Danno74Z Posted October 15, 2007 Share Posted October 15, 2007 That is great news - almost got it licked! Might be a volume issue now with the smaller diameter feed lines. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted October 15, 2007 Share Posted October 15, 2007 My fuel rail/intake is from a 1993 engine(whole engine is minus the wiring/opti, which is 1995). Thats just the way my fuel rail came. Bart, I just figured Harbor freight would have something cheap that you could get for testing. I don't know for sure if they actually have somthing. I think the regulator is a nice piece. Quality seems very good. You can get them for the LT1 fuel rail inplace of the stock one that are adjustable too. I used that one because I had no good way of connecting my fuel system to the fuel rail. So when I put the fittings in the back of the rail I had the fuel pressure regulator ports welded shut. This just made it easy to connect everything. Guy Quote Link to comment Share on other sites More sharing options...
deja Posted October 15, 2007 Share Posted October 15, 2007 I picked up a Greedy electronic fuel pressure gauge on Ebay a while back for $75. Its dash mounted and since I'm redoing my whole dash it seemed like a nice thing to have. There are some on Ebay now but pretty expensive. http://cgi.ebay.com/ebaymotors/GReddy-52mm-Electronic-Fuel-Oil-Pressure-Gauge-BLACK_W0QQcmdZViewItemQQcategoryZ6763QQihZ008QQitemZ180152847539QQrdZ1QQsspagenameZWD1V Quote Link to comment Share on other sites More sharing options...
Bartman Posted October 15, 2007 Author Share Posted October 15, 2007 So I'm looking for a fuel pressure gauge to determine if that's still the cause of my problems. From what I've found the LT1's are extremely sensitive to even small fuel pressure changes and that even minor modifications can push its fuel demand high enough to require additional fuel pressure. Quote Link to comment Share on other sites More sharing options...
X64v Posted October 15, 2007 Share Posted October 15, 2007 Bartman - if your stumbling is happening upon mild acceleration, then I can say that it is not because of the fuel lines you're using (as long as they're not clogged or anything). I'm using the stock '73 feed and vent line as a return (same as you) on my turbo motor with no flow issues whatsoever. Granted my turbo motor is no lt1, but I doubt your lt1 needs more fuel upon mild acceleration than my turbo motor does at full boost/7000rpm. Quote Link to comment Share on other sites More sharing options...
Guest christeon Posted October 27, 2007 Share Posted October 27, 2007 Hey guys I had a similar issue with my LT-1, I found it with a fuel pressure gauge while running it. My fuel line from the tank to the pump was snug between a mount and had rubbed a hole through it. It was a tiny hole that was blocked at times against the mount. I almost bought a pump before pressure checking my lines for leaks. This would be obvious of course checking a running motor with a gauge. This motor is in a Mastercraft with the tank lower than everything else, so the leak was never apparent. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted October 28, 2007 Share Posted October 28, 2007 Here is what I'm doing with my fuel rails and plumbing. I got these fittings (both are -6 AN) from TPI_Parts on Ebay. http://cgi.ebay.com/ebaymotors/93-97-LT1-LS1-Camaro-Corvette-Fuel-Rail-6-AN-Fittings_W0QQcmdZViewItemQQcategoryZ42604QQihZ012QQitemZ220152054154 I also picked up this fuel rail with a Aeromotive fuel regulator - great deal on Ebay too. I'm going to polish the rails. When I'm done sell my original fuel rail and regulator. I will most likely purchase several 90 degree elbows to route the main fuel lines down and under the regulator. Danno74Z Quote Link to comment Share on other sites More sharing options...
Z48LT-1 Posted December 1, 2007 Share Posted December 1, 2007 Bartman, Were you ever able to solve this puzzle? Inquiring minds want to know! Cheers -- Gary Quote Link to comment Share on other sites More sharing options...
Bartman Posted December 2, 2007 Author Share Posted December 2, 2007 Bartman, Were you ever able to solve this puzzle? Inquiring minds want to know! Cheers -- Gary I still haven't completely resolved the issue and I haven't been spending any time on it as I've been working on finishing a room addition for my daughter. I bought a spare PCM recently as well as an adjustable fuel pressure regulator and a fuel pressure gauge with a hose so that I can monitor pressure while I'm driving. I just need to get around to working on it again. Quote Link to comment Share on other sites More sharing options...
Bartman Posted December 22, 2007 Author Share Posted December 22, 2007 I finally hooked up the fuel pressure gauge and rigged it up on the outside of the windshield so I can monitor the pressure while I'm driving. With the new wiring the fuel pressure looks good. It runs around 45 at idle and about 50 under acceleration. I hadn't driven my car for a while and it felt realy good to drive it around. The initial problem is almost non-existant and it may in fact be resolved. I think the fuel pressure wiring was the problem and the aftermarket wiring kit gave me the voltage my aftermarket Walbro pump needed. Perhaps the plugs need to be cleaned and the BLMs need to be relearned from driving around with low fuel pressure for so long. Quote Link to comment Share on other sites More sharing options...
deja Posted December 23, 2007 Share Posted December 23, 2007 I finally hooked up the fuel pressure gauge and rigged it up on the outside of the windshield so I can monitor the pressure while I'm driving. With the new wiring the fuel pressure looks good. It runs around 45 at idle and about 50 under acceleration. I hadn't driven my car for a while and it felt realy good to drive it around. The initial problem is almost non-existant and it may in fact be resolved. I think the fuel pressure wiring was the problem and the aftermarket wiring kit gave me the voltage my aftermarket Walbro pump needed. Perhaps the plugs need to be cleaned and the BLMs need to be relearned from driving around with low fuel pressure for so long. I hope you're right. I know you've been fighting this for a while when you have other things you want to accomplish. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted December 23, 2007 Share Posted December 23, 2007 Hi Bart, Like you mentioned you have been trying to figure this problem out for some time. Before you installed the upgrade wiring did you take a reading of the fuel pressure? How low was it? What is next on the to do list? Danno74Z Quote Link to comment Share on other sites More sharing options...
Bartman Posted December 23, 2007 Author Share Posted December 23, 2007 Hi Bart, Like you mentioned you have been trying to figure this problem out for some time. Before you installed the upgrade wiring did you take a reading of the fuel pressure? How low was it? What is next on the to do list? Danno74Z It was reading around 31 PSI before I installed the upgraded wiring. Since the fuel pressure appears to be correct, the stock fuel lines must be sufficient so I'm going to stick with them for a while at least. I'm going to continue to drive it around and see how it runs before I do any other mod's to the engine, fuel system, etc. I want to work on the body next and get her painted ASAP. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted December 24, 2007 Share Posted December 24, 2007 Man I sure hope you got this problem figured out! I want to see your car painted asap too! LOL Guy Quote Link to comment Share on other sites More sharing options...
sweetride2go Posted February 27, 2008 Share Posted February 27, 2008 any luck bart??? i partially fixed my lt1... pulled the dizzy off and something wasnt right inside, cuase there was metal and plastic dust all over inside(msd optispark dizzy, fairly new, installed wrong?), wich we figured gave us our backfire problem... and since we fixed that the other problem went away... but i still dont know what caused the initial problem... hmm... Quote Link to comment Share on other sites More sharing options...
Bartman Posted February 27, 2008 Author Share Posted February 27, 2008 I think ths issue reported by this thread was due to low fuel pressure which was resolved by installing the upgraded fuel pump wiring. The stock wiring may have worked fine for the stock pump, but the Walbro requires more power. I recently had another issue related to a coolant leak that may have taken out my Opti. I found a new genuine GM unit on eBay for $123 shipped that I will install to see if that really is the problem. If not I'll just have a relatively inexpensive spare. Quote Link to comment Share on other sites More sharing options...
timothybailey35 Posted February 19 Share Posted February 19 i have a 1996 . chevy caprice ss and when you first start it. it runs fine to it hits closed loop then it will start to miss fire. will move around some then stick to number for cylinder mainly. engine was out he vehicle for about 6-7 months then reinstall to repair oil leaks. checked compression ok 150-160 on all cylinders, performed a running compression test seems to be normal. sent injector off and had cleaned and checked which came back ok. replaced opti spark, mass air flow sensor. all four o2 sensors, both converters, new plugs and checked for vacuum leaks none found. can use scanner to switch ecm into open loop mode and vehicle runs fine. can anyone help me with this issue. Quote Link to comment Share on other sites More sharing options...
Bartman Posted February 20 Author Share Posted February 20 16 hours ago, timothybailey35 said: i have a 1996 . chevy caprice ss and when you first start it. it runs fine to it hits closed loop then it will start to miss fire. will move around some then stick to number for cylinder mainly. engine was out he vehicle for about 6-7 months then reinstall to repair oil leaks. checked compression ok 150-160 on all cylinders, performed a running compression test seems to be normal. sent injector off and had cleaned and checked which came back ok. replaced opti spark, mass air flow sensor. all four o2 sensors, both converters, new plugs and checked for vacuum leaks none found. can use scanner to switch ecm into open loop mode and vehicle runs fine. can anyone help me with this issue. Ultimately I had to program my car to always run in open loop. The rational is that my cam is large enough to throw off the readings at the O2 sensors. It works great for me, but I can’t say if you need to go this route as well. Quote Link to comment Share on other sites More sharing options...
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