<SOLVED> Stuttering

[Steve Wood]

The egr has been in the back of my mind....

With regard to the maf, we are always leery of the rebuilt ones.  In park, when missing, what is the rpm and what is the maf number?

Does this occur in both open and closed loop modes?

[daveismissing]

Rigged up a big a*ss analogue meter and tested the TPS- very smooth no dropsies.

Swapped the MAF, no change.

Looks like open and closed loop are the same
( that flashing DP is way slow and being it happens just off idle which is open loop- PITA to tell).

Was cold this AM, took a long time to hit the magic 180deg and go away.
Not fun in traffic.
 

[ULYCYC]

Did you check the EGR as I suggested?

[Steve Wood]

The only reason I have stayed away from the EGR is that the blms usually go high to make up for the leaness that occurs when the egr is open, but I would certainly check it as Ed has suggested to eliminate it.  Hate to go 17 pages like I did on someone else's car to find out the egr was stuck open and leaking at the same time.

First, a car that misses when it is cold is often too lean and needs to be "choked" to run right.  When the problem is not gigantic, the symptoms can lessen as it warms up.  I forget all the conditions for closed loop, but the temp is something like 145F and the O2 has to be warmed up.  As it appears to still be missing when it goes closed loop, it would seem to be something more basic.

Is the coolant temp on the SM reading properly?


Once again, see if you can give us the fuel pressure when you first start the car with the hose off and again when it warms up enuf to quit stuttering.  Also give us the O2s and blms once it goes into closed loop and again when it stops sputtering.

This would be a lot easier if you had a modern chip that stayed open loop at idle so you could get consistent readings.

How old is the fuel pump?  I am sure you have a reasonably new fuel filter?

[daveismissing]

Modern chip:

Now TT 5.6 installed so I'll look at open/closed loop.

Sorry if that wasn't clear -injectors on hand were larger thus TT chip.

Todays observation:
Magic number seems to be 180deg - car stayed at 171-175 in the highway for a stretch and it wasn't behaving. 

[daveismissing]

I'm trying to get to the EGR thing-- I can access the diaphragm from under the dome?

Bear with me ,4 out of 5 cars in the family fleet are broken/semibroken, ($ :o $)
most of my warmup windows are in rushhour.

[Steve Wood]

put your fingers...use both hands...under the egr and you can feel the diaphragm. Lift up and you should feel it move against a spring...when you let go, the spring should pop it down.  Lift it all the way up and let it pop down a few times.  helps to pop the cover off the egr to give more room for your fingers....do it when the engine is cold!

[Steve Wood]

On the week end, crank it up, drive it around the block, or whatever to warm it up a bit....say to 160 and then read the O2s at idle.   then watch them at idle as the car warms up further until it quits missing to see if anything changes.

Except for the blms which are confusing me, I would say the pump is getting tired...of course the fuel pressure did not seem to say this, but, you seemed to be driving so that can add to the confusion a bit.

Did you just change to the TT chip or has it been in during this episode?  Do you have an adjustable fuel pressure regulator so you could set fp to 43# or did you tell Eric you have a non adjustable regulator so he could change the chip to make it work properly?

Be sure you are using a proper fuel pressure gauge to measure with as the little mini gauges are often 10% off when new and get worse.  Some local expertise to help you look would be nice....

[daveismissing]

Well, I couldn't pronounce xylene so I swapped the injectors ( and ancilliary items).
no change.

As of this (above)date: TT5.6 + 42Lb green stripe + Accufab @43lb aka ancilliary items

[Steve Wood]

raise the hose off pressure to 48 psi which will be about 6% increase and see what happens

[daveismissing]

Not driving the car today, the need to mash the throttle to get past the stutters not compatible with the rain.

Noticed Eric says he disables the EGR, does that mean the plunger can still mess thing up sitting there?

[ULYCYC]

If the egr is not seated it can cause a problem. Only real cure if your not using it is to take it off and get a blockoff plate. You can pull the hose and plug it. Then move it up and down with your fingers and make sure its seated.  Then drive.   Its a free easy test and get it off your list as a possible problem.

[Steve Wood]

Not driving the car today, the need to mash the throttle to get past the stutters not compatible with the rain.

now, you lost me...you said it did it in park...the car is not moving in park 

[daveismissing]

You guys are hard to please, throw out a little anecdotal conversation and you're all over me.
"Just the facts 'Mam"

[daveismissing]

Found some lost gauges> new "enhanced" directors cut videos-


same settings, car is warming so only slight stutter at 6-9 seconds-


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