1998 Neon ACR Fuel System

I'm looking for a Gen1 Neon expert that wouldn't mind giving me a hand with a few questions related to my build specific to a fuel system problem I'm having.

The ACR fuel system is not unique.

Go ahead with your questions?

I’m found that although my fuel pump sounds like it’s running since I can hear it priming when I switch on the ignition, it’s not pushing out any fuel. I determined this by first verifying no fuel was getting to the rail and secondly by disconnecting the accumulator output flex line from the hard line that travels up to the front of the car. Switching on the ignition I can hear the pump cycling but no fuel comes out of the hose, not a drop.

It’s tight quarters in there so I expect I have to drop the tank to proceed, but if maybe you would suggest a different approach.

Is it the original pump or an aftermarket one?

This is my first neon but based on the appearance I'd guess it was original. Is there an easy way to tell?

Not really. Some of the aftermarket pumps come with a hose to connect the pump to the pickup that isn't rated to be submerged in fuel. My guess is either its the original pump and that hose blew out, or it's been replaced and the hose disintegrated. You'll have to drop the tank and pull the pump.

I'm plan to do that then and report back what I find. Thanks a lot for the help.

moparman76_69 wrote: Not really. Some of the aftermarket pumps come with a hose to connect the pump to the pickup that isn't rated to be submerged in fuel. My guess is either its the original pump and that hose blew out, or it's been replaced and the hose disintegrated. You'll have to drop the tank and pull the pump.

I agree. The original fuel canister has a plastic hardline internally, so I'm guessing it's an aftermarket replacement. You might also try removing the fuel pressure regulator and see if it will dispense fuel then.

Is there enough room to remove the regulator? I see it but can't get my hands around it.

You pretty much just need to get the quick connect fitting to the accumulator off, and then there's a tab to release it and it twists off. It's been close to a decade since I've had to do one, but I don't recall having to drop the tank to change it.

The FPR/filter can be removed without dropping the tank, but it is in very tight quarters. I don't think I had any skin on the back of my hand by the time I had mine swapped out.

Seems easier to take the tank off. From what I see it's the electrical connection, the regulator to hard line connector, the filler neck clamp and the accumulator itself (one bolt, but kind of buried). Unbolt the straps is it looks like it should come right off.

If I can get the filter/regulator off without removing the tank, how do I determine if it's functioning properly or not or is it something I just replace and then re-test the system to see if fuel starts flowing again?

And by the way, this forum completely kicks #@% !

Got the accumulator, harness connector and fuel filter/regulator off last night. A little gas spilled out of the accumulator and filter/regulator so it seems neither was blocking flow so it must be down to the pump. I've got a very rusty hose clamp to remove so I can disconnect the filler tube and then it looks like the tank can come off.

Next Problem: This car is running very, very rich. I’m getting maybe 15 miles to the gallon and the smell of the exhaust is heavy with unburnt fuel. Throttle response off idle is very sluggish but the motor will pull to redline and it feels reasonably strong. I replaced the coolant temperature sensor early on when I was dealing with the starting problem so I know that’s good. What do the neon experts say should be my next step?

Could be a stuck injector or a bad injector o-ring.

I'd hook up something to your OBDII port and verify that the PCM is seeing the right temperature. Also, you might verify that the MAP sensor is sending sane data.

If the cam position sensor was going, I think that would result in a no-start condition, so that's probably not at fault. Same for the crank position sensor.

Can you check fuel pressure?

In reply to wae:

I have a friend with a scanner and we're going to hook it up tonight and see what it tells us. It will list the codes and can see real-time data. I'll post what we find.

So we were able to check the car with a scanner and there were no codes. With the car idling we looked at all the feedback and everything (MAP, TPS, CTS, etc) checked OK except for the 02 sensors. The upstream sensor constantly cycled between 0.2 and 0.9v and was never stable. The downstream sensor was stable at 0.47v. We listened to the injectors with a stethoscope and they all were clicking over the same way so unless one is leaking they are likely OK. Which sensor is working correctly?

Both

Well that's good news in a way. I'll just keep driving it and see what happens.

I'd pull the mass airflow sensor (or whatever neons have) while it's idling to see if it changes. If everything is the same, I'd figure out how to test it, cause it's probably bad and running in "limp mode."

When you got the tank off, how junked up was it inside? If there was a lot of junk, your injectors can be wedged open... especially if the car was sitting for a while.

Might be worth a junkyard set.

In reply to WonkoTheSane:

I'll test your sensor theory this weekend, thanks. There was a lot of crap in the tank but my long and short-term fuel trim numbers are spot-on. If the injectors were leaking I'm informed those numbers would reflect it.

Double check cam timing on the belt. Major pain, but will do this on the dohc neons. Usually it kicks a code for cam a tooth off, but not always.

Also check rail pressure. If the regulator has failed in wide ass open, will also cause these symptoms. Same with a jammed open egr.

I checked everything and found the connector on the MAP sensor had one of the four tabs broken off and was likely intermittent. I'm going to cut a connector from a donor tomorrow and solder it in to fix the problem which I have successfully patched at the moment with aluminum foil. Thanks or the suggestions.

Cool! Glad you found it, and glad it sounds cheap to fix :)