Ques about fuel pressure regulator diaphragms
06-13-2008, 10:00 AM
#1
Melting Slicks
Thread Starter
Ques about fuel pressure regulator diaphragms
Ok guys, here's one for the experts. I ordered my injectors the other day from Jon at FIC, whose a great guy with a wealth of knowledge by the way, so I trust what he has to say.
Anyway, he suggested that I rebuild the fuel pressure regulator on my 85 being the car has 149K original miles and the fuel system has never been overhauled. I went looking for a rebuilt kit and I only came across ones for the 86 and above. I tried Corvette Central and Ecklers and they're prices are almost double from what I can pay locally. Corvette Central has a listing the 85 only, but its been discontinued. They only list one for 85-91 now which is the same one I found locally. The supplier near me that sells them is telling me all the diaphragms are the same from 85 on up. In essense, a diaphragm for the 86 will work on an 85. However, application charts from parts manufacturers leave out the 85 L98 in their listings.
Jon told me that the fuel pressure rating is different for the 85's regulator, it is less than in 86, so I am confused. The quicker I get the correct regulator diaphragm, the quicker I can install my injectors. I don't want to install something that will be a headache so I come to you guys for insight.
Anyway, he suggested that I rebuild the fuel pressure regulator on my 85 being the car has 149K original miles and the fuel system has never been overhauled. I went looking for a rebuilt kit and I only came across ones for the 86 and above. I tried Corvette Central and Ecklers and they're prices are almost double from what I can pay locally. Corvette Central has a listing the 85 only, but its been discontinued. They only list one for 85-91 now which is the same one I found locally. The supplier near me that sells them is telling me all the diaphragms are the same from 85 on up. In essense, a diaphragm for the 86 will work on an 85. However, application charts from parts manufacturers leave out the 85 L98 in their listings.
Jon told me that the fuel pressure rating is different for the 85's regulator, it is less than in 86, so I am confused. The quicker I get the correct regulator diaphragm, the quicker I can install my injectors. I don't want to install something that will be a headache so I come to you guys for insight.
Last edited by ejscarfo; 06-13-2008 at 10:05 AM.
06-13-2008, 10:10 AM
#2
Supporting Vendor
Ok guys, here's one for the experts. I ordered my injectors the other day from Jon at FIC, whose a great guy with a wealth of knowledge by the way, so I trust what he has to say.
Anyway, he suggested that I rebuild the fuel pressure regulator on my 85 being the car has 149K original miles and the fuel system has never been overhauled. I went looking for a rebuilt kit and I only came across ones for the 86 and above. I tried Corvette Central and Ecklers and they're prices are almost double from what I can pay locally. Corvette Central has a listing the 85 only, but its been discontinued. They only list one for 85-91 now which is the same one I found locally. The supplier near me that sells them is telling me all the diaphragms are the same from 85 on up. In essense, a diaphragm for the 86 will work on an 85. However, application charts from parts manufacturers leave out the 85 L98 in their listings.
Jon told me that the fuel pressure rating is different for the 85's regulator, it is less than in 86, so I am confused. The quicker I get the correct regulator diaphragm, the quicker I can install my injectors. I don't want to install something that will be a headache so I come to you guys for insight.
Anyway, he suggested that I rebuild the fuel pressure regulator on my 85 being the car has 149K original miles and the fuel system has never been overhauled. I went looking for a rebuilt kit and I only came across ones for the 86 and above. I tried Corvette Central and Ecklers and they're prices are almost double from what I can pay locally. Corvette Central has a listing the 85 only, but its been discontinued. They only list one for 85-91 now which is the same one I found locally. The supplier near me that sells them is telling me all the diaphragms are the same from 85 on up. In essense, a diaphragm for the 86 will work on an 85. However, application charts from parts manufacturers leave out the 85 L98 in their listings.
Jon told me that the fuel pressure rating is different for the 85's regulator, it is less than in 86, so I am confused. The quicker I get the correct regulator diaphragm, the quicker I can install my injectors. I don't want to install something that will be a headache so I come to you guys for insight.
http://www.tpis.com/index.php?module...uel+Components
06-13-2008, 10:39 AM
#4
Melting Slicks
Thread Starter
it really doesn't make sence to not have and AFPR. check out this TPIS unit adjustable is a much better way to go try this link
http://www.tpis.com/index.php?module...uel+Components
http://www.tpis.com/index.php?module...uel+Components
06-13-2008, 01:03 PM
#5
Le Mans Master
All that is good advice...and for anyone else...don't mess around with the diaphragm....if is is old replace it.
Doesn't seem to be a big deal with Vettes, but other makes have had hell with these things...
first, getting old
second, breaking and leaking fuel on top of the intake mani
Third, you know what happens next
Doesn't seem to be a big deal with Vettes, but other makes have had hell with these things...
first, getting old
second, breaking and leaking fuel on top of the intake mani
Third, you know what happens next
06-13-2008, 01:13 PM
#6
Melting Slicks
Thread Starter
All that is good advice...and for anyone else...don't mess around with the diaphragm....if is is old replace it.
Doesn't seem to be a big deal with Vettes, but other makes have had hell with these things...
first, getting old
second, breaking and leaking fuel on top of the intake mani
Third, you know what happens next
Doesn't seem to be a big deal with Vettes, but other makes have had hell with these things...
first, getting old
second, breaking and leaking fuel on top of the intake mani
Third, you know what happens next
That's what I want to avoid.
06-13-2008, 01:26 PM
#7
Le Mans Master
^^ to be fair, that fire came from a rear wheel bearing being bad......so that is also an issue with our C4s....I just searched out a Vette fire and that is the pic I came up with...
06-13-2008, 01:47 PM
#8
Team Owner
Seriously be careful when screwing around with these things. I've had to replace mine twice already. The reason the '85 is different is because it uses a 30# regulator and the later years use a 38# regulator. Yes the later one will fit but it will run pig rich. Might as well get a AFPR but AVOID Holley at all cost! Mine broke 2 weeks after I installed it spraying fuel all over my engine. They're known to break quite often.
10-27-2008, 10:30 AM
#11
Melting Slicks
Thread Starter
10-28-2008, 08:40 AM
#12
Racer
Member Since: Jul 2008
Location: LA
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I just went through this with my 85. I replaced the original injectors with 22 pound after market injectors. They were $149.00 for a set of 8. The OEM injectors are 21 pound and cost $169.00 each rebuilt with core exchange. The OEM system was built to run at 32 psi at idle. The replacements needed about 42 PSI at idle. I rebuilt the pressure regulator with the adjustable reglator. I started at 38 PSI and adjusted it up until the engine ran well. This is about 42 PSI at idle. Fuel economy is good. Power is good. No check engine lights.
You have to pull the plenum to do this job so replace or check the EGR and the manifold temp sensor.
You have to pull the plenum to do this job so replace or check the EGR and the manifold temp sensor.
10-28-2008, 09:59 AM
#14
Race Director
it really doesn't make sence to not have and AFPR. check out this TPIS unit adjustable is a much better way to go try this link
http://www.tpis.com/index.php?module...uel+Components
http://www.tpis.com/index.php?module...uel+Components
10-28-2008, 10:39 AM
#15
Racer
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Location: LA
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The pressure regulator rebuild is very easy. Remove the screws, take out the old diaphram, install the new one, put the screws back in. It's the plenum that takes the time. If the seat is pitted you will need a new fuel rail assembly. After its in, there is a fitting to check the pressure.
