OB fuel injection question
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Race Car
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Thanks for all the info guys. Went to Auto Zone today and got the hose clamps and 40 psi fuel hose. Took me about 45min to an hour to change the one side that was leaking. Put it back together to leak check it and it was good but I still smelled gas. Looked around and one of the hoses on the other side is now leaking pretty bad. Guess I dodged the bullet twice now. The recent cold wether here really did a number on these old hoses. Doing the other side tomorrow. I can't seem to figure out how the lock rings work. They do not seem to lock anything. Also Roger seems to think I need higher than 40 PSI rated hose. What do you guys think? Jason
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From: Da Island, mon! (VI,BC,CA)
40psi is marginal; you should have 120psi rated hose. Not that you need that much, but if you ever decide to boost, you will need to be able to raise the pressure, and safety margins are alway good.
ken
ken
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
At this point no interest in boosting this motor. I just want a dependable ride right now. Would you agree that 40 psi is enough for a stock fuel system or not? Jason
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From: K-town, Germany
Jason - 1st time I did it, I used some fuel hose I had laying around. That soon started to bulge and leak on the injector(s). I also reused the O-ring seal things so maybe that didn't help. 2nd time, I went to AutoZone and bought the fuel injector hose (by the foot) and clamps. Unfortunately, they too started to bulge and felt soft. (like you could press a finger nail into it). When I bought it, I asked for fuel injector hose, but honestly, I don't know if the kid gave me fuel injector hose or heater hose--just has a bunch of codes and numbers on it--nothing I understood like "high pressure fuel hose, Idiot". 3rd time, I said screw it and mailed the injectors to witch hunter for cleaning and also ordered the 928 Intl hose kit AND injector seals. Their hose kit comes with the hose and right size hose clamps. And, the way the old seals felt hard and brittle, air was probably getting by them.
Now, perfect and no leaks or bulges; good to go for another 100K. Good luck--and congrats, sounds like you just saved it from going up in smoke! / Bruce
Now, perfect and no leaks or bulges; good to go for another 100K. Good luck--and congrats, sounds like you just saved it from going up in smoke! / Bruce
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From: Da Island, mon! (VI,BC,CA)
Its marginal...I think the stock pressure from the fuel pump is about 45PSI, but I cannot claim this to be perfectly accurate. Hopefully someone with better info can chime in here. There is a safety factor built into the hoses, so its not like it will blow apart tomorrow, and its certainly better than what you had.
Personally, I would trade up to higher-rated hoses, and take a good look at the feed & return lines on the passenger side, and any other fuel hose; some OBs have flexible hoses mating the rails & pulsation dampers.
Ken
Personally, I would trade up to higher-rated hoses, and take a good look at the feed & return lines on the passenger side, and any other fuel hose; some OBs have flexible hoses mating the rails & pulsation dampers.
Ken
Drifting
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From: Seattle, where everyone is above average, and the women are all beautiful
the proper bulk hose is available at your local parts store, (if they cut it from the correct roll) If you get a goodyear hose, like I did, it does not have the pressure on the hose, but if it says "fuel injection" it is OK.
http://www.goodyearep.com/productsdetail.aspx?id=5250
as the link says, it is rated up to 100 psi.
http://www.goodyearep.com/productsdetail.aspx?id=5250
as the link says, it is rated up to 100 psi.
Thread Starter
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Jason - 1st time I did it, I used some fuel hose I had laying around. That soon started to bulge and leak on the injector(s). I also reused the O-ring seal things so maybe that didn't help. 2nd time, I went to AutoZone and bought the fuel injector hose (by the foot) and clamps. Unfortunately, they too started to bulge and felt soft. (like you could press a finger nail into it). When I bought it, I asked for fuel injector hose, but honestly, I don't know if the kid gave me fuel injector hose or heater hose--just has a bunch of codes and numbers on it--nothing I understood like "high pressure fuel hose, Idiot". 3rd time, I said screw it and mailed the injectors to witch hunter for cleaning and also ordered the 928 Intl hose kit AND injector seals. Their hose kit comes with the hose and right size hose clamps. And, the way the old seals felt hard and brittle, air was probably getting by them.
Now, perfect and no leaks or bulges; good to go for another 100K. Good luck--and congrats, sounds like you just saved it from going up in smoke! / Bruce
Now, perfect and no leaks or bulges; good to go for another 100K. Good luck--and congrats, sounds like you just saved it from going up in smoke! / Bruce
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Ok guys here's an update. The hose actually says 50psi instead of 40psi. Went out this afternoon and changed the 2 hoses that go to the fuel pressure regulators and the passengerside fuel rail hoses. All went good except for slightly dropping the AFM. I think that's what it's called. It hooks to the air filter housing. Now the bad part. Started the car and it runs horrible now. After I changed the driver side hoses earlier in the week I started the engine and it ran great. Before I did the job today I didn't start the engine due to not wanting to pressurize the fuel system. I checked the AFM with a multimeter and it appears to operate properly. When I start the car without the AFM connected the car won't hardly run. With it connected it runs slightly better but still horrible. After searching the forums I found info on the pressure regulators going bad. I've found fuel in the vacume inlet for the front large regulator(above the thermostat housing) and the passenger side regulator at the rear of the motor. The driverside rear regulator appears to be good. I know this is a bad thing but I need to know how to make sure these are both leaking. Can I just turn the ignition switch on and pressurize the fuel system to check them? Are all 3 of these parts called fuel pressure regulators? I assume from what I've read that if these fail fuel leaks past the diaphram and in to the vacume system. I guess the cold weather we just had did these in as well. If these fail the car will hardly run right??? Thanks for the help guys. Jason
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Thread Starter
Race Car
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
I found this on the forums. "L-jet cars have 1 fuel damper and 2 fuel pressure regulators." From a post from John V. I guess the front diaphram is a damper. Is this info correct? Jason
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From: Da Island, mon! (VI,BC,CA)
rough running
Yes, if I am not suffering total brain fade, the front is a pulsation damper, and the 2 at back are pressure regulators. A leak in any of these will cause running problems.
Are you sure you securely plugged in all the injectors? You should read my old post here about all the details that can trip you up.
My intake rebuild
Regards
Ken
Are you sure you securely plugged in all the injectors? You should read my old post here about all the details that can trip you up.
My intake rebuild
Regards
Ken
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Ken I did the job without pulling the injectors. I cut the discs with wire cutters and then slit the hose with a utility knife. No problem at all. I'll check your post out. If these start leaking will the car run extremely horrible and barely run or will it just run not at peak? Jason
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From: Da Island, mon! (VI,BC,CA)
If the pressure regulators are leaking, they will not be able to maintain the proper pressure (they keep the pressure by restricting the RETURN of the fuel), and this will affect fuel delivery at all RPMs as the injector is not delivering enough per pulse.
Is there a chance that dirt/old hose pieces may have fallen into an injector? When I did my injectors, I had a LOT of crud shake loose from inside the rails, which could easily clog an injector.
FWIW, if you are going to all the trouble of the hoses, its really worth considering the O-rings; they will be very hard & possibly cracked, allowing air leakage.
HTH
Ken
Is there a chance that dirt/old hose pieces may have fallen into an injector? When I did my injectors, I had a LOT of crud shake loose from inside the rails, which could easily clog an injector.
FWIW, if you are going to all the trouble of the hoses, its really worth considering the O-rings; they will be very hard & possibly cracked, allowing air leakage.
HTH
Ken
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From: Nova Scotia
At this point, you should consider pulling both rails and all injectors for inspection, cleaning, and replacement of both small and large sealing rings: do not rely on gas line hose .... get proper Porsche LH injector hose kits or a length of the correct fuel injection hose a la Rog100.
Cut 8 pieces of hose exactly the same length as the originals ( plus two pieces for the pressure thingies at the back of the vee): reassemble, and install injectors to the rail. Follow by installing a completed rail per side - then one will see why the exact length is critical .... BTW, I have always used or reused the 'cups', and have not found clamps of any value if the hose size is correct.
While I have replaced hoses, it was done as preventitive care: any fuel leaks I've seen have been from the top seal on the injector bodies = dead injector.
The other benefit of pulling the injectors is to flush them through with WD-40 under pressure while tapping the injector open with a 12v source ( home made injector test bench): if done correctly, the desired conical spray pattern can be confirmed prior to install.
Cut 8 pieces of hose exactly the same length as the originals ( plus two pieces for the pressure thingies at the back of the vee): reassemble, and install injectors to the rail. Follow by installing a completed rail per side - then one will see why the exact length is critical .... BTW, I have always used or reused the 'cups', and have not found clamps of any value if the hose size is correct.
While I have replaced hoses, it was done as preventitive care: any fuel leaks I've seen have been from the top seal on the injector bodies = dead injector.
The other benefit of pulling the injectors is to flush them through with WD-40 under pressure while tapping the injector open with a 12v source ( home made injector test bench): if done correctly, the desired conical spray pattern can be confirmed prior to install.
Thread Starter
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From: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Before reinstalling the new hoses I used a can of cleaner with the small red hose and flushed out the inlet of the fuel injectors just to make sure the inlet was clear of debris. For now the fuel hose is staying. It is rated at 50 psi and should be ok for now. Down the road if the fuel rails need to be pulled for any reason I'll move up to the 110 psi hose. From what I've read 50 psi should suffice for now. I talked to Rog100 tonight and tomorrow I'm going to pull a vacume on my regulator and damper to confirm they are leaking. I'll replace them first and see what happens. If that doesn't do the trick not sure where I'm headed. Incase you don't know when it comes to 928's Roger is the greatest thing since sliced bread. What a great guy!! Jason
