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overwhelming exhaust smell (updated 10-7-14)


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When I start up my mj and idle it (because it doesn't move much now adays) its overwhelmingly potent. I "think" its running rich. I get about 12-14 mpg on highway. New Fuel filter , New Fuel pressure regulator, 4 hole neon injectors. I have the stock 1988 renix 4.0 (106,000) auto 4x4 with 32's, 4.10's. I have some bolt ons. Running a pacesetter header with a new O2 sensor high flow cat and magnaflow muffler. 2.5 inch exhaust from header back. Also Egr is blocked off. Runs pretty good untill I get to 1/8 tank and you hit the gas and it hesitates real bad like it has no gas or its dirty. 

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I have a very similar setup to yours. My EGR is working and mine is an 89 2WD. Other than that pretty much the same. I just went through a bunch of rough idle/hesitation diagnosis and here is the thread for it. The thread is very long but has a lot of good info.

 

http://comancheclub.com/topic/42581-renix-dead-spot-and-idiling-low/

 

I know during startup the truck runs rich anyways until the O2 sensor is hot enough to be operational and go into close loop mode. The O2 sensor is in open loop mode when warming up meaning it isnt sending any signals to the ECU.

 

I smell a good amount of exhaust as well on mine during startup. Then its not so bad after its warmed up.

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I think the "Neon" 703 injectors (Bosch 0280155703) might have too much flow for your engine. I am running the same injectors on the stroker and after break-in I had to crank down the pressure regulator to correct the A/F ratio on the meter. The 703's flow quite a a bit more than your stock injectors did.

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I think the "Neon" 703 injectors (Bosch 0280155703) might have too much flow for your engine. I am running the same injectors on the stroker and after break-in I had to crank down the pressure regulator to correct the A/F ratio on the meter. The 703's flow quite a a bit more than your stock injectors did.

 

What A/F meter do you have?

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  • 4 weeks later...

I just put new coil, rotor, distributor, cap, plugs, and wires in it this weekend. still smells rich. has better throttle response but some times when I hammer is while driving it fills sluggish at first and then picks up.... some what like bogging down but maybe that might be the wrong way of describing it. I have never replaced the Tps( which does stick some times) or the Map sensor. Will a ban map sensor cause it to run rich? should I try to go ahead and replace those?

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the new exhaust parts smell wore off many many months ago. I forgot to mention that I get about 10 mpg and got that even before I did the injector swap.

 

 

Here are the spark plugs I pulled this weekend. They defiantly show me that its running to rich.  I also feel like I don't have as much power as I used to. Is it possible to be down on power if I'm running to rich?

 

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