Fuel pressure ok?

Jffr you are right, you don't have to vary the fuel pressure.  Jeep and Dodge systems put the fuel pump , filter , and pressure regulator in the basket in the tank.   There is no reference to the manifold pressure and runs around 39-40 psi all the time.

    With a reference line showing in the photo I had assumed it is not a dummy. A 1/8 inch pipe plug or a rubber cap from the auto parts store would blank it off if not in use.  They do make regulators without reference as well.  They also make regulators that are not 1 to 1 but don't know how or when they are used. 

 I have seen a equalizing chamber with spider legs to each throttle body used on IR systems.  I would expect with out one the engine would be running alpha n  fueling.    MAP sensors can be directly mounted to a manifold or remotely mounted with a rubber hose.  Another thing to check.  A rotten or split hose would mess things up here.  

 I would expect a back fire to be tough on a MAP sensor. 

 A digital dash on a tablet or phone would be a help here.

  I think the Speed Pro system is now part of F.A.S.T.

  Looking for bent throttle blades might be jumping the gun.

Jan -

That sure looks like a fuel pressure regulator to me, the black thing.

 You are NOT dumb!!  Auto mechanics might not be your specality but every day is a oppertunity to learn something new.  I have very little hands on experience with EFI but have bought a pesonal library of text books off Amazon.  It may be a morbid sense of curiosity.

  Trouble shooting auto mechanics is a art.  Think it through , start with the simplist or cheapest possible fault and work it forward.  Some systems have known weakness and it doesn't hurt to know your enemy.  Youtube is not a bad resource , you just have to recognize BS when you hear it.

   The injector cleaner and a Italian tune up is not a bad idea.  ( drive like it is stolen)   I doubt any Pantera owners drive like old ladies , the Pantera has long legs.

Yes, that is the fuel pressure regulator. Here is a photo of my FAST XFI Edash monitor. It tells me everything that I want to know about my EFI system, but am afraid to ask. Or put another way, too scared or lazy to hook up the laptop to the ECU.

Your dash monitor looks great. Had trouble getting the Fuel Pressure Regulator hose off, but it does move around so I know it isn't fixed. But for a quick test I wrapped the connection itself real tight with some electrical tape and tried the car and still bad. Idols around 50 then is still rough when I give it some gas. Then by the time I turn the car off take the key out and run to the back the PSI is 0. I thought there should be at least some PSI remaining with immediate turn off.  Tomorrow will try and get that hose off and look at my vacuum tool instructions to see how to test at the FPR and at the hose too. But for my sake in understanding my car can anyone tell me what items 1, 2 and 3 are for? I see the eight hoses labeled 2 go into the manifold but can't see where the eight #1 hoses go. Maybe item 3 screw is for some type of test gauge or just secures it to the car straight through the FPR?

  Hope you have a fire extingisher in the garage and is handy.  Those are vacuum lines and no fuel should be present.  # 2, should be 8 of them and they appear to all be going to a common chamber so you should have a solid vacuum signal.  That is what jffr refered to in a previous reply.

  # 3 is the adjustment for fuel pressure and does NOT need to be adjusted. The hoses appear to be hard plastic and may damage the end trying to get it off the regulator.  You are not apt to find hose like that easily.   The fitting on the regulator is a barbed adapter.  It is slightly tapered on has sharp edges around its diameter to grab the hose.  You may not want to take it off and damage any thing.  Pretty obvious you have a vacuum signal to the regulator.   You could try to ID the brand and part number off the regulator and go read about that regulator and see how it works.   With a vacuum line reference I think the pressure should vary with load.  There is no other reason to supply a vacuum reference.  The specs may say "vacuum/boost rise ratio 1:1" , that means on a boosted engine 1 pound boost raises fuel pressure 1 pound.  On vacuum it is around 2 inches HG (mercury) to equal 1 pound less fuel pressure.

   The sudden lose of fuel pressure would lead to hard HOT restarts.   Without pressure the hot fuel can boil in the fuel rails and when you try to start, the injectors and fuel lines have vapor rather than liquid fuel.    At this point we don't know if that is related to the problem or has always done that but no one noticed.   Again in theroy it should hold some pressure for hours. 

    You should try a phone call to the guy that tuned the car and hope he can / will answer a couple of questions.

    A fuel pressure regulator is about $150 for a house brand (summit racing) to $350 for aeromotive brand , so determine that really is your problem rather than throw money at it.

   I said before no hands on expereince with a system like this but have read about so I am not selling myself as a expert.  

#3 in the photo is the fuel pressure regulator adjustment screw and lock down nut. #2 in the photo appears to be vacuum lines that are coming off of the throttle bodies and going to the vacuum supply pod. I don't see the #1 photo, but it looks like there is another line coming from the fuel pressure regulator body that also goes to the vacuum pod. That type of set up looks like what my old factory 1988 Ford Ranger 2.9 V6 engine used on its fuel injection system and it was tied to the fuel return that went back to the gas tank. On that particular system, when the fuel pressure regulator began to  fail it caused major flooding problems with the engine. Without actually being there to look at your engine's fuel injection set up,  it  would be hard to pin point exactly what is going on. It would help if you could find out who built the original system for that car and what tuning mode is being used. From what I understand about those type of IR throttle body systems, they either use Alpha N or Speed Density tuning. I think Lance Nist  from southern California built at least one system like that in the late 1980's or early 1990's. I will bet that someone on this forum knows where he is these days, but Lance certainly knows how these systems work and was a pioneer with fuel injection and other cool stuff for Panteras.

  Can't tell for sure but there is a 3 wire plug visable  on the rear of the "pod" , I would guess the MAP sensor.  So would say speed density fueling stratage.

I agree that the plugged in connector would most likely be the MAP sensor.

why not try that go pro camera you have.  aim it at the fuel pressure gauge and go for a short test drive.  include idle  , economy cruise and a very brief high load.

no need to go on the express way or any high speed driving just show a range of loads.  I maintain the fuel pressure should "mirror" engine load.  low load low fuel pressure , high load higher fuel pressure.  did the fuel pressure vary?

If   NO  , loosen the lock nut on the regulator and back the adjustment screw out until fuel pressure drops to around 28-30 psi.  Re tighten the lock nut.  now a short test drive keeping speeds and loads low.  did drivability inprove?  Remember that leaned the fueling so no hot rodding.  now restore the fuel pressure setting and decide what to do.  careful around the opening in the bellhousing and the rotating flywheel / clutch  and don't let the car roll away on you. ( wheel chocks)  Not trying to be insulting , just safe.

    If you have a oxegen sensor in the exhaust it will try correct the mixture.  no action needed just an observation.

    Again see if you can get any information on your regulator.

   Now you should know enough to talk to your tuner , or some one that knows your system.

I've been interested in EFI conversions for the Cleveland (or Fontana) but I really know very little about the systems. In one of the books written by a company called "TPS" decades ago (1988), they mentioned fine-tuning their GM system by varying the fuel pressure. On a dyno, they ran from 40 psi on the low end to 55 psi and the throttle response & bhp varied considerably.  And that was with stock GM-style injectors. Do 8-hole throttle bodies change the rules on varying fuel pressure? 40 psi seems low based on what little I think I know.

That threaded stud (#3)  with locknut is how one changes fuel pressure on a regulator. If you remove the 4 small screws, that part of the housing comes off and there should be a rubber diaphragm underneath with a fairly weak coil spring. Possibly the old diaphragm has a small puncture maybe from using CA gas and that's why the thing doesn't hold fuel pressure when switching off.

Thanks for all your help. Sorry, I got caught in all the Huntington Beach protest mess about beach closures but am home now. Yes you are right the car does have an Aeromotive FPR. I am not sure if this one in the link below is the one I have (or may need) but for illustration it does show what the small vacuum connector looks like. So it looks like I should be able to slide the hose off without damage and test at the FPR metal line and/or at the hose/engine line. I have a hand vacuum pump as shown but can't find my instructions or even youtube or google for use on the FPR. But I am thinking if I attach it to the FPR with the engine off and pump the vacuum pump to lets say 10 or 20, then shouldn't the pump hold that same pressure? If it would drop maybe the diaphragm may have gone bad? I like the suggestions to drive the car hard too, but if the FPR is bad I am thinking it may be putting small amounts of gas in the engine which may not be good. Thus trying to test the FPR first.

FPR

  Boss Wrench is right could be a hole in the diaphram.   Maybe areomotive might sell just that part as a repair kit.

   A hole in the diaphram would explain why you don't hold pressure when the engine stops.  It would explain why the fuel pressure does not move from 40 psi.  It would explain why the car is not running well.

   You are right the hand pump should pull a vacuum and hold when you stop pumping.  

    If you do get the small hose off you will have fuel present IF the diaphram is ruptured. 

   You might take a electric heat gun or a hair dryer to heat the plastic line to soften it.  to aid in removal.  NO FLAMES might encounter raw fuel and that extingisher!!!

  If the diaphram is ruptured , it has been adding  fuel like a 9th injector.

  Might sniff the oil on the dip stick to see if there is raw fuel in the pan.  That would be extreme but doesn't cost a dime.

Great idea with the heat gun on that plastic line, maybe it will help it come off. Yes, another excuse for Harbor Freight tomorrow, $10 heat gun on sale. I forgot how great that store is. Main thing is to test that FPR at this point. I had already sniffed the dip stick and there was slight engine smell, but not really gassy smell that I could detect. Already had planned oil & filter, but now waiting till this is solved. When that day comes I will save an oil sample too. Would also like to know how to do a vacuum test at the engine hose. Maybe its the same process or does the engine need to be running?

that heat gun would have no trouble melting the hose so easy does it.  I have 2 of those heat guns.  softened sheet flooring for removal in the house.  I hate sending any more money to China but buy the heat gun else where and it may have rolled off the same assembly line. 

    here is a link to a youtube video that is decent on fuel pressure regulators.

             https://www.youtube.com/watch?v=aWuFFhKuQZs

I am amazed that nobody offers to do what any good mechanic did before gas analyzers and other lambda sensors exist: disassemble and observe the spark plugs after operating at idle and immediately after a full loading, it costs nothing and, even with unleaded gas, indicates a lot about AFR.

first post of the tread  Jan took the plugs out and "cleaned "them.   He did not observe anything worthy to report.

If its running rich / poorly maybe even smoking looking closely at the FPR is a good place to go based upon my recent experience with the 348.  The FPR diaphragm developed a small hole in it.  Fuel would push out the diaphragm and into the vacuum line.  This caused the engine to progressively run richer and richer.  When the problem just began I noticed it just wasn't running quite right.  Finally the CEL came on and we began hunting for the problem.  By the time we found the problem it was smoking really bad it was so rich.  It eventually dumped so much raw fuel into the intake manifold that I had to change the oil / plugs and run the car quite a while before all the un-burnt fuel cleared up.  Two months later it began running slightly off again.  This time I changed the other FPR on the right side and problem went away.  I did dissect / destroy both old FPR's and found both had holes in the diaphragm.

I don't know if that's your problem but this is what happened to my 348.

That's right, back in December I suspected the plugs as a possibility so I cleaned them up even though they didn't look too bad. It did run nice after that but on the next run it started acting up a little. That's when I began hunting around on the web and with you guys for suggestions. I got a heat gun which did help in getting the plastic vacuum line off, then hooked up my vacuum pump to the FPR. Took it up to 20 and it dropped pretty fast (see video). I even tried some other connections to be sure my connections were as tight as possible & thumbed at the end too. Did the plastic hose sniff and it seemed to have some fumes there too. So it seems like that is most likely the issue. Now to find the actual Areomotive unit I need, and as suggested maybe I could just replace the diaphragm from Aeromotive rather than the entire unit. My thought is that I would not prefer to mess with any of the existing fuel line connections, especially if the top just opens and I could replace the bad diaphragm that way. Thanks for all your help with this. I guess in the end the tell tail sign was that pressure drop when turning the car off. 

Jan, If the FPR is your problem I would just replace it instead of trying to replace the diaphragm.  I just went to the Summit Racing web site and looked them up.  They range in cost from low $100's to low $200's.  Look for the correct fitting size and inlet / outlet ports etc. and replace it.  Not a difficult job at all.