Beretta.net

Haven't been on the forums for a while and sadly have not posted much but i got a problem that has driven me UP A WALL!


So the car ->1992 Beretta(duh ) GT, 2003(i think)3400 swap no mods Spliced injectors to old harness, Muncie 5-speed, Wrapped up with a tune chip from WOT.

So it was happening before the tune chip when it was running rough but i would drive along and the car would stall out when coasting in gear(low rpm you'd feel the engine "shift" and then pull outta gear and die) coasting in neutral, and very typically in neutral up to a stopsign and such. it almost always starts right up by key or popping the clutch. after the tune ship car ran great and went like stink in comparison, yet still stalled. we've checked a couple of the airflow sensors and throttle sensors and cleaned the K&N, actually went to check the fuel filter and put a new one in.

Any thoughts to try or personal experience?

Check the IAC valve. Take it apart and clean it, and then set it about 50% of the way out. Then do an idle relearn. The procedure is on here somewhere. Basically just start the car, don't touch the gas pedal or anything, let it come up to operating temp and let the fan cycle on and off twice. Once it shuts off the 2nd time you should be good to go. You can shut the car off and the idle should be good. If you still have a problem the IAC motor might be no good, so buy a new one.

i had the same problem it was my crank sensor...not sure if yours has one but mine got real bad before i found the problem

I appreciate the input fella's. My mechanic buddy that helped me with the swap had suggested the IAC and because it wasn't to pricey i just replaced it cause the one i had started with was from the original 3.1 setup and had 190K+ miles on it most likely. at first i thought i was good but then nothing really changed, the old one had been quite dirty so it was still worthy changing.

Now i do have the crankshaft sensor and i cant recall for sure but we did lengthen several of the wires in the bay to reach the new locations from the old ones. I'm gonna look into replacing that one as i can't remember if i used the new one or the old one.

Except for one random bad 20 minutes where the car ran like crap and wouldn't stay running and the engine light was on when it was and then suddenly cleared up and drove fine like nothing had happened, scared the crap outta me. and i realize i worded that horribly but when i meant to say is that it runs great and strong 99% of the time.

My only other thought is that i did use the old coil packs as the engine had sat outside and rusted the terminals on the 3400 and cracked one of them while it was in it's wreck/lived on the ground in a junk yard. Now i had borescoped the engine and opened up the bottom end to check the caps and bearings. Other then that the engine is pretty much factory built with an rumored/estimated 30K when it was dropped at the yard.

Do the idle relearn as I suggested and see what happens. Anytime you disconnect the battery you are supposed to do it.

3400beretta wrote:Do the idle relearn as I suggested and see what happens. Anytime you disconnect the battery you are supposed to do it.

haha oddly enough.... i've been woring away from home 2 weeks of every three and it's winter here in Alaska and been cold so while i was away i was pulling the battery and keeping that indoors, so i do need to do the idle relearn correctly obviously. now sometimes the car after having sat for a while and then battery put back in and start it to warm it up, i probably used the accelerater once or twice getting it started form the cold thus not allowing a idle relearn to work right, but it would randomly, idk after how long cause i was inside where it was warm, would shut off on it's own leaving the car on but not running. This did not happen 100% of the time though.

But i can also add that the car never seems to idle rough, tho some times seems to idle high, can anyone chime in to the stock Idle for the 3400 in our setups like these.

It looks like the mystery might have been solved as to why it does this, so now you just need to find a solution. You could try bumping the minimum idle-speed up with the set-screw on the throttle-body... It might cause more problems than it solves, but if your idle issues can't otherwise get resolved, it might be the best way. I know some people will put a 9-volt battery in via an adapter for the accessory outlet that will retain radio-station presets and computer settings, that might work, or you could hook up a low-amperage trickle-type charger to keep your idle speed set while the battery is staying toasty-warm. Last thought would be to install a battery-warmer and leave the car on life-support while you are away.

Sadly doing an idle relearn didn't help. it's the summer time now (after a snowfall and freeze on may 17th) so i won't be pulling the battery anymore. i'm thinking i'm just gonna have to let it go till my mechanic can really sit with it and maybe we can pinpoint something else with the help of driving it with the computer hooked to it.

I still think your best bet is to bump the minimum idle-speed up with the set-screw on the throttle-body.

I had a similar (though not as severe) problem with my '89 GTU's 3800 when I first swapped it in, but that was caused by the fact that the computer was looking for a non-existent automatic transmission and wasn't receiving any VSS (Vehicle Speed Sensor) data, and therefore couldn't figure out why the RPMs were mysteriously staying up during the deceleration it didn't know was happening. . A bump in minimum idle speed virtually cured that with no ill effects.

My 'old' '88 Camaro also had the same problem as your car, even to the point of actually stalling on a semi-regular basis after I bumped-up the displacement by 45 cubic inches. A bump in minimum idle-speed either did or would have fixed that (I can't remember the order of things now -if I tweaked the idle set-screw on the original throttle body first for the extra .7 litres, or if I swapped in the CFI (Cross-Fire Injection) manifold I ported-out for the engine and then tweaked the idle-speed on the twin throttle-bodies for the bigger engine), it might help your bigger engine too.

Hey, if I'm wrong, you've wasted three or four minutes of time, plus the test-drive. Keep track of how many turns (or half-turns, or quarter-turns, whatever works better for your case), so you can reset it if it doesn't help or makes things worse...

Good Luck.