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FAST EZ EFI Problems - Ask Anything

Fast Mopar - FAST EZ EFI Problems

Larry Wahrmund; Brenham, TX: Five years ago, my son and I bought a ’69 Charger. It was as junkie a car as one could find, but we have had (and still have) a blast messing around with it. We swapped in a Dana and a four-speed from a donor Charger and have rebuilt the 440 with an Edelbrock top-end kit and an MSD distributor. We then added a FAST EZ EFI fuel-injection system that my son installed. We robbed the fuel-sending unit from the donor car and used the smaller line as the return.

He finished the FAST EZ EFI conversion last summer. Within less than 1,000 miles, the fuel pump gave up. It looked like it had some sort of varnish coming out of it. I took it to be overheated or something. FAST EZ EFI sent us a new one, and we installed it last fall. We also installed a fuel filter between the pump and the gas tank at that time. The car has not been driven much since, as my son is in college. We drove it last week, and it sounds like the pump is going out again. I do not know much about the FAST EZ EFI system. Would the smaller return line be causing this? Also, the car misses at full throttle. We do not have a working tachometer, but I think it starts around 4,000 rpm. My son says the FAST EZ EFI system is supposed to learn by itself, and the more we drive, the better it’s supposed to run. He is communicating with the FAST people about the FAST EZ EFI problems, but he is deep into a bio-medical degree and really does not have any spare time to worry with it.

Any advice regarding the FAST EZ EFI problems would be greatly appreciated. FYI, I subscribed to Car Craft 30 years ago. My son got a subscription five years ago, and I started reading it again. I forgot how much I enjoyed the magazine.

Jeff Smith: This is slightly different from our usual approach to answering a question, as Larry’s situation required several emails back and forth between my buddy Ed Taylor, Larry, and me. I will recount the exercise we ran through in order to solve Larry’s FAST EZ EFI problems, illustrating the technique we used to arrive at the solution. As is often the case in situations like this, there appeared to be more than one factor contributing to the overall problem. At first, we thought the issue might be electrical in nature, so we instructed Larry to perform a simple voltage-drop test by measuring the voltage between the positive terminal on the battery and the positive terminal on the fuel pump, and then perform the same test on the negative side. The positive-side test revealed a loss of 1.35 volts, which is significant, as anything more than 0.50 volts can be considered major. A voltage drop occurs because there is resistance in the circuit. If you wired simple, 12-volt circuits in shop class in high school, then you know that any resistance in the circuit reduces the voltage to the load—in this case the fuel pump. Remember that the voltage has to travel from the battery, through the load, then return to the battery. If the resistance is on the return (negative) side, the whole system suffers. Larry routed a larger wire circuit using a relay between the battery and the pump, thereby eliminating the voltage drop. This made the pump run much more efficiently. One problem solved.

During our evaluation, Larry sent us a video of the car running, and in one portion of the clip, he showed a shot of the fuel-pressure regulator with a small fuel-pressure gauge mounted in line. He had previously mentioned that the pressure seemed to fluctuate, but it wasn’t until we saw the gauge go from roughly 45 psi to 90-plus psi and then return to 45 psi that we realized there was a more serious problem, since with a return-style fuel system, the pressure should never vary more than a few psi. This required more testing. Taylor and I initially thought the original feed line used as a return might be restricted, so we had Larry create a separate return line into a fuel jug to isolate the return. When the regulator continued to fluctuate wildly, Larry then created a temporary inlet for the pump, using the same fuel jug to remove the fuel-tank pickup as a possible restriction. The problem persisted, leaving the regulator as the only remaining variable. FAST sent out a new regulator, which when replaced, immediately stabilized the fuel pressure and solved the problem. The 90-plus psi fuel-pressure spikes caused by the faulty regulator and the resistance in the electrical circuit were the main reasons the first fuel pump failed. All this sounds pretty simple—and it was—once we isolated the problem. The point of all this is to demonstrate the process of identifying a problem as opposed to just replacing parts until it goes away. It took more time to perform the testing, but in the long run, we discovered more about how the system operates and made some changes to the electrical side to make it run much more efficiently. Larry reports the Charger currently runs great, but now his wife is concerned that with all this extra horsepower, Larry might be more than tempted to not act his age behind the wheel! We also should give a shout out to Larry’s son, Christian, who did most of the mechanical work in between studying for college. According to Larry, it was a great opportunity for the two of them to work on this project together. It doesn’t get much better than that!

More Info

Fuel Air Spark Technology EZ-EFI (FAST); 901/260-3278; FuelAirSpark.com

May the Force Be With You

Dan Svegliato; via CarCraft.com: I just finished reading the Sept. ’12 issue. Nice work, as always, especially the carb vs. EFI comparison (“Quick Test: Carbs vs. Fuel Injection,” page 30). OK, maybe it was a little unfair having two carbs against one EFI, but at the end of the day, carbs still do have an advantage against EFI, as far as peak power.

The minor correction is regarding a discussion on bottom-end loading vs. rpm (page 40.), where you mention that bottom-end “g-forces increase geometrically as engine speed increases.” For the record, those forces actually increase exponentially! As engine speeds increase, the forces increase as a second-order equation. I did a nice little chart to show the differences. If the connecting-rod big-end pin loading at 1,000 rpm equals 1, then the as the speed goes up, you can see how fast pin load increases:

At 2,000 rpm, connecting-rod big-end pin loading is four times higher than at 1,000 rpm

At 5,000 rpm, connecting-rod big-end pin loading is 25 times higher than at 1,000 rpm

At 8,000 rpm, connecting-rod big-end pin loading is a whopping 64 times higher!

Sounds scary, eh? It’s really not that bad. When you design a race or high-performance engine, you know the desired rpm range, so you calculate connecting-rod big-end pin loading and design the bottom end to that running condition. So if you know you’re going to spend a lot of time at 8,000 rpm, you design it to last at 8,000 rpm. Running at lower engine speeds just makes everything last longer. Again, kudos on the magazine—time for a mimosa. Bottoms up!

Jeff Smith: Great stuff, Dan. Thanks for the information!

Cylinder-Head Test Feedback

Michael Yount; Charlotte, NC: First off, I’m enjoying my subscription. There’s pretty good diversity in the articles and coverage—always something interesting for me in every issue. Keep up the good work.

With regard to the SBC cylinder-head test (Sept. ’12 issue), it would sure be nice if dyno tests were run over a range that shows what’s going on at lower rpm. The article stated that “a typical street engine will spend 70 percent or more of its time in between peak-torque and peak-horsepower engine speeds,” which couldn’t be more inaccurate. A typical race engine will spend more than 70 percent of its time in that rpm range. But a typical street engine spends 90 percent of its time between idle and 3,500 rpm. We occasionally get the chance to open it up on the street or at the track.

Most of us, especially when we were, uh, younger, put together a combo that was optimized for peak torque and horsepower in the upper third of the rpm range. And then, after a period of denial (for some, this period of denial goes on their entire life), we realize we spend almost all our time on the street in the bottom third of the rpm range. We discovered we had a street combo that was an absolute pig from idle to 3,500—simply not much fun to drive on the street. So how ‘bout starting the dyno runs much lower in the range? That combo that kicks out highest averages between 3,500 and 6,000 may well be the dog of the group from idle to 3,500. At least arm us with that info so we can decide what we want.

Jeff Smith: First of all, we totally agree with all your statements, Michael. It sounds like you speak from experience. However, I think a little clarification is in order. I think you may have taken out of context my statement about an engine spending 70 percent of its time between peak torque and peak horsepower. I should have made it clear that I was talking about when the engine is making a pass down the dragstrip. If you go back and read where I made that statement, it was within the context of a discussion about what affects dragstrip elapsed times. When it comes to street engines, I totally agree with you that low-speed performance should be taken into account, especially with cylinder heads of this size that are just slightly bigger than stock and generally not combined with long-duration, big-lift camshafts.

You are also right to ask for power numbers at lower engine speeds. We actually did test down to 2,500 rpm, but the story was already way too long, forcing us to cut out all the flow testing that was done (you can find that now on CarCraft.com if you search the story and then find the link to the flow tests). To save space, I cut out the testing at 2,500 and 3,000 rpm. To fill in some of the information, here is the torque and horsepower numbers for all eight heads at 2,500 rpm:

Head Torque HP
Jeg’s 340 162
Flo-Tek 340 162
Dart 338 161
Summit 337 160
Vortec 337 160
Patriot 333 159
Edelbrock 331 157
Stock Iron 318 151

Head Torque HP
Jeg’s 340 162
Flo-Tek 340 162
Dart 338 161
Summit 337 160
Vortec 337 160
Patriot 333 159
Edelbrock 331 157
Stock Iron 318 151

As you can see, there were some surprises, particularly with the Flo-Tek doing very well and the Dart, despite its larger size, producing excellent torque down low. Scott Patterson of Oxford, Massachusetts, sent us an email asking why we tossed in a 200cc Dart head instead of the smaller 180cc port head that would have created a more appropriate apples-to-apples comparison. While Scott makes a good point, the price on the larger heads was still under our $1,000-limit budget. If you had a similar budget, wouldn’t you go for the largest head you could afford? As you can see from the test, the 200cc intake port did unexpectedly well in the low-speed area. It’s entirely possible that the smaller 180cc head would make even more low-speed torque, but given that the spread between all seven aftermarket heads is only a spread of 9 lb-ft of torque, it’s likely that the 180cc Dart would have made substantially more. When we get into the single-digit differences, it’s likely you would be hard-pressed to tell the difference between 340 and 331 lb-ft of torque. Now you have even more ammunition for the decision-making process.

More Info

Dart Machinery; 248/362-1188; DartHeads.com

Edelbrock; 310/781-2222; Edelbrock.com

Jeg’s; 800/345-4545; Jegs.com

Patriot Performance; 888/462-8276; Patriot-Performance.com

Scoggin-Dickey Parts Center; 800/456-0211; SDParts.com

Speedway Motors; 800/979-0122; SpeedwayMotors.com

Summit Racing; 800/230-3030; SummitRacing.com

Failure Warning

File this under “you’ve been warned.” We received these photos from Eric Rosendahl, who recently purchased his ’66 small-block–powered El Camino and has been slowly updating the suspension and drivetrain. In his letter to Car Craft, he stated, “at least it didn’t fail at speed.” Yes, Eric, you are lucky. What happened here is a common problem with ’60s Chevelles in particular: A crack forms at the point at which the steering arm contacts the lower control arm as a steering stop. Multiple strikes at full-lock steering create a small stress crack that travels toward the opening of the lower ball joint. Given that all the load on that corner of the car is carried by the lower control arm, it’s easy to see how this failure could happen. The situation is compounded by the fact that these cars are nearing 50 years old, and those suspension components have been cycled and abused millions of times. We wanted to bring this to our readers’ attention and encourage folks to do a quick visual inspection of their lower control arms to ensure there is no crack that could lead to a failure. What would be far worse is a failure at the top end of the dragstrip at 120 mph. The results would be far more devastating than just a destroyed lower control arm. Of course, other older muscle cars may also be susceptible to these kinds of structural failures, so it would be in your best interest to closely inspect your car. When it comes to early Mustang suspensions with the spring located above the upper control arm, the load is concentrated on the upper control arm rather than the lower, so that would be where you’d want to spend a little more time inspecting.

A small crack can be repaired by drilling a hole at the end of the crack and then repairing the fissure by TIG-welding, but the best solution is to replace those aging lower control arms with either new, repro lower control arms or performance tubular arms. Among the many companies that sell tubular lower control arms for Chevelles are CPP, Global West, Hotchkis. These tubular arms are expensive—starting around $450 per pair—but they are also much stronger than simple stampings. If you’d rather keep your car looking original, there are also stock replacement units for less than $180 per pair from companies like Original Parts Group (OPG) or Year One.

More Info

Classic Performance Products; 800/ 522-5004; ClassicPerform.com

Global West Suspension Components; 909/890-0759; GlobalWest.net

Hotchkis Performance; 562/907-7757; HotchkisPerformance.com

Original Parts Group (OPG); 800/243-8355; OPGI.com

Year One; 800/932-7663; YearOne.com

Trans Choice

Mike Mann; Porter, IN: I’ve been a subscriber and a fan of your articles for the past 20 years. I love the budget ideas like the rear disc-brake conversion and the 10-bolt swap for early Camaros. I’m going to put together a ’79 Trans Am and will use my Chevy 0.060-over 350/TH350 trans combo from my old Vega project. The motor has 10:1 compression, Performer RPM heads and intake, a Comp Extreme XE274H cam, and a Holley 750 double-pumper carb. The trans is a TH350 with a 2,500-rpm ‘no-name’ converter and B&M manual-shift kit. It worked pretty decently together and had a best time of 12.55 at 108 mph in the Vega with minimal tuning. This combo is going into the Trans Am for now with a rather crummy 2.73:1-geared 10 bolt. I will eventually swap in new gears.

I plan on a quality transmission to handle everything I want to do. I want to drag race at times, try out some auto crossing events, and still be able to drive it anywhere and keep up with traffic but without 3,500-rpm cruise speeds. I also have a NOS Cheater plate to play with, too.

In your opinion, which transmission style is a better setup for all-around usage? Your orange Chevelle has the Art Carr trans and the blue ’65 has a manual trans. Which is better? I looked at the Gear Vendors add-on units for my TH350, Art Carr 200-4R, Monster 700R4, TKO 600 conversions, and even the used LT1-style T56. All are very pricey. Which trans would be the most dependable, durable, and cost effective? My kids want to go to college, and unfortunately they come before my hot rod addiction. Thanks, Jeff! Keep up the good work!

Jeff Smith: This is more a question of personal preference, Mike, as both transmissions have advantages and disadvantages. My Chevelles use those specific transmissions because, for me, they are the best solutions for the applications. With my blue ’65 Chevelle, I use a Richmond four-speed because the car is used almost exclusively on track days and autocross events, so I don’t really need an overdrive transmission. I chose the Richmond four-speed because it is the lightest, most affordable, and most durable of the four-speeds available. The difference in weight versus a six-speed is significant since the Richmond weighs around 70 pounds, while a T-56 weighs nearly 140 pounds. Another option is a Tremec TKO 600, and while it might be stronger, it’s heavier. I broke the Richmond last year at the 341 Challenge hill climb after 11 years of road-course, autocross, and open-road racing abuse. I allowed the gear-lube level to drop too low. I had Liberty Gears do a surface treatment on a set of used gears to reduce the gear-lube temperature a little. My orange ’66 Chevelle uses an Art Carr California Performance Transmissions 200-4R automatic overdrive that is great for drag racing, street, and highway use. Art used a tight, 10-inch, non-lockup converter for the car, which works great on the freeway, and the trans has been absolutely bulletproof. Our next abuse plan might be to drop in a big-block in front of the trans, but Art says it will more than durable enough to run low 10s.

Since your application will see both autocross and street driving, an overdrive is a good choice. An automatic on the autocross is not necessarily a detriment, since virtually all autocross events begin with standing start that might be easier to modulate compared with a manual transmission. For a manual, you will need to step up to a trans like the TKO 500 or 600. Yes, they are pricey, but there may be some good used boxes on the market that cost less, but you must tread carefully here; unless you really know transmissions, you might be buying somebody else’s problems. I’m assuming the Trans Am is currently an automatic-trans car. If you go with a manual gearbox, you will have to convert your Firebird over to a manual-pedal and hydraulic-clutch assembly. Once that’s done, you will then have to purchase a new flywheel, clutch, pressure plate, bellhousing, and probably a new driveshaft. Plus, the shifter may not be in the right place, which might require more sheetmetal surgery. We are currently converting my V8 S-10 to a T5 five-speed, because the truck is light enough that the trans will live just fine. It seems you would be money-ahead to go with an automatic, since a good trans and converter will still be less expensive than all the pieces required to do the manual-trans swap, even if the car is already has a manual gearbox. In addition, the automatic will heap less abuse on that stock 10-bolt rear. I happen to prefer the 200-4R automatics because they are very durable. If you decide to go the automatic route, I would recommend the largest trans cooler you can fit in front of the radiator. An autocross is a relatively short-duration event, but it’s still a good idea to keep the transmission temperature under control.

More Info

California Performance Transmission; 800/278-2277; CPTTransmission.com

Gear Vendors; 800/999-9555; GearVendors.com

Monster Transmissions; 800/708-0087; MonsterTrans.com

Tremec; 800/401-9866; Tremec.com

Ask Anything— We’ve Got Solutions!

CarCraft@CarCraft.com

Car Craft Mag

831 S. Douglas St.

El Segundo, CA 90245

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3 comments
cyclone68
cyclone68

Jeff, Regarding John Ondick's oil pressure problem in his '99 Suburban. I had a similar problem with my '89 K2500 with 180,000 miles. I changed to a high volume pump and switched to 10W40 oil and problem persisted. Turns out the pressure sending unit was bad and I now have very high pressure. This isn't so bad unless air temperature drops to -30 and thick oil will break roll pin on distributor drive gear. hope this helps Aaron

Chrishjc12
Chrishjc12

Need Jeff's opinionI got a Howards retro roller 270 5.10 lift Part # CL113215-10for my 383 SBC70 cc edelbrock Vic jr. headsSpeed Pro Flat tops with 2 reliefs (5cc I think together)Should to be around 10.5 to 1 ( the pistons said 9.5 to 1 with a 76 chamber)Did I go to small with cam for the compression.This will be a street/ strip weekend car, so I stayed small to keep vacuum for the power brakes. Should I rum 1.6 to 1 rockers to help bleed off compression.ThanksChris

pgenterprises68
pgenterprises68

to jeff smith about his ask anything article in the february issue- one piece or two. most often you are spot on and have alot of good info, but in this cause you couldnt be farther the truth. a 98 k1500 chevy did not have a tbi motor, it is a 5.7 vortec with PFI. even the block is different, ie- there is a crank sensor in the timing chain cover ( which is different from the 2 piece seal block). this is a mass air flow system- they make great torque and horsepower in stock form. to put a 383 cid in you need to start with a vortec block, the stock injecters are fine as is the distributor and mass air flow sensor. you do need to reflash the ecm for the new bigger cid . you will then a solid engine that makes great power and shouldnt hurt mileage too bad . always wrenchinjerry

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