engine issues

[dirtyhorse]

Another question my engine dose not run well at low rpm it sputters and surges until I put the hammer to the floor and then it goes real good I can't pin point the cause I replaced o2 sensor and new plugs and wires also a new egr sensor and fuel filter idk what else to look into maybe timing but I'm not sure I'm no mechanic I just know enough to get into trouble

 

[LIMA BEAN]

Dirty MAFS could contribute.

 

[wildbill23c]

Could be that the carburetor just needs adjusted. I found out the 2 screws on the front of my carburetor were self adjusting while driving due to weak springs. I pulled the springs off another junk carb and fixed the problem. So try adjusting those 2 front screws I turned mine all the way in till just slightly seated, then backed them out 2-1/2 turns and adjusted from there till it idled smooth. After I did that my fuel economy got extremely better as well, I also tied my choke plate open as the choke wasn't working correctly which caused it to stall and idle very weird sometimes. Another thing I had an issue with on mine was the EGR valve was bad, so it was causing all sorts of weird idling, stalling, hard to start sometimes, etc. I disconnected the vacuum line from it and plugged it and after that I was able to actually tune the carburetor completely.

 

[kimcrwbr1]

Disconnect the battery and clean the intake air temp sensor with rubbing alcohol. Clean the throttle body around the butterfly and then connect the battery and run it for 20 mins or so and see how she idles. Whenever you clean or change a sensor you need to reset the computer by disconnecting the battery for 1/2 an hour. Have you replaced the PCV it is allways the most neglected part of regular maintenance. Just change the PCV when you replace the plugs, It will pay for itself in short order in fuel effeciency plus it keeps the internals in the engine from gumming up.

 

[kimcrwbr1]

Sorry you have the ACT air charge temp sensor clean it with rubbing alcohol or elect cleaner.

 

[dirtyhorse]

It dose not have a mass air sensor and its throttle body

 

[dirtyhorse]

It idels just fine its only when I'm just a Lil in the throttle it acts up it only has a tps no mafs I Believe the egr valve is good no intake temp sensor my dad helped change plugs and wires and messed up firing order and back fired threw the intake blew apart my air box so I put a cold air cone filter on it and it still runs the same as it did with the air box so I know the intake temp sensor ain't it also the exhaust smells very rich and the back cylinder on driver side keeps fouling out plugs this idk why and my fuel mileage really poor could it be as simple as a cap and rotar not getting the right spark at low rpm

 

[Earl43P]

http://oldfuelinjection.com/index.php?p=28

http://oldfuelinjection.com/index.php?p=29

http://oldfuelinjection.com/index.php?p=30

ACT and ECT are major drivers for the air/fuel ratio and can make it run very rich, as if it were cold.

Test them.

The fact that it runs better when pedal is floored confirms that you have an Emissions system problem. When WOT (wide open throttle), the computer ignores whatever the sensors are reading and uses stored values.

http://oldfuelinjection.com/?p=27

The MAP isn't easily tested, so if you can, grab one of those at the junkyard if you don't find anything wrong with the other sensors.

Here's some good reading about how the Emissions system operates.

http://oldfuelinjection.com/?p=64

You might also consider testing the Fuel Pressure Regulator http://oldfuelinjection.com/index.php?p=41

That's not the best test, you should goose the gas hard and note the change to fuel pressure from idle to high rpm. Another test is to idle, check fuel pressure. Remove vacuum line to FPR and note change in fuel pressure and idle.


If I read your most recent post correctly and you don't have an intake air temp sensor installed, THAT is a problem.

 

[dirtyhorse]

Ok ect , act, map, rtfm what are the full names I'm no bueno with that sensor abbreviations mumbo jumbo I'm a smart guy just not professional mechanic like I said just know enough to get myself into trouble I'm a welder fabricator give me blue prints and weld symbols I can read em like book lol but this all is much appreciated I've talked to mechanics and none have been able to tell me squat at least not as much as you have and just a fyi it's a 87 Broncos11 with a 2.9 liter 5 speed trans it's the silver one in my pics the red one is almost road ready just needs a clutch bleed and cross member moved back because the new/used tranny I just put in it is 2.5 inches longer in the tailhousing area because I'm almost sure it came out of a extended cab ranger and that Broncos runs like it's new got a hell of a deal for 300 bucks came with new tranny just had to put it in

 

[LIMA BEAN]

Ok ect , act, map, rtfm what are the full names I'm no bueno with that sensor abbreviations mumbo jumbo I'm a smart guy just not professional mechanic like I said just know enough to get myself into trouble I'm a welder fabricator give me blue prints and weld symbols I can read em like book lol but this all is much appreciated I've talked to mechanics and none have been able to tell me squat at least not as much as you have and just a fyi it's a 87 Broncos11 with a 2.9 liter 5 speed trans it's the silver one in my pics the red one is almost road ready just needs a clutch bleed and cross member moved back because the new/used tranny I just put in it is 2.5 inches longer in the tailhousing area because I'm almost sure it came out of a extended cab ranger and that Broncos runs like it's new got a hell of a deal for 300 bucks came with new tranny just had to put it in

Cheat sheet.:icon_thumby:

http://www.therangerstation.com/resources/terms.htm

 

[adsm08]

Dirty MAFS could contribute.

Could be that the carburetor just needs adjusted.

Gents, thinking caps please.

1987, Bronco II.

This means that it has a 2.9, without question.

The 2.9 had neither a MAF nor a carb. Not in 87 anyway. A few 91s got MAFs.



Dirty, pull the vacuum line off the round jigger on the fuel rail and make sure there is no gas in the vacuum line.

 

[wildbill23c]

Yeah good point, but god knows the way people swap engines around here on this forum LOL. You never know he may have a 460 under the hood...Oooh I wish LOL.

 

[LIMA BEAN]

Yeah good point, but god knows the way people swap engines around here on this forum LOL. You never know he may have a 460 under the hood...Oooh I wish LOL.

Or he could have some sort of anomaly occuring within the matrix of his flux capaciter.

The fuel regulator was a good thought though.