92 Infiniti Fuel/Air stutter????HELP

[odyyss]

I have a 92 Infiniti that has recently started acting like it cant breath. While driviing at speeds of atleast 40mph the car does ok until i come to a red light. when i stop the rpm's drop very low and the car dies, not every time I stop just most times. It will restart very easily but when I take off from the light it acts like it is either smothering or flooding and will not take off like it should. But if i get it up to 40 again it does fine. i have replaced the air filter and the fuel filter. What is weird is.... when its acting like its flooding if you put it in neutral and rev the engine it does just fine. That makes me think the problem isnt in the injectors, fuel pump. Does anyone have any ideas? Does the 92 have a MAF? Or should I try the Throttle positioner or the fuel pressure regulator? PLZ HELP GUYS YOUR BROKE FEMALE INFINITI OWNER

[maxnix]

Well, first off, read the timing chain guide article immediately! That may help you decide how to proceed.

With so little maintenance history, it is difficult to guess how to proceed. But as fuel demands vary not just by rpm but also by load, I would obtain and post the results of a fuel pressure test.

I also would post this in Infiniti Online Mechanic with a more complete maintenance history and ask the moderator to delete this post with a link to it in the new post.

Welcome to NICO!

[Haitian_King]

I have a 92 Infiniti that has recently started acting like it cant breath. While driviing at speeds of atleast 40mph the car does ok until i come to a red light. when i stop the rpm's drop very low and the car dies, not every time I stop just most times. It will restart very easily but when I take off from the light it acts like it is either smothering or flooding and will not take off like it should. But if i get it up to 40 again it does fine. i have replaced the air filter and the fuel filter. What is weird is.... when its acting like its flooding if you put it in neutral and rev the engine it does just fine. That makes me think the problem isnt in the injectors, fuel pump. Does anyone have any ideas? Does the 92 have a MAF? Or should I try the Throttle positioner or the fuel pressure regulator? PLZ HELP GUYS YOUR BROKE FEMALE INFINITI OWNER

I'd like to think that it is the MAF. It may not even be dirty. Just a loose connector.

zerothread?id=82862 http://q45.org/maf.html

I can't find the thread/picture that shows the loose MAF connector pin, but if you take a look at yours, you would be able to see what I was talking about. It could be possible that one of the pins has become "uncrimped" and isn't making solid contact. It's possible to just push down on the offending pin and "recrimp" it. Cleaning the pins and applying dielectric grease to them helps as well. Better conductivity (I think) as well as corrosion protection.

[goody90q45]

......I can't find the thread/picture that shows the loose MAF connector pin, but......

This one?

[Haitian_King]

You got it. I need to save that picture so I can find it easily. It didn't come up in a Google search earlier.

[odyyss]

I have a 92 Infiniti that has recently started acting like it cant breath. While driviing at speeds of atleast 40mph the car does ok until i come to a red light. when i stop the rpm's drop very low and the car dies, not every time I stop just most times. It will restart very easily but when I take off from the light it acts like it is either smothering or flooding and will not take off like it should. But if i get it up to 40 again it does fine. i have replaced the air filter and the fuel filter. What is weird is.... when its acting like its flooding if you put it in neutral and rev the engine it does just fine. That makes me think the problem isnt in the injectors, fuel pump. Does anyone have any ideas? Does the 92 have a MAF? Or should I try the Throttle positioner or the fuel pressure regulator? PLZ HELP GUYS YOUR BROKE FEMALE INFINITI OWNER .........

Ok I have since taken the car to a mechanic here in town... He replaced the MAF, spark plugs, and charged me for a oil change that he didnt give me, go figure! He suggested that I replace the catalyic converters because he didnt feel any exhaust coming out of the back of the car. So for a temprerary fix we just simply cleaned the converters out, they were clogged. The car is still acting the exact same way as the original post. Today I unhooked the tps and drove the car and yes, still the same, no fix. Should i be looking somewhere else?

[maxnix]

Well, definitely look for a technician familar with the VH45DE.

Which catalyts? Pre-catalysts on the headers or main under the cars? Did they rattle?

Why didn't he measeure your fuel pressure after the filter?

[qship96]

Ok I have since taken the car to a mechanic here in town... He replaced the MAF, spark plugs, and charged me for a oil change that he didnt give me, go figure! He suggested that I replace the catalyic converters because he didnt feel any exhaust coming out of the back of the car. So for a temprerary fix we just simply cleaned the converters out, they were clogged. The car is still acting the exact same way as the original post. Today I unhooked the tps and drove the car and yes, still the same, no fix. Should i be looking somewhere else?

There is just soo much WRONG with that paragraph....no exhaust coming out of tailpipes...clogged converters....we cleaned them....they were dirty,etcGet the car to a competant technician who will not play games with you or your Q

[odyyss]

First let me say, i appreciate your interest in trying to help me figure this issue out. I took the car back to the mechanic this afternoon to inform him of what his business has done to my car. I forgot to mention that they somehow either shorted or wired my interior light to where it does not shut off on its own. They didnt notice that because they just simply reached up and turned the switch off but didnt notice the floor board light was staying on. That should have been a sign to them when i picked my car up and they had to JUMP it off! The main catalyic converters just past the headers are what we cleaned out. No they did not rattle but however they did stink quite often! The reason for not replacing is because here in Memphis the trusted company i know that does that wants roughly $3000 for the repair on the converters. I see no need in spending that much just yet when the car doesnt drive well in the first place. As far as the fuel pressure, i changed the filter and didnt think i needed to check the pressure. At this point, i still dont think that is it, maybe i am wrong. But with the converters empty, I can see that dark white blackish smoke coming out of the tailpipe. To me that tells me the car is getting plenty of fuel. I am always up for suggestions since I dont think this mechanic is gonna solve my problem, especially after me ringing his ear earlier. Once I get my moneys worth out of him i will be taking it to a foreign mechanic shop!

[qship96]

How did you clean out the catalytic converters?

[odyyss]

We took the converters off and knocked the guts out of it, then replaced the shell!

[Q45tech]

Felony violation of Federal Clean Air ACT to tamper or remove cats or precats.

[maxnix]

Well, smell alone is not sufficient to diagnose a failed converter. If they didn't rattle, they weren't blocked.

Did you always burn Tier 1 Premium fuel?

I just think you are engaged with the wrong shop. You must measure the fuel pressure to eliminate the FP and FPCU. Do these guys even have a FSM? Do you have the bible sized one that came with the car?

[telcoman]

Ok I have since taken the car to a mechanic here in town... He replaced the MAF, spark plugs, and charged me for a oil change that he didnt give me, go figure! He suggested that I replace the catalyic converters because he didnt feel any exhaust coming out of the back of the car. So for a temprerary fix we just simply cleaned the converters out, they were clogged. The car is still acting the exact same way as the original post. Today I unhooked the tps and drove the car and yes, still the same, no fix. Should i be looking somewhere else?

odyyss

I feel your pain but I learned the hard way that sometimes you just have to suck up the $$$ the dealers charge. If you want to keep the vehicle, then one of those high priced $100k top technicians needs to troubleshoot your vehicle. Replacing parts without resolving generated trouble codes is the wrong way to go. Fuel pump and a possible fuel filter in the tank are possibilities? With a vehicle that old you should have a hard copy of FSM to refer to. Just my $.02

Good luck

Telcoman

[odyyss]

I realize I am replying way late but decided it may help someone else, so here I go. My problem ended up being the fuel pump. After taking the car back to mechanic and screaming about the car. I decided I needed to tell him the order in which to check the car out. CHECK FUEL PUMP PRESSURE! Go figure thats the problem. Hope no one has to go thru what I went thru.