Hello,
I have another post in here about idle shake but I was doing some research and was doing a check on the engine to see if there was a vacuum leak which I was told not because #7 cylinder is dead but the read out just shows 5% loss so I am not convinced that the shake is from that.

Well in any case I have never seen this before. I unhooked the air filter at the intake and the engine immediately died. So I pushed the tube back on and started it then tried again and the same results.
Is this normal for a 5.4L. The truck it is in is a Lincoln Blackwood which I wouldn't know why it should be any different from a F150 but I don't know if it does it with them.
Anyone know about this or heard of this?

Thanks

 

Not familiar with the Blackwood's intake and whether it's different from the F150...

Having said that, was the MAF sensor still in the intake air stream when you disconnected the air filter? If you also interrupted air for the MAF, that would be why it stalled.

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Yes the whole induction was together and I just unhooked at the throttle body to test vacuum by covering up intake and see if it revs up or stalls out but I didn't get the chance. lol

I had a 5.4 engine before but it was a 200 Lincoln and it had no issue with ought induction but I am seeing that this is a whole mother beast with different electronic aspects to it.

I guess I can unhook the Maf first and see what happens.

Was just very strange to me that it died right away.

Thanks

 

The MAF is what tells the computer how much air is going in so that it can compensate with the fuel required. When the MAF is not in place it is totally confused.

 

Yeah, when you pulled the tube off the throttle body. Your ECU basically thought it was getting no air so it cut back on the fuel, and died...

 

Unhooking the electrical on the MAF is different from disconnecting it from the airstream and leaving the electrical connected. The first will generate a code. The second will likely cause the engine to stall and generate a code.

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I appreciate the lessons guys. Thanks.

I guess I should've known that but I really miss the old days when you had the one nut to the air filter and then there the 4 barrel carb staring at you. lmao.
They sure don't make em like they used too.

I guess if I am to check vacuum that way it will have to be before the MAF.

Thanks again!! Cheers

I just got my X4 tuner today and tunes from 5star. Can't wait to install and test out the beast. lol

 

Keep us updated on the tune and if that helps

 

Most likely, the engine died because it was supposed to due to the PCV monitoring software that was phased in around '02. Vacuum leaks of the size of a disconnected PCV valve is suppose to make the engine stall.

 

I installed the 93 performance tune tonite and she has Power! lol

She didn't peel out taking off around a corner but I think its the gear ratio. The tune did have a few hard shifts at WOT but she was at 80 in no time. I thought I was racing my Lincoln LS again, only it may be faster. Gonna have to test it.
I put the 93 Economy in to run it and see about the fuel mileage.

But as to what you were referring to, it did not change the slight shake at idle. lol I just can't comes to terms with 7 cylinder being "dead" as the dealer said. But I guess I will have to unless I just want to keep throwing new parts at it instead of saving up and buying me a new engine.
I figured the way she runs, the engine should last 18-24 months before the shake gets worse, but I could be wrong. I f I am then I will buy one.
(still need to test induction before the MAF to see if it revs or stalls and test the Upstream O2 sensors then I think I am done for the time being)
For some reason I want to think its the torque converter but the truck doesn't lunge with the shake when idle and foot off brake. I was on the EGR for a time but mechanic says not likely.

In any case I will update the thread as I hat it when threads go unanswered or even if they just gave up.

Cheers

 

The dealer told you that it has a dead cylinder? Run a compression test.

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Yeah this is the readout from Lincoln dealer. I just don't understand cause 5% is normal but it is in grey and not black so not sure. I just don't see how that could equate to a miss like shake in the body. Had induction cleaned and seemed to be better for a few days but the shake came back-hence the trial of pulling cold air tube off. Im learning though.
I tested for vacuum leak and cleaned the mac today and no leak.
Maf counts on my act x4 is at 220 in idle and during acceleration it is 520. Still need to learn what that means. lol
My engine load is at 19% at idle and 49% at acceleration. I am guessing that is normal.
Trans temp 160. Coolant temp 190.
Throttle pos Absol is 202 idle 315 at acceleration
Spark is 12-13 degree at idle and 29 at acceleration
Battery voltsage ranges 12 to 14

Going to go googling right now. ---------well I searched around and it looks like all the values are correct or right around correct. lol

Thinking of just replacing upstream O2 sensors but they looks like a pain to get to. lol I'm at the point to just believe the dealer about dead cylinder and deal with the slight shudder and wait until it gets worse to replace engine. Can't just do head cause replacing engine is only like 1500 more due to having to pull engine for head and they are aluminum which is like 3k. For 6K I can have the whole engine replaced out the door cost. Its a real pretty truck. lol