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Thread: Firing on 3... sometimes

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Posts: 1-10 of 13
2012-01-06 13:26:14
#1
Firing on 3... sometimes
Ok so it's become more prevalent as I've been driving it. I'd be driving along on 4 and then as I push it a little bit, it shuts off a cylinder. Eliminated sparkplug, wires, distributer. I don't think it's the injector or a seal. It feels and acts like an electrical issue. It's easy to get it to fire on 3, but getting it to fire on 4 takes patience, constant rpms, and as little throttle as possible. Even when it's on 4 it doesn't seem like I have it cpnsistently through the rpm range. It seems like as it demands more voltage from the throttle, it cuts cylinder #4. I've tried wiggling wires and such and had no luck. My theory is that it's the injector harness, but do those usually even go bad on the b13 se-rs? Do I just grab an extra harness and swap it? Thanks
2012-01-06 14:54:09
#2
had same problem, it was fuel issue i blame crap gas and the car sitting for 5 years

injector sticking at high rpm and flooding cylinder, goes back to running on all 4 when operating under lean conditions such as idle or up shifting (5th gear at 30mph with no throttle fuel economy gone down?

if you get it to stay on 3 cylinders when you park it you should be able to pull the plugs quick and smell gas or see that a piston is wet.

if you smell gas already and it's on 3 cylinders just pull the wires while the motor is running to decide which one it is.

you can also check for leaking o-rings if you want by pulling the rail and turning the key to "on" so the fuel pump is on and watch for leaks. while you have the fuel rail out and key to "on" you can also remove the distributor and manually turn it which will allow you to watch the injectors fire, and also the ignition so don't shock yourself or set yourself on fire.

i got lucky and got another fuel rail, you can also replace the injector or try some fuel treatment crap.
2012-01-06 15:43:31
#3
To answer your questions, yes it is possible to replace just the injector harness. But no, that's not a common point of failure on our engines.
2012-01-06 16:48:45
#4
Give me a call tonight, I might be able to come up and give you a hand diagnosing it.

Did you check the grounds that bolt to the back of the intake mani?
2012-01-06 17:05:51
#5
Originally Posted by b13gfb4
Give me a call tonight, I might be able to come up and give you a hand diagnosing it.

Did you check the grounds that bolt to the back of the intake mani?


Thanks George. I would but I'm busy tonight. Oh and I moved too lol. It's not a real rush to get it sorted out because I'm driving the truck, but I'd like to diagnose it. I may give you a call soon though.

Cause4alarm, I don't think it's because of the crap gas and car never sits more than a few weeks, if that. I'll try to take the fuel rail off and check out that. Fuel economy has gone down 3-4 mpg since the issue got worse. It may be a sticking injector.

And Ben, thanks for the help. I'll try to toy around with the rail. I'm pretty sure it could only be that. I'm getting spark and everything else checks out.
2012-01-06 17:35:10
#6
Check the grounds on the back of the intake mani, I hade a loose bolt and it was running all funky.

So where you living at now?
2012-01-09 13:06:35
#7
Originally Posted by b13gfb4
Check the grounds on the back of the intake mani, I hade a loose bolt and it was running all funky.

So where you living at now?


Ya I'll recheck my grounds all over. I'm living in Lebanon now, which is a farm town near Willimantic and Hebron. I bought a house out there and it actually has a garage, for once haha. I'll dig into the car this week and keep this updated. Thanks guys
2012-01-09 13:22:09
#8
Nice man, I def know where your at. Im over near Backus/NFA area. Let me know if you need a hand.
2012-01-09 19:50:58
#9
I had a very similar issue, and it was due to shotty wiring from previous owner. basically, the wires on one injector came loose and disconnected from the injector causing the injector to stay closed. I know you said you wiggled the wires and such. also another idea to ponder: if your motor mounts are bad, and there is excessive movement from the motor under moderate throttle, the motor could pull plugs loose. (ie. a maf plug pulling loose in the middle of the intersection causing your car to die when your already late for work :rolleyes
2012-01-16 18:54:36
#10
Ok, update: I took a look at a bunch of connections being that I think it's an electrical issue. I believe it to be one of two things. First, I realized that the plug on cylinder 4 was not getting wet. So, I pull out the connector that connects the injector to the harness and noticed that one of the prongs on the injector is tweaked a little bit. I bent it back... still on three. So, I put some electrical grease on the prongs and reconnect it. Back on 4! But then I drive down the road a little ways and the cylinder shuts off again. So I'm thinking it's gotta be either the injector (which I hear is unlikely on an import) or the connection to the harness is bad. In either case, I think I might have to replace the injector because of those finicky prongs. What do you guys think?
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