Injector bank dumping fuel when key is in the on position

dat240zt · Post by **dat240zt** » Sun Jul 09, 2006 10:16 pm

I had my car running not perfect but it ran, (lean) so Friday I found a map that looked good and plugged it in . took the car out and it ran really good for about 2.5 mile and than it died. I tried to get it started but couldn't so I had the car towed home. The rest of the day Friday and the weakened I tried to get the car started. (Adjusted and recalibtared the TPS ) I pulled the plugs and as I suspected they were fouled . I noticed that 1,2,3 were not as bad as 4,5, and 6 as they socked. I decided to turn the car over to see if any gas would squirt out of the holes and sure enough 4,5,6 shout fuel out all over the car and walls. I then drained the oil but it was mostly gas that came out. Replaced the oil installed new plugs and the car started but ran for a few second and died again. So I pulled out the railed with the injectors still attached and turn the switch to on and as I suspected 4,5,6 dumped a lot of fuel, then I removed the connector from injector #4 and #3. I installed the connector for #4 to #3 injector and turn the switch to on and #3 dumped a lot of fuel as well as 5 and 6. This leads me to be live that something is wrong with the bank that runs 4,5,and 6. Would you guys have any idea, were I should start. Could something not be set up right?
Thanks

Post by **jsmcortina** » Mon Jul 10, 2006 2:24 am

Sounds like a FET or flyback failure.

Like it says in red above when you post:
Please note in your post if you are using MS-II/MS-I/MSnS-E, the code version, MegaTune version, as well as V1.01, V2.2 or V3 main board, etc.

What board, are these low-z injectors. What are your pwm settings?

James

dat240zt · Post by **dat240zt** » Mon Jul 10, 2006 3:30 am

I'm not sure what board I have as I bought my ECU build from DYIAUTOTUNE, I did have them set it for spark control. I have 370 cc low impedance injector, my PMW setting is 30. I'm running the 029s code MS-N-SPARK- EXTRA on megatune. So if it's my FET or flyback, do I have to buy a new ECU?
tHANKS

dat240zt · Post by **dat240zt** » Mon Jul 10, 2006 4:44 am

A little update I checked the voltage at the injectors and found that I have 12 v on 1-3, both side of the injectors and 4-6 have 12 v on one side and 3 v on the other side, and injectors 4,5,6 are very hot. I checked the relays in the relay board and fount the far left relay (as you are looking at the relay board) is hot as well. Could this mean a bad ground?

keithmac · Post by **keithmac** » Mon Jul 10, 2006 6:07 am

You should have 12v on both sides of the injector when the ignition is on but engine not running, it sounds like you have a leakage to ground on the 4,5,6 bank injector trigger wire. The injecors will be hot because they`re stuck open all the time, the coils inside acting like mini electric fires!

Do as James said, or send the board back for testing/ repair if you`re unsure. I run 440`s (high impedance), they work fine. I went the highZ route because there`s less to fail and leas loading on the electronics.

You can fit a set of balast resistor and convert yours to highZ, if you have re-occuring driver/flyback failures.

FoundSoul · Post by **FoundSoul** » Mon Jul 10, 2006 9:49 am

Carl -- that's a PCBv3 ECU right? It's pretty unusual to have a flyback failure with that board but that's what this sounds like. We can take a look at it for you if you'd like and see what's been cooked. The real question is 'why'. I'd go over all wiring on that bank closely, all the way back to the ECU and see if you can find any shorts to ground anywhere. You can start with a multimeter to ground (with the car off) to see if there is resistance. Here's another thought, with the ECU disconnected and the fuel pump jumpered on, if you turn the key to the ON position does fuel flow from the injectors? That would indicate a short in the wiring, and would be a good first test before you move any wiring around and possible 'fix' the short, until it moves back ;).

Just shoot me an email if you'd like us to take a look at the ECU.

dat240zt · Post by **dat240zt** » Mon Jul 10, 2006 12:35 pm

Jerry I disconnected the ECU and relay board. I then removed the fuel pump wire from the relay board and jumper the pump by running the wire I removed from the relay board to the positive side of the batt. and the pump ran but no fuel came out of the injectors.

dat240zt · Post by **dat240zt** » Mon Jul 10, 2006 8:19 pm

Can I run all six of the injectors off just one bank

FoundSoul · Post by **FoundSoul** » Tue Jul 11, 2006 4:12 am

The fuel pump wire your removed from the relay board would need to be grounded to turn on the fuel pump relay-- the ECU provides a ground not 12v+.

I'd sort the root of your problem out rather than trying to runn all 6 low-z injectors on one bank.

Did you try using a multimeter (continuity checker--ohms) between your wiring and ground to see if there is a short? There should be no continuity with the engine off.

dat240zt · Post by **dat240zt** » Tue Jul 11, 2006 2:31 pm

Thanks Jerry but I have decided to pull the plug on megasquirt. This system have been a nightmare since day one. I have been working on this set up since April and have spend $1000.00 and have not gotten anywhere, just one problem after anther. I just discover that megasquirt is not firing the coil on every rotation of the engine, which is why the car will not start or run more than 3 sec. when it does start.Still can't get bank one to work.

FoundSoul · Post by **FoundSoul** » Wed Jul 12, 2006 4:28 am

I'm sorry to hear that man-- I really think you can work through these issues if you stick at it, generally the coil not firing all of the time isn't a problem with the MegaSquirt but with the configuration of the ECU affecting the timing of the engine, or another timing related issue. We'll still be glad to check out the ECU to see what's going on with it, and the possible configuration issue can of course be worked through as well I'm sure....

FoundSoul · Post by **FoundSoul** » Mon Jul 17, 2006 1:13 pm

Carl-- I just got finished going through your ECU and I found a couple of things. First, the board had obviously gotten VERY hot as all of the glue had melted from all of the nuts on the heatsink bar. I was able to determine that was from Q16 overheating when the SPARK INVERTED setting had be set to NO as you mentioned you might have done.

I also did find your injector circuit failure, and I replaced Q2, Q11, Q15, U4 and D18 which repaired that issue. I highly suggest going over your wiring very thoroughly to make sure there is no short anywhere. The only other scenario I can think of that could have caused this is the overheating due to Q16 (above) as that warmed up everything on that heatsink bar far beyond where they would normally be. I can see how Q5 or Q11 could have decided it didn't like that.

Lastly- the firmware appeared to have been corrupt. I reflashed it with MSnS-E 029q2 which is the latest stable release.

You should be good to go now. I'll shoot you an email as well.