Fuel System Links

- Dennis Doza's Fuel Pump Modification Page (AKA. the spoolboy mod).
- Click here to see the most recent dyno charts for the car.
- Click here to go to the 1:1 Fuel Pressure Regulator Install page.
- Click here to see some Fuel System Pictures.
- Click here to read my on going Hahn RaceCraft PortFueler installation guide.

Fuel System:

5/01 - Stock.

5/02 - The New fuel system is composed of:

Cartech 20007 Rising Rate FPR, 36pph Mustang Injectors, Walbro 255lph High Pressure Fuel Pump, Autometer Air/Fuel Gauge, fuel pressure gauge, OEM fuel line return line, and a stock Neon fuel rail. This is going to be the part that will be add to the turbo engine to add the fuel at a constantly equal rate to the amount of air being rammed into the motor.

8/02 - A failure occurred one of the homemade gaskets (1/8" long piece of 1/2" fuel line) that goes between the hose barb and the fuel pump module. This obviously caused fuel to come out of the fuel tank while the pump was on.

After further inspection it turned out that one of the gaskets didn't go bad it was the rubber fuel line that went from the hard line to the hose barb that had burst. In forking around with the stupid hose rubber fuel line I broke the hose barb that goes to the module (Mental Note: always remember to do all of the difficult stuff while the tank and module are on the ground and not while it is attached to the frame). The hose barb was eventually upgraded to a bigger hose barb since I had difficulty with drilling out one of the smaller ones so that the fuel pressure would drop back to where Dennis had it set.

11/02 - It has been a 2 months since the car was dynoed and we have yet to fix the problem with the fuel system. We think that all we need to do is set the static pressure level with a 1:1 regulator and readjust the Cartech so that the pressure doesn't come up so fast that the causes a lean condition. We also think that there could be a problem with the map sensor since it threw engine code 14 - MAP sensor voltage too low. We are getting closer to finding the problem.

12/02 - After taking the car out for a few 120mph runs in the highway at WOT we noticed that the car was showing the proper voltage to everything. So that ruled out the MAP sensor going dead. We did however notice that the TPS was doing something weird. It was not showing the computer that the throttle blade was completely open at WOT in fact it was showing 0% open which means that the computer was getting the wrong reading and it was throwing off the fuel tables.

I replaced the TPS and reset the computer to clear all of the codes and learned values to start over. I also reconnected the turbo. What I didn't do however was test the car when it was warm to see just how it reacted to boost. The next day on the way home from my fiancée’s parents house I floored it and the car made a jerk going into boost. So I tried it again in it jerked again. I am beginning to wonder if there is still something wrong with the MAP sensor or the little black box that tells the computer that there is no positive pressure in the intake manifold. I am going to look into the problem next weekend (if it isn't snowing). I may try to remove the black box from the car and see if the potentiometer is set to the right setting to show the PCM that there is no positive pressure in the manifold.

7/03 - Fuel system problems are still persisting and I have begun trying to trouble shoot the cause. My first step was to hook the Cartech regulator up to a cleaner vacuum signal from the vacuum "T" just below the throttle body. So I took the reference hose that was connected to the brake booster and moved the reference point to the new location. Then I proceeded to follow a set of instructions that Cartech has posted on their website. The old system went something like this: vacuum "T" - vacuum line - brake booster - boost reference line - check valve - restrictor - Cartech - needle valve vent to atmosphere. The directions told me to put the reference line on just below the throttle body and put the check valve on the needle valve vent. The only problem with that system is that every time I hooked up the boost reference line the car would practically stall out because the vacuum on the Cartech would pull fuel out of the system when it was in vacuum. The only time that the car ran right was when I had the boost reference line disconnected. I later came to find out that the way that the Cartech was designed doesn't work well with a Neon fuel system. So after some research I have been instructed to go back to the way Dennis had the system set up except I am not hooking the boost reference back up to the brake booster to see if that helps solve some of my fueling issues.

8/03 - I am still playing with the fuel system and I have bumped the static fuel pressure on the Cartech up from 30psi to 32.5 and I will probably bump it up even further to 35psi to see if it helps the car run any better. Running at 32.5psi the car feels really strong so 35psi will probably be where I want it at for extra safety. Another scary point that Dennis mentioned recently is that there is an outside possibility that the injectors that I currently have are not the 36pph injectors that I once thought I had. We bought the injectors from a guy on E-bay and didn't think to have them flow tested to see if they were really 36pph injectors. I am going to be flow testing them sometime in the near future to see if I really have 36pph injectors. If not then I will have to scrape together the cash to buy a set of "REAL" 36pph injectors from Ford Racing.

Apparently 35psi of static fuel pressure isn't the answer that I needed to cover the boost thresh hold lean spot (stumble). So the only current fix for the stumble is to install a 1:1 regulator to set the static fuel pressure and then use the Cartech as it was originally designed to work.

9/03 - You guessed it I am still messing around with the fuel system. I finally got the fuel lines too and from the fuel tank reattached and I am currently waiting for a set of 4 Accel 36pph injectors to show up from Modern Performance. The estimated time for arrival is this coming Friday and hopefully I can do the entire install of the fuel system this weekend which will include the 36pph Accel Injectors, 1:1 Mallory Fuel Pressure Regulator w/ 1-25psi spring, and connect the Cartech FMU the way it was designed to work.

10/03 - Well a month has passed since I ordered the 36pph Accel injectors. I installed the injectors about 3 weeks ago with the 1:1 regulator and I have driven the car since and I notice that there is a definite difference in the way the car feels. The car use to take forever to get through 2nd gear (40-80 mph) and now it pulls hard all the way through 3rd gear (120+ mph). I have been kinda lazy these days about working on my 1:1 Fuel Pressure Regulator install how-to but I assure you I have tons of pictures and have a general idea as to how I am going to write the how-to. All and all the car is running really good but due to lack of time/funds and other issues that are stopping me (Leaking Radiator) I have yet to hit the dyno to tune the car the rest of the way (It runs a shit load richer these days since I can actually watch the fuel gauge on the dash board move when I am in boost).

11/03 - The car has been restored from questionable to running condition and as of now it has yet to be tuned. I still have the boost threshold stumble with the Cartech set to 35psi at the on set of boost. I adjusted it to 40psi this past Saturday and I will be driving the car again this coming weekend to see if I can tune that stumble out. It did however seem like it was less of a shock to the system when I had it set to 35psi so I am hoping that 40psi will be the answer. I am currently working on the how-to for the 1:1 regulator install and I hope to have it up by this coming weekend.

Well I finally finished the How-to for the 1:1 Fuel Pressure Regulator install page. I got the blessing from Dennis that it was pretty good and there are some tips that I have in there as per is instruction. So I hope it helps you out on your installation of a 1:1 FPR. Also the format of the install page is the general direction that I am headed with the updating my older format for the 2.4L page.

The fuel system battle still rages on behind the scenes here. Last weekend Dennis and I were working on the tuning phase of this beast and stumbled across some interesting things about my car. The first thing we noticed is that my Map sensor tricking device was the cause of those wonderful stumbles at the onset of boost. So make sure you have your Map sensor tricking device set to cover the voltage properly otherwise you will get that wonderful stumble because driving the car either on boost or off boost sucks. The next thing we noticed while having the OTC scan tool hooked up is that even with the larger injectors the 2.0L computer wanted to keep adding more fuel to the long term adaptive learn and short term adaptive learn pulse widths which means that in all reality I could actually bump up to a larger injector from the Accel 36pph one that I currently have to something like a 42pph or even 44pph injector and still be able to have the car idle properly. After playing with the fuel system Dennis wanted me to take the car out for a drive so we could test the fuel system to see how it was doing. I did some nice 6psi brake torque burnouts and almost got pulled over by a county mounty doing 120mph (Smokey and the Bandit just in case you didn't get that one). After that we were pretty satisfied and decided not to tempt fate anymore and called it a night. The next day I had an appointment to get my car tuned the rest of the way on a Dyno Dynamics chassis dynamometer. After getting completely lost (Thank you Mapquest) in Belleville, ILL we finally were lead there by the shop owner who seemed like a tool in the beginning but he turned out to be a cool guy. So we spent 2-1/2 hours playing on the dyno tuning the car, upping the boost, messing with the onset of boost fuel pressure, and the steepness of the climb of the fuel pressure to match boost. So after all of that we were not able to keep the A/F from being lean in the beginning at 14:1 and then running off the darn chart at 9:1. Another funny thing about the car now is that when driving the car I can do the 1-2 shift and the AF gauge will be pegged at 1 bar green and then do the 2-3 shift and the car will go from 1 bar green to 1 bar red. I am not sure if this is caused by the car running too rich or something else. I haven't had time to look into the problem but this weekend if I have some time I will look into seeing if my fuel pressure is dropping off or something. The nice thing about the car now that it is running right and I finally get to do fun stuff like this rather then fork with general maintenance. I am currently looking at saving up some dough for an LM1 Wideband O2 Sensor so I can tune my car when ever I want to rather then always have to hit a dyno when ever I change something. This is probably not going to happen until next January or February after I own GT and have more cash available since my wedding is coming up in just a little more then 4 months and there are still some things that need to be paid.

1/04 - Well another year has begun and wouldn't you know it I am still working with Dennis on figuring out my damn fuel system. We are getting closer to getting a handle on this monster. I also have some recent updates on the car: That strange lean spot on the AF gauge at the top end of 2nd and into 3rd was caused by running too rich if there is such a thing. I also get the same lean spot on the gauge when I hammer it from a dead stop and the fuel pressure spikes to 100psi before the boost has time to climb fast enough to keep up. I know this because a few weeks ago I had the car out with the gauge zip tied to my windshield wiper I watched the fuel pressure go from 30-100psi which out ran the boost gauge to its wrong number of boost pressure of 0-17psi (more like 0-13psi). Some things that we are considering is using an adjustable needle valve on the reference port of the Cartech like there is on the bleed off port to limit the amount of boost pressure that the Cartech sees so that we can get the AF to stabilize at 12:1 rather then fall off the chart at 9:1. Another thing that Dennis wants me to try is to see if using a SOHC PCM will help us get a grasp on the fueling problem. It is known that the DOHC computer likes to dump a shit load of fuel into the car under WOT. Well, I could care less what damn thing wants to do with the fuel because we are covering the fueling under load with the 1:1 regulator and Cartech. So Dennis thinks that the PCM is adding an extra variable into the mix by adding in more fuel in the top end of the RPMS that I really don't need which is probably causing misfires and all sorts of unhappy shit. So need less to say the fuel system is still under construction at the moment. But I am hoping for progress here in the next few months because I would like to attend the first Test and Tune of 2004 to see if I can break my own personal record of a 13.5 @ 104mph on street tires. I am hoping for high 12's on street tires after the car is properly tuned and the boost gets jacked up a few more pounds.

2/04 - Wouldn't you know it I get one problem fixed and two more pop up. One problem that came up had to do with the fuel system. While I was testing the new oil flange drain for the turbo I was under the hood manually revving the motor by moving the butterfly on the throttle body. In doing this I was causing the oil pressure to raise and lower to see if any oil was spraying from the return line on the turbo. After about 10 minutes of messing with the car I started to smell gas. I thought my car was running rich but I didn't know it was that damn rich. So I went back to the back of the car and sniffed the exhaust gas coming from the muffler. It seemed ok to me but while I was down there I noticed a small puddle under the car near where the fuel pump module usually hangs out. I then though oh shit and ran to turn the car off immediately.

3/04 - After two days of disassembling the car I got to mess with the fuel system to figure out what was wrong with it. I bypassed the fuel pump relay with a wire and proceeded to drain the fuel into a gas can. 5 gallons later I had to get another can to put another 4 gallons into it. I was pretty loopy after working with the gas so I don't really remember how exactly I dropped the fuel tank from the car but I did and apparently I didn't brake anything. I also removed the external fuel filter since it probably needed to be replaced after two years of on and off use. I inspected the bulkhead fittings on the fuel pump and they all looked good but the line coming from the fuel pump looked pretty ragged and abused. It was also very squishy like it had been weekend and wasn't doing its job anymore. I am going to place my bet on the bad hose as to being the problem. So I will probably replace that hose and try to figure out a different way to route the hose. I will also be refurbishing all the homemade gaskets with real gaskets for the bulkhead fittings to keep the fuel from getting out of the tank (which could also be causing fuel to leak out). I am basically going to be doing a complete overhaul of the fuel pump module and replacing stuff that looks worn and ragged.

I am making some progress here in the fuel system department. Today I got the entire fuel module back together and put all new gaskets and fuel line into and out of the module. I also got to enjoy putting the dumb lock washer on the fuel pump module to hold it into the fuel tank. I only have one tiff with this damn thing and the person that thought it was a good idea to put one on there. The lock ring absolutely sucks to get back on without cross threading it and every time you think you have it on straight it gets all crooked and you have to start all over. I was to the point where I was trying to hammer the damn thing back in but alas that did not work. 30 minutes later I figured it out, tightened it up, and stumbled back out to the dark shed to put the fuel tank away for the night.

5/04 - I was not feeling good about the gaskets I bought to replace the homemade ones on the fuel pump module so I decided to take the module back out of the tank (which was even less enjoyable the second time around) and replace them with homemade gaskets again made from thin pieces of fuel line which were then put over the bulkhead fittings on the pump. Learning from my past displeasure with the lock ring I managed to get the ring on the tank in the first try. I even bought a big strap wrench to tighten down the lock ring so I didn't have to use a hammer and a screwdriver like I had been using which really messes up the ring something fierce.

Rich came over the next day and helped me do some miscellaneous stuff to the car and one of them was to hook up the fuel tank to the car and reconnect the fuel lines. Rich pretty much watched me work my magic with the tank and helped where I needed it since I have had the thing out a half dozen times alone and got pretty good at installing and uninstalling the tank by myself. In less then a half hour the tank was in and everything was hooked up correctly (or so I hoped).

9/04 - Today Dennis and I were on a mission to get the car tuned at the dyno shop and before we made it to the shop we needed to do some running around. One nice thing to report though is with the granger valve installed and half way screwed down the turbo made a whapping 19psi of boost for all of about 4 seconds until it blew the IC pipe from the TB with the BOV on it completely off which caused it to smack the hood. After that Dennis and I fixed it and adjusted the boost pressure down a notch or two and took it out for another test and the vacuum "T" from to the brake booster and boost gauge blew apart. After fixing that we decided we better get to the dyno before anything else happened. The dyno tuning didn't go quite so well after the Dennis and Dave circus rolled into town (as Dennis put it). After the initial base run things started to go down hill and Dennis could tell that the guy running the dyno was kind of getting agitated with our disorganized and haphazard process of attempting to chase down the tuning of the car. To add insult to injury while I was taking out the plug wires to install new plugs one of the Magnecor wires decided it was done living under the hood of the turbo car and busted apart leaving part of the plug wire attached to the top of number 1 plug and destroying the rest of the wire rendering it completely useless.

After the big day at the dyno shop Dennis and I have been in agreement that something is seriously wrong with the TPS on the car which is throwing the entire tuning process out the window. If you look at the new charts you will see the really nasty A/F spike on run 27 which is not as bad for run 15 which was done at a lower boost level (12psi) last November. So before I can go back to the dyno I need to install a new TPS sensor (IAC is shot too) and Dennis wants me to take out my Cartech so he can take it apart to see if some of the tuning issues are being caused by the unit itself. So if I get some free time tomorrow (Labor Day) I will uninstall it and connect my boost reference to my 1:1 FPR. Also if I get the chance Dennis wants me to remove the SOHC MTX PCM and put the DOHC ACR one back in because he thinks that using the SOHC one isn't going to make a big enough difference as far as advancing timing and adding too much fuel (which too much fuel would be a good thing at the moment). I finally got around to installing the ACR PCM on the car after I got the oil line issue figured out. So I went over to my parents house to fire up the beast and after idling for a minute the CEL went off. I stopped the engine and checked the code, which was 51, and though sheesh another code and a new one this time. So I thought nothing of the code and went to the turbo guys house to have him look at the downpipe design I currently have. I leave the turbo guys house after he looks over my car and spoolboy's handy work and mentions that it is a pretty cool setup. On the way back I merge into traffic at 3/4 throttle and the boost rises up to about 2psi (with the wastegate disconnected and flapping in the breeze). The car pulls good due to the torque but I notice out of the corner of my eye that the AF gauge was in the stoich region while on boost. I pull the car into the driveway and just as the car comes to a stop it just dies completely as if either it ran out of something (fuel or spark). Then after a few seconds with the key in the ignition in the on position the car refires up again by itself. Now if that isn't messed up I don't know what is.... It looks like I will be working on the car this weekend after I get back from the junkyard with the pigtail of wire for the Neon IAC motor to figure out what the heck is up with it now. Gotta love those Neon's.

10/04 - The fuel system is still giving me trouble (imagine that huh). The car seems to idle fine with the current setup but it is not right. It will idle for a while but then it will just up and die for no reason after sitting for a few minutes. I have been told that after it refires the smell coming from the car is almost like the engine got flooded with fuel. Other then that happening the car runs fine under load and 3/4 throttle without a snag. I have also been told that while driving there are clouds of black smoke coming from the exhaust whenever I lift of the throttle. Not only that but the deck lid is starting to collect a film of black on top of the paint. Yeah I know the car is black but if I run my fingers across it a black soot comes off the trunk onto my fingers. Since I am fed up with the Cartech I am going to throw it as far away as possible and find a better way. The car has been in a state of being untuned for at least a 1 1/2 years. So I have been talking to Bill Hahn from Hahn RaceCraft and I will be upgrading my fuel system over the winter to their new PortFueler system. In the process I might have to put the Neon DOHC intake back on but if it helps me fix the fuel system problem then I am all for it and it will be a nice thing for Bill to get free advertising from me on how much I am going to like the system (lets hope I like it for $1000). Stay tuned......

5/05 - A few months back I took the plunge and purchased the HRC PortFueler fuel system regardless of the may people that said it was a huge waste of money. As of now I am happy with it and tuning is relatively easy and even in it's untuned state the car still runs so much better then it did with the old fuel system. I have flogged the car a few times since it was installed and it runs strong so things can only get better from here.