I have a modded S4 13BT running on an old Electromotive TEC-I, I've been driving this set-up for about 2 years and it's been almost scary reliable until now...

A problem started to develop where the car would crank but not start; sometimes it would fire up on the 1st try, sometimes it took 10 tries. I figured there must be a bad connection somewhere. The next day, I was driving along and the ignition began to cut-out, then the car completely died. Pulled over to the side of the road and tried cranking it, about 5 minutes into this it started up. Got back on the road and a few minutes later, the ignition starts cutting out again, and it dies. Back to the shoulder. I could hear a clicking, when the key was turned to "ON" which I later found to be the fuel pump relay. I crank the car, nothing, I hopelessy check connections, crank it again, nothing, etc. Eventually it starts immediately and runs fine, so off I go again. Not even a mile later, car dies and won't start again. I try fooling around with various wiring again and nothing seems to help, eventually the battery starts to die from all the cranking and I throw in the towel and give AAA a call. The car was towed to a shop, they replaced the fuel pump relay and the car seemed to be fine. I picked it up and drove it to a gas station, low and behold when I tried start it again, all I got was cranking, I could hear the relay clicking back and forth sporadically and the (noisy Bosch external) fuel pump turning on and off. I fiddled around with the wiring hoping to find something, but to no avail. After about 15-20 minutes of this I cranked the car just for the hell of it and it fired right up and idled. It ran for about 3-4 minutes then died. Every 5 minutes or so I'd try to start it, and eventually I cranked it and it fired up instantly. I decided to risk it and try to drive the car home, and it made the 30 minute drive home with no incident. I put another relay in and drove the car around, seemed to be fined until about 45 minutes into the drive, the ignition cut out and the car dies. Clicking relay, crank but no fire, same crap.

Since then I've replaced the front fuel filter and installed a fuel pressure gauge just to make sure the lines weren't clogged. Clicked the key on and it was getting around 41-42psi, started the car and it was at 31-33psi idling, so fuel seems fine. Drove the car around the block, I tried accelerating once and the ignition cut-out hard for a second, loud backfire, but continued to run fine. Parked the car, and it just kind of died by itself, and I could hear that damn relay clicking again. Wouldn't start up again. I haven't really driven the car all summer because I know its going to leave me stranded somewhere.

>>>Cliff notes: Ignition randomly cutting out after car is warm, fuel pump relay clicking sporadically and crank/no start. Replaced relay three times, fresh plugs, new fuel filter, fuel pressure normal.

Most of the wiring was done by the previous owner so I'm kind of learning as I go. The signal for the fuel pump relay is wired directly into the Electromotive, so I'm thinking something internal is preventing it from sending a constant signal to the relay, it keeps opening and closing the circuit like the signal is fluctuating. Either that or perhaps the fuel pump is going out, and thus overheating or drawing too much power. The problem seems to be heat related, as the relay does not click, and it starts immediately if the car has been sitting overnight. The Electromotive is mounted in the engine bay between the battery and the strut tower, so although its not near the exhaust, it's still exposed to quite a bit of heat and moisture.

I still have a few things I want to try, but if any of you guys could offer some insight, it would be greatly appreciated.

 

Also, I forgot to mention that I replaced the entire key cylinder and ignition switch. Before that I could take they key out of the ignition and the car would stay running, and while cranking I would have to turn the key backwards slightly to get the engine to fire. I thought for sure this was the problem, but apparently not. Anything else I could try?

 

I question why you are asking us in this section?

This is more of an Electromotive matter, so I'd suggest taking it to an Electromotive shop or the shop that did the original install and tune?

I'd suggest checking the mag pick-up's for the trigger wheel.
those things are notorious for picking up debris and screwing with the ignition trigger.


-Ted

 

There is a possibility you have a problem with the wire from the pickup being broken internally. The easy check is to start the car, then wiggle the wire from the pickup. If it cuts out or misses, you need to replace the pickup.

 

Thanks Ted, my last resort is to send the computer to Electromotive for diagnostics, but I want to make sure its not being caused by something else before I do so. In my experience the most annoying problems are caused by little things that get overlooked.

I'll make sure to check the pick-up, the spot that its located definitely would make it prone to getting gunked up.