bobco Posted October 6, 2008 Share Posted October 6, 2008 have a 1988 v6 pathfinder with 141k miles on it, has had intermittant poor running problem for some time. i took it to the local nissan dealer to be checked, they said bad/dirty injectors, mixture plate heater bad and tps bad. I put in an aftermarket tps (not sure the idle circuit is workin), still runns like crap, ran some techtron concentrate thru with no help, check fuel pressure with gauge and it is ok. Question is how can I test the injectors? are there some inexpensive injectors that are ok for this engine? Is the throttle plate mix heater and issue or just on cold start ups? thanks for any help I want to enjoy driving this thing again!!! Link to comment Share on other sites More sharing options...
Precise1 Posted October 6, 2008 Share Posted October 6, 2008 I can address some of this but I don't know the TBI systems well. Try using Lucas injector cleaner... Run the ECU diagnostic codes (especially when it is acting up). The directions are here... http://www.nissanpathfinders.net/forum/index.php?showtopic=21 No, I don't believe there are cheap injectors available. Good news is that yopu only need 2. Somewhere around here is a link to a factory service manual. It should help with the trouble shooting/testi9ng. Let me find it... B Link to comment Share on other sites More sharing options...
GrimGreg Posted October 7, 2008 Share Posted October 7, 2008 As for the heater, it can be done away with entirely. Link to comment Share on other sites More sharing options...
bobco Posted October 7, 2008 Author Share Posted October 7, 2008 As for the heater, it can be done away with entirely.remove it? I plan on pulling throttle body off, can I just forget to put the heater back on? no noticable effect on performance??? Link to comment Share on other sites More sharing options...
bobco Posted October 7, 2008 Author Share Posted October 7, 2008 I can address some of this but I don't know the TBI systems well. Try using Lucas injector cleaner... Run the ECU diagnostic codes (especially when it is acting up). The directions are here... http://www.nissanpathfinders.net/forum/index.php?showtopic=21 No, I don't believe there are cheap injectors available. Good news is that yopu only need 2. Somewhere around here is a link to a factory service manual. It should help with the trouble shooting/testi9ng. Let me find it... B ran diags , no codes on the ecu, where do ya get this lucas cleaner? factory service manual would be SUPER!!!!! Link to comment Share on other sites More sharing options...
GrimGreg Posted October 7, 2008 Share Posted October 7, 2008 remove it? I plan on pulling throttle body off, can I just forget to put the heater back on? no noticable effect on performance??? Supposed to increase performance with it removed, it restricts the air flow and fuel mixture ability (at least that is what Lee, from the former L&P, told me once). I think it is purely for emissions purposes when cold, not for helping start up when cold. Link to comment Share on other sites More sharing options...
bobco Posted October 7, 2008 Author Share Posted October 7, 2008 Supposed to increase performance with it removed, it restricts the air flow and fuel mixture ability (at least that is what Lee, from the former L&P, told me once). I think it is purely for emissions purposes when cold, not for helping start up when cold. sounds like it needs to go away Link to comment Share on other sites More sharing options...
bobco Posted October 8, 2008 Author Share Posted October 8, 2008 a little update. I pulled the throttle body off last nite. the mixture heater was fried so I busted out the grid and cleaned it up, will not be hooking power back to it. noticed a passage that is open to the intake was all clogged up with carbon depsoit , this passage was on the throttle body and under the maf, don't know its purpose but it is going to get a good flush with throttle body cleaner tonite. injector tips look clean, but the injectors could still be the issue. going to pull the EGR out tonite and clean that up, looks like passage to it has allot of crud in it. I think I will give it all a good cleaning and put back together and see if any improvements. Link to comment Share on other sites More sharing options...
Precise1 Posted October 8, 2008 Share Posted October 8, 2008 That sounds like a good place to start. where do ya get this lucas cleaner? I got mine at Autozone for $5, but it should be almost everywhere. Lucas is a well known brand... I believe the only link we have to a FSM is for a 94 which won't help you for this. I could have sworn there was one for TBI years, but perhaps it is defunct. I'll let you know if i find it. B Link to comment Share on other sites More sharing options...
bobco Posted October 8, 2008 Author Share Posted October 8, 2008 That sounds like a good place to start. I got mine at Autozone for $5, but it should be almost everywhere. Lucas is a well known brand... I believe the only link we have to a FSM is for a 94 which won't help you for this. I could have sworn there was one for TBI years, but perhaps it is defunct. I'll let you know if i find it. B thanks, I think I know where to find that lucas stuff now. a fsm for a 88 would be worth GOLD, well maybe Link to comment Share on other sites More sharing options...
bobco Posted October 9, 2008 Author Share Posted October 9, 2008 update, truck is running like a million bucks, pulled the egr out and cleaned upthe passage, it was not to bad. throttle body cleaner on all of the passages on the TB and especailly the one on the bottom that looks like it feeds back to the maf. put all back together and turns out is just need a good cleaning, no parts required. feel better about getting the heater grid out of there that was falling apart also. I believe that one passage that was totally carboned up was the problem. thanks evrybody for the help. Link to comment Share on other sites More sharing options...
Precise1 Posted October 9, 2008 Share Posted October 9, 2008 I'm glad you got it figured out and it was a cheap fix!! Good job. B Link to comment Share on other sites More sharing options...
GrimGreg Posted October 9, 2008 Share Posted October 9, 2008 Yeah, they can carbon up a good bit. I think it was 88 one time posted a pic of either his, or one he was working on that was clogged almost solid. Link to comment Share on other sites More sharing options...
Morydees Posted October 11, 2008 Share Posted October 11, 2008 (edited) I found your thread in searching because I have a similar problem. Unfortunately, I cleaned everything mentioned and I still have the two main symptoms: 1) extremely bad gas mileage (9-10 mpg highway) and 2) running rough at low speeds and occasionally it'll fall on it's face with no power from a stoplight. And recently when it's warmed up, sometimes it'll be hard to start I took it to my mechanic and we did a full tuneup, replaced all filters, replaced the catalytic converter, checked fuel pressure, compression check and checked for codes. Nothing at all. The puzzling part is he mentioned something strange that he thought it might be. It's a fuel injected car obviously but he said there's some sort of "carb-like" part that he thinks is the problem. That and he can't seem to source the part new or find it at Pick-U-Part. Does anyone know what that part could possibly be called or have any other things to try? I greatly appreciate it! Mory 1988 Pathfinder SE V6 Los Angeles Edited October 11, 2008 by Morydees Link to comment Share on other sites More sharing options...
GrimGreg Posted October 11, 2008 Share Posted October 11, 2008 Well, the VG30I has a Throttle Body Injection system, basically it is just a pair of injectors firing into the intake. The throttle body unit does resemble a carb in looks, but that is about it. Link to comment Share on other sites More sharing options...
Precise1 Posted October 12, 2008 Share Posted October 12, 2008 Mory, I have no idea what this part may be, but your symptoms sound like bad O2 sensor. I believe there is a thread on how to test it and another one where it outlines taking it out and cleaning it off... with a torch. If you can't find them, I'll be glad to help. B Link to comment Share on other sites More sharing options...
Morydees Posted October 12, 2008 Share Posted October 12, 2008 Thanks for the quick responses guys! I can't believe I never thought to check the O2 sensor and if my mechanic hasn't yet, he should have! Link to comment Share on other sites More sharing options...
bobco Posted October 13, 2008 Author Share Posted October 13, 2008 Thanks for the quick responses guys! I can't believe I never thought to check the O2 sensor and if my mechanic hasn't yet, he should have! could be the mass air flow meter on the side of the throttle body. did the mech clean this?? Link to comment Share on other sites More sharing options...
bobco Posted October 14, 2008 Author Share Posted October 14, 2008 I spoke to soon, darn it , running like crap again. got to believe the injectors are questionable at this point...how do I test them? Link to comment Share on other sites More sharing options...
jlewis2 Posted October 15, 2008 Share Posted October 15, 2008 could be the mass air flow meter on the side of the throttle body. did the mech clean this?? So the TBI 3.0 engine (Mine's an 89) DOES have MAF? I have been searching for days about this info. I know the MPFI has one in line of the intake duct but I have not been able to find anything detailing an MAF for the throttle body other than this post, in this thread, anywhere. Im assuming it is mounted external though I recently had the air cleaner assembly off and I didn't see it. I'm blind? a picture would be worth 1000 words. Link to comment Share on other sites More sharing options...
bobco Posted October 15, 2008 Author Share Posted October 15, 2008 So the TBI 3.0 engine (Mine's an 89) DOES have MAF? I have been searching for days about this info. I know the MPFI has one in line of the intake duct but I have not been able to find anything detailing an MAF for the throttle body other than this post, in this thread, anywhere. Im assuming it is mounted external though I recently had the air cleaner assembly off and I didn't see it. I'm blind? a picture would be worth 1000 words. the maf is on the right side of the tb, black little box held on with 3 screws, search on this site someone has a procedure on how to clean it with PICTURES Link to comment Share on other sites More sharing options...
Morydees Posted October 16, 2008 Share Posted October 16, 2008 (edited) The puzzling part is he mentioned something strange that he thought it might be. It's a fuel injected car obviously but he said there's some sort of "carb-like" part that he thinks is the problem. That and he can't seem to source the part new or find it at Pick-U-Part. Does anyone know what that part could possibly be called or have any other things to try? I greatly appreciate it! Quoting myself here because I have an update: I called my mechanic and it turns out the "mystery part" was just the entire throttlebody assembly (and all the attached sensors like TPS and such). I don't know why he didn't just say that originally but that implies they don't know what's causing it and they wanted to just replace everything. He was trying to get those parts used since all of them new are probably $$$. Unfortunately no one has them used locally so new is the only bet. I'm really torn here because I could end up spending double what I paid for the car just to take stabs at random parts and it might not even get fixed. Edited October 16, 2008 by Morydees Link to comment Share on other sites More sharing options...
Precise1 Posted October 16, 2008 Share Posted October 16, 2008 I agree, just replacing things is a stupid and wasteful way to 'fix' it. It doesn't sound like he knows Nissans or electronics very well. B Link to comment Share on other sites More sharing options...
GrimGreg Posted October 17, 2008 Share Posted October 17, 2008 Yeah, the injectors and sensors can usually be tested by checking their resistance. The FSM will give the proper resistances for each. Link to comment Share on other sites More sharing options...
bobco Posted October 21, 2008 Author Share Posted October 21, 2008 Yeah, the injectors and sensors can usually be tested by checking their resistance. The FSM will give the proper resistances for each. what the ohms on the 88 injectors?? dam thing is running great now but cannot be trusted, I hate that in a vechicle!!! Link to comment Share on other sites More sharing options...
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