2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

My secondary injectors aren't coming on

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Old Apr 27, 2003 | 02:29 PM
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Rick James
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Angry My secondary injectors aren't coming on

I have checked them at the ECU. 3H (front injector) & 3F (rear injector)both get 12.2 volts with the key "on".

After I start the car & let it idle, 3F goes up to 12.4 volts but, 3H drops down to 1.3 volts. We took the car out to see what it's doing over 3800 rpm and the LED that is hooked to 3H came on, only for a second, then never came back on. 3F stayed on but never flashed/pulsed.

I put in a diff. ECU and it still does the same thing.

What else could it be?
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Old Apr 27, 2003 | 07:03 PM
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Rick James
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anyone?
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Old Apr 27, 2003 | 08:19 PM
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Rick James
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Could my fuel pump rewire play a part in the ECU not sending power to the secondarys?


HELP!!!!!
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Old Apr 27, 2003 | 08:23 PM
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I have heard that in limp mode the car will not go over 38oo rpms. I don't know though.
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Old Apr 27, 2003 | 08:28 PM
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limp mode? Thanks for the info, but I can redline. It's just that the secondarys are not coming on, i think.
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Old Apr 27, 2003 | 08:28 PM
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That's 3,000rpm usually. Perhaps you have a short in your injector wiring, or you have a bad injector.
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Old Apr 27, 2003 | 08:37 PM
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Rick James
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If I had a bad injector, could that make a diff. on the ecu turning them on?
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Old Apr 27, 2003 | 08:38 PM
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Rick James
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this was started here...........

http://www.teamfc3s.org/forum/showth...threadid=12362
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Old Apr 27, 2003 | 08:44 PM
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there is no way I can drive this car and keep it under 3800 rpm. If I don't get this worked out, my engine will go POP.
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Old Apr 27, 2003 | 08:45 PM
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Well, check all your injector wiring again, then maybe reground the ECU, then check your boost/pressure sensor, then run more grounds to from the frame/chassis to the engine block.
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Old Apr 27, 2003 | 08:55 PM
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I thought this may come up. I don't have a boost sensor. I know, WTF, right? When I got the car it was gone. It was running 18psi w/ no probs. that was years ago. I don't know how it works without it but, it always has.

I have regrounded my ECU months ago.

The injector wires are good & have new injector clips on the end. I out them on when I had them cleaned at RC.

I have a hyper ground on the car. Tons of 4 gauge wire, all going back to the neg. bat post.
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Old Apr 27, 2003 | 09:03 PM
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Could I have not hooked up one of the wires right, where the resistor/relay used to be (by the stock air box) when I did the fuel pump rewire? I would think this wouldn't play a part in the injectors not comimg on. The pump works great though.

I don't know..........just thinking.......
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Old Apr 27, 2003 | 09:12 PM
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That's screwed up. The primary injectors at idle should be around 10-11 volts. The secondary at battery voltage.

IF your primary is showing one something volts, there is a wiring problem or a real, real, real bad primary injector.

I'm tempted to unplug my boost/pressure sensor and see what the primary reads at idle. Maybe tomorrow when there is light and time.

I do know that if the vac line is pulled off the pressure sensor (see this test in the manual), that the secondary injectors will come on line at 3500, even sitting in the driveway. Normaly they won't come on until 3500 PLUS the car being under a load (vac line off simulates load).

There is something amazingly wrong with that car.

Priority list....buy a boost/pressure sensor for the car. Make sure its the one for your model. Not all pressure/boost sensors are the same. They are not the same.

I have no idea what year your car is or ???????
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Old Apr 27, 2003 | 10:22 PM
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I never checked the primarys> Just the secondarys. I don't have any probs. with the primarys.

I would say that the boost sensor was removed to lie to the EUC. I don't have a FCD, never did, but I never, hit fuel cut,even at 20psi of boost.

The car is a 8810th anny. with alots of mods.

The car runs great even at higher rpms. & 10 psi of boost. The reason I asked about the secnodarys in the 1st place is because my a/f gauge falls off @12 psi + boost. I did check the injectors (secondary only) the way you said too and what I found out is, the front injector is not getting power at idle or under a load. It does get power when the key is "on" , that's it.

What would make that happen?

As far as a boost sensor, I don't think I am going to put any more moeny into the stock stuff.

I hope to get a MicroTech. For now, I have to find out why the front injector is getting 1.3 at idle etc.
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Old Apr 27, 2003 | 11:32 PM
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I'll tell you exactly what I think it is..... There is a ceramic resistor that is on the lower front strut tower on the passenger side of your engine bay. It controls your injectors. I've burnt out two of these already, and it most likely is what's causing your problems. Just undo the two 10mm bolts, and uplug it, and pop in a new one. Problem solved. Hope it works out for you.......
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Old Apr 27, 2003 | 11:56 PM
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Rick James
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Thanks bro..........BUT I GOT IT!! You will have to look at the link to see the jpg he put up for me.

I was looking at the jpg back-asswords. I see it now.... I always look at harness diagrams from the the front .(the side that plugs into something/ the side that I test off of.)

That jpg is looking at the harness from the wire side, not the female side.
I didn't see it till now cuz it didn't have any wire colors. But I checked it to the one in the FSM. If you flip it around you will see that 3H becomes........3D. I'm checking the wrong f@#king wire!!!
Well, I know that the inhibitor switch wire is with-in spec.
The volts match

3H is LG/W. The one i taped into for the front injector was B/R .... :-O

It's always something dumb, always!

Last edited by HIMNI Racing; Apr 27, 2003 at 11:59 PM.
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Old Apr 28, 2003 | 12:56 AM
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hmm yea check your secondary injectors wires are bunched up or thats a bad injector or something. i know when my wire had a short in it and i accidently knocked it loose my car would backfire like a **** when it got to 3800. i dont see how your going to redline. put your fuelpump back to stock and try that also
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Old Apr 28, 2003 | 12:59 AM
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Lol, someone's not paying attention Good find though, I tend to screw those up too and end up looking at the wrong wire, always good to go by color AND pin location :-D
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Old Apr 28, 2003 | 07:53 AM
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HAILERS
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*****..........BUT I GOT IT!! **********

Great. I was about to go out and pull the plug on my boost/pressure sensor.

Can you tell us a bit more about this phrase **my a/f gauge falls off @12 psi + boost****??????? Gauge reads real low or real high? Just goofy acting?

Must mean reads high afr. You might check your fuel pump voltage at boost. It should go from about 9volts to battery voltage when you get into boost. Hey, thats gotta be it. The ECU is the one who determines if the resistor is bypassed in the resistor relay package. It takes a ground off a relay in there and bypasses the resistor, giving you the full battery voltage. I'd run a meter to the fuel pump wire (blue) and check the pumps voltage during normal driving and then when you go to boost. Should rise during boost.

IF that happens, I'd get me fuel pressure gauge and rig it to you fuel intake line at the motor and observe the gauge while driving the car. During boost the pressure should rise as the boost rises. On your car you should see about fifty psi on the fuel pressure gauge. Figure depends on the amount of boost. I think (know) that the factory fpr only rises to fifty max. Been there, seen that.

EDIT: Ooops. Did a re-read. Seems you removed the fuel pump resistor relay?????? I'd still look at the fuel pumps voltage at wide open throttle and load.

Last edited by HAILERS; Apr 28, 2003 at 07:57 AM.
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Old May 13, 2003 | 08:16 PM
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what link? what jpg?
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