So something got messed up. Put in some new injectors, bored TB and a cowl intake today. Went to start up the comanche and it would barely start. Rough idle then dies shortly after and backfires coming down from 3.5k RPMs or so when I rev the engine to keep it from dying. Throwing codes 24 and 65. Any ideas before I start back tracking everything I did today?
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New Fuel Injectors, TB and intake running horrible
- Thread starter SBpunk
- Start date
- Location
- Southern Maryland
Did you upgrade the injectors or just replace with stock
Sorry was typing on my phone.
Injectors were upgraded to Bosch 703's (black ones), throttle body was upgraded to a 63mm from strokedjeep.com and its a THOR cowl intake.
I got it running, sort of, and unplugged the both the sensors from the back of the throttle body with no real noticeable change. The TPB had a second or so pause then went back to the rough idle. The IAC had no change what so ever.
Fuel injectors were primed prior to starting to ensure no leaks and installed using Vaseline to prevent tearing. The intake holes for the fuel injectors were cleaned as well and carefully as possible. For some reason I've never had any luck with injectors so I'm guessing this is going to be my problem. I kept the stock ones just incase.
For the intake I did something you probably shouldn't and took the tube off the throttle body to see if it wasn't getting enough air but beside the noise there was no change in the idle or start up.
Injectors were upgraded to Bosch 703's (black ones), throttle body was upgraded to a 63mm from strokedjeep.com and its a THOR cowl intake.
I got it running, sort of, and unplugged the both the sensors from the back of the throttle body with no real noticeable change. The TPB had a second or so pause then went back to the rough idle. The IAC had no change what so ever.
Fuel injectors were primed prior to starting to ensure no leaks and installed using Vaseline to prevent tearing. The intake holes for the fuel injectors were cleaned as well and carefully as possible. For some reason I've never had any luck with injectors so I'm guessing this is going to be my problem. I kept the stock ones just incase.
For the intake I did something you probably shouldn't and took the tube off the throttle body to see if it wasn't getting enough air but beside the noise there was no change in the idle or start up.
- Location
- Southern Maryland
Code 24 is a concern: http://www.allpar.com/fix/80s-codes.html
You said you got the code right away. Did you try to start with the sensor unplugged before you got that code? If not then it could be damaged from being removed/reinstalled (they are pretty fragile)
Otherwise I would guess you just need to let the ECM relearn. What year is your heep?
You said you got the code right away. Did you try to start with the sensor unplugged before you got that code? If not then it could be damaged from being removed/reinstalled (they are pretty fragile)
Otherwise I would guess you just need to let the ECM relearn. What year is your heep?
Last edited:
1992 4.0 AX 15
She started up about the same with and without the TPS plugged in. Before I swapped parts over she ran like a champ also. Toil had a slight gas smell so I figured a leaking injector which prompted me to swap them out in the first place.
I'm going to go over all my vacuum lines and some other things when I get home. I'm really hoping its something simple that I can figure out because pulling the injectors is a pain.
She started up about the same with and without the TPS plugged in. Before I swapped parts over she ran like a champ also. Toil had a slight gas smell so I figured a leaking injector which prompted me to swap them out in the first place.
I'm going to go over all my vacuum lines and some other things when I get home. I'm really hoping its something simple that I can figure out because pulling the injectors is a pain.
Alright on my lunch break now and found the flat sensor on the top of the firewall backside engine block (egr?) was unplugged. So now I cleared the engine codes. Still a rough idle but I'm draining the ECU battery and going to give it some time to adjust. Hoping this is the problem since its still backfiring from the exhaust coming down from 3.7kish rps when I give it some gas.
- Location
- Southern Maryland
backfire is unburnt fuel, usually indicates ignition problem (spark doesn't ignite everything) but can be from extra fuel/flooding
Could that be causing the engine stutter as well? Just let the jeep run for about 20min and no change. When I get home again I'm going to unplug the O2 sensor to see if it does anything but so far nothing else is really giving any ground. Here's a crappy video not sure if you can really hear or not.
Backfire went away after the engine warmed up. Maybe I fouled a spark plug or two. Going to try this when I get home.
Unplug O2 sensor see if the problem goes away.
Check spark plugs
Put some fresh gas in it
Change the fuel filter
That's about all I got left. I would be worried about the distrib cap but like I said it ran just fine before I started messing around. Thinking the extra fuel from the new injectors mightve messed up the O2 sensor or spark plugs.
Unplug O2 sensor see if the problem goes away.
Check spark plugs
Put some fresh gas in it
Change the fuel filter
That's about all I got left. I would be worried about the distrib cap but like I said it ran just fine before I started messing around. Thinking the extra fuel from the new injectors mightve messed up the O2 sensor or spark plugs.
- Location
- WA state
Did you make sure your MAP sensor is working and vac line is good and plugged into the correct spot on the TB.
- Location
- Southern Maryland
If there was no difference unplugging the O2 then it might be defective?
All the vacuum lines seem good. It seems to be running better now without the O2 sensor plugged in which means its probably bad. I'm ordering a new one today since they're pretty cheap off amazon for a Bosch. Hopefully the down pipe isnt rusted. Knowing my luck the last few days it'll snap on me. I'll update shortly.
On the bright side I got my WJ control arms installed, finished wiring up my CB/PA (my girls like yelling 'Autobots Rollout' over the PA" and the floor finished bed lining.
On the bright side I got my WJ control arms installed, finished wiring up my CB/PA (my girls like yelling 'Autobots Rollout' over the PA" and the floor finished bed lining.
- Location
- Southern Maryland
Are you messing with the O2 after it has reached operating temperature? Its ignored until then
Any chance the coolant temp sensor is unplugged? That would make it run like a turd
Any chance the coolant temp sensor is unplugged? That would make it run like a turd
trippled
NAXJA Forum User
- Location
- colorado springs, co
Didn't getting of the injector connectors swapped did you? Seen 1and 2 misplaced before. Also sounds like a map sensor problem too.
I'll check out the coolant temp sensor. Didn't even think of that and its close to where I was messing around. Didn't get it up to operating temp again but I will before I order it. Didn't even think about that.
Fuel injector plugs are good. Labeled each one prior to pulling and did the wiggle test.
I might be paranoid and just need some time for the computer to adjust to all the crap I did to it over the past week. I'll know more after work today but thanks again everyone I'm already seeing improvement since I plugged in the map sensor.
Does it seem like it's missing? I had an intermittent miss that I finally traced to the cable (not the plug) for the injector. I replaced all the injector plugs and about 18" of lead with units from Rockauto for $5 each. Soldered the leads, etc. Haven't had a miss since.
Perhaps with moving the wires, a marginal connection finally broke?
David Bricker / SYR
Perhaps with moving the wires, a marginal connection finally broke?
David Bricker / SYR
