mikeviera Posted May 14, 2010 Share Posted May 14, 2010 Aother post from the noob...LOL! Would anyone know if there is a fuel rail or a manifold that houses the fuel injectors? I was told that if i replaced that as well i would get better performance.... is that true? what is the right name for it so i can look it up and buy? I'm looking to replace my 2 port fuel injectors with the 4 port that have been posted in the forum. Thanks in advance MJ 88 Jeep Comanche 4x4 i6 4.0l Link to comment Share on other sites More sharing options...
Geonovast Posted May 14, 2010 Share Posted May 14, 2010 Yes, all 4.0s are multi port fuel injection. Should take you all of about 5 seconds to locate it with your hood up. There are injectors that are an upgrade, but not really anything in the terms of an upgraded rail. What you're probably thinking of is the upgrade for the older 2.5L 4cylinders. 86-90 4 cylinders were TBI, or Throttle Body Injection. They have one injector, in the throttle body instead of one at each intake port in the intake manifold. In 91, the 4 cylinder went to MPFI, and has an injector at each cylinder. Older TBI 4 cylinders get a significant power upgrade if you convert to MPFI... which is a lot of work. Link to comment Share on other sites More sharing options...
mikeviera Posted May 14, 2010 Author Share Posted May 14, 2010 Yes, all 4.0s are multi port fuel injection. Should take you all of about 5 seconds to locate it with your hood up. There are injectors that are an upgrade, but not really anything in the terms of an upgraded rail. What you're probably thinking of is the upgrade for the older 2.5L 4cylinders. 86-90 4 cylinders were TBI, or Throttle Body Injection. They have one injector, in the throttle body instead of one at each intake port in the intake manifold. In 91, the 4 cylinder went to MPFI, and has an injector at each cylinder. Older TBI 4 cylinders get a significant power upgrade if you convert to MPFI... which is a lot of work. I was told that the stock fuel injector for this model truck was a 2 port injector... I'm planning on getting these viewtopic.php?f=9&t=7770 .... Which is the upgrade for the fuel injector. But, i'm not trying to upgrage the manifold that is already housing the fuel injectors... is that what it is called...manifold? What I was told is, if i install a new one(not upgrade) i would get better performance.... is there any truth to this? If so i would like to replace it or clean it up if that will improve the performance. Link to comment Share on other sites More sharing options...
Geonovast Posted May 14, 2010 Share Posted May 14, 2010 If your fuel rail leaks or is gummed up, then yes, installing a new one(I hope you mean *NEW*, and not simply another one) would help performance. Link to comment Share on other sites More sharing options...
mikeviera Posted May 14, 2010 Author Share Posted May 14, 2010 If your fuel rail leaks or is gummed up, then yes, installing a new one(I hope you mean *NEW*, and not simply another one) would help performance. OK yea... that is what i was talking about... so it is a fuel rail :cheers: . I'm pretty sure that it is gummed up. I don't think the previous owners ever did any work other then when something broke. It looks to me that almost everything on this truck is stock, besides what i have done to it :thumbsup: Link to comment Share on other sites More sharing options...
dasbulliwagen Posted May 15, 2010 Share Posted May 15, 2010 Fuel rails don't give many issues, and it is unlikely that there is any problem with yours, just get a bottle or 2 of Berrymans B12 Chemtool from the auto parts store and soak your rail if you think it might be gummed up, but unless it has been sitting not running, and the rail dried up with old fuel in it, you probably won't have any problems, just install your new injectors with new O-rings properly installed and youll be fine. Link to comment Share on other sites More sharing options...
mikeviera Posted May 15, 2010 Author Share Posted May 15, 2010 Fuel rails don't give many issues, and it is unlikely that there is any problem with yours, just get a bottle or 2 of Berrymans B12 Chemtool from the auto parts store and soak your rail if you think it might be gummed up, but unless it has been sitting not running, and the rail dried up with old fuel in it, you probably won't have any problems, just install your new injectors with new O-rings properly installed and youll be fine. Before i bought the truck, I believe that it sat without being started for a year or two... It took me a bunch of money to get it back up and running.... while i had it.... i had some issues with it and took a bit for me to get to back to a good state... Now that i'm working on it and not bringing it to the shop.. I am slowly geeting her back to 100%... I would think that it would be gummed up, just from that bit of history that i know about it... I will go and pick up some B12 Chemtool and give that a try... thanks for your help.... Here is my WIP viewtopic.php?f=7&t=23458 Link to comment Share on other sites More sharing options...
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