Update - Here is where the 7M stands... It still has a random misfire, under heavy load. Ignition timing was taken down to 9 then 8 degrees base timing, AFR still are choppy (10.3 -10.9:1), occasional timing retard during WOT runs.
Checked the knock sensors and both are working. He tried runing the car w/o one then both, but the AFR's were still choppy.
I ran these symptoms by an engine builder, who builds drag racing motors. He asked what the 7M's compression ratio is, I said 9.4:1. He asked what the stock computer was programmed for by Toyota, I said, 8.5:1. He said that 9.4:1 on a stock computer, is a problem. He suggested a custom computer with new timing and fuel maps, will solve the 7M's misfire problems.
I later mentioned that the CPS is old and the plug wires, oil soaked. He suggested I replace the wires and the misfire may go away, to try that first. I ordered new plug wires. He also said to check the CPS again for specs and replace as necessary.
Also check the igniter, even though it is only three years old, and to do the full diagnostic and check that the transistors are still in spec by doing a load test. I have no idea what he's talking about...:1zhelp:
I just checked the TSRM: I think he meant to apply 3V DC to the four pin connector on the igniter and check for momentary continuity.
At VIP Performance, they retorqued the head nuts, replaced the cam cover gaskets and the cam cover grommets and bolts, placed FIPG where Toyota suggests. Ryann reported that there was very little loss of torque on the ARP's studs, a few foot Lbs off on some and a couple on others.
The AFC swap out didn't show any difference w/ misfire or the choppy AFR's, so Ryann replaced the AFC NEO w/ my old NEO dynoed the car, reset the AFC and the AFR's at WOT to 10.5:1.
Also, Ryann replaced the old CPS connector with a newer one from a newer CPS w/a bad bearing, I had lying around at home, and soldered that connector to a CPS that just came off a 7M crate engine from Japan, all for 80 bucks! He installed that newer CPS on the motor before the dyno testing, but all that work had no effect on the misfire.
So, for the meantime, this is where the 7M stands; very usable for DD, but still dodgy during WOT runs.
I'll keep you posted. Van
Checked the knock sensors and both are working. He tried runing the car w/o one then both, but the AFR's were still choppy.
I ran these symptoms by an engine builder, who builds drag racing motors. He asked what the 7M's compression ratio is, I said 9.4:1. He asked what the stock computer was programmed for by Toyota, I said, 8.5:1. He said that 9.4:1 on a stock computer, is a problem. He suggested a custom computer with new timing and fuel maps, will solve the 7M's misfire problems.
I later mentioned that the CPS is old and the plug wires, oil soaked. He suggested I replace the wires and the misfire may go away, to try that first. I ordered new plug wires. He also said to check the CPS again for specs and replace as necessary.
Also check the igniter, even though it is only three years old, and to do the full diagnostic and check that the transistors are still in spec by doing a load test. I have no idea what he's talking about...:1zhelp:
I just checked the TSRM: I think he meant to apply 3V DC to the four pin connector on the igniter and check for momentary continuity.
At VIP Performance, they retorqued the head nuts, replaced the cam cover gaskets and the cam cover grommets and bolts, placed FIPG where Toyota suggests. Ryann reported that there was very little loss of torque on the ARP's studs, a few foot Lbs off on some and a couple on others.
The AFC swap out didn't show any difference w/ misfire or the choppy AFR's, so Ryann replaced the AFC NEO w/ my old NEO dynoed the car, reset the AFC and the AFR's at WOT to 10.5:1.
Also, Ryann replaced the old CPS connector with a newer one from a newer CPS w/a bad bearing, I had lying around at home, and soldered that connector to a CPS that just came off a 7M crate engine from Japan, all for 80 bucks! He installed that newer CPS on the motor before the dyno testing, but all that work had no effect on the misfire.
So, for the meantime, this is where the 7M stands; very usable for DD, but still dodgy during WOT runs.
I'll keep you posted. Van
Last edited:
)