mikestewart395 Posted June 2, 2014 Share Posted June 2, 2014 A few months back I ran into a problem where the engine won't go over 3k rpm. So at 55 the engine would shutter and back fire and no matter what it will not go past 3k rpm. The Ecm gave me the code "injector circuit" I commute through city traffic so not going over 55 was something I could live with for a while. Now going to work yesterday, it started doing the same thing, except now I can not go over 2k rpm, thats about 42 mph. When starting from a stop if I floor the pedal, or get down on it pretty good it will start shaking and stuttering immediately. It is almost like I have trash in the lines, but I put a new fuel filter on a couple weeks ago. I am really getting frustrated here. My plan is this weekend install new fuel injectors, then a couple of weeks new fuel pump, lines then tank. My idea is have everything from fuel tank to injectors be brand new. Link to comment Share on other sites More sharing options...
Nefarious Posted June 2, 2014 Share Posted June 2, 2014 (edited) Mass air flow sensor. Clean and tighten electrical connector first as sometimes its just bad electrical connection and if problem persists run maf diagnosis test VIA factory service manual. You just described text book Nissan maf issues. Edited June 2, 2014 by Nefarious Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 2, 2014 Author Share Posted June 2, 2014 I cleaned the sensor a month ago, should I just get a new one? And where can I find a factory service manual? Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 2, 2014 Author Share Posted June 2, 2014 $400 for a new sensor? lol. Forget that. I will get some cleaner and try it again. I'm going to chase the wires down tonight as well, checking the connectors. Link to comment Share on other sites More sharing options...
5523Pathfinder Posted June 2, 2014 Share Posted June 2, 2014 I'm sure you dropping a injector. Only two in your rig, change them both and see how it does. Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 2, 2014 Author Share Posted June 2, 2014 I'm thinking the same. I can not get the injectors until friday, so I will go home tonight and play with the MAF sensor and all connectors. Link to comment Share on other sites More sharing options...
Nefarious Posted June 3, 2014 Share Posted June 3, 2014 Is there no factory service manual in the garage section posted for tbi models? Should have a test to perform with a multimeter to test the maf. Link to comment Share on other sites More sharing options...
ahardb0dy Posted June 3, 2014 Share Posted June 3, 2014 (edited) Not sure if the MAF sensor is included in this part but if it is for $75 surplus brand new part you can't beat it ! Looks like the MAF is on the part. http://www.oem-surplus.com/nwp/truck-1.htm top row far right for VG30 auto second row far left for VG30 auto with cruise Both say 86-87 D21 but should be the same You can download the 89 FSM for the hardbody, the engine and EF/EC sections should be the same: http://www.nicoclub.com/FSM/Hardbody/d21_truck_1989.pdf Edited June 3, 2014 by ahardb0dy Link to comment Share on other sites More sharing options...
Kingman Posted June 3, 2014 Share Posted June 3, 2014 I had the same issue with the same injector code. The problem was the CHTS, the injectors were perfectly fine. Might be worth a look. Link to comment Share on other sites More sharing options...
PeteyPathy Posted June 4, 2014 Share Posted June 4, 2014 I had similar symptoms on mine when I first got it, after a couple hours of frustration i realized that choke butterfly was partly closed. When i tracked down the wires for automatic choke i found a loose wire at plug. Repaired plug and it and it went back to running normally. Choke is normally closed has to have signal to open so with engine running look down into TB and make sure choke plate is completely vertical. Link to comment Share on other sites More sharing options...
Kingman Posted June 4, 2014 Share Posted June 4, 2014 The TBIs don't use a choke, all fuel injected bud. Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 4, 2014 Author Share Posted June 4, 2014 What is a CHTS? I cleared the ECM and getting the same injector circuit code, but I did find out it is in Limp mode, not allowing the engine to go over 2k rpm Link to comment Share on other sites More sharing options...
Kingman Posted June 4, 2014 Share Posted June 4, 2014 That's usually the MAF sensor or wiring. Just bounces at 2K right? Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 4, 2014 Author Share Posted June 4, 2014 Yep. For a while it wouldn't go past 3k, now it won't pass 2k. But it is intermitten.<-- however thats spelled. Coming to work today it would actually go to about 2500, not stuttering. Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 4, 2014 Share Posted June 4, 2014 CHTS = cylinder head temp sensor. Weird that the max speed is fluctuating. Link to comment Share on other sites More sharing options...
Nefarious Posted June 4, 2014 Share Posted June 4, 2014 My 1993 sentry classic did the exact same. It was tbi injected and had intermittent bounce at 2k-2.5k. All the symptoms you described. If the chts doesn't work out I would look at the maf... a bad maf is one of the few symptoms that will put an ecu into limp mode. Link to comment Share on other sites More sharing options...
Nefarious Posted June 4, 2014 Share Posted June 4, 2014 You should be able to ohm test your injectors. If their impedance is in spec, there's not much else to go wrong. Its just a solenoid valve (electrical coil and actuator). Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 4, 2014 Author Share Posted June 4, 2014 I'll ohm test it tonight. Link to comment Share on other sites More sharing options...
Kingman Posted June 5, 2014 Share Posted June 5, 2014 Limp mode is a hard set limiter at 2,200. It just revs and bounces there. Link to comment Share on other sites More sharing options...
mikestewart395 Posted June 5, 2014 Author Share Posted June 5, 2014 Yea, that's what it's doing. If I actually hit 2500 it will start bogging down after a min until I slow to 2000. I use 2000 loosely, it is 2200. Update though. I just got home, put new batt in my meter, now one injector is reading 1.4 ohm, the other is 1.0. This doesn't sound right does it? Link to comment Share on other sites More sharing options...
Nefarious Posted June 5, 2014 Share Posted June 5, 2014 That doesn't sound right, no, check Google or the fsm for injector spec on the tbi model. I know later high impedance injectors are spec at 10-14 ohms, not sure of tbi models though . Link to comment Share on other sites More sharing options...
PeteyPathy Posted June 5, 2014 Share Posted June 5, 2014 The TBIs don't use a choke, all fuel injected bud. I'm sorry perhaps you should explain that to the butterfly in my TB under the injectors. "you are not a choke you are an air flow restriction plate :-[" Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 5, 2014 Share Posted June 5, 2014 That's the throttle plate. Break it to the poor thing slowly, though, it might take a minute to sink in if it's thought it's a choke plate all its life. Anyway, I just took a look at the '89 D21 FSM (because I fill my hard drive with such things) and found the following: "If one injector malfunctions, it is possible to drive the vehicle and start the engine. But engine speed will not rise over 2800 rpm in order to inform the driver of fail-safe operation while running." (EF&EC 40) I haven't found a test procedure for the injector malfunction yet that isn't just listening for the click. I guess you could pull the injectors, have someone crank the motor (coil wire pulled), and see which one sprays. Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 5, 2014 Share Posted June 5, 2014 Stupid edit timeout... EF&EC 121 says they should be around 1.5 ohms. Maybe that 1.0 is suspect? Unrelated, these old manuals have some really odd illustrations in them.. It's like pictionary on hallicinogens. And for this test, you need Christopher Robin to crouch in the back seat area while somebody else drives. Sorry, back on topic. Injectors. Apparently there's a California-only code for a leaking injector. If yours is California-spec, you might check for that as well. I don't know if that failure was tied to limp mode or not, but it apparently trips the check light on those. I got the FSM from a link somebody posted a while back; might still be in the FSM downloads thread. Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 5, 2014 Share Posted June 5, 2014 Forum isn't displaying the FSM page right on my end, here's the direct photobucket link: http://i244.photobucket.com/albums/gg10/Darwinpasta/Picture1_zps4ed7fa9b.png Link to comment Share on other sites More sharing options...
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