve at the side of the fuel distributor.

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

numbbers · Posted: Wed Apr 30, 2003 10:45 am Post subject:

The gas guage on these cars is not accurate. The first quarter tank on my guage will take me about a hundred miles. The last quarter tank will only take me about 20 miles.

If your car starts after sitting 20 minutes, your check valve is working fine. You seem to have the typical hot start problem. Remember, the switch is supposed to supply ground to the cold start valve. Not battery voltage. You will get battery voltage to the valve anytime you are cranking, but the ground comes from the thermo-time switch. The thermo-time switch tend to time out too quickly when the engine is warm. The next time your car won't start when hot, spray a little starting fluid (either) into the air intake, and crank it again. If it starts, you are not getting enough fuel from the cold start valve during a hot start due to the thermo-time switch timing out too quickly. That means your hot start switch is either not installed properly, or it is not working.
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1980 924 Turbo

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

My cold start switch is hooked up correctly, and I have tried spraying starting fluid into the intake. No success. Here's the latest and I feel really stupid, but I don't care if this solves things: I was looking for something else in the owners manual and discovered the instructions to hold the pedal to the floor when starting a warm engine! Every modern fuel injected vehicle I've owned says DON'T depress the pedal to the floor so I thought that was the wrong thing to do. I have to admit trying it when all else failed, but never the first time I try to start it when hot. I'm anxoius to try it tomorrow.
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Mike

64 Volvo 1800s

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

Never mind any of my last comments. None of them worked. I'm right back to the same old problem. This stinks.
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Mike

64 Volvo 1800s

924 turbo · Posted: Wed Apr 30, 2003 11:58 pm Post subject:

I think your mixture is way off (rich). Take it to a shop and have them set the mixture, idle, and timing settings using a carbon monoxide tester. Or, just try leaning the mixture out.

Have you verified that your cold start valve isn't spraying gas during hot starts? Too much gas will cause a starting problem as well. If your engine starts fine cold, but won't start when warm, and everything else seems fine, I'd suspect the mixture was rich.
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Jon Furst

Roger · Joined: 06 Jan 2003 Posts: 1235 Location: Cordova, TN

It is hard to diagnose but you need to set the fuel mixture and run test's cold then hot and compare the results. One test at a time otherwise you wont know what helps and what makes it worse. I dont have a clip but I will get you one this weekend when I go to the junkyard. Its they type of thing you can get off any VW or Audi.
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1981 924 NA

Some people are like Slinkies. Not really good for anything, but you
still can't help but smile when you see one tumble down the stairs.

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

For the record, since its' come up in this thread, the part number for the external check valve that goes "straight through" (does not use a banjo bolt type fitting) is 911.608.951.00. It has a different male thread size on each end, one that fits into the fuel pump, and the other that fits into the fuel line leading to the accumulator. This check valve can be used with the newer Bosch pump, and the older plumbing. Couldn't find the receipt real quick, but I think it was about $16.50 US at the dealership
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'79 Eurospec 931