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Re: surging idle

Posted: Mon Jun 04, 2012 10:06 pm
by Koots
Spray cleaning the TB is a good way to get rid of carbon buildup, but leave most surfaces very dry. Try spraying a light spray lubricant, not WD-40, it is useful for many things, but it is not the best at any of them. I like Liquid Wrench, PB Blaster, M16 (local parts store brand) and any Wurth product (seems to make a solid product in every line).

This might help loosen up a sticky IACV, but it's just a free shot in the dark for you to try :D I've spent many an hour, fuming over "impossible" fixes, only to stumble on a simple answer after spending too much money and/or time. I hope that this knowledge can be useful in some way to another.

Re: surging idle

Posted: Mon Jun 04, 2012 10:32 pm
by BerettaMN
Im willing to try anything at this point but I cleaned the idle air control valve and TB already. thanks! Oh and I forgot to add I tried starting it with starting fluid. Didn't start with that

Re: surging idle

Posted: Tue Jun 05, 2012 11:32 am
by 3X00-Modified
Fuel pressure will drop at idle when the vac line is hooked up to the regulator, if you disconnect that the pressure should jump up to the ~43PSI... But it sounds like you have bad or stuck open injectors... You need to ohm test them and or replace them with some others. If adding more air to the situation causes the engine to start then your flooding it when not opening the throttle.

I would also try changing out your Coolant temp sensor, BUT This is all guess works since you really only have one test result posted to work off of...

If you can have someone scan the ECU with a OBDI tool then you can see what your sensors are reading and that would definitely point you in the right direction when it comes to repairing the issue, otherwise you'll have to just keep throwing parts at it.

Re: surging idle

Posted: Tue Jun 05, 2012 1:19 pm
by BerettaMN
Thanks for the reply modified. Yeah it did jump back up in psi when disconected. I did replace the coolant temp sensor about a year ago, because of a fan not coming on issue. So it probably still should be good? Ill start looking for someone who can scan obd1

Re: surging idle

Posted: Tue Jun 05, 2012 1:28 pm
by 3X00-Modified
Its probably fine then... I would see if you can source a set of injectors, or ohm out the ones you have to see if any show up funny... and as another test, pull the rail out and turn the key on see if any are leaking.

Re: surging idle

Posted: Tue Jun 05, 2012 2:21 pm
by BerettaMN
Sounds good. I went to get a service manual but they weren't in stock, ill have to remove the intake plenum to do this right? Sorry first time doing this. Also any one know what the ohm specs are for 91 3.1?

Re: surging idle

Posted: Tue Jun 05, 2012 2:26 pm
by 3X00-Modified
yes you'll have to remove the plenum to check for leaking... as far as the ohm test goes, they should be around 16-17ohms...

Re: surging idle

Posted: Tue Jun 05, 2012 8:47 pm
by felixGTU
I thought the ohm should be between 12-12.5 ohms.

Re: surging idle

Posted: Tue Jun 05, 2012 9:52 pm
by BerettaMN
I went and got myself a nice equis auto-ranging multimeter just now. all my injectors were at 12.5 or 12.8 ohms

Re: surging idle

Posted: Wed Jun 06, 2012 8:10 am
by 3X00-Modified
According to Bosch the PN that should be on a 91 3.1L spec is 16.15ohms

Find the number on the injector and find it on this chart and see what it says.

I was using 0280150221

Re: surging idle

Posted: Thu Jun 07, 2012 10:18 pm
by felixGTU
So the resistance on your injectors are good they may still be the problem because the filters in the injectors might be dirty or stuck open. I am also currently having problems with my Beretta also and it acting up almost like yours I still cannot find the problem.

Re: surging idle

Posted: Fri Jun 08, 2012 8:05 am
by 3X00-Modified
Pull the injector rail and prime the pump, see if there are any drips from the injectors... That will tell you if they are leaking or stuck open.

Re: surging idle

Posted: Fri Jun 08, 2012 11:47 am
by Money pit Beretta
So it's 16 ohms for 3.1 injectors and 12 ohms for 3100's?

Re: surging idle

Posted: Fri Jun 08, 2012 11:54 am
by scd88ga
Money pit Beretta wrote:So it's 16 ohms for 3.1 injectors and 12 ohms for 3100's?
No, 3.1's and 3100's are both 12-13 ohm.

Re: surging idle

Posted: Fri Jun 08, 2012 12:52 pm
by Money pit Beretta
It's weird that Bosch would list it a 16.