'86 RX7 Rally Car

Fidelity, did the injector driver failure have similar symptoms? I wouldn't want wvumtnbkr to send me an ECU for no reason.

you have a rally car and a rotary now! Spares are good (common) things. but I still think its grounds for you but this is an easy rule out.

What number is your ecu? What do your injectors look like? Do you have the resistor pack under your AFM?

Last question... What is the orientation of your AFM?

In reply to wvumtnbkr:

Injectors- rusty, am I supposed to look for a color here?
Resistor pack- there is a rectangular thing bolted to the chassis under the AFM
AFM- stock orientation? Plug points towards driver's side, stock airbox is intact
ECU- I couldn't read anything so I tried to clean it, and whatever was on it disappeared completely. I think it ended in a 6?

Also I changed the leaky water pump. Scraping the old gasket took more time than everything else combined!

In reply to ¯_(ツ)_/¯:

wire wheel on a drill next time. works like a charm, just use RTV. skip that gasket crap.

¯\_(ツ)_/¯ wrote: In reply to wvumtnbkr: Injectors- rusty, am I supposed to look for a color here? Resistor pack- there is a rectangular thing bolted to the chassis under the AFM AFM- stock orientation? Plug points towards driver's side, stock airbox is intact ECU- I couldn't read anything so I tried to clean it, and whatever was on it disappeared completely. I think it ended in a 6?

Oval or square top injectors?

In reply to wvumtnbkr:

Square.

Those are at least the right style to use the resistor pack. My guess is that they are right.

Next it is either grounds / connections OR ECU.

I am pretty damn sure this is a ground issue.

There are rightups to reground the ECU right near the ECU. I would do that.

Then I would run a ground from the battery to where the injectors ground (Under the Upper intake manifold).

If this doesn't solve your problem, we can look at getting you a different ECU.

http://aaroncake.net/RX-7/grounding.htm

OK, aside from removing some of the emissions junk, are there any major "while you're in there" things I should do when the upper intake manifold is removed? I've already got a big hefty ground cable running to the unibody so I'll tie that into the ground under the intake as well as regrounding the ECU.

In other news, after driving the car to work today we've crossed 500 miles since getting this beast back on the road!

Call me. 724. Eight five eight o675.

I'll talk you through it and provide pics by text.

I'm rob.

After a conversation with Rob, I made new grounds for the ECU (3 total, one for each splice near the connectors) and ran an additional ground wire to the bracket which holds the engine grounds under the intake manifold- although the location under the manifold is inaccessible, the bracket it bolts to has other bolts which are easily reached, so I went to one of those.

On the test drive immediately after adding the grounds, I was unable to reproduce the hesitation issue and the butt dyno says the car runs smoother in the 5k-redline range. I'll tentatively call this a success, but more miles are needed in order to confirm.

I got a color matched tow vehicle! Everybody meet Chief:

lol...that is so you...you gonna leave the lights on it?

In reply to irish44j:

For now at least, but I may build a full length roof basket for it once it gets warmer out.

you know, as you were talking about expeditioning in it - you should do one of those fold-out racks that mounts a tent on the roof...

Aaaand it started doing it again- I got one cut out in 1st, 2nd, and 3rd gear today. WTF? It will be fine for a while and then just come back again. Runs great otherwise.

Hmmm. Do you have a wideband 02 sensor? If so, what's it doing?

Does this happen after aggressive cornering?

No wideband, I should get one. Doesn't seem to be related to cornering, I can't provoke the car into doing it by throwing it side to side, tapping the brakes, hitting bumps, etc. and its' happened in a completely straight line most times. Fuel level doesn't seem to matter either. It does seem to occur more when the car has just recently warmed up.

Loose/breaking connector at a sensor?

Besides "just warmed up" what else can you come up with it being connected to? Has it EVER done it when thouroughly warm and been running for an hour? Start looking at everything the car does when the ecu recognizes "just warmed up." Open/closed loop switchover? Any vacuum actuated valves that open or close at that time? Do rotaries change anything with fueling when crossing that threshold? Fan kick-on causing a voltage drop? Etc.

Good luck. Mine had a bad hesitation/power cut, but only on cornering that was caused by the fuel pump mounted pickup filter. Changing it fixed the issue 100%, but it doesn't sound like that's your issue.

bluej wrote: Loose/breaking connector at a sensor?

This was my first thought as well. I cleaned the MAP sensor connector and zip tied it snug so it can't move.

It didn't do it once in my 45 mile commute today, but if I've learned anything at this point it's that it can go 100+ miles between occurrences.

RedGT said: Besides "just warmed up" what else can you come up with it being connected to? Has it EVER done it when thouroughly warm and been running for an hour? Start looking at everything the car does when the ecu recognizes "just warmed up." Open/closed loop switchover? Any vacuum actuated valves that open or close at that time? Do rotaries change anything with fueling when crossing that threshold? Fan kick-on causing a voltage drop? Etc.

The only other thing I've noticed is my "shift up" light is flaky- it tends to stop working after driving for about 20 minutes. I don't think it has ever hesitated after the light stops working.

I toggled fans and lights while at WOT multiple times and that didn't do anything.

Do you run the stock fuel pump relay? The shift up light doing weird things concerns me a bit. That could be caused by a few things.

Did this car start life as an NA car or a turbo car? If turbo car, the fuel pumps are wired differently. I was wondering if there could be an issue with how that may be wired.

At this point, with it being so intermittent, it is hard to diagnose what is going on.

I am pretty sure it is either fuel or ignition...