Running rich

[olddirtyrake]

95 path running rich and getting bad mph, not sure what I should do about this. I've cleaned the sensors, changed plugs cap wires, all new gaskets, may be a vacuum leak but I dont think so as I replaced all vacuum lines and triple checked. I have 1 broken exhaust stud so theres a little exhaust leak manifold to head but other than that I dont really know. I'm not getting any error codes just running rich and not exactly sure what to do about it. Could the TPS be misaligned?

I love driving my path but its killing me at the pump.

[krmiller07]

95 path running rich and getting bad mph, not sure what I should do about this. I've cleaned the sensors, changed plugs cap wires, all new gaskets, may be a vacuum leak but I don't think so as I replaced all vacuum lines and triple checked. I have 1 broken exhaust stud so theres a little exhaust leak manifold to head but other than that I don't really know. I'm not getting any error codes just running rich and not exactly sure what to do about it. Could the TPS be misaligned?

I love driving my path but its killing me at the pump.

 

Hey Dirtyoldrake,

 

For what it's worth, I had the same issue going on with my 89 pathy for months. It baffled me to the point of frustration, I t did all the 'common sense' diagnostics, from vacuum leaks to 02 sensor, head temp sensor, plugs, wires, cap,rotor,plugs, cleaned the MAF sensor etc. I finally took to 3 different 'techs' one told me I had a bent valve, one said it was an intake gasket leak and the other said I had broken rings and one 'dead' cylinder. Well, after ruling out all of the expensive possibilities. I stumbled across an old FSB written by an engineer at Nissan back in the 80's. It simply addressed the basic head, intake design of the VG 30 series engine. Apparently at the dealer level, the techs were experiencing the same poor, rough running, excessive fuel consumption problem.

 

At that time, his recommendation was to 'media blast' (Walnuts) the intake runners and valves to remove carbon build up in those areas, followed with adding fuel injector clear to the fuel. Well I didn't pull the heads to do this. But I did run a super concentrated dose of "TECHRON" (made by Chevron) fuel system cleaner through the gas tank with about an 1/8th tank of gas. The bottle recommends using ONE bottle with One tank of fuel. I wanted to keep it as undiluted as possible, but It ran like crap (no change) until that tank was almost gone. Then I filled up with a tank of mid grade regular, and by the new tank was half gone, the truck started to come to life! The mileage got a little better, idle smoothed out considerably, and the power came back, like it never was before!

I've talked to several 'older' techs that have been around awhile, and they all agreed that carbon build up will cause these symptoms. Carbon acts like a piece of charcoal and will absorb unburned fuel like a sponge. Eventually this will also clog injectors and not allow them to close or spray an erratic pattern. All of this will cause rough running, poor idle, high gas mileage, richness, and over all poor performance.

Give it a try. This cleaner is alot less expensive than all the other possibilities! I did a fair amount of research on TECHRON, and have used it for years in my Porsche's. It was the only fuel system cleaner approved by Porsche, Ferrari and BMW factories. I'm sure there are others out there, but I couldn't confirm what was actually in those 'cleaners'!After the initial cleaning, I'd run a bottle through the fuel tank every 3000 miles to keep it clean. With the low grade gas being sold around the country, any thing can be added to get the crap to burn !

Hope this helps.

[JamesRich]

Hey Dirtyoldrake,

 

For what it's worth, I had the same issue going on with my 89 pathy for months. It baffled me to the point of frustration, I t did all the 'common sense' diagnostics, from vacuum leaks to 02 sensor, head temp sensor, plugs, wires, cap,rotor,plugs, cleaned the MAF sensor etc. I finally took to 3 different 'techs' one told me I had a bent valve, one said it was an intake gasket leak and the other said I had broken rings and one 'dead' cylinder. Well, after ruling out all of the expensive possibilities. I stumbled across an old FSB written by an engineer at Nissan back in the 80's. It simply addressed the basic head, intake design of the VG 30 series engine. Apparently at the dealer level, the techs were experiencing the same poor, rough running, excessive fuel consumption problem.

 

At that time, his recommendation was to 'media blast' (Walnuts) the intake runners and valves to remove carbon build up in those areas, followed with adding fuel injector clear to the fuel. Well I didn't pull the heads to do this. But I did run a super concentrated dose of "TECHRON" (made by Chevron) fuel system cleaner through the gas tank with about an 1/8th tank of gas. The bottle recommends using ONE bottle with One tank of fuel. I wanted to keep it as undiluted as possible, but It ran like crap (no change) until that tank was almost gone. Then I filled up with a tank of mid grade regular, and by the new tank was half gone, the truck started to come to life! The mileage got a little better, idle smoothed out considerably, and the power came back, like it never was before!

I've talked to several 'older' techs that have been around awhile, and they all agreed that carbon build up will cause these symptoms. Carbon acts like a piece of charcoal and will absorb unburned fuel like a sponge. Eventually this will also clog injectors and not allow them to close or spray an erratic pattern. All of this will cause rough running, poor idle, high gas mileage, richness, and over all poor performance.

Give it a try. This cleaner is alot less expensive than all the other possibilities! I did a fair amount of research on TECHRON, and have used it for years in my Porsche's. It was the only fuel system cleaner approved by Porsche, Ferrari and BMW factories. I'm sure there are others out there, but I couldn't confirm what was actually in those 'cleaners'!After the initial cleaning, I'd run a bottle through the fuel tank every 3000 miles to keep it clean. With the low grade gas being sold around the country, any thing can be added to get the crap to burn !

Hope this helps.

I think that may be more of a problem with the older engines with TBI instead of MPI. Or maybe just the older casting, when I pulled the heads off my wife's 01 Quest van (VG33) with 118K the ports and valves were clean.

I didn't use TECHRON but the STP in the black bottle in my 87. I used this on my week and a half hunting trip which I rolled over 500 miles so it could be just the long runs that helped. It has a little more power than it had before but it still drinks gas. I didn't concentrate it as much as you did though I just dumped it in a full tank. I will let you know what the ports look like when I yank the intake off in a few weeks. I am going to try and convert it over to MPI from a 94 truck.

James

[carv504]

I think that may be more of a problem with the older engines with TBI instead of MPI. Or maybe just the older casting, when I pulled the heads off my wife's 01 Quest van (VG33) with 118K the ports and valves were clean.

I didn't use TECHRON but the STP in the black bottle in my 87. I used this on my week and a half hunting trip which I rolled over 500 miles so it could be just the long runs that helped. It has a little more power than it had before but it still drinks gas. I didn't concentrate it as much as you did though I just dumped it in a full tank. I will let you know what the ports look like when I yank the intake off in a few weeks. I am going to try and convert it over to MPI from a 94 truck.

James

I am having a similar problem. The exhaust smells rich, and the idle is wild to the point of the motor stopping. It's frustrating.