1979 porsche 924 2.0 engine flooding/won't start

[TimTMP]

So I decided to buy a 924 cause I found one for a good price and its been a struggle ever since I got it. Im very new to trying to work on foreign cars outside of the u.s. and I wasn't very good at working on cars to begin with.

First thing I had to do was replace the fuel pump after learning it was getting no fuel whatsoever. I learned about the in tank fuel pump but found that most people just bypass it because the thing is so darn expensive l. So with a little luck I was able to remove the in tank pump and got myself a new pump. Then I noticed almost every single vaccum line was gone so I replace all the vaccum lines. After trying to start it for a little while me and my dad found that it would have good crank but refused to start no sputtering or anything. We checked all the spark plugs and they were good. We still ended up replacing them but we did find that each one was completely black on the tip which if im not mistaken most likely means an extremely rich mixture. We found that the plunger in the fuel distributor was stuck so we took it apart and cleaned it good with some b12 and let it soak. After determining it was no longer stuck we put it back in and tried starting it and still ended up with the same issue. If we start it for a little while then take out the fuse for the fuel pump it does run with the excess fuel in the combustion chamber. Most of the time after burning all that fuel it would just sputter out. Sometimes it would somehow still get fuel even without the fuel pump and we have had it running for over 10 minutes. I assume its some how pulling gas out of the fuel tank with just the pressure in the combustion chamber or something but I dont know. Even if we did get it to stay running without the fuel pump you couldnt give it any throttle or it would die out. Thats about how far I've gotten with it so far. Oh and I have doen an oil change on it and given it a new battery.

I hope that someone is able to help me finally get this thing running.

[944 Ecology]

Now you know why they are cheap (to buy, anyway).

You will need the factory workshop manual and a fuel pressure gauge (as specified by the manual) before you can even begin to understand the CIS fuel system.

You may wish to look for help at 924.org

Good luck...

[wwdwgs]

1979... it would be a good idea to give us a bit more information on the car - what condition it is in, was it stored or just parked outside and for how long, what other work or repairs were performed by the previous owner or yourself.
Also, too often we trace problems to the wiring and its corrosion, especially connectors outside the cabin and the ground points. it's hard to diagnose the electrical issues. Be methodical.
You said that you replaced the fuel pump. Did you replace the fuel filter (if it's a separate from fuel pump)?

[TimTMP]

Id say its in pretty good condition and as for what the owners have done in the past im not entirely sure. I believe its been through a couple owners and the person I bought it from didn't really do much wkth it. All he told me was that he knew it turned over and he said he messed with the brake system. He did not give me much to go off of. I believe he only had it for a couple of months, not too long. I have not replaced the fuel filter yet do you think that would be able to cause it to put out too much gas.

[wwdwgs]

OP, presume that your car was not maintained. Therefore all fluids, consumables must be replaced. The brake calipers should be inspected for rust. Mine were rusty (inside) as &&&& and I rebuilt them. Your car has, I think, an AUDI engine. If you can find another forums that "cover" this type of engine, that would be great. In addition to this forum, I mean. 924board dot org is one of them.
Good luck, be patient, don't screw up. If you do screw up, remember, it's only 924 )))
Have a great 4-th of July!

[Legit Salvage]

+1 on the recommendation for a fuel pressure gauge. There's a whole host of problems that can result from incorrect pressures... but without a pressure gauge to diagnose them, you're flying blind in the dark.

There is a high likelihood that the entire fuel system is contaminated with old, varnished fuel. Once you get it running (even if poorly), get some genuine techron fuel additive.

[TimTMP]

Alright thank you for the suggestions ill definitely try them

[TimTMP]

Okay so I guess ill try to find somewhere to borrow a fuel pressure gauge where should I be connecting it to test for pressure

[wwdwgs]

You can loan it from Autozone or the like. Check if a fuel rail has a "plug" at one of its ends. Maybe.. maybe not.
LInk: https://youtu.be/H1UP-CyRcs4?t=114

[924RACR]

No fuel rail on a CIS (2.0L) motor guys.

As George B said, the fuel pressure gauge as specified in the manuals (Haynes or factory) will be needed, and this type is unlikely to be available at any typical auto parts store.

Time to join us at 924board.org for more accurate direction - though I do wholeheartedly agree, assume everything consumable will need to be replaced.

Odds are the fuel distributor and warm-up regulator (WUR) are both gummed up... the pressure gauge, properly installed and operated, will reveal the details. Will probably show your next required step is cleaning the WUR, to get it controlling the pressures properly...

Please tell me you've obtained a Haynes manual for the car?

[wwdwgs]

Haynes repair manuals, as well as Chiltons after they were bought by Haynes, suck.

[curtisr]

Originally Posted by wwdwgs

Haynes repair manuals, as well as Chiltons after they were bought by Haynes, suck.

Oh, I dunno...at times I find them to be quite handy.

[wwdwgs]

curtisr,
At least you oriented it face up. That is the correct way!
reading your signature - you had toooo many 924S waaayyy too many!

[924RACR]

They're no factory manual, but far better than nothing, and entirely suitable (with respect to accuracy) for a '79 NA.

[Monkey Wrench]

ive been trying to start a car I had sitting, I found that the fuel filter which is near the pump and not very obvious, was plugged.
perhaps you cna check fuel flow ( carefully) Id put the fuel line directly into a gas can, give it a crank, you should see amle flow, measuringpressure is good to do as well,
If you find no flow or very little flow you are onto something.

cars with tank pumps usually pull gas from the top, this may be more safe, my early 944 spilled its gas from a roitted hose at the bbottom of the tank and this is a dangerous event.

the prepump may be unnnecessary when tank is full, in most volvos with tank pumps
thats the case. after about 1/2 tank it may starve for fuel if in tank pump dies.

if the main pump is gravity fed a volvo ill normally startto starve for gas at about or below 1/2 tank.
in general I htink a lot of older cars just pulled from the bottom of the atnk and to pump the fuel out of the top was basically a safety change that affected many makers.
I like to run a small bulb off the main pump to verify when it has power, for troubleshooting purposes.

[TimTMP]

Originally Posted by 924RACR

No fuel rail on a CIS (2.0L) motor guys.

As George B said, the fuel pressure gauge as specified in the manuals (Haynes or factory) will be needed, and this type is unlikely to be available at any typical auto parts store.

Time to join us at 924board.org for more accurate direction - though I do wholeheartedly agree, assume everything consumable will need to be replaced.

Odds are the fuel distributor and warm-up regulator (WUR) are both gummed up... the pressure gauge, properly installed and operated, will reveal the details. Will probably show your next required step is cleaning the WUR, to get it controlling the pressures properly...

Please tell me you've obtained a Haynes manual for the car?

I do not have a Haynes manual. I do have the manual that came with the car though will that help. I took apart the fuel distributor and cleaned by soaking all the parts in b-12 for a couple hours. I then got a kit for it that replaced all the banjo screws and the copper washers. The plunger was stuck before I cleaned it but it seemed to be fine after I finished. I also took apart the warm up regulator to check if anything was stuck or if it was gunked up and it looked perfectly fine I did still clean it though.

[TimTMP]

Should I also be replacing the fuel accumulator

[924RACR]

So... "a manual?"

I really have no idea - can you be specific, at all? Owner's manual?

You need to measure the fuel pressures.

[TimTMP]

Originally Posted by 924RACR

So... "a manual?"

I really have no idea - can you be specific, at all? Owner's manual?

You need to measure the fuel pressures.

Yes just the owners manual.

[Monkey Wrench]

spray some ether (quick start) into near the throttle body , if it starts you probably do not have an ignition issue.

" I assume its some how pulling gas out of the fuel tank with just the pressure in the combustion chamber or something but I dont know."

this isnt valid. the engine doesn't suck , it could get fuel by way of gravity.

" I learned about the in tank fuel pump but found that most people just bypass it because the thing is so darn expensive"

no I would not omit the prepump if it had one. if it is expensive , well Ive replaced the one for my volvo for 15 bucks or my 88 ford van has one. Id try to adapt if you need to.

the pre pump gets the fuel to the main pump, it is low pressure. I dont know what the pressure after the main pump should be, does your manual have that info?

the pump does not create pressure, the pump creates flow. pressure is created by the restriction to flow, no restriction, no pressure. higher restriction, higher pressure.

the pump has a maximum pressure capability. for example it may attain 50 PSI but not 200 PSI when fully restricted.

the unused fuel may be returned to the tank. most of the later cars pump a lot more than the car needs with exss returing to the tank. Im unsure about your car.

in nost fuel injected cars made later there is a pressure regulator that is controlled by a vacuum line to the intake, when you open the throttle , the intake manifold pressure DROPS because the open throttle is letting lots of air in, the regulator respoinds to the low vacuum with MORE pressure because at open throttle the engine needs more fuel ..

I owned an older injected volvo 240 with a fuel distributor setup, it may have similarities. that engine had a flapper that was raised by the airflow and this may have influenced fuel pressureby mechanical means.

in a early 944 there is a "barn door"it works on a similar prinicple of being lifted by airflow, the difference is that this is moving a potentiometer ( or variable resistor) this resistance is recognised and computed by the ECU. the ECU is controlling the open time ( dwell) of the fuel injectors, influencing fuel ammount.

Im not familiar with your engine but I "think" it is a more mechanical system , and later cars uitilized electronics more. since many issues are caused by electronic failures I'd personally see this as a good thing.

if you follow the fuel line from the main pum to the engine bay, you can check the pressure at the fitting. some cars ave a tire valve, or a fitting to make coupling a fuel pressure guage more easily. if not what you may need is some fittings so that you can couple the end of the fuel line to the guage and also keep it connected. these may be metric fittings and they may not come with a fuel pressure guage.

you can buy or rent the guage so that you can know what the fuel pressure is. mine does have a tee fitting , I could cut the line I suppose but it's a little crude. best if you have the correct fittings.

my 88 ford van has the shraeder( tire valve) it has a 1/4" pipe thread if I unscrew it so I couple to that port.

newer injected engines like my 85 944 or 88 ford van or 88 volvo , they have a fuel rail and no fuel distributor. the functionality is similar bu thtey work differently. in the van the manifold air pressure is checked and reported to the ECU, in my volvo it uses an air mass meter, the meter has a wire and as air passes over it cools the wire and this changes the wire's resistance. In the 944 it uses the barn door resistance, later 944's use an air mass meter.

the technology changed over the years after your car and although there were differences perhaps you can make comparisons.

with my porche there never was a carberator used on that engine so its hard to do but with my 88 van or with my volvo there were earlier versions of the engine that had a carb.

it is then possible to ditch the ECU and its complexity and "dumb it down" to a carb. this also requires a n old style manifold , a lower pressure fuel pump, a carb.

doing this alone can lower power, unless other things are done to the engine, if it is "hopped up" eg hot cam polished ports bored out engine. larger exhaust..

a bg carb can make more power and is also less fuel efficient.

in many cases the act of removing the ECU simplifies things down to a more mechanical and less electronic dependant system, prehaps increaseng reliability.

I suggest keeping it stock and not making changes, if you speak to other owners of that engine you may learn a lot more. you an ask if its possible to covert to carbs, IF parts are unavailable maybe it is an option ?

my brother changed some volvos to carbs just because he wanted the reliability that alone reduces maximum HP. a lot of other ford six owners are converting to carbs and using that older carb system to increase power in conjunction with engine mods.

probably the best way to fix your car is to keep it stock

I just had a volvo with a plugged fuel filter i twas sitting around, the pump ran so I was confuese about why it had no fuel I removed the filter and found it completely plugged up . I could not blow through it.

the filter is a sealed cannister under the car beside the main pump. my van and porche also use a Bosche filter and Bosche pump in a similar arrangement.

If you remove the filter and it has a similar configuration , prepare to struggle a little with corroded fittings. find wrenches that actually fit properly or you can round things out and cause an even worse struggle. if it is an assembly mounted along with the main pump Id suggest removing the whole affair so you can work at a bench.

If you unscrew the fuel line from the pump tothe engine . and put it in a gas can give it a crank you should see lots of fuel flow, careful not to overflow the can, it moves lots of fuel fast.

the quantity of fuel per minute can be measured as well as the fuel pressure and you do not need a guage to find out if it has at least an ample flow. if it does have an ample flow than the filter probably is not plugged up and pump and tank etc are probably not the issue.

be very careful if you open a fuel line not to be near fire or sparks , go get a suitable extinguisher that is suited ot a fuel fire and put it right beside you before you undo fittings and don't fo this in your shop, take the car outside . be careful!

injectors can sometimes stick open tey can be flushed or rebuilt you may have a place that services injectors locally they could check them out for you if you suspect bad injectors.

if you take th eplugs out and clean them and then run the car then youcan start to get an idea if it is rich or lean by the color.

I think in my volvo , the one with a fuel distributor, it was perhaps around an 85 or so, the rich and lean was by way of a mechanical adjustment. I remember making it lean to get through the pollution testing which was then required. I liked the system, it worked fine.

I suspect you car doesn't have or need an ECU but I am unsure of this.

a pressure "accumulator" if it has one probably looks like a sealed piston with a spring behind it, it helps reduce the "hammer" cause by the fuel quickly stopping and starting , it probebly is not the issue.

its possible that someone previous messed about with the adjustments of the fuel distributor , flapper , etc or similar, sometimes people go and turn screws not even aware of what they are adjusting and end up in trouble.. Somtimes creating two or more reasons why a car wont start in the process. You want to avoid that.

most cars have a crankcase vent that is plumbed into the intake so that the engine reburns the smog, that may be low down on the engine , greasy cramped and hard to see , the crankcase fumes can wreck rubber id check for air leaks in that area. a split hose can cause lots of trouble. In a volvo there is screen that can plug and cause it to blow out the engine seals or push the dipstick out when running. in a volvo there isa plastic container called the "Flame Trap" it can split open.

a split hose can cause excess air to be drawn in unmonitored, the fuel sustem cant; compensate as this is a path where air enters but is unmonitored, causing a lean condition. perhaps hard starting. poor idle etc. at wide open throttle the effect may be less affected because then you have more flow of air and fuel

at idle or when starting the engine doesn not have high air or fuel flow so this air/fuel percentage is then more easily upset.