MrVito
03-24-2008, 10:39 AM
Ok, so my intentions for this thread is partially to put my thoughts down about this motor that is driving me nuts, and to hopefully get a bit of insight to my situation.
Background:
I bought my 89 TII in January, it had 231,000 miles on the original motor, a blown turbo, vacuum leaks all over the place, 4 blown shocks, blown coolant seals, hunting for idle, and a host of other small issues. My solution for this was to pick up a JDM TII motorset form a local reputable importer (JHot). This solved my tranny, turbo, and seal problems. I'm currently running the USDM ECU (370), and the car runs fairly well. With a few small issues still. It sometimes hunts for idle, no matter how often I readjust the TPS. It will sometimes idle ok, and other, seemingly random times, it will hunt for a bit before settling down. BAC, ACV, split air pipe, and air pump were all eliminated, and the JDM motor had no AWS on it. Rats nest has been removed and all extraneous vacuum nipples have been properly blocked and show no signs of leaks.
Right now the biggest issues are the hunting for idle, the idle sometimes raises about 500 rpm when the clutch pedal is pressed, and the car has trouble recovering after I let off the throttle. Like I mentioned before the hunting for idle tends to cure itself, but the recovery issue is what is really bothering me. The car is acting like it has an atmospheric blow off, it gets overly rich when I let off the throttle in neutral and tries to die. Since all vacuum and boost checks have shown no leaks, the timing has been properly set, all connections are solid, and the TPS is adjusted and in spec, the only thing I can see is a mechanical problem with the lower primary and secondary butterflies. I think I'm going to see if there is some way I can mechanically open them a bit more at idle and adjust the main primary butterfly down a bit to maintain idle at or below 1000 rpm. This is my thought for a temporary fix while I finish the work on my spare TB to eliminate the secondaries.
Now to eliminate any thoughts about the BAC removal, it was removed primarily because all of the wiring on that "leg" or the USDM harness was cracked and brittle, and for the most part was breaking off with the slightest pressure applied. I had to make a new line for the O2 sensor, since that seemed to be the only important one on that part of the harness. I'd rather have kept the BAC, and still may put it back on, but even when I did have it hooked up, I was still getting a BAC error code on the ECU.
So I guess what I'm getting at is, am looking at this from the wrong perspective? Is there something else terribly obvious that I'm missing? Am I just a hopeless n00b that needs a serious pwning?
One more thought, the other day I tried the JDM ECU (374), when I hooked it up, I had to raise the idle and readjust the TPS jsut to get it to run, and the timing was 20-25 degrees off. Easy enough to fix, but the idle with that ECU was still very rough, and it had a neutral rev limit of 4800 rpm. I didn't try driving it like that, it was mostly just curiosity as most people had told me the JDM ECU wouldn't even work. I didn't believe them and insisted on being a stubborn idiot and checking for myself. The JDM motor is a 1990 vs my 1989. Does anyone else with a 90 or newer TII know if the car does a 4800 neutral rev limit, or is that a known symptom of a limp mode? The US ECU has never given me a neutral rev limit, not that I make a habit of revving in neutral, was mostly just curious.
/end rant
Background:
I bought my 89 TII in January, it had 231,000 miles on the original motor, a blown turbo, vacuum leaks all over the place, 4 blown shocks, blown coolant seals, hunting for idle, and a host of other small issues. My solution for this was to pick up a JDM TII motorset form a local reputable importer (JHot). This solved my tranny, turbo, and seal problems. I'm currently running the USDM ECU (370), and the car runs fairly well. With a few small issues still. It sometimes hunts for idle, no matter how often I readjust the TPS. It will sometimes idle ok, and other, seemingly random times, it will hunt for a bit before settling down. BAC, ACV, split air pipe, and air pump were all eliminated, and the JDM motor had no AWS on it. Rats nest has been removed and all extraneous vacuum nipples have been properly blocked and show no signs of leaks.
Right now the biggest issues are the hunting for idle, the idle sometimes raises about 500 rpm when the clutch pedal is pressed, and the car has trouble recovering after I let off the throttle. Like I mentioned before the hunting for idle tends to cure itself, but the recovery issue is what is really bothering me. The car is acting like it has an atmospheric blow off, it gets overly rich when I let off the throttle in neutral and tries to die. Since all vacuum and boost checks have shown no leaks, the timing has been properly set, all connections are solid, and the TPS is adjusted and in spec, the only thing I can see is a mechanical problem with the lower primary and secondary butterflies. I think I'm going to see if there is some way I can mechanically open them a bit more at idle and adjust the main primary butterfly down a bit to maintain idle at or below 1000 rpm. This is my thought for a temporary fix while I finish the work on my spare TB to eliminate the secondaries.
Now to eliminate any thoughts about the BAC removal, it was removed primarily because all of the wiring on that "leg" or the USDM harness was cracked and brittle, and for the most part was breaking off with the slightest pressure applied. I had to make a new line for the O2 sensor, since that seemed to be the only important one on that part of the harness. I'd rather have kept the BAC, and still may put it back on, but even when I did have it hooked up, I was still getting a BAC error code on the ECU.
So I guess what I'm getting at is, am looking at this from the wrong perspective? Is there something else terribly obvious that I'm missing? Am I just a hopeless n00b that needs a serious pwning?
One more thought, the other day I tried the JDM ECU (374), when I hooked it up, I had to raise the idle and readjust the TPS jsut to get it to run, and the timing was 20-25 degrees off. Easy enough to fix, but the idle with that ECU was still very rough, and it had a neutral rev limit of 4800 rpm. I didn't try driving it like that, it was mostly just curiosity as most people had told me the JDM ECU wouldn't even work. I didn't believe them and insisted on being a stubborn idiot and checking for myself. The JDM motor is a 1990 vs my 1989. Does anyone else with a 90 or newer TII know if the car does a 4800 neutral rev limit, or is that a known symptom of a limp mode? The US ECU has never given me a neutral rev limit, not that I make a habit of revving in neutral, was mostly just curious.
/end rant