Is there any way someone could reverse the fuel lines on a 87 L98 without knowing while putting their intake back on?. Will they fit reveresed?

 

Have you looked at the schematic posted by Agent 86. I personally don't know but if the fittings are the same size and thread it looks possible.

 

the reason i ask is Stewball's problem.. He took apart his top end. put it back together and now his fuel pressure jumps to 45 when he turns on the key.. as soon as he releases the pressure drops like a rock. I have never hooked one up backwards so I don' know what would happen. Would the rail pressurize running in from the regulator. It could blow the diaphragm and work. Just a thought.. Has any one ever hooked one up backwards.

 

I am 99.9% sure they are different - of the top of my head I cant remeber the sizes - but they are 2 different saginaw fittings on the tpi lines

 

http://store.summitracing.com/partde...5&autoview=sku

Fuel Rail Fittings, Aluminum, Blue, TPI, One -6 AN to 16mm x 1.5 O-ring, One -6 AN to 14mm x 1.5 O-ring, Pair

 

On a 91 you can hook them up backwards. They are both 3/8" lines. The earlier years had a 5/16" return line, which would make it easier to tell which is which. I'm not sure what year they switched to the 3/8" return line setup.

Edit: you can physically hook up the lines backwards, but it won't run.

 

It can't be. Even if the lines connect up, he is feeding the fuel pressure regulator in the wrong direction. Even if the regulator could work backward, there would be nothing in the supply (previously return) line to prevent the free flow of fuel back to the tank. There could be no fuel pressure at the Schrader valve with the pump on or off.

RACE ON!!!

 

I am real sure I have the lines installed correctly. The feed line is a larger diameter line than the return line. Both are matched up correctly at the fuel rail and at the sending unit.

I have a couple of questions. When you set the timing there is a plug on the passenger side that must be unplugged when setting. What does this do exactly? When pulling the distributor and replacing it this was never unplugged. Would this cause a problem? Also when I tried moving the plug wires forward once and backwards once this wasn't unplugged? When twisting the distributor a little each way while running this wasn't unplugged?

Second, would it hurt to put a small bead of Permatex around the flange of the Cold Start Injector/Valve? There is no fuel leak there and the flange looks good when you put a flat edge against it, you can see no light under the flat edge?

Third, the manifold bolts are to be at 25 ft/lbs and then are they suppose to be tighted to 45 ft/lbs? I only did the 25 and didn't continue tightening to 45?

Last, when seating the Cold Start should you hear the same sound you would when seating a fuel injector kind of like a swoosh when the greased O-ring seats into the rail and manifold? The Cold Start went in real loose but again it isn't leaking fuel.

 

ned
its got to be a timing issue. start from scrach. line up #1 cyl and put the dist to 1 then follow 1 wire at a time in the firing order

 

Stew, the brown EST wire only needs to be disconnected when you are adjusting your timing with a timing light. Disconnecting it prevents the computer from adding any advance or retard to the timing, IIRC. Do you have a timing light?

If you didn't go back and tighten the intake to 45 ft/lbs in your 2nd stage, I'd go back and finish it - not sure if that's enough to cause a leak or not. If you can keep the engine running, spraying some soapy water around the intake might give you a visual clue to a leak.

 

Setting the timing isn't going to fix THAT. If it isn't leaking externally and making a mess and causing a strong odor, there are only three places the fuel (and pressure) can bleed off; the supply line, the return line, or through the injector(s) themselves. A little trouble shooting will tell what is happening with the fuel pressure. To me, it makes sense to trouble shoot and repair the known problems, in this case the fuel pressure, than to go off like a fart in a skillet chasing possibly imagined, nonexistent, problems, like the timing. One thing at a time. Good luck.

RACE ON!!!

 

Ok let’s put this timing issue/non-issue behind us. Today I made zero progress again. I pulled the distributor and hand cranked the motor till I felt pressure in the #1 cylinder. Then I moved the pulley until I had the timing mark to 0 deg. and lined the rotor to the #1 cylinder and close to #8 on the distributor cap. FSM said to line it up between #1 and #8 on the cap. Took me a couple of tries the first time it didn’t start and I didn’t force it, the second time it started right up but was back to it’s normal/abnormal self.

Other tests performed today were the TPS. At start it showed .5 and some change and then when trying to keep it running I noticed it did start climbing as I gave it more gas so I have ruled that out. Next was making a gasket for the Cold Start flange. No fuel leaks from there and now there is a gasket so I am ruling that out as a possible vacuum leak.

When I had the incorrect injectors in it did the same thing it is doing now. This tells me the problem started after I installed the new intake gaskets. I am just wondering if they slipped down and are blocking a port somehow. All the bolt holes lined up correctly so an assumption (the mother of all screw-ups) was made it was on there correctly. One thing I did notice and didn’t tell the friend that was helping me was the gasket set had two little tabs and instead of them point up and sticking out of the intake they were pointing down towards the valley. The Indian head had already started to dry and I didn’t want to move them. I really hate to tear all the way down again but things are starting to point in that direction.

Fuel pressure test showed to be at 45 PSI as soon as I turn the key without starting. When starting it remains pretty constant at 43 to 45 PSI. Although there is a leak down problem because as soon as I shut it off the pressure starts to drop pretty fast. I didn’t Teflon tape any fitting and I did have fuel leaking once I shut it off so that could have been my fault as well. I have not done a vacuum pressure test so that will have to be on my to do list. I did notice that when I pulled the HVAC vacuum line close to the distributor that there was a noticeable sound of air so my guess is the vacuum test would show normal as well.

I pulled all the plugs on the driver’s side today, for only having about 1000 miles on them they were full of carbon. I cleaned them with some sandpaper so they were nice and shiny when I put them back in. Even if they were fouled the damn thing should run and idle.

Tomorrow is another day. Have a funeral to go to so I have the day off. A friend/neighbor called one of his co-workers and he has a scanner. Have never used one so I will be trying to learn to read that hoping that will point me in the right direction. The new/reconditioned MAF will be here tomorrow so I can install that as well.

Thanks for everyone that has offered suggestions and additional information for me to try. Please don’t give up on me just yet, I need all the help I can get from here.

 

ALL-IN-ONE thread.

45 psi fuel pressure.
45 lbs torque.
timing setting.

Anything else?