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Discussion Starter #1
Guys, it's been a while here since I haven't been driving the MK3 lately. My 89 is a stock turbo. No mods have been performed. She has 147k on the clock, 5 spd. I've searched for a few days and can't get the right info. The car started jerking back and the engine light flashes when the turbo pops in. probably at about 4 psi. I just replaced the plugs and the wires to see if that was the problem, and although she now has more power, it still doing it. I tried boosting it today, and it did it, but I kept trying back to back and it just kept jerking. As soon as I let go of the pedal, the light goes off and she continues on driving normal. Drives normal without using the turbo. I was also getting a nasty smell in the cabin, but I've since disconnected the CC and the smell stopped. Has anyone experience this issue, and if so, what should I look into in order to fix the problem?. I'm blocking the EGR next. Thanks in advance.
 

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When the check engine light flashes it should store a code.
Did you jumper Te1 and E1 on the diagnostic plug? If no codes are stored it should just blink on and off.
Do you have a wide band gauge?
 

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Discussion Starter #6
O.K. tested again and it has the 34. I've checked all hoses, adjusted the BOV and it still happens. Also, I've notice the car jerks back and forth while driving. It feels like an old Buick in need of shocks. What else would you suggest I do? TY
 

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You can statically test it here as well as inspect it.
You can rule out the intercooler, if there was a problem with that you would have loss of boost or symptoms of a clogged exhaust.
If you had a wideband you would probably see the AFR's leaning out when this happens.
 

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Discussion Starter #9
Thank you very much. Will do this weekend. I did clear the code and boosted it again, and again the 34 came back on. I just noticed the hose up above and behind the air intake plenum is cracked with tape around it.
 

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I bet you've got cracked/dry-rotted intercooler piping.
You're probably experiencing fuel cut due to all the boost leaks.

Look into how you can make your own boost leak tester to find leaks.

Have you ever replaced any of the intercooler piping?
 

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Thank you very much. Will do this weekend. I did clear the code and boosted it again, and again the 34 came back on. I just noticed the hose up above and behind the air intake plenum is cracked with tape around it.
Is that the one for the brake booster? If so then that could be your problem. A huge air leak in the intake can cause a lean spike and and would probably cause a fuel cut condition.
 

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Discussion Starter #15
I'm thinking the same. I'll look into and get back. I'm also thinking about the other day replacing the air filter and the car driving better. The filter was clogged. The entire system might be that way. Thanks, again.
 

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yeah I was also going to say it sounds a lot like fuel cut, but its hard to say without being present in the car. I'm also not a professional yet so I figured id wait to see who said what and I gotta agree I think it sounds like some cereal fuel cut
-JS
 

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Discussion Starter #17
I bet you've got cracked/dry-rotted intercooler piping.
You're probably experiencing fuel cut due to all the boost leaks.

Look into how you can make your own boost leak tester to find leaks.

Have you ever replaced any of the intercooler piping?
You're right. all the hoses were dry rotted and cracked. Nice weekend gig...:LOL:
 

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Sorry for not replying earlier.. yes bucking and engine light is for sure boost cut and you have a boost leak... The rubber on the intercooler hoses are so old and garbage by now... Replace with the eBay silicon should Outlast the car
 

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Discussion Starter #20
See, I ain’t crazy 😆
Dude, you were right. I took entire system apart and replaced every hose. I also did a tune up, replaced wires, removed the egr, and added a new thermostat. Now the car responds and drives like new. My only issue now is that the cooling temp needle won't move from cold. I let it run with the heat on. I get heat in the cabin and still, the needle won't move. Any suggestions?.,,.Thanks.
 
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