PCM GT40 Idle surging Please help!?!?

[Canuck-Surfer]

Emil,
I suspect the same thing on my engine as well. Over the last week I’ve replaced everything. Tonight I replace the map and the bypass valve. I did not clean the filter. Tomorrow my plan is to clean the filter but if that’s not it I’m out of ideas on mine as well. I’m also having a hard start issue that I had hoped replacing all of the other components would have resolved. The only thing I haven’t touched at this point is the injectors. I’m pretty close to pulling the trigger on ordering a new set from Summit.

[ibelieve]

Sorry but I have been away. Thanks for the description and suggestion. It will take a look!

[phillik]

Emil,
pretty close to pulling the trigger on ordering a new set from Summit.

Before you drop that cash on new ones, send your old ones off to be tested. We used Fuel Injector Clinic in Florida. The price was very reasonable and they were able to bring our old ones back to life.

Also for sensors, this video is a good one for testing with an ohm meter.

Sensor video:
https://youtu.be/hFmI-_B9IVs

[ibelieve]

I removed all of my injectors and built a little jig with a 9V battery and switch, to energize them with a can of carberator cleaner connected to the injector. Push the switch to open the injector and spray the cleaner at the same time. I was able to find one that was clogged and after a few tries it opened up and has been working for years. Not sure if I have pics but will see what I can find and post it here.

/Steve

Before you drop that cash on new ones, send your old ones off to be tested. We used Fuel Injector Clinic in Florida. The price was very reasonable and they were able to bring our old ones back to life.

Also for sensors, this video is a good one for testing with an ohm meter.

Sensor video:
https://youtu.be/hFmI-_B9IVs

[ibelieve]

Asking about the by-pass valve. If I blow in one side, there appears to be some air that passes thru. I assume this should not be the case. Can I engage the valve with a 9V battery or other 12V source in order to clean it? I need to open or operate it in some way to try and clean the valve seat. Either that, or buy a replacement.

Thanks,
Steve

[ibelieve]

To operate the by-pass valve, you need 12V. Polarity only matters as it has to be correct to open. If you have it reversed, it just tries to close it more ... seems a bit odd. I have mine actuating and cleaned. I'll see what happens with the idle when I get it all put back together.

Thanks everyone for all the help. I will post info on the injector cleaner under a new DIY topic ... https://www.planetnautique.com/vb5/f...jector-cleaner

/Steve

[phillik]

I removed all of my injectors and built a little jig with a 9V battery and switch, to energize them with a can of carberator cleaner connected to the injector. Push the switch to open the injector and spray the cleaner at the same time. I was able to find one that was clogged and after a few tries it opened up and has been working for years. Not sure if I have pics but will see what I can find and post it here.

/Steve

That's very cool and really like your DIY. To be honest I looked into this but got cold feet when I read about side effects of doing this. Not saying that is true and I really don't have experience building a test jig like that. It was enough for us to send them off.

I'm not sure if these are the right injectors. In some research I found that Bosch has a new version that went from blue top to gray top. Part# 0280150965
https://www.fiveomotorsport.com/bosch-0280150965-24lb/
I think these are also in some 1995-1996-1997-1998-1999 Mitsubishi Eclipse. If you search for them online, I found some really cheap ones for ~$17.00 per injector!
Would love to know if these would work as backup or to upgrade to a 4 port one.

/Kyle

[FMSKI]

RE: Injectors - 9V battery is a nice trick. Noted in the manual, the coil of the injector will burn if 12volts is applied directly. I cleaned up Porsche/Bosch injectors, using same idea with cleaner and some compressed air. An engine that sits is prone to fuel issues and clogged injectors. But using that trick you can totally see them work properly after cleaning.