2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Bad hesitation and backfiring.

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Old 07-18-04 | 05:54 AM
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Bad hesitation and backfiring.

Get ready for a long story.

So I decide to drive my 87 TII up to a place here in oregon called Olallie Lake- Unknowing about the 15 miles of gravel road, 5 miles of which is a incline enough to overheat any car.

On the way there, I stop after those 5 miles, my temp guage is about at 1/2, and I hear pinging .

I pull over, let it cool down, and call it good. Try and start it, no go- just floods. I pull the old EGI trick, starts weird- holds a 400 idle- Im assuming I have reached the "hot start" issue- Drive it the other 10 miles to the lake, park it for 4 days, and leave.

Starts right up, drive great on the max 20mph road, and then the fun starts.

I noticed I have a oil pressure of 90 constantly. Now I am using a K&n oil filer, so I always got 60-90- but never at idle that high!
I reach paved road without a sweat, and bam. No boost.
When I step on it, it chokes and backfires, cant build boost past 4 psi- and when it does- it chokes even worse.

So I limp home staying out of boost.

Flash back to when I got the car- I have a oil leak on the turbo side of the oil return line, the bolts head broke off, it drips one or two drops of oil now and then.

We stop halfway home, I crack the hood- flames from the oil.
Turns out it flooded so bad, all the gas made it into the oil-
I put it out- no big deal- no damage-

So I make it home- no other problems. I tear the turbo off and fix the line- put it back on. Change the oil.
Yay! I have boost. All the way to 8.8 psi (est top).
I notice when Im doing this, the green plug, by the coil pack is jumpered for adjusting the BAC. I yank the wire because the idle was ok.

But when I get on it from 1k-4k- It backfires, chokes, studders, and makes makes me wonder what the hell did I do.

Im going to tear the intercooler off and check everything.
I already went over the work I did on the turbo, but it leads me to believe that a vac line or something somewhere is loose.

Time for a new oil filter too mabey?

I found 2 missing vac lines, replaced those, still hesitates and everything.
Im tearing the UIM off. I think a vac line slit or something down there.
Old 07-18-04 | 09:56 AM
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good luck..dont forget to check the turbo inlet hose for cracks!! and make sure it is on right! this will cause hesitation too
Old 07-18-04 | 10:50 PM
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100-100 compression.

Plugs are fowled to hell and back.
Going to replace ASAP.

I had 2 broken vacume lines under the TB- replaced and checked all.
Still NO clue on the oil pressure, unless he bypass is stuck open?
Im going to replace it too.

I hope something dint clog .

Oh and now the hesitation and backfiring is only 2-4k.
The broken vac lines were for the fast idle cam I guess.
Old 07-18-04 | 11:25 PM
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Replaced plugs with some old ones out of my SE.
No more hesitation.

Still a HUGE lack of power and minor backfirings.
Also a still 90 oil pressure.

Oil filter replaced tommorow.
Old 07-19-04 | 01:40 AM
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Would bad/ malfunctioning primary injectors cause this?
Because I still have no power after 4k, but its MUCH smoother.

Also I think I need to retighten the turbo.
I smell exhaust when workin on the motor.
Old 07-19-04 | 11:03 AM
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dont replace it with old plugs. get brand new ones, trust me...there is a lot of difference
Old 07-19-04 | 05:36 PM
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Well.

I tightened the manifold to block bolts- leak seems to be gone.
I also took off the primarys and cleaned them.
I have solid acceloration to 2k- then from there- 4k-
Shaking, backfiring, and no power.

I can build boost at reving it in neutral..... Never did before really? Cant remember?

Im at a loss. Why is my OP so damn high?
Im replacing the filter asap.
Old 07-19-04 | 06:50 PM
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One OP sender line was disconnected.

My BOV wasent venting correctly, allowing boost to the TOP of the guage. +40.

Wastegate/ BOV something isnt working right there.
Im building insane ammounts of boost, way to fast for it to actualy be going INTO the motor.

I have the speed of an NA right now .
Old 07-19-04 | 08:13 PM
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Theres two wires running down by the oip pan/side of the block, drivers side.
Both white connectors, one red wire, one brown wire.
The red ones connected. The brown is not.

Whats the Brown one for?
I hope I dint tear a sender off the pan .
Old 07-19-04 | 09:55 PM
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It sounds like a vacume leak to me, if the other wire isn't connect down below that could be tripping something on the computer too.

I never really did catch were that exhaust leak was exacly at. And also was it there before?
Old 07-19-04 | 10:19 PM
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Well,
You can do a fuel check pretty easy.

Pull your spark plug wires and crank the engine to flood the **** out of it.

Now pull the EGI fuse and remove one leading plug(only one at a time)
Crank the engine. If you have a huge gas cloud poof out then your primaries are atleast functoning in that housing.

Try this for the next housing.
No cloud? then that means the injector isn't firing.

I had this problem in my rear housing. It loos like my HKS FCD was bad and sending it into fuel cut.
Old 07-20-04 | 01:47 AM
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Will do that tommorow-

I broke my stock TID, so I pulled the $17 one.
$9 pipe from local muffler shop-
2.5"

2-2 pipe adapter
2-3 adapter from HD.

Works great-
My idle is great now.

Now the exhaust leak was from the manifold to block seal- needed to be tightened just a little more.

I tore ALL the piping off.
Replaced what I thought even looked shady. I also used a aftermarket BOV.

Im build boost to the top of the guage and still no power .
I even build boost in neutral with NO LOAD. Waste gate and BOV work fine from what I can watch. I dint think I should be able to build boost in neutral reving it??

I drove it with 2 friends, and they both agreed that the car was hitting fuel cut, because of the boost getting so fast at low rpms.

Is it safe to drive the car slowly keeping out of boost? I have ALOT to do tommorow.

Last edited by The Spyder; 07-20-04 at 02:07 AM.
Old 07-20-04 | 02:48 AM
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Im thinking the rough road shook up all the crap in my fuel tank and clogged it.
Im going to clean the filter tommorow.

No Idea about the boost thing yet.
Old 07-20-04 | 07:40 PM
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Filter was clean.
Tank looked brand new.

Fuuuudge....

Off comes the turbo..... again.......
Old 07-20-04 | 08:12 PM
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ok if its building boost under no load that doesnt mean its bad
but your wastegate might be sticking a little
and those stock boost gauges are really shitty
get a real boost/vacuum gauge and do some research
Old 07-20-04 | 08:27 PM
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Right off the elbow on the feed line for the actuator there was a huge crack in the 2" of rubber hose.

Replaced that.

Awaiting turbo to cool a bit more and im going to check the waste gate again.
Old 07-20-04 | 08:40 PM
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Hurm. So durring NO load, I should have no boost, and the waste gate should be opening to prevent the turbo from spooling.

But its not opening until I hit high boost and let off- kinda like my BOV right now.

If my twin scroll was screwed up... could this cause something also?
Old 07-21-04 | 12:48 AM
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Plugs replaced- twin scroll line replaced. It was kinked a tad-
Ok.

Now when I step on it- I get turbo lag- then vroom- then past the redline for the stock boost guage.
When this happens- I loose all power.
But as soon as I let of and build boost again and keep it below the 40 mark- it gets going.

So I need a FCD, and a real boost guage.
My wastegate seems to work fine, I just dint think fuel cut happened like this.

Now the only thing else I noticed- is a screwed idle and flodding problems.

I start the car- warms up- barley holds a 500 idle. My bac plug finally shattered- so Im getting a new one and soldering it on.
Shut it off- if I cant get it started on the first turn- it floods- have to pull the EGI (or install the fuel cut switch thats just not wired in yet)
Old 07-21-04 | 01:13 AM
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Old 07-21-04 | 08:50 PM
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So Im thinking I need new/cleaned primary injectors because im having flooding issues and hesitation.

Damn it.
Someone wanna tell me im atleast headed in the right direction? Ill do the injector test today someone mentioned earlier in the thread.
Old 07-23-04 | 02:02 AM
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Well- replaced the primary injectors- fixed about 1/2 the problem.
The secondaries are leaking too it seems.

I also think I need to check my timing because the turbo ir red hot after just a bit of driving.
Its also been suggested that my CAS could be malfunctioning?

How would I go apart checking this?
Old 07-23-04 | 01:37 PM
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please...........help me..........





Old 07-23-04 | 09:50 PM
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Mother.....

Snaped the two bolts that hold the TC and CC cables onto the UIM.

Thank god for easy outs.

Also broke a damn plastic fitting.

Fixed all of that.
Still runs like ****.

Well ok- heres what Ive done.

New TID.
Replaced fuel injectors with other non leaking ones.
Replaced all vacume lines with new ones.
Checked fuel filters and pump.
New Plugs.

Now. Cold start:
Starts great- holds idle.

Warms up- Holds a 1100 idle.

Drive it- warms all the way up- hits 450 then dies.
It was NOT doing this before I replaced the secondaries today.

When I try to restart the car after its been warmed up-
Nothing. Catches a little- then floods the **** out of it .

Im still building boost in neutral .

I really think my timing or CAS is broken/off somehow.

Any ideas welcome.
Old 07-23-04 | 11:45 PM
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Man I got similar problems.....not as severe but similar. I've got an n/a and mine does it at a certain throttle position. Generally at around 1/8th throttle. I don't know what to tell you but maybe someone will help us both.
Old 07-24-04 | 12:56 AM
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HOLY MOTHER OF SWEET JESUS.

My timing is WAY off.
I am amazed the car ran as well as it did!!

Sooo now that I know the marks on my pully are NOT even close- that and they are left over from someone else workin on the car. (white and green wtf)

So Im cleaning off the existing marks- moving the marks to where they should be- and re stabing the CAS.

How do I re stab the cas?
How do I move the timing marks, guestimation?

Thanks.
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