fuel pressure problem
Thread Starter
Burning Brakes
Joined: Oct 1999
Posts: 1,236
Likes: 91
From: Pittsburgh,PA
fuel pressure problem
First the problem, the car does not want to run very good above 3000 RPM. I had this problem last year it turned out to be the FPR. the pressure reads 25PSI with the vac and 40 PSI with out that sounds like to much of a swing to me? Is the diaphragm a dealer item? Could it be the regulator?
Dave
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Dave
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Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: fuel pressure problem (opel)
I am not sure if it is your FPR daiphram or not, but with the vacuum hose on , i fyou are getting only 25psi, that IS low. The '85s are supposed to be slightly higher psi than the latter years, so are suposed to be between 36-42psi + or minus a few stock. Did you fix this same problem you had last year?
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: fuel pressure problem (MrNuke)
i fyou are getting only 25psi, that IS low. The '85s are supposed to be slightly higher psi than the latter years, so are suposed to be between 36-42psi + or minus a few stock.
<BLOCKQUOTE>code:<HR><PRE>
Year Ign. On Idle Fuel Pump*
1985 34-39 24-36 60min
1986-1990 40.5-47 30.5-44 60min
* = With fuel line briefly restricted.
Pressure measured at fuel rail.</PRE>[/QUOTE]
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: fuel pressure problem (MrNuke)
Dunno where you get your book smarts scorp, but I've yet to see a TPI L98 with 25psi Fuel Pressure at idle.. :lol:
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: fuel pressure problem (scorp508)
Dunno scorp.. Which manual lists it that low? I'll have to check mine out. I haven't looked at it's sets in a while, but I knwo I read in teh gm service manual for the 85's they a=were at a higher fuel pressure by a few psi than other years. Ahh i dunno. I just think that 25 is too low. the jump from 25idle to 40 wot is too great I think. Heck mine only jumps from 41-42 to 47 at wot.
ALthough I do have an AFPR.
When I had the stocker, it was at 35-36psi idle to 41psi wot. I remember that. My friends 88 was 34-38psi stock when we tested it. Better to be richer than too lean I'd say. :jester
ALthough I do have an AFPR.
When I had the stocker, it was at 35-36psi idle to 41psi wot. I remember that. My friends 88 was 34-38psi stock when we tested it. Better to be richer than too lean I'd say. :jester
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: fuel pressure problem (MrNuke)
Check out Corvette Fuel Injection & Electronic Engine Management by Charles Probst. If I remember correctly 85 had slightly larger injectors requiring the lower PSI.
Your 85 is on the high side of acceptable and his is on the low side. Personally I'd say your 5psi increase at WOT is way too little.
When I had the stocker, it was at 35-36psi idle to 41psi wot.
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