92 RS being a pain
 

Before I start, yes I'm aware there's a search option. But, I feel my issue is a little different. Plus I want to keep everyone updated, so let's dive in:

So, my RS (3.1 v6) ran great, and I mean great! I love it. But then it started to act up, I would be driving and everything is okay if I'm in 3rd through 5th gear, but when I'm in 1st and 2nd gear the car acts like its starving for fuel or spark. It jerks violently and wants to die, I can only move if I ride the clutch pretty bad. But even if I do that while gaining in rpm's quickly it bogs super bad and when I left off the throttle and push in the clutch to change gears it dies. So I changed the O2 sensor/spark plugs and TPS sensor, now those did seem to fix it until the next day I went to leave for work in the morning and my battery is dead, never have I had issues with the battery. So naturally I think I left something on, but that wasn't the case. I jumped the car and off I went to work BARELY making it, the car died 5-7 times on me and my job is 20 minutes away. But with all the lights in between it kept dying at each one, it fired up after work and same scenario getting home. The next morning the battery was dead again so I decided not to drive it to work. Could it be a bad fuel pump that is on its way out and maybe somehow never turns off and kills my battery? Or spark? A sensor or 4? I tested the alternator and it pumps out 14v while the car is on, I left it idling for 30 minutes and it charged up the battery and everything so I'm not sure the alternator is an issue or the battery, but could be wrong. Also, if I rapidly tap the gas but keep the rpm's under 2500 it gurgles really bad and dies out. This could be a simple fix and it could be elaborate, looking to you guys and your experiences for guidance! Any info helps!

Re: 92 RS being a pain
 

See this is your first post, welcome to the forum. First, I'd have your battery checked, for free, to see whether it is holding a charge. Things that affect fuel and spark from easy to hard - ohm your injectors to see if any are bad, pull the vacuum from your fuel pressure regulator and see whether you have a ruptured diaphragm, gas will trickle or flow out, pull your ignition control module and have it checked to see whether it's providing a sufficient spark. Keep us updated, other members will chime in.

Re: 92 RS being a pain
 

If the original Multec injectors are still in the engine, replace them.

RBob.

Re: 92 RS being a pain
 

You sound like you've got more than one problem here , so in order ;

The battery being dead in the morning but being able to start the car after being jumped and left to run a bit really could only be a bad battery that takes a "surface charge" but won't hold it over time , or something's staying on that drains it over time when the engine is off . If the fuel pump were to stay running full time you'd certainly hear it with the engine stopped , DO you hear any whirring sounds from near the fuel tank with the engine off ? Any lights left on , even the interior light , would be enough to drain a marginal battery overnight and also a shorted "isolation diode" in the alternator could present a key off drain as well . I'd fully charge the battery , disconnect one battery terminal (don't matter which one) and hook up an ammeter between the battery and the disconnected terminal and read the draw . I can't recall the specific numbers so don't quote me on it , but I think anything under about 65 milliamps is ok and anything approaching 250 milliamps (1/4 Amp) is cause to believe somethings excessively drawing . Like I said , search out the exact numbers of amps because I can't recall off the top of my head the actual numbers but this will at least give you the general idea of what to look for there .

As to the poor running , that could be just about anything from fuel delivery to spark to even yes I've seen a partially clogged catalytic converter keep the engine from breathing well enough to run well when the gas pedal is pressed but idle and run Ok under very light throttle opening .

Re: 92 RS being a pain
 

I've come to the conclusion the battery is junk, charged it with the terminals off and it didn't hold a charge, I also replaced my MAP sensor and it didn't help, one thing I did notice tho is if you stand behind the car you can smell gas not being burned off, I backed up to my garage and let it idle and the whole garage smelled like unburned gas

Re: 92 RS being a pain
 

Ok , Great , with your finding of it running pig rich , the very next thing to check is the fuel pressure regulator . If it fails , it can allow raw fuel to be sucked into the throttlebody through it's vacuum line . Disconnect the vacuum line from the regulator and turn the key to the ON position to let the pump prime . Does gas squirt out of the vacuum port on the regulator ? If yes , that's your problem with the rich running . The regulator is known to fail in exactly that way , the diaphragm gets old , brittle , splits or cracks a bit , and lets raw fuel get sucked into the intake through it's vacuum control line .

:) Good luck and report back with how checking the regulator goes .....

Re: 92 RS being a pain
 

I popped it off and no fuel came out unfortunately

Re: 92 RS being a pain
 

Does the engine still have the OEM Multec injectors?

RBob.

Re: 92 RS being a pain
 

I believe so. I found a good deal on a Chevy 2.8l intake manifold and carb, should I just carb this motor and put an end to all of this electrical nonsense? I don't want to end up buying a million parts and it not working. Ive done that in the past and it sucks. Also, this is my daily and I have to go back to work Monday haha

Re: 92 RS being a pain
 

:( Darn , when you said it was really rich running I thought for sure the regulator would be the culprit . Excessively rich running could have any number of causes and one of the next things I'd check would be the temp sender that the ECM uses to determine mixture based on engine temperature .

Hi Rob ,

I had thought of the injectors also , but isn't the usual failure mode of the Multec injectors to go low ohms such that the ECM can't power them open and the end result is no fuel rather than too much ? Not trying to one up your idea here , i'm just wondering cause if a stuck open failure is common for the multecs that would be a great explaination for what the OP has going on ?

Re: 92 RS being a pain
 

Honestly , it will be far easier to repair this fault once you find it than it would be to switch over to a carb setup . To fix the failure , all that's required is to find out exactly why it's running so rich and repair it . To convert to carb isn't only a matter of just swapping out an intake manifold , your ECM controls the spark advance of the distributor , for instance . If you remove the injectors and leave the stock distributor it'll run really poorly since without the full system working as intended , it will not "know" how to adjust the advance and will resort to "limp home" values . So now you'd need a manifold with carb AND a distributor , not to mention other things you'll likely run into like the fuel pump pressure for MPFI being much higher than for a carb , so a regulator or pump would need to be thrown into the mix as well .

Were this already converted , I'd say we have to work with what we've got , but where it IS still original and un modified you'll be miles ahead (and dollars ahead too) to repair the system as it now exists .

Please read up on "testing the ECM's CTS" and check that sender next . If the CTS fails and makes the ECM "think" the engine is always stone cold , it'll cause it to enrichen the mixture falsely when it's actually warmed up and at operating temperature ....

Re: 92 RS being a pain
 

I'll look into that now

Re: 92 RS being a pain
 

The coil shorting get worse as they get hotter. The ECM has issues driving the injectors, but this is also PW based. Give it more throttle and the cutout gets worse. At this point they likely could have the resistance measured and have some show up lower then 12 ohms.

As for getting too much fuel, over time injectors get dirty. This causes them to flow more then they should as they dribble and leak.

RBob.