90 spirit won't run

Yup,

Open circuit on the ground leg of the TPS.

I'll check for this tomorrow. Thanks for the tip. I just found some more things to check tomorrow if this doesn't work. Thanks, Wes

If you are still getting the fault for the TPS sensor, or the vehicle speed sensor, that could be the problem, check all grounds for the TPS circuit, if the Vehicle speed sensor is faulty and telling the PCM that it is going

114 miles an hr or more it will cause a no start or shut down, also, if possible, check fuel pressure when the problem is occuring. Glenn Beasley Chrysler Tech

The TPS fault code isn't coming up since I disconnected the battery. I even kept it running until it warmed up, but the only fault code that comes up is code 12 ("Battery was recently disconnected") and code 55 ("End of Fault Codes"). Wes

Alright - here's an update. We checked the resistance to the ECM from the speed sensor, TPS, AIS, and fuel injector cap. The only thing with a noticeable resistance was the ground from the fuel injector cap, which read between 9 and 10 ohms. I was able to keep the car idling using starting fluid. While it was idling, the hot wire going to the fuel injector cap was reading a steady 14V. From this info, I have a few questions.

1. I assume I should replace the ground wire from the fuel injector cap - 9 ohms is way too high.
2. Is the 14V for the injector cap within reason?
3. Is there anything else it could be besides the fuel pressure or the injector itself? I'm checking to see if I can get my hands on a fuel pressure guage tonight. Thanks, Wes

There is no ground from the fuel injector. One terminal of the injector is fed constant12 volts (14ish with engine running), the other terminal is pulled to ground thru the ECM.

9 ohms is meaningless, a voltage drop would be a more meaningful measurement. Tough to do without an oscilloscope though... 14 volts is nominal when the engine is running and the alternator is functioning correctly.

You haven't checked fuel pressure and volume yet?

Alright - I took a look at it again last night. Fuel Pressure was reading a steady ~14 PSI which should be fine (14.5 is what the manual said). I looked down the throttle body while my brother cranked it over last night and I think I found the problem. Fuel is injected when it's cranking and when you first step on the gas pedal. It does NOT continue to inject when it idles or while you hold the gas down. I don't have an oscilloscope, but my multimeter showed a constant 14V at the fuel injector, so it should be injecting fuel. I called the local dodge dealer, and the technician said it sounded like the fuel pressure regulator. I guess I'll replace that tonight and see if that fixes it. Any other suggestions on what it could be? Thanks, Wes

Is there a way to test the fuel pressure regulator? When I tested the fuel pressure, I pinched off the return line, and the pressure (on the intake) did increase. Wes

The car starts, but immediately dies if I don't keep pumping the gas. I noticed something else last night. The engine seems to bog down for a fraction of a second when the gas is first injected. If I remember correctly, it didn't accelerate until the gas was no longer being injected. Then it dies if I don't pump the gas again. No dark smoke like it's too rich. Thanks Wes

oscilloscope,

The spark became less frequent as the car died, but it kept sparking until it was dead. I assumed the spark was slowing down because the car was dying (since it wasn't getting gas). There was no fault code for the fuel injector - just the TPS and the Speed Distance sensor. I ended up replacing the TPS because of the fault code, but then I went back and tested the original and it tested fine. I also tested the speed\distance sensor and it tested OK (8 spots of 8 ohms and infinity between). After I disconnected and reconnected the battery, I have yet to come up with a fault code besides

12 and 55. If the fuel injector is bad, how could it inject while cranking and when you first press the gas pedal? Wes

Well, yeah, that would be a definite problem...how did you determine this? If it was idling, it was running. If it was running, the injector was injecting fuel.

A digital multimeter wouldn't be fast enough to keep up with the voltage pulses to the injector, so we can't really draw too much of a conclusion from this.

No, if you were reading ~14 pounds' pressure at the fuel rail near the injector, it's not the fuel pressure regulator. The regulator is not turned on and off; it works or it doesn't. If it sticks open, there'll be very low (or no) fuel pressure when cranking OR running. If it sticks closed, there'll be very high fuel pressure when cranking OR running. If it works, there'll be 14.5psi or so when cranking OR running.

I think you have an electrical problem. Somehow, that injector isn't being given the right signals.

Another hint: Dealer techs absolutely hate it when do-it-yerselfers call up and ask for diagnostic help over the phone. Many of them are not above sending such callers on wild goose chases, and I'm not entirely sure I can blame them, for such calls amount to unfair demands that they work for $0.00/hr.

DS

OK, it wasn't injecting while it's supposed to be idling. It stops injecting when you stop cranking. It fires, then decelerates until it dies. Likewise, it injects when I first press on the gas pedal (the engine actually bogs down for a second while it's injecting), then it accelereates for a second, then it decelerates until it dies.

I've checked the TPS, replaced the AIS, checked the Speed/Distance sensor. What other electrical sensors/relays, etc... do I need to check? The ASD relay shuts off the ignition, doesn't it? So it shouldn't be that.

When depressurizing the fuel system, the chiltons says to ground one terminal of the fuel injector, and touch the other terminal to the positive battery terminal. I assume that's just pumping out any gas that's in there. Can I bypass the computer for the fuel injector and do the same thing and make sure it sprays every time the circuit is completed? That should tell me if the injector's OK, shouldn't it?

Thanks for the info, Wes

What is gum cutter? I am able to keep it running with starting fluid. If I remember correctly, it was staying at 14 psi while it was dying. After it died, it dropped to 10-12 psi. Is there a way to test the injector without taking it into a shop? If the pintel isn't opening up, does that mean it's just gummed up, or could it need replaced? Wes

disconnected

The ASD relay controls the ignition, yes, but also the fuel pump and also the injection. It is the "master shutdown switch".

Ooohboy. Chilton books will get you nowhere in a big hurry. You need a factory book. They're not hard or expensive to get.

Good way to fry a fuel injector.

Has the throttle body itself or the fuel injector been swapped? Although physically interchangeable, different-year versions of this same system run at different pressures. Starting in '91 or '92, the system pressure was increased to 39psi, and the later injectors aren't compatible with the early lower-pressure system.

Try this: Remove the battery negative cable from the battery and leave it disconnected for two minutes, then reconnect it. Get in the car and crank it, then check the codes and report what you find. I'm beginning to suspect you'll see an 11.

Daniel J. Stern wrote in article ...

Does removing the battery negative for 2 minuits reset the computer ?