FD. Engine rebuilt, hasn't run right since. Idles fair, but a little rich. Pulled cap off vacuum port and idle RPM went up. Will rev up smoothly to 5K on the primary butterfly. But when the secondaries get to about 1/4" open it begins to go lean. At WOT it runs so lean it will barely stay running. RPM drops to around 1500. Spraying carb cleaner into the intake makes it rev up. It does the same thing whether the horn is on or off.

Only mods---K&N filter and Flowmaster exhaust. All else is stock.

What I've done---

Pulled codes. I have 40 (purge control solenoid) and 44 (Turbo control solenoid) Haven't repaired those yet---I don't think they're related to my problem.
New TPS.
Repaired TSP wiring.
Adjusted TPS to correct voltages
Tested boost sensor. It is good.
New coils, plugs and wires.
Fuel pressure running is 40 warming up, 30PSI all the time after that.
Grounded the fuel pump relay while at WOT to force pump to 40PSI---small increase in RPM, but engine still barely runs.
Checked secondary injectors for clicking by grounding at the ECU connector.
Grounded secondary injector w/ engine at idle and engine quit, verifying that fuel was getting in via secondaries.
Sprayed carb cleaner around checking for intake leaks. Found some change when spraying around secondary injector.
Pulled UIM, checking all other vacuum lines. (Previously replaced all lines with silicone) Found no problems.
Pulled secondary injectors and found the possibility of leaks at the insulators---ordered insulators.
Tested injectors.

It seems to me I have insufficient fuel. If I had a massive intake leak it would show up worst at idle and get better as vacuum decreased, and would result in a rich mixture as the intake pressure went positive.

What might be the problem? Computer not telling the secondaries to fire? Could leaking injector insulators cause the problem I'm having? Why isn't the fuel pump going to the higher voltage/pressure at WOT?

I'm new to this car and could really use some direction. Thanks in advance.

 

I was going to say to check your fuel pump relay(speed) at the front of your car. But it sounds like you did already. Therefore, I'd look at the troubleshooting chart in the manual. You can e-mail Dave Barninger at kdrotary@enter.net. He's nailed a few problems I've had just by giving him a detailed description like you posted.

 

Check your coolant temp sensor. Once I had the coolant temp and fuel temp reversed and the car ran like ****. If your wire harness is old check all the connections. My crank sensors looked plugged in but when I barely moved the harness the wires lifted right out of the connectors.

 

Clogged fuel filter?

 

Were the injector diffusors reinstalled? I heard you'll get flooding issues without them.

 

I agreed with Dave here, sound like you might have a clogged fuel filter not delivery the sufficient amount of fuel when secondary kicks in.

Not sure if you know to check the volume test for the fuel system. I believe the FSM also covered that.

The car might have enough pressure but insufficient volume of fuel being delivered.

Perform the fuel volume test with your injectors out and see what you got. But i would replace the fuel filter first if you havent replace it for at least the pass year or two.

Good luck!

-AzEKnightz

 

Diffusers are in.

I thought about the filter and may replace it on principle, but could that be the problem? If the flow were low wouldn't the line pressure drop when the injectors started demanding too much fuel? I have no fuel pressure drop at WOT.

 

Yes. You are correct. It is likely not the filter.

Dave

 

limp mode? Try resetting the ECU...

 

For others who may be helped, I thought I'd post a follow-up. I was out of the country for a while, hence the long time lapse.

What I did---cleaned injectors, replaced the injector rubbers, cleaned injector connections and ensured they were on tight. Replaced the bad solenoids (purge control and turbo control; they were open, not shorted). Installed different Air Control Valve because one solenoid was damaged. Reinstalled UIM and it ran almost perfect.

I wish I knew what fixed the problem. It may have been cleaning the injectors, it may have been the reseating of some electrical connector. It may have been the Air Control valve. But whatever the reason, the only issue I have now is the 3000 RPM stumble when cold.

Thanks to all who replied. I've learned a lot that I didn't know. Still have a long way to go.

 

I never saw this post the first time. I suspect you were running rich (not lean) due to leaking injectors. Glad to hear its running right now.