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Fast EZ EFI-RPM module issues

9K views 10 replies 4 participants last post by  71'bu 
#1 ·
Hey guys, almost done, however not getting any RPM signal on the hand held, even though it's all hooked up per the instructions. I've contacted Fast, but they don't have weekend hours. Maybe I can get some weekend input from you guys. Below is the email I sent them back answering some questions they sent me Friday morning. Anyone else have issues with the RPM module? I know they recommend an ignition box, but it should still work with the RPM module.


"To answer your questions.


Are you getting an rpm signal to the hand-held when you try to crank?

No, I'm not. At first I wasn't sure if I was supposed to while the engine was only cranking. After doing some reading I realized I should be.
Currently the RPM module is connected as follows:
Yellow-plugged into main wire harness
Black-grounded to intake manifold
White-connected to Negative side (yellow wire on this distributor) of the coil.

Voltage going into the module per the White wire is 12.6+V, voltage coming out of the module per the yellow wire and going to the wire harness is ~1.2+V. Should the voltage be that low?

What are you getting for voltage during start?

I didn't look on the hand held what voltage was pulling at. All I know is that the battery was fully charged at 12.6+v. I will check again this evening when I return home. Is there a specific voltage I should look for?


Are you grounding to the battery or to the chassis?


Grounds are as follows:
RPM Module ground-grounded on Intake manifold. I do have a few ground straps that go from the engine block to the chassis.
Wire harness/CPU ground - grounded directly to negative battery terminal.
Thanks
 
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#2 ·
What are you getting for voltage during start?

I didn't look on the hand held what voltage was pulling at. All I know is that the battery was fully charged at 12.6+v. I will check again this evening when I return home. Is there a specific voltage I should look for?
I've never used their RPM module as I have an ignition box. That being said, the voltage is actually pretty important. If you are seeing it drop to 10 volts or less, put the battery on a booster/charger. You should definitely see RPM signal when cranking though. If the ECM is not registering cranking RPM it will never fire. The voltage really can make quite a difference though!!
 
#3 ·
Yeah, I made sure the battery had a full charge. If it started to go low I charged it up. I put some gas down the TB directly, and the engine turned over/fired up right away for a few seconds. So I know I have good spark. However because the ECU isn't getting a tach signal=> doesn't know when to fire injectors I'm guessing. The only part that I'm not sure about is the RPM module. So I'm waiting to hear from their tech support regarding what I should be looking for.
 
#4 ·
So, I finally got it started. I had to send the ECU & RPM module back to FAST for them to diagnose it. Turns out the RPM module was bad out of the box. Finally got it to start, however now a new problem has reared it's head. I've set the RPM idle to 650 rpms, and done the TPS calibration twice, however upon startup it jumps to 3000 rpms and stays there. I thought it might be a vacuum leak, so I checked all those hoses, base plate gasket, etc - good to go. After doing some reading, it seems other people have had bad TPS sensors from them for this kit out of the box. They've either had FAST send them a new one, or replace it with a GM version. I would understand if it was something I setup wrong, or something I didn't wire right, however so far everything points to bad parts out of the box. It's Friday night, so I can't contact FAST until Monday. It's now been a month since I've installed the kit. However, considering the issues I'm seeing before even getting to drive it, I'm seriously considering going back to a carb. Perhaps I should have bought the Edelbrock kit...
 
#5 ·
FWIW I have the FAST XFI EFI for my engine and it works perfectly. I have heard that FAST is not doing the same quality now as it was back when I got my gear back in 2008. Are we looking at Chinese parts here?

I should say that the last time I drove the car my FAST system worked perfectly. It's been a couple of years since the crankshaft in the car failed. The EFI worked perfectly right up to that event. Hopefully it will work perfectly again when I get the new engine running.
 
#6 ·
After finding a couple of threads, it does indeed seem like the TPS that comes with the current kit could be chinese made. That's too bad, I was very excited to get this thing running. People have also listed AC Delco part numbers for GM TPS sensors that seem to work with the system. I may just order one as they're about $40, and would take less time than having to contact FAST again and send a part back to them to be tested. Turn around time for my RPM module was 2 weeks.
 
#7 ·
Hey James, I have the FAST EFI an for me, it was trial and error setting it up. The directions were off sometimes so we had our own troubleshooting to do. It runs perfectly now, but I know the frustrations you are having. So back to your question, hows the seal between the Throttle body and the intake? I know you look for a vacuum leak, but did you try using some brake clean around the area to see if there is a leak? when you do this, the engine tends to increase rpm. For the TPS to go bad in between the old ecu to the new one seems a little off.
 
#8 ·
That's what I did, used some carber clean around the base. The thing is, this is the first time I've had the engine actually start since putting the kit on. I was not able to before because of the bad RPM module. When I was finally sent the new one, along with the original ECU (I wrote down it's serial # before sending in), it finally started, but immediately jumped to 3k rpms with the throttle at idle. I turned the car off, and tried again 3 more times, each time it goes straight to 3k rpm.

So far I've recalibrated the TPS 3 times. Opened/closed the throttle by hand, checking the handheld for reference. At idle fully closed it reads 0, as it should. At WOT it reads 99, as it should per instructions.
 
#9 ·
hows the timing? I had this problem when I put a blower on an 89 gt. As soon as you start it, it would jump to 3000 rpm. hows the MAF sensor?
 
#10 ·
So figured out the problem, turns out it WAS a vacuum leak. The cheap gasket that came with the kit was tearing away underneath the throttlebody, and it was good when I set it on, too. So now it's idling at 1100 rpms, even though it's set for 750 at idle. I'm guessing this is because I haven't driven it yet. However I've run into a new problem, see video...


http://vid190.photobucket.com/albums/z2/Blackstar145/Chevelle/IMG_4223.mp4

Not sure what that whistle/whine noise is, but it's pretty bad. Goes away when I tap the throttle, and seems to come back randomly. Sounds louder on the passenger side. Another vacuum leak, perhaps?





The timing was fine, haven't had to mess with that at all, as is the MAF sensor.
 
#11 ·
Good to hear you figured it out. Mine whines also, but I contribute that to the air being sucked in mixed with the injectors
 
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