Hey guys, I've been an SDS customer for about 5 or 6 years and have installed 4 of their systems, all of them being EM-3 systems with distributors. I've been very satisfied with the performance and reliability of this product. I have only experienced one component failure and it was the fuel pump priming circuit on my personal truck. I recently purchased an EM-4 F system for an 86 Buick T-Type 3.8 liter V6. We started out with a set of 60lb/hr injectors (high imp) and the car ran great. It would scream all the way to the 5500 red line. This is a customer's car and it is equipped with a 72mm turbo, capable of making 800hp. We had it tuned up on race gas; the customer filled the tank with pump gas against my advice and blew a head gasket. He brought the car back to me; I pulled the engine, cleaned everything up, and reassembled the engine with a set of cometic head gaskets. He told me he would like to max out his combination. So we ordered a set of siemens 83lb/hr injectors (low imp) and put a resistor pack in the harness. Now here is where the trouble starts. The car set for about 6 weeks while the engine was down. We get it back together; took it for a spin and at about 4700 rpm's the car noses over and begins to miss, almost like the plug gap is too wide. The car is not as fast as the previous set up with the 60lb/hr inj. I have reinstalled the 60's and removed the resistor pack, checked the hall sensor alignment and have been over this thing with a fine tooth comb several times. I am at my wits end! I can free rev the car in the shop and when the tach reaches the 4700 mark, the motor picks up a stumble and the needle on the tach becomes erratic and falls rapidly. The rmp's on the programmer are unaffected by this symptom. I have disconnected the autometer tach thinking it was a problem and the symptoms still persist. I have been through the programming a hundred times and all the programming values are consistent in linier. If ANYONE has ANY suggestions, I would appreciate any advice. Thanks for reading this long post. Chris B.
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I know you said it feels like a missfire, but can it be a fuel starvation stumble? What fuel pump, filter and regulator are you using?
Try shooting the timing with a gun and trouble shooting what happens to the timing as it reaches the 4500 RPM mark. Ohm out the plug wires, use new spark plugs.
Are you using a distributor? Or the F coil packs?
How well are the ground wires grounded?
Is your switch +12V to the inj, and coil driver(if using) geting the correct voltage?
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if its a hall sensor issue it should read error in the rpm gauge of the display when the engine miss.i will try a new set of msd red 8.5 wires and spark plugs.recheck the grounds.
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hi i have the same probleme,i have a dodge omni glh 2.4l from a pt turbo,6.5 diesel turbo,big intercoold,walbro 255 fuel pump,stock presure regulator from a 2.2l t1,accel 8.8 300+ race wires,new ngk plug smaler gap,and the em4 coil pack sds.im not sure if my misse fire is do to rpm or boost,i double check evryting i think,but when i change the magnet position to lower (80 normaly 60 lower)i dont get any misse fire but it pings a lot.
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