Sorry to have gone dark on you, <img src="/ubbthreads/images/graemlins/ooo.gif" alt="" /> I have been working through all the good suggestions you’ll posted on this “Running rich” problem and I’m happy to report the issue(s) have been solved. <img src="/ubbthreads/images/graemlins/rofl.gif" alt="" /> Here is what I found and in the order that they were addressed. (I am spelling out all these acronyms the first time I use them because I had to do a some searching to figure out what they were the first time I read about them)
1) Leaky Injectors - I did a visual check both with the engine off and running for leaky injectors. I also rotated them back and forth a few degrees while the engine was running to see if anything developed….no signs of any leaks here. I had replaced the insulators/seals on both end a few years ago when I got the car.
2) Fuel Pressure Regulator (FPR) – I did some searching on-line to determine what the FPR output pressure should be and started down the path of machining up a fixture/tester. Before I finished the tester I came across a spare FPR from another VR4 that we had parted out. I installed it and went for a drive. Not only did the car accelerate smoothly the raw gas smell seemed to be gone. The “Running rich” issue seemed to be solved! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> However I was not satisfied with just smooth acceleration; I wanted to get to the bottom of the “lack of power” issue. No one drives these cars because they want smooth acceleration.
3) Oxygen (O2) Sensor – Because alansupra94 suggested it I pulled the O2 sensor and checked the resistance of the heating coil and voltage on the signal line at an elevated temperature. This checked out fine as expected since the check engine light had not been on and no codes had been thrown. For completeness and to answer alansupra94’s suggestion I should note here; to my knowledge the fuel pump is still the stock one.
4) Boost Leak Test (BLT) – Note: you need to position the crank at 30 degrees After Top Dead Center (ATDC) before you start to prevent being in a valve overlap condition; this is where both the exhaust and intake values are open at the same time in the same cylinder. I performed a BLT by starting with the area behind the Throttle Body (TB) with some soapy spray to determine if there were any leaks in the TB gasket, BISS screw, TB shaft, intake manifold gasket, injector insulators, brake booster, air side of the FPR and all vacuum lines/connections. This also lets you help hear leaks cause by the Pressure Control Valve (PCV), valve seals/guides and rings by taking off the oil fill cap. If you put your ear next to the end of the tail pipe when you pressurize the system (I do not recommend going higher than 20 psi) you can also pick up leaks cause by the Exhaust Gas Recirculation (EGR) value, valve overlap, burn or unseated valves or bent valves caused by a broken timing belt. Here is a picture of my home made BLT in place: (I can put together a quick article on what it takes to make this BLTer if it would help someone out).
5) I did find a small leak around the BISS screw. I am not sure how best to seal it but I am considering just using some silicon sealer. Any suggestions?
6) Next, believe it or not I found a leak around the replacement FPR, see picture below:
7) Since I took the spark plugs out to position the crank for the BLT and check them out for carbon deposits I re-gapped them and re-installed them. Overall the plugs looked good so it couldn’t have been running too rich. For some reason the gap was low by 0.010” so I was glad I checked them.
8) I hooked the TB hose back up and moved the BLTer to the turbo inlet and checked for leaks on the turbo housing, Blow Off Valve (BOV), intercooler ends and all intercooler plumbing and fittings. I have previously found a hole in the intercooler which was caused by a rock during this test. There will be some air leak past the turbo shaft oil seals into the crankcase but this is normal as long as there is no shaft play. During this test you can also determine the pressure level your BOV open up at. My stock one was about 17 psi. No problems found here.
9) I started to wonder what pressure my waste-gate was starting to open up at. After a few hours of forum research on this site and
www.DMSTuners.com I found that the waste-gate along with the Boost Control Solenoid (BCS) device that really determines what your boost pressure will be during hard acceleration. THE BCS is the two port electronic solenoid on the stock air cleaner housing closest to the stock battery location or front of the car. A good factory waste-gate opens at about 9 psi and the BCS increase the factory boost to about 11 psi if everything is working. With a 0-15 psi pressure gauge that I pickup up W.W.Grainger I was able to verify this. (detailed steps/procedure not included). You don’t have to read very long on these forums to quickly figure out that you would be doing yourself a big favor by installing a Manual Boost Controller (MBC). These MBC’s allow you to increase your boost over the stock setting. You can also get an electronic version that can be controlled inside the car but I happened to have on that I found on a parts car we bought. It is simply a ball and spring one way check valve with adjustable spring pressure. After some playing around with the MBC on the bench with a pressure regulator, pressure gage and an air supply I was able to get an initial setting of about 12 psi to start. I then installed the MBC between the waste-gate and the hose that comes off the j-pipe on the high pressure side of the turbo. You can disconnect the BCS hose that goes to the T-fitting in the high pressure hose. This is where I installed my pressure gage to check the boost. You could also use this location to connect up a boost control gage if you want one inside your car. (all these hoses are 3/16 or 7/32 small diameter hoses). Here is a picture of the MBC I used to test out the effects ….
Conclusion: 360/2000 is no longer stock but the MBC valve did the trick; the car pull harder now then every before. The car runs so good now that I may get wrench happy next winter and rebuild the motor with a bunch of the performance mods I read about on this site. I still need to get a replacement FPR so if anyone has one for sale let me know. I checked at NAPA but they have two versions, one set at 50 psi and another set at 51 psi; both are higher than the factory spec so I hope to find a good used one.
A special thanks to brunoboy, alansupra94, 1990ggsxnj, Red Bird, kitcho and 1gkfwd for their help answering this post and the many site members that have contributed to this Technical Forum in the past and left behind a trail of very helpful trail of bread crumbs; this car wouldn’t be running without all you all. <img src="/ubbthreads/images/graemlins/worthy.gif" alt="" />
Thanks again,
-Kevin
