That would mean that all my injectors are the wrong impedance, so if that's the case why haven't I had apparent issues with the primaries? I'm not arguing with you, I don't know the answer. How do I find out if I have the resistor pack, and can't I tell if they're high or low impedance by a resistance check on the injectors?

 

Lol -5F Not possible in anywhere on earth as far as I know.. maybe its -5 celcius which is still not even cold

I'm tellin you though go straight to the ECU plugs, just check them with an ohmmeter. Go to pin 1, red on pin...black on ground...get a pad and paper and write everything down.

 

what boost are you hitting a 6500 rpm???

 

I have a similiar situation but I would hit a wall at 3500. I concluded that it's my injectors and fuel filter. I have my injectors out for cleaning with KGParts right now and when they come back and have them installed, I'll let you know if it fixes my problem. (I do plan on replacing the fuel filter too) Hopefully sometime this week.. Might be a little while

 

Um, I'm pretty sure it was well below 0*F a few weeks ago, and again this morning. Fahrenheit is calculated with Celsius as its only variable, any temperature in Celsius can be represented in Fahrenheit. *F = (*C x 1.8) + 32
Just for anecdotal evidence, an excerpt from Minnesota weather records:
Lowest Temperature −60 °F (−51 °C) (Date) February 2, 1996 (Location) Tower

Up to 10psi. I could go higher but I monitor it as best I can and let up if it gets to that point. Usually if I get that high I go ahead and shift around 6250 just to be safe. Nothing is terribly steady because the weather is so erratic and my mbc is your run of the mill mbc; the temperatures (*F) I've experienced the last few weeks have ranged from subzero to 35+. Sometimes I only see 5 psi up there, because as things are right now I'm not going to screw with readjusting the mbc every day, or every time I drive for that matter. And like I said I think the mod I did to my air filter box was detrimental. However, this morning on my way to work I hit 10psi, as it was painfully cold. The car did fine up to around 5.5k or 6k in third gear, I didn't push it farther. I didn't push it at all on the way home, I just wanted to relax.

edit: I've hit ~12psi before for only brief moments, this was when I was figuring out how my mbc wasn't really working right. I drilled a small hole into the turbo side of the mbc and it works more like it should now.

 

I went and reread the thread I started about my injectors. Apparently I have low impedance injectors, so the first thing I will check (which I will attempt tonight) is to see if I have the resistors needed to run the injectors.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/swapping-injectors-87-tii-i-think-702534/

As a side note, what exactly does the initial set jumper do to the ECU? I'd like to know all I can, but specifically does using a jumper reset any stored errors?

 

It would be?

This problem seems to be pretty damn persistent, but then, I think that once you fix it, you will feel very good about yourself, and be shure that your car runs right.

Can you say, OWNED?

 

edit

 

Yeah I must have forgotten a word somewhere in there.

I tested my AFM tonight and the ground to the MAP sensor (I think, same thing as the boost pressure sensor, right?). The AFM passes with flying colors and the connections all looked really, really clean, and I'm not talking 'clean-for-a-21-year-old-car' clean, they looked almost new. The boost sensor connections didn't look bad either and I had more trouble finding a good engine ground than a good connection to the sensor's plug. I don't have a vacuum... tool (not sure what those are called...) so I couldn't test the boost sensor. I was going to add a ground to the boost sensor, but the resistance between the sensor ground and a ground to the engine was next to nothing. I also looked for my resistor pack, and sure enough it IS there. Arg.

And yes, when I finally fix this I'm going to give the '7 a thorough flogging 'til she's red in the tach

...probably more than I should, but I'll have to make up for lost time, eh?

 

I think this is what I'm going to do today after I finish testing the AFM (and if it comes up good), because I accidentally left some of the FSM papers I printed inside so I missed some of the tests.

If I get negative results with those things then I may go over my ground points again...

Any comments on grounding the boost sensor?

 

Also, I think I just found the difference between the MAP sensor and boost sensor. The first is the atmospheric pressure sensor, right? (so what does MAP stand for?) And the pressure sensor is just the boost sensor. Their names are a little confusing...

 

MAP=Manifold absolute pressure

with a bad MAP, the engine will run, but very poorly

 

Ok, so the MAP sensor is what's commonly referred to as the boost sensor.

I'm going out now to run more tests.

edit: wow, my computer and our wireless are doing the weirdest crap and being slow, I'm not sure how that zip code bit got in there...

 

Checked my AFM completely this time, it is within spec as far as I can tell. My garage is freakin' cold and I wasn't 100% sure on the ambient temp out there, so I put my tiny space heater blowing on the sensor while I watched the resistance drop. From the looks of it that was good, too. I came in for food; I'll be going back out to check my frackin' ECU wiring...

 

Your injectors went back out today. FedEx should email the tracking to you.

I would not recommend using them again. We have seen plenty of bad... I would not say they were the worst that have even came in, but they would be rated up there in the top 50 sets... Not sure what happened to these, but three of them were filled with rust. One to the point of it not flowing enough to even register in the condition they were when they arrived.
They were brought back to flow what they should, but still would not recommend extended use.
Sorry for the bad news on your injectors.

 

Why wasn't that conveyed via PM? I guess it does explain why lax-rotor had that problem, nevermind.

 

Hmmm, not exactly what I wanted to hear. I just got tired of the break wall. Let's see if this fixes the problem. I may have some other ... less than prestine ... injectors to send to you shortly.

But I'm not planning on using them for too much longer. I'm hoping to get the turbo setup and installed during the summer. We shall see though.

Sorry about the thread jacking, but I think our two problems may be much more related than previously thought. Have you removed the injectors and inspected the mesh on the top of the injectors? Mine were filled with large deposits of crap... and as already stated filled with rust--I'm still scratching my head on that one.

 

Since your issue was around the secondary staging RPM I suspect your injectors were hardly working at all. It looks like mine are cutting out at 6500 regardless of duty cycle, which I don't think would line up with clogged injectors.

I finally got some more things tested:
-Checked my fuel pump resistor relay, resistance a-b is good (~0 ohms), c-d was within spec at 68 (68-92 ohms), e-f supposed to be .64 ohm and I got a wavering between .3 and .4 ohms. Also keep in mind, I think this FSM is actually for the '89 TII instead of my '87 TII, I need to download the right one, so currently I'm not sure on a couple things with the FPRR: A) what e-f resistance affects and B) if the '89 is the same as the '87 on this detail.
-Measured/recorded resistance at all ECU lines. I haven't seen anything in the FSM utilizing that measurement to test the ECU wiring, but apparently somebody has done this before. Here you go:

 

how does it rev at partial throttle compared to wot?

 

Under load it's very smooth except for the occasion when it stumbles*, which if it does it's usually at about 3500, but sometimes it will stumble once or twice on the way up anywhere between 3500 and 4300. WOT I think I rarely if ever have any such issues.

*The stumbles usually occur very near 0psi of manifold pressure, which I found weird because of the alleged Rtek fix. I think I mentioned though it's better than it was before, but the stumble still exists

Free revving it's pretty smooth comparing partial to WOT, but I can check again if that would help any.

 

I'd think to check the secondary injectors. Look in the mesh on the top of the injector. I just don't see it being electrical when you're having these issues at specific instants of when the duty cycle is altered on the secondaries.

 

The injectors themselves? Remember, I had the 6500RPM wall with the 550cc injectors as secondaries, too. I could see me maybe having two faulty injectors out of four, but that they would act up at exactly the same RPM?

edit: I guess I assumed 6500RPM was not another significant staging point (is it?), as I figured that the only change aside from increasing/decreasing load from some other preexisting load was the secondary staging point where the secondaries begin firing.

 

Does anyone have comments on my ECU line test? I'll try a search to see if that has been posted before.

 

at 6500RPM your injectors are approaching 80% duty cycle (i think--depends on size).

If you've already swapped the injectors though and you're still having the problem, I'm not sure. I know I went through just about everything you did while I was trying to track down my wall. I think this was it for me, but again I'm not sure until I have them installed.

 

Yeah, I installed the 720's months ago with the Rtek 1.7 and sold the fairly new pair of 550's, about which I received no complaints.

Maybe I should also mention, it probably won't help but just in case, I checked each pin for voltage before checking resistance just to make sure nothing had power and I wouldn't blow anything. The only pin with power was the one that's supposed to with the ignition off (3J).