Fuel Pump not trigering

[Olds442FI]

Hello All,

i am very new too the forum and very new to Fuel injection in general. I finally set up my VEMS ECU and my very first problem is that the fuel pump is not triggering. I checked continuity From the relay to the ECU and everything is ok in that respect. If i manually ground out the relay the pump works beautifully. I checked the settings in the extras drop down, fuel pump is set a p259 on channel 5. I get nuthin! since the first power up i got nuthin. No indicators that i may have fried something. I have considered running the pump off of a switch to simplify things but decided i would rather have things work the way they are supposed to. Outside of that i did get the first start out of the car by by passing the pump. Seeing that i am so new to this i figure that there is a strong possibility that i am overlooking something stupid. I have read a few other posts regarding the matter but nothing to helpful in my situation. I do see that the ECU is picking up RPM and TPS. I am hoping to god that this circuit is not fried. I have read in another post that someone has simply used different firmware, and this got it working but i don't even know how to do that at this point. I am a very fast learner but i dont have any fast teachers. I Give Jay from VMS props for helping me out thus far but i try not to be to much of a nusense. The only things not connected are the WBo2 sensor is not welded into the exhaust yet and the MAP is not hooked up.I dont believe either of these would affect the operation of the fuel pump. I am running a very simple system for now. (at least until i learn a little). Any and all help is greatly appreciated.

[rob@vems.co.uk]

The fuel pump will trigger the moment that the RPM signal is picked up.
If the RPM is showing then the P259 circuit should be fine.  Do you have a spare IGBT channel available?
You could try wiring a test light to Ch5 and setting it to i5 (which will force it on when its normally off - and off when its normally on).
It is possible to blow a relay channel without destroying the whole chip - so if you have damaged that channel - and its only rated at 350mA you can find out why (dodgy relay coil drawing too much current?) you can change the output channel.

Rob

[lost]

Dont use p259 use spare ignition channel to switch fuel pump relay. You have eight of them.

[Olds442FI]

Ok. in response to Rob, I do kinda get what your saying but i need a little clarification just to reassure a little confusion i have. This may seem a little silly but i only have one little star next to my ID and its not only because i'm new to the forum but also that i'm new to the whole game . first i am assuming that IGBT is one of the ignition channels? i do need to get used to the acronyms and abbreviations but i promise i am paying attention. If this is the case yes i have several ignition channels open. Secondly, (and mind you, i already know this is probably an uber noob question).... as an example why is pin 15 also referred to as channel 5?  and how does I5 differ. I have a funny feeling the answers are going to really enlighten me. By the way, thank you for the response. I can already see that you are going to be a major credit to my project and i appreciate that alot!

Now in response to Lost (but anyone is welcome to answer). if i were to use a spare ignition (which i have available) how would i go about telling that pin to be a fuel pump pin and work correctly? Also, would i have to make any changes to the wiring of my relay? Is  the ignition channel putting out power, or offering a ground, or can i simply tell it to do which ever i want?

I just want to thank you guys again. Bare with me, im not used to being this lost around my own car as i did build it, but the programming of an ECU is like learning a second language and it didn't come with Rosetta stone. so for now, i nod and smile but soon ill get a few more stars next to my name. It would seem there aren't many Chevy heads around here so i am going to have to start representing soon

[rob@vems.co.uk]

No problem on the level of questions here, what you're asking is not immediately obvious when you start with these systems.  The pins are grouped in a way that does not immediately make sense to anyone except those who understand the circuitry behind them (and I'm not expecting you to read the schematics), so:
There are a bunch of devices behind the pin groups - the P259 is there for driving low current devices, the INJFETs for driving Injectors and Solenoids, and the I259 for driving IGBTs which are super hardcore transistors that can drive ignition coils directly.  There are a few other drivers for stepper motors and the wideband - but we wont worry about them just yet.

When you go to the Fuel Pump settings there a dropdown box for the device type (although its not called that), which will offer the P259, INJFET, I259, S259 etc.
After that you have a channel number. With the P259 its simple - the number correlates to the channel as shown on the pin out: P259 ch5 is pin 15, ch6 is pin 31.
If you select the I259 channel you will get a list of channel options, select 06 as it maps to Pin 24, and thats on the end of the connector - and easy to access the pin.

When you see the channel number i5 the i means inverted, so when the channel is normally off its on, and visaversa.  A good way to test the fuel pump relay would be to invert the channel as this will turn the channel on when the engine is not running - and that will prove your wiring/configuration is correct.

Before doing any of that though - check the resistance of the relay coil - its not unknown for them to short - lowering the resistance and causing the current to go skyhigh and kill a p259 channel, so you might be able to replace the relay, and change the channel in the setup, and repin the connection to get the fuel pump running.

[Olds442FI]

Excellent explanation. That does give me a much better understanding of what is going on here. So at this point i have checked the draw from my relay and it is at about 150ma. The relay is brand new FI relay kit from summit so i really didnt think it would draw any ridiculous amount of power due to some kind of fault. after that i did try changing to channel 7, but rather than just trying to hook it up, i played it safe and  used my multi meter to see whats happening. after changing the channel i had a buddy turn the key on and off to see of that channel was cycling anything. I did an ohm test, continuity test and even a voltage test. Then I tried switching to channel I7 and still got nothing. I did see a slight amount of voltage but i thing that may have been reading from me holding the wires to the probes. Now i am trying to put on my logical hat! Ultimately, what tells the fuel pump that the key is turned on and that the engine is running? we know that i read RMP at crank over,  but is that the signal that tells the pump to go? According to the wiring schematic, a hall trigger should be connected to the 5v hall trigger pin. this isn't the case for me. I have a somewhat unique Mallory distributor specifically for a Pro-Flo System and that uses a 12v power source and reduces power at the distributor itself. This causes me to tap the distributor power from the same power as the ECU. Now, because i don't want power to the distributor when the the key is off i have to hook the distributor/ECU power to a switched ignition source which obviously shuts everything down when the key is off. Finally, and i dont think it will effect to much but i thought it may be worth mention. The 5v TPS power is not coming from the normal TPS PIN but rather the 5v Pin next to it that would normally power the Hall. Is there anything in this sequence of events that could cause the ECU to not know the ignition switch is on and tell the car is actually trying to start?

I don't know, it sounds logical right? I just looking at what might be different then the normal set up.

[rob@vems.co.uk]

You're best to use a test light with a +12v feed and ground it through the P259 channel

[Olds442FI]

Ok, i used a test light. First i went to channel 5 set on p259, with one oend of the test light connected to power, i touched the other side to channel 5. when nothing happend i turned off the key and turned it back on while thest light was still connected. Got nothing. I repeated the same steps after switching it to channel I5 and still nothing. Then i switched to channel 7 and used that lead on the harness and followed the same steps i did with channel 5. Still no light .. Whats my next step?

[Olds442FI]

I just dont know. I am at a complete loss here.. I get nothing on a test light and it seemes it just never worked or even tried to work. Is it possible that it could be something wiith the firmware or maybe i missed something when downloading megatune? I am still getting an rpm reading while cranking and the relay is working and wired correctly. I tried 2 different channels and even tested them before trying. Maybe the ECU needs constant power like its supposed to have and not turn on with the ignition?

[Olds442FI]

i am actaully not complaining here. Dont want to sound like a whiner Just putting all the possibilities i can thiink of. I am not used to having the car off the road and im goiing through some serious speed withdrawals. somebody mentioned hooking the fuel pump up through an ignition channel. is this a possibility? how would i go about that option?

[rob@vems.co.uk]

What's happening seems very strange, both P259 channels not working suggest that the chip might be blown - but you have an RPM reading, which does not happen.
Are your pump prime and pump off after timings sensible?  I guess that doesnt matter as you inverted the output.
To use an ignition channel you need to select I259 and which ever channel is most suitable.

Failing that put the pump on a switch temporarily, and make sure that the switch is powered from the key so that it cant run when the keys are out.

[Olds442FI]

yes, i have a knack for having problems that know one can explain or simply rarely happen.. i have been racking my brains out on this because i was told by both you and jay that if the rpm is being read then the chip is ok. I went over my wiring dozens of times and tested the pins dozens of time. It just seemed so strange to me that i figured there might be some kind of setting that doesnt allow the fuel pump to kick on. well, ill try the i259 setting now and see how that works tonight. I would prefer not to use a switch A. for safety reason and B. because i simply want it to do what its supposed to do. I have no future plans on running several coils so if that work then that is the way it will be. I am hoping this will all work ok, i would love to have a Hot Rod with remote start

[gunni]

Have you tested connecting the wire that goes from the ecu to the relay to ground?
i.e knowing then that the circuit is working.

Maybe you can try some other function outputs to see if they can make that output channel work.

[Olds442FI]

Well, so far i had it just hooked up and when the pump failed to go on or even do a prime pulse i disconnected it from the ECU and grounded the relay end to see if i could force the pump on and that works just fine. I have pretty much done all of the tests on both channel 5 and 7 while set on p259 and i simply get no response at all. Now i tried switching to I259. Well, this messed with my head a little because i was expecting the choices of channels to change from 1 through 7 to something else like 00,10,20,30 ect. i was still left with the 1 thru 7 choices. Only now did i realize (looking at the configuration tool) that I259 set to 5 would be ec36 pin 12?! So now that i am home i have to wait until tomorrow to try that out. I cant help but get this sinking feeling that i may be in a little over my head with this. I haven't even begun to tune and i am already up a creek without a paddle. at least i got the darn thing to kick over and catch ignition and fuel. that's a sign of hope right? . anyway, i was hoping to actually drive this thing by the end of the week but the way things are looking i am going to have to take a college coarse on how to tune my car LOL!

[rob@vems.co.uk]

You might be in over your head - but thats no reason to stop swimming!  Fitting any ECU to a car is a non-trivial task, and VEMS (because of the huge range of setting options) is tricky to master.  I often complained that we should have one pin specifically for a fuel pump, one for a fan etc but it was pointed out that if someone wires something wrong they could take out a channel and the ECU would become effectively broken through one simple error.

Working out what channel does what, is again a Nightmare - the I259 chip deals soley with the IGBT channels, but when it comes down to ignition, theres the option to use the Stepper Motor driver chip (S259), in order to make that easier to configure the 00, 10, 20, 30 settings came in...

I agree totally that the relay drive needs to be done correctly, I was suggesting the switch as a temporary fix in order to get you to the tuning stage.

While you're trying to figure things out, you could relax and pass the time by taking some photos and getting them posted up here - always keen to see some V8 pictures.