924Board.org

[amieander]

Hi,

I’ve lurked on this board for so many years that I should have been paying rent; I know my car has been on the 924 registry for well over two years now. Most of what I've learned about K-Jet I've learned from you folks, and for that, I thank you. So I tried to be respectful, do my research, and get my poop in a group before I posted.

I ‘inherited’ this project when the boyfriend and his equally-as-mechanically-inept brother tore into this car and decided that K-Jet was beyond their level of expertise. All I specifically remember about their work with this car is watching the distributor explode like a can of prank snakes when they got the halves apart. Oddly enough, they did get it back together with all parts accounted for. But I digress.

Anyways, this mars red yard ornament has the common been-sitting-won’t-run issue. It starts, and catches (fire) occasionally, especially when it's cool out. It never runs, though, for more than say, fifteen seconds (assumably just off of fuel from the cold start) and sounds like death when it does. I'm surprised the engine is still attached to the mounts.

System pressure is right on at 5 bar however my control pressure is exactly the same at 5 bar...the needle barely even wiggles when you close the tap on the gauge. I have two separate used (but clean) WUR’s and I get the same equal readings with either WUR. Just for giggles I even went so far as to do what I read in a Benzworld post and removed the WUR from the engine while leaving fuel lines intact, tore the back off of it and removed the pin and spring...identical 5 bar control and system pressures-even with the WUR dismantled and basically MIA.

So with that said, I'm thinking it's safe to say I’ve got distributor issues. It almost seems like a blockage, like the fuel isn't making it's way back to the gas tank somehow...I know there isn't a blockage in the return fuel line itself (ran air through), but I don't know how much of a role the system regulator has in the return feed and I can't seem to find a "rebuild kit" for that part for a 1977.

The car has a clean gas tank, new fuel filter, new fuel pump (see ‘mechanically inept’ reference above), no blockages in any fuel lines to and from all CIS components, AAV seems to work (freezer test anyways). I have also since tore the dizzy apart twice since the above-mentioned disaster, and am fairly confident from what I've read and seen all the parts are intact it's been put back together correctly...but I also know that even if you're careful, a home rebuild isn't always successful.

The other random thought I had was within the air meter...I know the guys had the allen in the CO2 adjuster screw hole while trying to run the car...is there a way the allen could have possibly messed up the flapper lever mechanism (fancy techspeak) so badly that it would keep the plunger from moving at all (or getting it stuck)? When the dizz is removed from the car and manually lubed with gas, the plunger moves freely within the distributor.

So...does this never-changing no-matter-what-I-do pressure scenario ring a bell? Is it fixable at home, or should I send the dizzy out for a thorough 'professional' workover? Or, is there something big and obvious I'm missing?

Thank you so much for your help!
_________________
early 1977 NA mars red 924

[Khal]

Mon Dieu!

Correct English... hyphenation and capitalization and punctuation... whole sentences and paragraphs... mentions ex-boyfriend...

Your ex. is not a bloke, right? (Hey, I live in Canada, it's all good)

You're not 65, right? (I might consider a pensioner... )

By the way, we're here to help.


_________________
'80 924 Turbo

[kingzetts]

I don't think this is an issue with the metering plunger, since control/system pressure differential is established even with the plunger at rest and no flow to the injectors.

Your symptoms certainly sound like either a dead WUR or a blockage in the fuel circuit from dizzy to WUR and back to tank. By the way, its probably more unusual to find a used WUR that is working than one that is faulty, so before concluding your fault is not the WUR itself you really need to get hold of a WUR you know is working OK - ideally pull one off a running car on which you have been able to measure control pressure.

Anyway, here's what I'd do;
Get a plentiful supply of shop rags and wear eye protection in a non-sparking environment. Jump the relay and run the fuel pump. Crack each of the following connections in turn, using your shop rags to mop up spilt fuel;
a) feed line from fuel distributor to WUR at dizzy. If the gauge reading drops, you have isolated the blockage to being downstream of the dizzy, so move on to the next connection. If not, suspect the dizzy.

b) next, crack the same line on entry to WUR. A drop proves that line is clear, move on, if not replace the line.

c) next, crack the return line from WUR at exit of WUR. A pressure drop shows your problem/blockage is downstream of the WUR. If not, WUR is shot.

d) next, crack the same line where it tees into either dizzy or return line to tank. If it drops now, the dizzy, or the line to the tank as appropriate, is at fault. If not, suspect the WUR return line is blocked.

(I think on a '77 that the return line from the WUR tees into the return line to the gas tank downstream of the metering head, while on later cars it goes back into the push valve in the metering head).

If you're already 100% confident all the fuel lines are clear then just try cracking the joints either side of the WUR itself. If cracking the upstream joint gives a pressure drop but the downstream joint does not, the WUR is toast.

Good luck!
_________________
John,
1980 924 turbo "timewarp" being restored

[amieander]

Good call; I don't know why I didn't think to check both sides of the WUR...I'll do that when I get home this afternoon. As for the return line, I think you're right about the split after the metering head; that's probably why I can't find a rebuild kit for that system pressure gizzie because it's just a piston with a spring and o-ring, unlike the plunger I've seen on later model pictures.

Thanks again, and I'll report this afternoon...BTW, khal, he's not an ex; he can rebuild a rochester carburetor...I've got to keep him around at least for that!
_________________
early 1977 NA mars red 924

[Grenadiers]

Also, don't forget to check the Fuel Pressure Regulator, built-in to the side of the dizzy itself. The little o-rings can gum up, disintegrate, and the piston can stick. Possible reason why your pressures are the same. Easy to check, big old nut/bolt on the side, just remove it. The piston can get hung up inside and using a toothpick or wooden match can help remove it.
_________________
'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

[amieander]

Thanks for the reminder, grenadiers. I've had the plunger removed before...that's the part I wish I knew of a rebuild kit for (perhaps I didn't use the correct terminology earlier). I was wondering how much of a role that played in the return back to the tank, since it is tied into that double nut on the side of the dizzy, but not in direct line with the return.

I tried once to adjust the shims within that to see if I could change the reading...I still got the equal control/system pressures, but proportionally lower from the shim change. I've since reinstalled the shims.

The O-ring on the plunger was intact and whole, and I would love to change it out but I don't know the exact size. There aren't many (any) places who sell fuel-resistant, metric o-rings in GF so I've had to order them in. Would you know what I would need to get? The guys at Napa pretty much froze and didn't speak to me when I told them I had a Porsche.

Thanks again for all of your help, and I'll keep you posted as to this afternoon's progress.
_________________
early 1977 NA mars red 924

[924RACR]

[amieander]

LOL...I hear ya on the Holley swap. This Rochester came out of my '69 C10 Chevy; as much as I love the truck, I'm not sure how much I want to sink into it. The electrics are fried, passenger footwell is rusted, et cetera...

As for the problem at hand, the weather took a turn for the worse and I didn't get much time to test. I've already ran air from the return banjo to the tank, and heard bubbles in the tank...so hopefully I'm good there. However before it got too soggy today I did have time to test both ends of the "out-to-WUR" line (but not the return half), and got the same goofy readings.

If the readings are the same on the return line, would the problem most likely lie in the system regulator plunger? And if so, is the o-ring the only easily fixable part there?

Thanks again!
_________________
early 1977 NA mars red 924

[ptheskil]

And if none of that works pick out the fine mesh filters on the wur inlet. There is a series of about 5 of increasing fineness and these can get blocked sufficiently to affect control pressure although they will blow through with an airline. If you are careful you can clean them in acetone and put them back.
_________________
1981 931 series2 Euro spec

[amieander]

holy crap...five layers? wow. The weather went to pot on me this afternoon but tomorrow is supposed to be better. I'll tear into my other WUR and see if I can clear out the screens in the meantime. I was just under the impression it was just a single layer of mesh. Thanks again and I'll update tomorrow!
_________________
early 1977 NA mars red 924