shortyboy

​​​​​I burnt up the ignition transistors, which from what I read is a common occurrence. I'm not sure if other components was damaged in the process. Basically, the issue I'm having and at least two other people, is.. We would need to start the car a few times to get a "good running "start condition. When it doesn't start good, it idles poorly, lean afr and sputters. So far, I've replaced fuel filters, bosch 044 fuel pump, injectors adjustable fpr, reference sensors, ignition coil pack ( wasted spark ) , starter, battery, tps ( aftermarket Ford tps ), clean up all grounds. I just ordered a new ignition switch is hopes to solve issue. My thinking is that the contact in the switch is ether poor or dirty, and the few times it takes to turn the car off and on, cleans the contacts thus making a good start/connection to starter. You can clearly know when I have a good start because when cranking over, if it goes past 1300-1400 rpm it's a good start, if it's anything below it will idle or run poorly. ive uploaded some videos on YouTube. Any help or ideas would be greatly appreciated. Will try and inspect all solder components. I hope Peep can chime in regarding the components and layers of board. Looks like a dual layer board. I replaced the traced with a jumper wire ( red)

Raceboy

It is not a common occurrance to burn out FETs!!! When something like that happens it means that there has been constant GND signal to the coil while ignition is on, usually happens when people update firmware without disconnecting coil and injectors (even though manual strictly says to do that).

shortyboy

Hi Peep,

Any insight on my issues after what ive tested and replaced so far?

blade7

Peep, if all is well with your installed map and autotune, is there reason to update the firmware?

shortyboy

Hopefully I stumbled across some progress in solving this issue. Began to wonder if it's a voltage drop issue at ecu or reference sensors. I have a few accessory electronics that tie into the same +positive and - negative lines of the vems ecu. I began to unplug them and the frequency of good starts got to 2 starts instead of 4-5. To further test this theory, I had fans running on high and could not get a good start condition. No matter how many starts it's was rough and lean. I've cleaned the grounds at bell housing and chassis. I have new cable lines I got from lart that were sharky cables with the quest alternator and hi torque starter. If this voltage drop is the issue, I'm hoping the new ignition switch will cure it. Any other ideas? I might have a voltage drop somewhere else also, maybe seats? Gonna unplug radio and amp. Also, for my reference sensors, I have a new Lindsey Racing harness.

Raceboy

There is no reason. Two of the cases where transistors were blown were caused by updating firmware in attempt to dagnose completely unrelated issues and the updating was performed without consulting with me. That's why it is important to listen to the suggestions and do things written in the instructions not by guesswork.

Raceboy

Fans running at high can cause interference, has happened sometimes (but never with sensors in factory locations, only when using front crank trigger and that is also rare).

Raceboy

If you look at the other side of the board then you see that the FET leg of the WBO2 heater is soldered. They are soldered from the bottom.

Droops83

Have you actually tested for voltage drops using a volt meter?

shortyboy

Will be testing with a multi meter once the weather permits. Thanks. I also have the updated reference sensor bracket with sleeve coming in also.

shortyboy

Had some time to work on the car. Went to install updated bracket with sleeve and found out that I already had one installed. Went ahead and regapped speed sensor using tape method and made it closer to 0.7 gap. After testing, still same issue. After my fiasco with ignition switch swap out. I found a replacement ignition switch pigtail to the fuse box, soldered it in place. Installed new ignition switch. Still same issue. Voltage drop theory out the door as I have constant 12v+ when cracking at ecu. No clue what to test next. Probably pick up a new set of high impedance injectors. Maybe gap the sensor even closer. Does anyone know at what gap does the reference sensor come in contact with eh pin?

Droops83

I just re-read this and noticed that you had tapped into power AND ground of the VEMS. The ECU needs its own dedicated ground circuits (with separate branches for sensor circuits and noisy devices like fuel injectors), with nothing else tapped into them. This could be your issue, especially if you are tapped into the sensor ground circuit.

shortyboy

Yup, in the process of removing the Hks ebc that was tied into it. That's basically the only thing tied in, that and a use charger, will move that also. Does anyone have instructions to wire in a boost solenoid? Emailed Peep a few times and no response.

Regarding the speed reference sensors. Curious if anyone you who are having same issues as I am is using the Lindsey Racing Reference Sensor Harness? I noticed the factory has two ground points, one pin of its own and a ground that shares on the oxygen sensor. I'm wondering if adding a supplement wire to the sensor grounds would help.

BTW, I wanna thank everyone in the thread that's been helping me to solve this issue. Much Mahalos 🤙🏽 - Wayne

Raceboy

You wire boost solenoid in place of factory cycling valve, easy.

There are many guys using Lindsay sensor harness, no issues with it. But I would suggest measure connections of the sensor harness just in case, it is possible to reverse the polarity when making the swap. Adding additionl ground wire does nothing good, you should verify that you have ground wires on the bellhousing all in good working order and tightened.

shortyboy

Hi Peep,

Thanks for the reply. Rechecked all grounds with my DMM, from sensor connectors, and bell housing ground, to front chassis grounds to battery grounds to dme grounds, all are 0.2 ohms. Next step will be setting gap closer at reference sensor, that way speed sensor will be as close as possible. Since I'm also tracking a fuel pressure loss issue that's intermittent, the final piece is new siemens deka high impedance injectors. I'll be sure to change pwm settings accordingly. I'll also try to find some type of EMI shielding for starter and sensor cabling.

Regarding boost solenoid, what do input in vems configuration? Thanks again sorry for all the trouble trying to fix this, hoping to fix my issue and others in the future.