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MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

So I finally got the 81 931 engine back together. to replace the WUR. started at 1030 pm finished at 6am... and 33 deg inside the garage.

Well so now it idles, slight miss, But if I give it any gas it will die.

Unfortunately Im not sure If I put the vac hoses back correctly (if it matters)
Since I had to replace all the ones in the intake area.

theres the 3 with the T, : one goine to the WUR, one going to the diaphram, and one to the throttle(but i wasnt sure which nipple on the throttle)

And a seperate line going from the Coolant line(?) to the throttle.
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Grenadiers · Posted: Sun Jan 05, 2014 12:39 am Post subject:

There should be a vacuum diagram on your inner fender, driver's side I think.
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

so heres how it ran.

at first it started and ran for about 15 sec then died, but I think i had the frequency valve unplugged.

then a few more tries and it would run then sputter and die
couple more tries and it would start to idle a bit, then the slowly the irpms would drop. but if I went an opened the idle control screw it would seem to level out but eventually die.

couple more tries and it it eventrually began to idle and not die. BUT any touch of the throttle and it would die immediately.
(actually if I cracked the throttle a tiny hair, the rpms would go up slightly)

Also when i unplugged the overboost switch it dies immediatley. this seem to cut out the frequency valve. SO I grounded it, and would heave the frequency valve run for a second.

and yes Im considering the pressure valve tool, but then again I plan to go EFI, ASAP, i simply want to make sure the car runs and drives Ok before I mess with it.

Ok now Im going to catch up on my sleep!
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It was either this or a giant box of legos

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

Grenadiers · Posted: Sun Jan 05, 2014 1:26 am Post subject:

What year car do you have? Many things can be the cause of your problem. The air/fuel mixture could be very rich or very lean for example. Check your plugs. The engine might be running only on the cold start valve, and then nothing. If a series one engine, the distributor might be set at a 'retard' position. Might have to pull your injectors and run a flow/volume test. Here's a link to a vacuum diagram for the series one engine.
http://www.924board.org/viewtopic.php?t=36134&highlight=vacuum+diagram
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Paul · Posted: Sun Jan 05, 2014 1:39 am Post subject:

After replacing a WUR, one should always check the system and control pressures. Then the timing and mixture.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

In answer to your original query, line connection definitely matters.

Here is a diagram:

However, Paul is absolutely right. . .with a new WUR, system pressure and mixture will need to be returned to baseline using the correct tools or the car will never run right.

And yes, you do need to purchase specialty tools to work on your vintage Porsche turbo.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

that diagram must be for an S1, where can I find one for an s2?
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kcoyle · Joined: 15 Jan 2011 Posts: 712 Location: Long Island, NY

Some here on the first page.

http://www.924board.org/viewtopic.php?t=22954&postdays=0&postorder=asc&start=0
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Relax, all right? My old man is a television repairman, he's got this ultimate set of tools. I can fix it.

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

Ok well it looks like my routing was right. The only spot im not sure of and the diagram is not clear on, is the throttlebody. One port on the TB is the tiny little vent that looks to be covered by the throttle plate.(the one sticking straight out 90deg) Now I dont know if it makes a difference. I have the line comming from the water tube connected to that one.(i think)

But it seems that if I do anything more than nudge the throttle by a half a millimeter the engine wants to die.

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It was either this or a giant box of legos

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

I doubt its a fuel pressure problem. the CIS plate has resistance and it ran better BEFORE I pulled the intake off and replaced the WUR.
I dont think its running only on the cold start valve, as it seemed to be running better at it started to warm up.

One thing I found (before I started it) was the thermostat was broken. Now Im not sure is that means it was always open, or always closed and never going to open? either way I took it out.

however now I heard the frequency valve buzzing, while its running, where as I dont recall that before? But as i mentioned when I disconnected the Overboost switch the Freq valve would stop buzzing and the car would die.

(BTW, since my garage is several miles away, I have to plan/research ahead, then take the info and go work on it, so since its 15* outside I'm staying in and try and take my guesses in the mean time)

anyone in denver got a Pressure tester I can borrow? ( I honestly don't want to put much money into the CIS, since im working on my EFI/ITB system.

I kind of wonder if I have a vac leak somehwere, but still I think it would run a little bit with some throttle even with a leak, But I dont see where the leak would be I checked all the lines.
BUT seemed all the old lines were very brittle and pretty much snapped right off. so I replaced them, the only line left was the one from the water pipe going to control valve near the fender.
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MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

also after the engine started to at least idle, I pushed on the CIS plate a tiny bit and again the engine wanted to die
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It was either this or a giant box of legos

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

Oh also to throw more into the mix. I just remebered. I put the WUR from the 80 model (into this 81) I read that it was acceptable and would have more enrichment (or something) and was commonly done, so since i wanted to up the boost I figured it should be ok. But either way it should run with it obviously.
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It was either this or a giant box of legos

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

any other thoughts here? what else could have changed? any tests I can do to rule out things?
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It was either this or a giant box of legos

scriblz7 · Joined: 07 Dec 2008 Posts: 112 Location: kirkland WA.

as was said earlier you should definately check the fuel pressures hot and cold after changing the WUR.

make the tool here: http://924board.org/viewtopic.php?t=38729&sid=6fa0c6fd1732d0e07a889c8450b7702b

procedure is here: http://www.924board.org/viewtopic.php?t=35734

check your fuel injector flows and spray patterns. ian showed that they can be way off on even a running car here: http://924board.org/viewtopic.php?t=39386&highlight=fuel+pressure+testing&sid=6fa0c6fd1732d0e07a889c8450b7702b

you also may have introduced some vacuum leaks while the system was apart so start checking for those too
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Riley
79 924 n/a with gt body
15 VW GTI