hanman

I have an 86 13B. The secondary injectors are not working. I am familiar with the grounding issues and plan to upgrade the battery cables and add grounding cables from the engine to chassis. But in the meantime, here is my problem.
With the ignition on, but the car not running, I should have constant power to one wire of the two that connect to the injectors. The other wire receives pulsating jolts of power, I assume this is what signals the injector to shoot fuel into the engine. Currently I only have constant power to one of the secondary injectors, not both. I am assuming this is the reason that my secondaries are not working. What would cause this problem?
Thanks,
hanman

skibum9199

Check the resistor bundle underneath the airbox. It is rectangular, maybe 1x1x2 inches. Just unplug it and hook up an ohm meter. I think they were something like 6 ohms.. could be wrong though. This was my problem when i got my car, one of them was burned out, so i only had one secondary running. Does your car stumble bad after 3500? Does it go ok to redline if you only use half throttle or so? Thats what mine was doing.. Good luck to ya,


~Jesse

hypntyz7

You should not have constant power to injectors.

Injectors work just like a light bulb...apply 12vdc to one terminal and ground to another and it will open. Remove either and it will close. Ground is automatically provided via the wiring harness ground under the intake. The ecu sends the power signals to open each injector, then removes the signal to close it.

It is simple as a toggle switch. To test if each injector works, take it out and apply 12vdc to the terminals, along with ground. You should hear it click(feel it also).

I think if you have constant power to an injector you have a problem in the wiring or the ecu, or your test method. You might also wanna be using an analog voltmeter, because the pulses are too short for a dMM to capture and display, but you can see the needle twitch on an analog.

How do you know your secondaries are not opening anyway?

hanman

Jesse,
Thanks, your post confirms my opinion. From looking at the wiring diagram, the constant power looks like it comes from the resistor. So that was where I was going to look for the problem.
And yes, those are the symptoms that I am experiencing.
Thanks again,
dave

hanman

Kevin,
Thanks for the reply.
Yes I do have power to one side only of ALL of the injectors except one of the secondaries. When I had the primaries loose I watched as the engine was turned over, I had constant power to one wire and intermittent power to the other wire. This makes sense to me. But obviously there is something wrong when only one injector does not have that power. They only have power when the ignition switch is on.
The reason I am fairly sure the secondaries are not working is the complete bog around 3500 rpm, unless you "baby" it beyond that rpm level by not applying very much throttle.
I double checked the primaries by holding them in the fuel rail and turning the engine over and watching the result. Pretty interesting, but not a good time to take up smoking as a habit.
Thanks again,
dave

fastrotaries

Dude get a Hayne's manual, and definitely get a shop manual. The Ohms are there for all this stuff. Good luck.

HAILERS

http://www.iluvmyrx7.com download section 4A. It has the method for checking the resistor solenoid. There should be 12v at the injector plug from this resistor solenoid when the key is on. The ECU pulses a ground circuit to turn the injector on and off. Could be that the harness has a break in it b/t the resistor solenoid and the injector plug. Just ring the wire out b/t the resistor and injector plug. There are wiring schematics in the above url. Its all free. Just download section 4A for a quicker download and look for Resistor Solenoid in section 4A. That was an interesting story by Skibum. Makes sense.

akageals

I had the exact problem on my '87 TII. Chased it for months...swore it was a wiring problem....almost rewired my injectors! Come to find out that one of the secondaries had either gone bad or was clogged (this was immediately after having them rebuilt and tested!). I confirmed this by swapping the primaries and secondaries (the car ran like **** after that all the time not just above 3500 RPM). Put in two used injectors and the car has run perfectly ever since.

Todd

hanman

Todd and Hailers,
Thanks for the reply. It gives me some ideas of things to look for. I own 2 Haynes manuals and a shop manual. I have done the resistance test on the solenoid, after messing it with it for a while it tested ok. Still makes me wonder though, it should have tested out easier. I don't think it can be the injectors because the key symptom is the lack of constant power to the injector from the solenoid. So I agree Hailers, it very well be a wiring problem in the harness, or a problem with the solenoid resistor. What a pain. Thanks for the input.
hanman

skibum9199

If you have a friend with a series 4 na(if not, find one!) and start borrowing stuff from his/her car... Thats what i ended up doing, and i found its a lot cheaper than trial and error buying parts!! I couldnt tell from your posts if you tested the resistor bank yet... if not, i'd do that... i've heard its pretty common. Luck to ya,


~Jesse

HAILERS

Seems you could put your meter on the injector wire that has the intermittent 12v and massage the harness from there to the solenoid resistor, and see when it makes and breaks. You have any splices in that injector plug where its been repaired before ? I had a splice job on my n/a due to a fire that the previous owner had, and it caused intermittent working of my secondary injectors(both were spliced, poorly spliced). I'd never buy a new solenoid resistor. Junk yard for less than ten bucks. Good time to pick up those other stray parts you need.