tugboat95 Posted January 30, 2021 Share Posted January 30, 2021 So I replaced the head gasket on my 4.0l. Along with that I installed new Bosch injectors. These were advertised as Bosch but what showed up in the mail had Chinese writing on the packaging. And look like cheap plastic. Engine fired right up but is running badly. Sounds like a misfire . very rough idle as well as at speed. Engine has a vibration. I can see it rocking in the engine bay. That transfers to the truck as well. So what did I do wrong? My first guess is the injectors. I've checked all the vacuum lines. They all appear to be hooked up. Head was checked and machined, I know it's good. Fuel lines are all good, injectors are not leaking. Injector Wires are Connected and locked on. 89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
jdog Posted January 30, 2021 Share Posted January 30, 2021 correct firing order? Link to comment Share on other sites More sharing options...
tugboat95 Posted January 30, 2021 Author Share Posted January 30, 2021 Everything is correct. I labeled all wires and they are still labeled89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
jdog Posted January 30, 2021 Share Posted January 30, 2021 did you pull the distributor? any smoke? Link to comment Share on other sites More sharing options...
dante2 Posted January 30, 2021 Share Posted January 30, 2021 Bad injector or 2? My wrangler popped a code 33 (injector circuit issue), turned out one injector was going out. Ran like crap when it started acting up. Replaced all of them with a new set no more issues. Link to comment Share on other sites More sharing options...
tugboat95 Posted January 30, 2021 Author Share Posted January 30, 2021 did you pull the distributor? any smoke?Lots of smoke on startup. But it cleared up. I chalked that up to using motor oil on the injector orings to seat them. I did not pull the distributor. As I didn't want to mess with timing. It's possible I moved it but then it would be loose now and it's not89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
jdog Posted January 30, 2021 Share Posted January 30, 2021 Well then its down to injectors, or bad plugs/wires, try installing the old injectors and see if the miss goes away Link to comment Share on other sites More sharing options...
tugboat95 Posted January 30, 2021 Author Share Posted January 30, 2021 Bad injector or 2? My wrangler popped a code 33 (injector circuit issue), turned out one injector was going out. Ran like crap when it started acting up. Replaced all of them with a new set no more issues.I'm leaning towards that. I just don't like the look of the new injectors89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
Fernando87mj Posted January 30, 2021 Share Posted January 30, 2021 15 minutes ago, tugboat95 said: I'm leaning towards that. I just don't like the look of the new injectors 89 Comanche Eliminator 2wd 4.0L 5 speed PukeGoat Factory Original if you have a multimeter you can try ohm testing the injectors , when injector #3 on my old wj went bad it showed up as an open while the others had some sort of resistance Link to comment Share on other sites More sharing options...
Limeyjeeper Posted January 30, 2021 Share Posted January 30, 2021 I put a set of Chinese Bosch injectors into my old LJ a couple of years ago pure junk. (Same as you I thought they were OEM Bosch) Bet that is your problem. No QC. Link to comment Share on other sites More sharing options...
tugboat95 Posted February 1, 2021 Author Share Posted February 1, 2021 Found the issue. While disconnecting the injector wires to pull the rail and reinstall old injectors I noticed a loose vacuum line. I thought it was hooked up but it wasn't seated. Pushed it on all the way, replugged the wires. Running like a top now. Gonna leave the new injectors in for now and keep the old ones as spares.89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
cruiser54 Posted February 3, 2021 Share Posted February 3, 2021 The line from the throttle body to MAP sensor? Link to comment Share on other sites More sharing options...
tugboat95 Posted February 3, 2021 Author Share Posted February 3, 2021 The line from the throttle body to MAP sensor?Yep...looked attached but when I touched, it wasn't.89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
tugboat95 Posted February 3, 2021 Author Share Posted February 3, 2021 I still don't like the cheap plastic look and feel of the new injectors, but they aren't leaking, and I just filled up the gas tank to do a mpg check over the next week or so. So the jury is still out there.89 ComancheEliminator2wd4.0L5 speed PukeGoatFactory Original Link to comment Share on other sites More sharing options...
coolwind57 Posted February 3, 2021 Share Posted February 3, 2021 That crazy line from TB to MAP is THE 1st place to look for those that say, "Man, my engine is running like $h%!". Been there, done that bro. Link to comment Share on other sites More sharing options...
cruiser54 Posted February 3, 2021 Share Posted February 3, 2021 That's why I came up with this fix. CRUISER'S MOSTLY RENIX TIPS THROTTLE BODY TO MAP SENSOR HOSE FIX JANUARY 23, 2016 CRUISER54 43 COMMENTS The Renix throttle bodies have a strange and failure prone connector on the side where the MAP supply originates and then runs up to the MAP sensor located on the firewall. This hose/pipe assembly is no longer available for purchase. The real kicker here is how critical this line is in supplying the correct vacuum signal to the MAP, the most relied upon sensor for the ECU to read regarding air/fuel ratio. Any cracks, melted spots, or loose rubber connectors can cause major starting and driveability issues. There’s a simple fix though. All that’s required is a 1/8” NPT tap, a new throttle body gasket ( Napa FPG 60742 ), a vacuum fitting (Napa 05703-B102), two vacuum elbows (Napa CRB2670), and a length of new plastic piping (Napa CRB2672). Remove the throttle body and take it to the workbench. Using an oiled tap along with a driver, carefully thread the lower of the 2 holes of the throttle body where the old fitting was plugged in. Don’t go too deep. These are pipe threads. Flush the hole with carb cleaner and inspect for any left over cuttings. This is an excellent time to do a complete throttle body and IAC cleaning. See Tip 11. Take the vacuum fitting (05703-B102 ) and apply a LITTLE bit of thread sealer on the threads only. I prefer Permatex #2 but almost anything is fine. . Carefully screw the fitting in until snug. Install one of the vacuum elbows on the MAP sensor so it points toward the throttle body, and the other vacuum elbow on your new throttle body fitting so it points up to the MAP sensor. Cut a length of the new plastic tubing (approximately 13 inches) to fit between the vacuum elbows and install it making sure there is enough slack for some engine movement. Route it according to the photo. We don’t want any rubbing or chafing with engine movement. Not a bad idea to use some contact cement or Gasga-Cinch sparingly on the tubing to elbow connectors. Link to comment Share on other sites More sharing options...
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