i need some help please!
10-08-2014, 09:22 AM
#11
Senior Member
I doubt it's injectors, as you mentioned it got worse after changing plugs and wires. I don't know the way the 4.2 works. Is it COP or distributerless? Either way I would check for good clean spark at each of the cylinders. Unplug one wire at a time, and if nothing changes that is your culprit cylinder. If it's not a spark issue, it's a fuel/air metering issue. Does it run poorly while driving or is it only an issue while idleing? If it's just and idling issue I would clean the IAC valve. I would also check fuel pressure. Got to get all the basics out of the way before we start throwing parts at it.
10-08-2014, 10:15 AM
#12
Junior Member
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To test the injectors, warm the truck up to normal operating temp. Then take and unplug each injector and test the ohms with a multi meter(to get your multi meter to test for
OHMS, turn the **** to the little "Omega" symbol). Plug the probes into the fuel injector make spade terminals and see what it reads and write it down. The average normal operating ohms should be 11-18. Do this individually to each injector and compare readings from all 8. If one or more are reading completely different, they're fried. If they all read about the same, then they're good.
OHMS, turn the **** to the little "Omega" symbol). Plug the probes into the fuel injector make spade terminals and see what it reads and write it down. The average normal operating ohms should be 11-18. Do this individually to each injector and compare readings from all 8. If one or more are reading completely different, they're fried. If they all read about the same, then they're good.
10-08-2014, 12:08 PM
#14
It just idles very bad, the reason it got new plugs was I thought that's why it was idleing bad, thanks for some more input on how to check the injectors and I'm going to test the egr I'll do that on Thurs,,I got called into work early today. I will be able to check the injectors this weekend and I will report back to let you guys know what happens, thanks again for the help!
10-10-2014, 01:49 AM
#16
Senior Member
Yea a none funtioning EGR won't hurt a thing, - except a little bit of economy. - If it's not working, - in your case it WILL NOTY cause a divisibility concern. The NLY time it cause a definit proble is when the valve won't completely close.
I believe you have a diaphragm problem. If by chance you used compressed air to assist in cleaning, you most likely compromised the Valve. It doesn't take that much, - that why the part is considered as none serviceable...because you can't.
So that's what happens commonly. BUT, if your valve will not close tightly at idle, it'll run and drive like the motor is done for... Don't worry, yuou can fix that swapping in a good valve.
This is all important figuring this one out.
You should know HOW it operates...In a nut shell... well okay, the short short version. The valve is suppose to open during the drivecycle and only at cruising speeds. 0nly then, - in gear when close to the same speed..you know, cruising.
Well, I got tired, hope I said enough. Keep in mind. The EGR system is still only a suspect, - at the moment.
I believe you have a diaphragm problem. If by chance you used compressed air to assist in cleaning, you most likely compromised the Valve. It doesn't take that much, - that why the part is considered as none serviceable...because you can't.
So that's what happens commonly. BUT, if your valve will not close tightly at idle, it'll run and drive like the motor is done for... Don't worry, yuou can fix that swapping in a good valve.
This is all important figuring this one out.
You should know HOW it operates...In a nut shell... well okay, the short short version. The valve is suppose to open during the drivecycle and only at cruising speeds. 0nly then, - in gear when close to the same speed..you know, cruising.
Well, I got tired, hope I said enough. Keep in mind. The EGR system is still only a suspect, - at the moment.