7mgte hesitation *videos* help me

ccguy

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Oct 26, 2011
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so this started as a cel 52 i rewired it with new rg58 wire and it fixed the cel. the problem was this hesitation. as soon as the hiccup would happen the cel 52 would come on so i thought it was a knock sensor problem.
now there is and are no cel codes showing or stored.
but between 1800-2800 there is a hesitation that as you can see in the videos it just falls on its face like a car running out of gas.
i just replaced the TPS with a new one and set it to spec. and it still has it the same as before. it is driving me nucking futts, i can open the throttle and it will fall on its face and not accelerating. but if let off and gas it again it sometimes will blow right through the hiccup range.
i can feather and rev it over the 2800 rpm it runs strong and no problems are evident. like in one of the videos.
-i do not have any intake leaks that i found by pressuring the IM from the first turbo coupler to the head.
-i have the oe fuel dampener on the fuel rail.
-the injectors are firing in a constant sequence when it is choking (listening through a stethoscope)
-timing is set to 10 deg btdc
http://www.youtube.com/watch?v=GjEoxA2D_80&feature=channel&list=UL
http://www.youtube.com/watch?v=TfSSCT24uAA
http://www.youtube.com/watch?v=8im9_5UFYaU&feature=channel&list=UL
 

onemancrew

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Feb 7, 2012
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Hmm, well without even watching those videos by what you have said im thinking its a big boost leak!

Check your pipe coming straight off the turbo, mine blew there and did exactly the same thing.

Update: I have watched your videos but i am wondering why didn't you include a video where you just tried to drive it normal.

The last video sounds like its stuck at 4000rpm and wont go higher, but you said yourself you were already past the bad spot. being around 2800 just when the IC pipes starting to pressurize, makes me think its a big boost leak.
 
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ccguy

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Oct 26, 2011
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it wont drive normal. from idle to 1800 it runs perfect. sometimes it will rev right through. if i am over the bad spot like in one of the videos if the throttle is cracked it will act like it is floored. boot leak tested it with smoke and also with soap water on everything. no leaks.
the 4000rpm spot is when i am barely cracked on the throttle. if i open it up more it will go all the way up no problem.
i am going nuts.
 

onemancrew

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Feb 7, 2012
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Are you sure you boost leak tested it properly?

It could possibly be the fuel pump intermittently not pumping under pressure, it happened to me once, the car would idle fine but not drive very well.

Also check the spark gaps, they could be gapped too big giving the illusion thats its running outta fuel. They should be gapped at 0.8.
 

ccguy

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Oct 26, 2011
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yes i tested it correctly multiple times. it is a high flow pump and not loosing pressure or flow when it is acting up. the plugs are at .030.
thinking it is the tps sure to the rising acceleration with the thrott barely cracked.
i am not new to motors or fabrication. just the 7m
 

onemancrew

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Feb 7, 2012
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Hmm, its definitely a unique problem, I would start checking all the coilpack grounds are connected properly, also have you checked the leads haven't got too much resistance. they could be broken inside the insulation.
 

hvyman

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Apr 17, 2007
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Make sure non of the coil packs aren't cracked. Not too common on the 7m but it does happen.

Also check the cps.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
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Although you aren't showing any codes, use a multi tester on both the tps and the afm.
Report back with the results when you get a chance.
 

onemancrew

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Feb 7, 2012
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ccguy;1851943 said:
sounds good.
what do you mean by "leads"?

Spark Plug Leads, also known as Ignition Leads.

They look something like this: One end attaches to the spark plug, the other end attaches to the coilpack.

2002-2006-cadillac-escalade-spark-plug-wire-ac-delco-cadilla.jpg
 
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IndigoMKII

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May 9, 2011
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My 7m was having this problem. It turned out to be that non of the coils were cracked on the top where it was visually seen. I took the coils off the pack and the bottom of them all was cracked up horribly.

My car REFUSED to run more than 4000 unless you were barely on the gas. It would also spit horribly around 2800-3000. Don't resistance check the coils because mine checked out perfect but still acted up.

If you're using a walbro 255 with the stock fuel pressure regulator you need to remove/drill out the jtube so you get rid of the rich condition you could also be having.
 

ccguy

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Oct 26, 2011
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bad wiring from the tps to the ecu. ran new wires from the tps to the afm/eng temp sensor and ecu. fixed the problem
 

onemancrew

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Feb 7, 2012
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Awesome glad to see you got the problem resolved. :icon_bigg

I love it when a problem is resolved and its posted in a thread like this.
 

ccguy

New Member
Oct 26, 2011
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so didnt fix the problem, just made it less bad. i did not wire in the hac. once i wired in the hac the problem came back just as bad. i think with the hac not wired in the ecu dumped more fuel or retarded the timing and caused it to run better.
so still open to suggestions. i am going to try a new afm from the parts store. seems like that is the most common problem i have been getting responses to from people with these symptoms.
 

ccguy

New Member
Oct 26, 2011
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az
so didnt fix the problem, just made it less bad. i did not wire in the hac. once i wired in the hac the problem came back just as bad. i think with the hac not wired in the ecu dumped more fuel or retarded the timing and caused it to run better.
so still open to suggestions. i am going to try a new afm from the parts store. seems like that is the most common problem i have been getting responses to from people with these symptoms.
 

MDCmotorsports

Offical SM Expert: Turbochargers
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Mar 31, 2005
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Most likely a new AFM from the parts store won't be for the turbo.

You'll need just the electronics, and not the whole housing. Check to make sure the housing has the honey comb inside.

Also, check to make sure you don't have any:

-Exhaust leaks (I can hear one in your first video)
-Intake / pirate air leaks (preturbo)
-Boost leaks (post turbo)

I've been down this road before and it has been one of the 3 conditions I have listed above and or a bad afm.
 

ccguy

New Member
Oct 26, 2011
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az
thanks for the reply. the first video had a exhaust leak due to the hole for the egt sensor i had to send back (it was warrantied).
the afm s i have do have the honey comb inside and i have swapped out 3 of them and still the same problem.
when i unhook the hac it runs better and does not hesitate as bad and is almost drivable.
no boost leaks (not much for piping) and i have leak tested it over and over again and cant find any. also i created a boost leak by unhooking a ic pipe and it acts totally different and smokes and runs worse.
if i unhook the bov return line from the turbo intake hose between the afm and turbo it makes not difference in how it runs.
so i am still looking into wtf could be the problem.

here are some more videos
http://www.youtube.com/user/cctool/videos?view=0&flow=grid