| Moderated by: Greg Fletcher | ||
| Author | Post | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
Randallclary@icloud.com Member
|
I've got a fuel pump from a Sunbeam Tiger (Ford) that puts out 4.5 psi just ahead of my Dellorto 45's. I had a pressure regulator in place that I thought was causing problems, so I removed the regulator and I still have the same misfire issue. The car was running like a champ but after the engine reached operating temp, the problems seemed to start. I'm really not shure where to go to trouble shoot this issue. I have brand new carbs from Delta Motorsports and am positive that I have all electrical ignition issues. Ixcept that I've heard that there may be possibilities of Distributor Cap or rotor issues from reading articles in the forum. Just looking for ideas. If anyone wants to call me direct, I would really appreciate it. I'm 99% done with this reatoration and want to get it on the road with some sense of confidence that it will get me home. The rebuilt motor is super strong when running. HELP PLEASE |
|||||||||
|
subwoofer Member
|
Just back from a test drive after swapping out the rotor, IT WORKED! If you have a rotor with a metal rivet in it, tear it out and throw it as far away as you can! Get a new one without the rivet and see if that doesn't cure the problem. -- Joachim |
|||||||||
|
gmgiltd Member
|
4.5 psi at the carb is on the high side 1.5-2.5 is the recommendation if your pressure regulator is adjustable. Gordon |
|||||||||
|
Brett Gibson JH5 20497 Member
|
Have to agree with Gordon, your running twice the PSI you should be, that can cause issues you probably never thought of, either get a pressure regulator back on it or a lower press. pump. Once you fix your known problems then fix what is left. Brett |
|||||||||
|
Randallclary@icloud.com Member
|
Well I replaced the regulator and set it for 2 lbs. Car ran great but then after a few minutes it started to miss again. I immediately checked the fuel pressure and it was near zero so I adjusted it again to 2 lbs and off I went. Same problem after a few minutes. I bought a new Holly 12-804 which is adjustable from 1 to 4 psi. I have an inline fuel pressure gauge just ahead of the Dellorto 45's and have a fuel filter between the new gas tank and the fuel pump. I'm thinking of adding one more fuel filter ahead of the pressure regulator. Tomorrow I am going to make sure the fuel line is clear from the gas tank to the engine compartment and then blow it out with compressed air. I will disconnect the line at the fuel pump and blow it out forward from there and then go to the engine compartment and blow it back to the rear and once more to be sure everything is clear. I will see if any debris comes out from either end. Are there any other suggestions that might help me with this problem that has plagued me for the past month. I really want to get the car road worthy. Thanks ahead of time for everyone's help. |
|||||||||
|
Brett Gibson JH5 20497 Member
|
There is a fuel flow restrictor on the return to the tank, http://www.deltamotorsports.com/products/pg4d-fuel-system.html item 33 on the diagram. is that in place and if so not plugged.? Brett |
|||||||||
|
gmgiltd Member
|
Hi Brett, Its a bit different layout from the GT but I believe the restrictor is to stop fuel being syphoned into the carbs. If the car was parked nose down a slope enough fuel can bypass the floats overnight to fill the cylinders. The restrictor allows a very small amount of fuel to be pumped back to the tank, prevents the fuel line from being pressurised when the pump is not running and, as above, prevents vacuum or syphoning. I would tend to concentrate on the ignition as Joachim suggested once the fuel pressure is sorted out. Gordon |
|||||||||
|
Randallclary@icloud.com Member
|
The return line is not being used with the Dellortos. I have the hose looped back to the fittings in the top of the tank and have the vent down thru the floor of the trunk. I also do not understand why the fuel pressure drops to zero when the pump is running. This even happens when I have the fuel pump running. I checked again this AM without starting the car and the fuel pressure was up to 5 psi. It needs to be adjusted down to 2.5 psi again. After I make sure the fuel lines are clear I will readjust the fuel pressure and check things out again. While running the car during the last test drive and after it started to miss, I pulled over and checked the pressure and it was zero with the fuel pump running. I popped the fuel cap and nothing changed. I readjusted the pressure up to 2 lbs and made it home . Most of the ride was fine but after 10 minutes it started to miss and drove into a level floor garage and again the pressure was zero. After I clean the line I will report back. I still would appreciate comments as to this seemingly fuel pressure issue. Last edited on 05-23-2016 02:59 pm by Randallclary@icloud.com |
|||||||||
|
Tim Murphy Member 
|
I had a fuel filter near the gas tank that was clogged. Car would start and run ok for a while, then would miss and not run. I would suggest replacing the fuel filter near the gas tank. |
|||||||||
|
Randallclary@icloud.com Member
|
Thanks for your suggestion. I have a glass encased fuel filter near the gas tank and it does not seem to have a lot of junk in it, but to be on the safe side, I will either replace the element or clean it if appropriate. FYI, I just found out from my friend Frank Zizzo that the fuel filter he gave me out of his Cobra has an internal screen. I will open it up and check the screen. I suspect that this may be the culprit. I sure hope so. I feel like I'm chasing ghosts right now! |
|||||||||
|
Randallclary@icloud.com Member
|
Thanks, I will check tomorrow on the fuel restrictor and get back to you. I do not think that I have a restrictor. Last edited on 05-24-2016 06:17 am by Randallclary@icloud.com |
|||||||||
|
gmgiltd Member
|
Again my plumbing is different because I am on fuel injection with low pressure 3psi side and a high pressure 45psi side. The line from the fuel pump outlet going to your carbs should be 8mm and there should be an 8 to 6mm T - the 6mm line goes back to the tank and originally contained the restriction- most people are not aware of it and bin it when they change out the fuel lines. It could go some way to explaining your pressure drop - without the restriction most of the pump output would just be returned to the tank. The tank vent is another line altogether and as long as that is clear there should be no pressure/vacuum issues. Gordon |
|||||||||
|
Randallclary@icloud.com Member
|
I have a single fuel line that goes from the tank to fuel filter to fuel pump into the fuel line to the engine compartment to the fuel pressure regulator to the inlet side of the Dellortos. there is no return line to the tank. I have the tank vented from the fitting on top of the tank via hose out the bottom of the trunk passenger side LHD car. |
|||||||||
|
Brett Gibson JH5 20497 Member
|
If you take another look at the diagram you will see that at the pump it will recirculate back to the tank so that there is constant fuel flow at all times, I can think of a number of good reseansons for this, one being "dead heading the pump" were the fuel may heat up as well as the pump. just a thought. Brett |
|||||||||
|
Randallclary@icloud.com Member
|
Well I'm keeping my fingers crossed and praying that things just may be ok now. I went for a drive this AM after having one of my experts mess with the fuel pressure regulator. Things went well after Dan adjusted the pressure while I started and stopped the car several times yesterday afternoon. Drove the car moderately hard for 30 min and the engine ran smooth and strong. This AM I went to drive it again and within 3 min the same problem again. After limping back home the engine missing most of the way I tore into the fuel filter. I had cleaned it up about 3 month ago before I replaced the fuel tank. It is a glass type filter with an internal plastic element. There was a little visible debris in the filter but not enough to cause and obvious problems, or so I thought. After putting it back in I again adjusted the fuel pressure to 2 lbs and again started the car up and took it for a drive. I drove the car for about 45 minutes today and no problems at all. I went ahead and perms toy mounter the pressure regulator on the bracket just to the left of the windshield washer pump and reservoir. Checked the fuel pressure gauge for final adjustment of the regulator and it has held steady at 2 lbs. I will again test drive tomorrow and see if the problem is finally cured. Today I also took the car back to the muffler shop and had another resonator added to the exhaust system to bring the exhaust noise down slightly. Drove it back from the shop and I would guess that the noise level has dropped 30% with a fairly quiet idle at 950 rpm. Tomorrow I will replace the broken speedometer cable and see how to stabilize my tach. It fluctuates wildly around 5000 rpm. I have a Pertronix Flamethrower system. And ideas how to stabilize so I have confidence as to what my actual rpm reading might be. |
|||||||||
|
Frank Schwartz Member
|
So the problem with it missing was the fuel filter all along??? That's where I usually check first.. Frank |
|||||||||
|
Randallclary@icloud.com Member
|
Well Frank, the filter did not look clogged visually. I did run the car this AM and drove about 40 miles. Took it out on the freeway to about 70mph. There was a very slight hiccup after a couple of minutes at that speed. Not sure what caused it. I would have loved to have seen the fuel pressure at that speed and rpm. I don't think that I have an accurate rpm reading so I need to sort that out. I've been told that the Pertronix sometimes has issues with the tach. Guess I will address my attention to that today. I will install my need speedometer cable this AM and make sure that it works. The car seemed to smooth out after running it and overall I'm very pleased with today's test run. I'm not wuite ready to drive it to Lake Arrowhead in the mountains up to 5400 ft. Maybe in a couple of weeks. The newly modified exhaust has quieted the car down about 40% and it is quiet at idle except at the exhause tips. We added one more resonator to feed the two resonators just before the tips. There is one larger resonator just after the header so it is still a free flow system using Flowmaster components. Hope the wife will be able to put up with this level of engine sound. (or as she calls it "engine noise"). |
|||||||||
|
Randallclary@icloud.com Member
|
I couold also use some ideas of what may be causing the indicated rpm fluctuations on the tach. The engine revs very smoothly but the tach shows wild jumps at around 5000 rpm. This is where i've been told this may be an issue with my Pertronix ignition system. HELP PLEASE |
|||||||||
|
Screenplay Member
|
This thread from last year may be helpful, with special attention to Nigel K's comment farther down the page: http://www.jensenhealey.com/forums/view_topic.php?id=1483&forum_id=7 Clinton Last edited on 05-26-2016 08:12 pm by Screenplay |
|||||||||
|
redracer Member
|
The early J-Hs did not have the anti-siphon valve(as Nigel stated earlier) for the gas tanks. After chassis # 13843, the tanks were slightly different; there is an extra port in the extrusion where the pressure relief valve is. This hose goes over to the white plastic "T" (only on the later tanks) where the valve is in the end of the hose. This is about the size of a 22 caliber bullet and consists of a small ball with a very low pressure spring in it. When the fuel pump is "ON" the fuel pressure forces the ball the hole in the "bullet" to prevent fuel from going back into the tank. When fuel pressure is "OFF" the spring pushes the ball forward to allow air. This valve MUST be located at the top of the tank so when parked downhill, there is no siphoning effect. Also, when replacing this short hose, SAVE THE METAL VALVE to put into your new hose. |
|||||||||
|
Randallclary@icloud.com Member
|
We finally found out what was causing the problem on my @13046 with the Delorttos and 2.2 Stroker Crank. Found out that the forward set of carbs was a little low on the fuel reservoir, This is fed by the needle valve and so we tried to adjust the float and still had the problem, Then we found out that there is a very small filter ahead of the needle valve that was plugged with debris. I cleaned the filter and restarted, Problem solved, the car has been running perfectly. We rebalanced the carbs and did a very slight adjustment on the fuel air mixture using an O2 sensor just being the exhause manifold collector. Life is again good until next time. Installing the replacement speedometer cable today and later this week will real the cam covers and complete that installation of the Accusump. Still looking for solutions to the tach issues with the Pertronix system. More reading ahead. This weekend will attend the San Diego British Car Show.. Think there will be over 200 cars there. |
|||||||||