Spark Plug Gap And Fuel Pressure Problems On 5.0 W/ Vortech

89gtsleeper

Member
May 20, 2016
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so I just bought an 88 lx coupe which was converted to mass air. The car was professionally tuned to a SCT chip a few years ago. At the time, the car had 24 lb Injectors and calibrated mass air. Since then, the car's previous owner added a vortech v1 blower at around 6-7#, 42 lb injectors, pro-m 75mm mass air calibrated for 42lb injectors, auto lite 3923 plugs (two heat ranges below stock), 340 lph fuel pump, pro charger surge valve, and an aeromotive adjustable fpr. The car was not driven or tuned since the build.

I now have the car and it will be going to the tuner in a week. As I have messed with the car to prepare it for the tuner, I have uncovered some issues and believe they may all be related.

I started the car when I got it, just to see what it would do. Idled very low and almost died. Throttle almost completely unresponsive like it was just totally bogged. Smelled of gas. I shut it down after about a minute.

Next day, after a bit of research, I pulled the SCT chip off and started the car. My reading told me that if the mass air was correctly calibrated for the larger injectors, the stock computer should take back over and begin to adjust itself accordingly. Started a little better this time. Didn't smell so strong of gas. Took a few minutes, but then the idle smoothed out. Couldn't find any vacuum leaks or fluid leaks. Drove the car very gently around the block a few times, then back to the driveway. Car idled just fine for several minutes and coolant temp never got out of norm. Shut it down and got everything ready to check the timing. Went to start car, and it won't start. Starter turning strong, but motor won't start. Smells strong of gas.

Next day, motor cold, starts right up, but same shaky idle. After a few minutes, idle settle out. This time I went to check the fuel pressure regulator thinking it is running very rich. I loosen the nut, remove he vacuum line, plug it with my finger and look at the fuel pressure gauge. Reading way low at around 33-34. As I understand, this is mire like how it should read at idle with the vacuum line attached. Let my finger off and pressed back down. After dog this a few times, the fuel pressure gauge slowly went way up to around 44. I reduced the fuel pressure to around 39 then plugged the vacuum back to the fpr. The fuel pressure then dropped to around 33-34, which seems normal... Then it just kept sinking and sinking until it went down to around 25. I shut the car down immediately. No clue what the hell happened. This was during lunch break today.

After work, came home and pulled oil dipstick. Smells strong of gas and is overfilled. Obviously fuel is super rich and leaking into oil. Pulled the plugs to replace them all, since they are likely worthless. I noticed that the gap on all but the #1 and #2 cylinders was down at around .027-.028. They were very black. However, the gap on #2 was around .032 and it was much cleaner. #1 was around .030 and was an 3-8, but not as clean as #2.

My research leads me to believe that the chosen plugs should be a good fit with my cobra intake, aluminum edelbrock performer heads and vortech blower combo, but the gap from everything I've read shows that it should be between .032 and .035.

Please help. Not sure what to do from here. Already replaced the plugs and gapped to .034-.035. Oil will get changed tomorrow. Now what?
 
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The wider gap may not work well under boost. Most people run .028.

You could have injectors that are leaking. If you come out after the car is sitting overnight and press the schrader valve on the fuel line, there should still be some decent pressure stored in the line. If it's not there, the system is leaking down. Black sooty plugs and gas smell in the oil sounds like leaking injectors to me.
 
Any thoughts on why the fuel pressure looked the way it did? The fuel pressure gauge has been installed where the Schrader valve would have been. Schrader not here any more.
 
As for the injectors, I was told that they are new. They definitely appear new. However, after doing some research, they appear to be a strange green top injector designed for Volvo motors. Part number 9202100. These are high impedance 42 lb, but they appear from online research to be very cheap and not really designed for something like this. Thoughts?