mbz

I appreciate your patience.....

OK So let's see if I understand this next test: Checking the vacuum on the fuel pressure regulator as it affects the fuel pressure while the engine is running. 1). Disconnect the vacuum line from the FPR while engine is running. 2). Check fuel pressure gauge. If pressure goes up that means _______________________. If pressure goes down that means ______________________. 3). Suck on the vacuum hose from the FPR. Check fuel pressure gauge. Fuel pressure should go down. 4). Blow on the vacuum line from the FPR. Check fuel pressure gauge. Fuel pressure should go up. Am I understanding this correctly? If I am, what do these results tell me?

Should I expect a mouthful of fuel....? Or would that be only if there was fuel leaking into the FPR? Pardon my ignorance, but I'm just trying to be prepared if I'm going to get a mouthful of fuel.

OK so when I disconnect the vacuum line from the FPR while the engine is running, what should I expect to see...? The fuel pressure rise or drop?

It is connected directly to the intake manifold.

OK, so to be clear.... you want to see a video of what happens to the fuel pressure gauge when the engine is running with the vacuum hose disconnected from the FPR to the Intake Manifold....? Is that right? Also, is there another place I could disconnect the vacuum hose from that is easier to access that would give the same results you are looking for...? (ie; the vacuum line going to the carbon filter canister).

The latest video is with the air hose from the intake manifold to the master vac disconnected.

Not sure if this helps with the diagnosis, but another quick test I did while I was at it, was to disconnect the air hose from the intake manifold to the master vac. Fuel pressure dropped (although still high) and engine idle went way up. Also, was able to adjust idle with the idle screw. Not sure if the helps with the diagnosis. (see video) engine_idling_with_vacuum_line_disconnected.MOV

OK so I had a chance to test the voltage with the engine running, it jumps between 12.95 - 13.07 volts. (see video) Then I tested the battery voltage with just the fuel pump on and it reads 12.34 volts. (see photo) I did a visual inspection of the cables and ground connection, they appear to be OK. Will pick up a new battery this weekend. voltage_with_engine_running.MOV

ZH & DaveWM, thank you for responding to this, I appreciate your help. I just checked the battery, it's giving me a reading of 12.13 volts. Tomorrow I should be able to test the voltage with just the fuel pump, and then also with the engine running. Will report results. Agreed this seems very odd, the fuel pressure should drop when the engine starts, but it's increasing. I'm trying to understand how it is that if the battery has low voltage, the fuel pressure increases.... wouldn't it stand to reason that if the fuel pump was not getting enough voltage from the battery, it would be under-performing and thus delivering LESS pressure, and not MORE pressure like it is?

Ok got a chance to test fuel pressure today (just the fuel pump this time.... engine NOT running). 35.5 psi Sent from my iPhone using Tapatalk

Yes, I had a replacement hose handy when I took the old one off. I kinda figured I'd need to slice it lengthwise to get a good look inside it, thus rendering it useless. That little hose is kind of a PITA to get back on!

Yes I'll do it when I get some time this week, next available opportunity. I tried to take care of 2 tests with 1 test in an effort to be more efficient with my time. (fuel pump & engine running fuel pressure). I didn't think anything of it because I figured if there was not sufficient fuel pressure it would show on the pressure gauge. Also figured that since the engine is running rich, the fuel pump must be functioning otherwise I would be experiencing a lack of fuel problem (running lean).

The first pic that I posted of the plugs was the OLD spark plugs. The second set of pics I posted are of the NEW spark plugs. I posted the pics of the new plugs earlier this week (Tuesday morning). The old plugs are the Bosch, the new plugs are the NGK. I did not clean the plugs, I figured they have told me all that they need to (too much fuel in the engine), which was confirmed by taking the oil cap off the valve cover. Checking the spark plug cables, the ignition coil and the distributor was really just a matter of good measure to be sure those are in working order and not contributing to the problem.

Plugs are filthy, see earlier in thread.

DaveWM, that was my bad.... I did not check fuel pump with engine OFF. I figured that if the fuel pump wasn't working there would be no fuel pressure at all. I will do that on the next chance to test it and will report results. Yes that is correct.

OK so here's the results of today's testing so far. DISTRIBUTOR: Distributor cap checks out OK. Inside contacts look a bit worn, but all functioning OK. No cracks or moisture in cap. Checked rotor, looks good. cleaned up contact surfaces a bit just for good measure while I was in there. Tested spark plug wires as well, each cable functioning properly. (see photos). IGNITION COIL: Ignition coil test results are: Voltage to coil = 11.93 volts ( a bit low, probably the old battery), Primary resistance: 2.3 ohms (a bit high but fine), Secondary resistance: 10.92k (fine) FUEL PRESSURE: Checked fuel pressure: 38.5 PSI with engine ON, 33.5 PSI with engine OFF. (see photos AND video) FUEL INJECTORS: Checked fuel injectors with stethoscope, all are working fine. HOSE CHECKS: Also checked hose connector to PCV valve, it is fine. Also, see last photo, it shows the crap that spews out of the exhaust. Any thought on this? I still have to check the following: Check Water Temperature Sensor. (resistance test to follow next) Check glue blobs on AFM for signs of tampering. Check boot from AFM to Throttle Body for cracks. Check Cold Start Valve. (not sure I need to do this as I am not having trouble starting engine unless it's flooded). Any comments or feedback on today's results? Any advice on what to check next besides Water Temperature Sensor, glue blobs, boot from AFM to Throttle Body, and CSV? Any other photos or video that would be helpful with diagnosis? As always, help is much appreciated. Thank you! IMG_1728.MOV

Siteuseen, thank you for the clarity on the glue blobs.... I was way off base on my understanding of this. I'll read up on it tonight. Got it. If this weekend's round of diagnostics don't result in improvement or a fix, then measure-check-fix-measure-check-fix, etc... is in order for next weekend. Hoping that's not the case, but have already realized this may be what I'm dealing with. Like I said, I plan on keeping this car for a while, so it's best to get the EFI sorted out now before moving on to other issues. (like suspension, AC, heater core, radio and other electrical gremlins). ? Thanks again for the feedback, I really appreciate the help!

DaveWM, again solid advice.... much appreciated. ? I agree with you and suspect the cause(s) of the running rich problem have existed for a while, hence the past smog failures. I plan on keeping this car for a while, so it's best to get it sorted out now before moving on to other issues. I'll stay on my original plan for this weekend of testing fuel pressure and distributor/ignition coil. Stay tuned for updates (bad pun not intended).

Thanks for the tip.... to confirm, it's item 14 in the diagram?

OK got a chance to check the vacuum hose from the FPR this evening. After idling the engine for about 10 minutes, the car finally died. I figure at this point the engine is saturated with enough fuel so time to check the vacuum hose. Took the hose off and sliced it open length-wise to inspect inside (I had a new replacement hose handy). The inside was BONE DRY... not a drop of fuel or anything. (see photo 1): Also, to be sure there is no fuel coming from the vacuum line of the FPR, I started up the car and let it idle without the vacuum hose to see if any fuel was coming out. The car did not idle long, and there was no fuel coming from the vacuum line of the FPR. (see video). IMG_1653.MOV Also, while installing the new FPR vacuum hose, I noticed that the air hose going to the rocker cover had a split at one end on the underside that was patched with silicone sealer..... so I replaced that as well with a new hose. (see photos). I am still planning on running diagnostics on the distributor and cap as well as the ignition coil this weekend. I need to address the running rich problem however, as it has been confirmed that the engine is getting too much fuel. Seems like it would be the result of a vacuum leak somewhere, however cannot rule out Water Temperature Sensor. Any thoughts on where to look next? (Besides the FI bible, which I am reading through). As always, comments and input appreciated. Thank you! IMG_1653.M

Yes will do. I'll pick some up this week along with a fuel pressure gauge. I'm planning on replacing old / damaged hoses as they are found anyway just as a measure of good maintenance habit.

Yes, will do. Agreed, great call. Thanks again guys, will report back when I have more news. One thing I forgot to mention at the start of this thread (and my apology for the oversight), this car is NOT a daily driver. Meaning there is no real urgency to get it fixed quickly. I'm more concerned about getting it fixed right as long as it takes. Hopefully not too long! I'd like to drive it some more!

OK so I got a chance to do a quick test of taking the oil cap off while idling. Engine runs better WITHOUT the oil cap on, then goes back to rough idle when oil cap is replaced. (see video) Also, with the oil cap off, the car starts and runs just fine. I repeated this 3 times consistently to be sure. (no video of this) I'm thinking at this point that I really need to focus on the Fuel Pressure Regulator as ZedHed and DaveWM indicated, however I am still planning on checking the distributor cap, spark quality, spark cables and ignition coil as well because the engine runs rough at higher RPMs (2000-3000 range). One last item of note; after sitting in the garage doing nothing for 24+ hours, the vehicle has a faint gas smell. I mention this because I am wondering if this may be a slow fuel pressure leak related to a failed FPR...? Please take a look at the video below and advise of your comments. I truly appreciate of all the help from the group.... thank you! IMG_1649.MOV