Thumper Posted October 28, 2003 Share Posted October 28, 2003 Well I was trying to chase down my slight miss at idle and was replacing vacuum lines and adjusting this and that. When I noticed my injector caps had some facing at 45 degrees and others at 90 degrees. Not exactly at those angels but close. Well I thought maybe a few of them got bumped and moved, so when idleing with the less air volume the spray was hitting the intake wall and clumping up and then going into the combustion chamber. So I loosened the screws ontop of the injectors rotated them to 90 degree position and started her up. Well she ran on like 3 or 4 cylinders. So I went and undid what I had done or I think I did I might have moved the wrong ones and then I went to start her and nothing. Not one cylinder trying to fire. I will be taking the fuel rail off in an hour or two too look at the injectors and clean the caps, but wanted your guys input on this before I started messing with things. TIA Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 28, 2003 Share Posted October 28, 2003 The injectors don't care what angle the plugs come out - they spray in a conical pattern. Make sure you didn't break the wires, it's easy enough to listen to them to determine if they are activating. Quote Link to comment Share on other sites More sharing options...
Thumper Posted October 29, 2003 Author Share Posted October 29, 2003 Well after an hour of removing the caps, cleaning them, putting them on, and sliding them back and forth finally I got the car to run again. Only now my miss at idle is slightly worse. Then when I rev ithe motor it goes away or is alot less. I believe it has something to do with the #2 injector. I removed it under idle and has very little effect on how the engine runs. So I am going to rebuild my injector caps so there is a nice tight connection. Has anybody done this b4?. Or is there a place I can buy new caps and then all I have to do is cut the old ones and wire in the new ones. TIA Quote Link to comment Share on other sites More sharing options...
jkube Posted October 29, 2003 Share Posted October 29, 2003 If youre talking about the electrical connectors on the injectors, I can tell you that Nissan has them avalaible. I just bought 6 of them for my F.I. conversion that I'm doing on my 240z. Apparently they have stock because of the recall situation with the older 300zx models. They were reworking the fuel system in those cars because of a fire hazard. Also MSD has them for sale. Part # MSD-2400. They fit the Nissan injectors. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 29, 2003 Share Posted October 29, 2003 I don't understand what you mean by "injector caps". Are you talking about the plastic tips over the pintles? They will have virtually no effect on how your car runs except if they are causing a vacuum leak. Have you verified that all the injectors are firing by listening to them with a screwdriver tip? If they are, you may have just created a bad vacuum leak. Just replace the o-rings at the injector tip in that case. Quote Link to comment Share on other sites More sharing options...
Thumper Posted October 29, 2003 Author Share Posted October 29, 2003 When I refer to the injector cap I'm talking about the brown electrical cap that connects to the electrical plug on the injector. It has two wires running into it. The #2 cylinder w/ the screwdriver test does not fire everytime. So I fiqure a lose electrical connector. I guess I will buy a few new ones from nissan. But for safe measure I think I will go ahead and replace the o-rings. Oh btw it has been missing for a few weeks not just after I adjusted them. Quote Link to comment Share on other sites More sharing options...
innerware Posted October 30, 2003 Share Posted October 30, 2003 I did this and my car ran sooooo much better. It took me 1/2 hour to an hour and it liiks so much better too. It is just amazing how brittle those old plugs can get. Not the cheapest thing too just for the little electrical cap, but definately worth every penny. Good luck Quote Link to comment Share on other sites More sharing options...
Thumper Posted October 30, 2003 Author Share Posted October 30, 2003 K I just redid my injector caps and no diff so it must be the o-rings in the injector. So I read in my haynes manual (my factory manual is in h-town) that there are two o-rings (or insulators) in the injector one upper and one lower. The lower one goes in between the injector and intake manifold and the upper goes between the upper and lower holder of the injector. So what one of these or both of them are causing the problem. What else should I check while fuel rail is off? Oh I have verified all of the injecotrs are working properly and that only at idle or low rpm use does the engine miss. So it is defiantly an air leak of some sort. I'll be getting the o-rings tom. Thanks sleeperz, jkube, and innerward. Ted Schmidt Quote Link to comment Share on other sites More sharing options...
stony Posted October 31, 2003 Share Posted October 31, 2003 get them cleaned and flow checked. I would almost guarentee that is your problem... dirty injectors Quote Link to comment Share on other sites More sharing options...
Thumper Posted October 31, 2003 Author Share Posted October 31, 2003 Well I just sprayed some carb cleaner near the injector o-rings and nothing happend. So I guess they are not leaking. So it is either a bad injector or it needs to be cleaned. I have my timing advanced so i've used 93 octane the last four tank fulls so I know the injectors are as clean as they will get without getting them done at a shop. I'm going to put a turbo motor in a week or two so I will prob leave it be. Oh one thing else I noticed is my valve cover gasket is missing on the back 1/4 of the engine. I haven't lost a noticable amount of oil but still with a lack of vacuum in the valve cover it could make it run rough so I will be replacing this tom. Let me know if you any other input. TIA Quote Link to comment Share on other sites More sharing options...
David K Posted October 31, 2003 Share Posted October 31, 2003 If you need to replace your injector pigtails, go to the junkyard and clip some off a z31 300zx!!!! Dont waste money buying them new. Quote Link to comment Share on other sites More sharing options...
D83ZXT Posted November 3, 2003 Share Posted November 3, 2003 Never replace injector wiring from a vehicle 14 to 19 years old. Geesh they have been under the hood for many of years with engine temps. It's not worth cutting corners by going the cheap route. They are very reasonably priced at any Auto Parts store. If you gotta do it.. Do it right the first time Donna Quote Link to comment Share on other sites More sharing options...
Guest 240hybrid Posted November 9, 2003 Share Posted November 9, 2003 I know it probalbly doesn't matter since you said your swapping motors soon, but just running 93 octane fuel isn't going to clean the injectors by itself. I only run 93 octane and have had 2 different occasions where the car started missing due to fouled injectors. I had to pull one injector and let is soak in the injector cleaning solution it was so bad, and just ran injector cleaner through the fuel system the other time. Quote Link to comment Share on other sites More sharing options...
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