4.0 engine vibration.

[That Baker Guy]

okay, lot of crap on my brothers truck in the past week.

tuesday his truck started vibrating horribly and smelled terrible. his catalytic converters were clogged so we have them cut off as a *temporary* solution we have new ones ordered.

now it was miss firing we changed out the coil pack and wires no more miss firing (the spark plugs were a year old). but now it vibrates when idling and when maintaining speed not accelerating just enough gas to stay up to speed.. it has always idled at about 1100 rpm. any idea what could be causing this problem we havent run a diagnostic on it yet which i know, cant help you guys much, we bought a code reader and it is en-route.

any thing else we could try? we have heard it maybe the IAC valve or the MAF not sure how to clean either. our next step after that would be to replace the fuel injectors. but we dont want to have to do that mainly because we dont know how. but im sure we could do it.

any ideas guys?

 

[aspevacek]

How were the converts clogged? Was it a melt down internally from raw full dumping into the exhaust? Liek when you looked into th econverters was it a honeycomb inside or a black sooty mess? Or was it a big melted chunk?

Pull codes on the OBD before you try to speculate what the issue may be. Some systems are able to connect to the system and read live data which can tell alot about what is going on with the engine real time and make diagnosing issues alot easier.


Pull the engine oil dipstick and smeel the oil se eif it smells like fuel.

 

[That Baker Guy]

We did not have a chance to look at them because we did not cut them off. The oil doesn't smell like gas. Also there is no noise associated with this problem just this vibration. The code Reade should be here tomorrow.

 

[That Baker Guy]

okay so we got a code read on the thing, it says a miss fire in cylinder 4 a [P0304] code *and* cylinder 6. [P0306] so theres the source of vibration. but we also got a [P0420] code that says catalyst system efficiency below threshold (bank 1) and a [P0102] mass or volume air flow circuit low input code. and last but not least a [P0171] system too lean (bank 1) code.

so summary of
[P0304]
[P0306]
[P0420]
[P0102]
[P0171]

so can anyone tell me whats going on? it seems that he's not getting enough air and the system is running lean. does that mean a clogged injector or something?

thanks
baker

 

[shane96ranger]

Change the plugs. I wouldn't go any further without putting brand new plugs in it. You need to rule that out first, no matter how old (or young) they are.

You've changed the coil pack and wires. Those plugs might fouled out, cracked, etc.

 

[That Baker Guy]

Change the plugs. I wouldn't go any further without putting brand new plugs in it. You need to rule that out first, no matter how old (or young) they are.

You've changed the coil pack and wires. Those plugs might fouled out, cracked, etc.

haha nice to see you here.

and we'll try that. can i take the plugs out and turn the truck on and see if they spark? i think ive heard thats how you check them... i could be completely wrong.


any ideas on the air situation and the lean?

 

[adsm08]

The plugs have to be in contact with the engine block or the body of the truck or they won't spark anyway.

Based on your codes I would start with 6 plugs, one MAF, and a can of seafoam into the intake BEFORE the new cats are put in.

 

[shane96ranger]

You can certainly try cleaning the MAF. I personally use a Q-tip and rubbing alcohol, and have never had any issues with the method. Some people frown at that method. You just need the right torx bit for the job. You can also buy a can of MAF cleaner from Autozone.

We found a leaky vacuum hose off the DPFE sensor on my buddies Explorer that caused a lean condition.

 

[That Baker Guy]

okay thanks for the input, we shall try to clean the maf and check for vac leaks. we switched the number 4 spark plug to the 5 cylinder to see if we get a diff code. i doubt it but we cant get to a parts store atm. low funds damn money pit.

 

[shane96ranger]

okay thanks for the input, we shall try to clean the maf and check for vac leaks. we switched the number 4 spark plug to the 5 cylinder to see if we get a diff code. i doubt it but we cant get to a parts store atm. low funds damn money pit.

I forget, are 4 and 5 the same coil in the pack? For some reason I'm thinking it is 3 and 4 you should be swapping.

EDIT: Yes, 3 and 4 are the same coil rather than 5 and 4.

 

[That Baker Guy]

I forget, are 4 and 5 the same coil in the pack? For some reason I'm thinking it is 3 and 4 you should be swapping.

EDIT: Yes, 3 and 4 are the same coil rather than 5 and 4.

what do you mean? im not familiar with anything engine related. i have the basic understanding but thats it.

what do you mean by same coil? same pair? also we just moved the spark plug from four to five then connected the correct wire to that cylinder what are you suggesting?

 

[shane96ranger]

Oh, you swapped the entire wire then.

The coil pack has 3 coils in it, not 6. So cylinders 1 & 5, 6 & 2, and then 3 & 4 share a coil. Sometimes people swap the two in a pair to see if the misfire moves.

 

[That Baker Guy]

Oh, you swapped the entire wire then.

The coil pack has 3 coils in it, not 6. So cylinders 1 & 5, 6 & 2, and then 3 & 4 share a coil. Sometimes people swap the two in a pair to see if the misfire moves.

okay thank you for that explanation, ever since we moved the faulty spark plug from cyl 4 to 5 the cylinder four misfire has gone away and only getting a cyl 6 misfire code now. wtf? all the lean codes have gone. and it doesnt vibrate as much now. maybe it is a bad plug we'll stop and get one after work. motorcraft have a warranty?

and we reset the engine light and only getting a 6cyl misfire, aswell as the faulty cats

 

[That Baker Guy]

well we got it all sorted out, misfire on 6 faulty plug thanks for your help. owning a code reader is the best thing imaginable

 

[shane96ranger]

That's great! I'm glad it was simple.