Cutting out at 1700RPMS

[XiKeiyaZI]

So I've read through a couple of threads here in distress and got the opinions of a couple of people that I know. I need some feedback/insight.

Okay, about 2 hours ago I drove about 14 miles to a friends house. Not a single hiccup. When I got there I checked my engine bay, as we all should.. noticed I had a small boost leak. No problem. I get in the car about an hour later and go to head somewhere else. I hit 1700RPMS and BAM. Engine cuts out. So I think " Okay, just cold. It's done this before. it likes to warm up " so I let it warm up to op-temp.. same thing in every gear. So it takes me 45 minutes to get home doing 42 at 1500RPMs in 5th gear. I get out. No knocking, rattling, smoking, oil is perfect and clean, coolant is all there. I can free-rev to the moon with the car parked. Vacuum is a solid 20. Oil is clean. No missing coolant. Nothing. I even checked for the dreaded case of crank-walk. Nothing.

It's about 20* outside tonight, coldest it's been yet. The car has always had an intermittent lean condition where the car would lose power for a split second and then pick right back up. It doesn't do it often, but it has done it. Just tossing that in there for speculation since I've asked a few people about it and no one has found a fix for it. I'm about to bundle up and go check plugs, wires, and pull my ECU to check and make sure that the EPROM chip is nice and snug in the socket.

For Reference : This is in the 95 GST. NOT the Talon.

 

[Tyeler18]

Uh.... boost leak?

 

[my dreamt dsm]

I had the same thing happen. I'm sure you know by now the common answer is boost leak. In my case it holds true. I have my hallman tuck under my intake where it's hard to see. I thought it was just to common spark issue. Found out my bov tee to my hallman came loose. I didn't notice a significant lost in hg but that was my problem.
edit: I was cutting out from 1200k rpm to 3000rpm. More like sluggish jerking feel.

 

[XiKeiyaZI]

See, that's exactly what Spawned is screaming at me. I KNOW where the boost leak it. It's staring me in the face. A piece of the coupler came out from under the clamp and I can see down into the coupler right off the J pipe. But jeeze, after knowing all of the POTENTIAL things that could go wrong, I'm panicking. I don't see how a boost leak could cause the engine to just completely die at 1700 RPMS consistently. Wouldn't it just make it run rich, period? Suppose I need to go out and fix that.

I just pulled the plugs. All look fine. No arcing from the boots of the plugs. Timing checks out. ECU board looks pristine. Coolant was a tad bit low, but ever since I put on that weird aftermarket overflow tank it's been doing that... did the same thing in the talon too. -shrug-. Idles perfect. Not smoking. Exhaust doesn't smell like coolant. No coolant resting on the tops of the pistons. >.< Now I'm thinking. "Bad injectors " "Bad Fuel Filter " " Bad Coils " or "Bad PTU "

 

[Tyeler18]

You're just freaking out.

Just get the boost leaks fixed and go from there.

 

[XiKeiyaZI]

Coupler back on. Started right up. It's idling and warming up now. Going to drive it around the block and see what it does.

 

[XiKeiyaZI]

No go. It's literally like there's a 1700-1800 rev limiter. Once I hit 1700 it falls back a few hundred RPM's and picks up again. I'm getting frustrated.

 

[Tyeler18]

You sure you don't have any other boost leaks? Any way to check fuel pressure?

 

[XiKeiyaZI]

Sadly I don't have a gauge or anything to check fuel pressure. I do on the talon...but that's about it.

I checked the turbo, it spins freely with no shaftplay what-so-ever. I'm at a complete loss...

NOTE : I CANNOT, repeat, CANNOT rev past 1700 even with the car out of gear and idling.

 

[Dave4g63]

i've got a friend who's gst started doing the same thing, it would rev up to about 1700 rpm and wouldn't go any higher. turned out some of the wiring fried in his MAF wiring harness, so i would check the maf and wiring for it.

 

[XiKeiyaZI]

It's more like a rev limiter, not so much that it won't go any higher. I just checked the MAF and it checks out fine. Wiring has never been tampered with.

I did find something unusual, though.... My fan is no longer kicking on as it normally does. Could a Coolant Temp Sensor cause this? The more I think about it, the more I realize that if I start my car on cold days and IMMEDIATELY try to drive it...it does this EXACT same thing until it warms up.

 

[fourgsixthree33]

A coolant temp sensor could definitly cause your problems. If it's bad, it's not giving the correct temperature. It's easy to change so I would swap it out with another that you know is good. If it doesn't change anything, you can check that off the list to be the cause of your problem. I would also do a proper boost leak test.

 

[XiKeiyaZI]

Well.. sadly I'll just have to wait until the morning to get it. I have a spare 93 R/T stealth sitting around as well as a 93 Talon. I don't believe the CTS would work off of either of those, correct?

 

[fourgsixthree33]

What is the car with the problem? What year?

 

[XiKeiyaZI]

95 gst.

 

[fourgsixthree33]

Yea it should work. I've never compared a CTS from a 1G and one from a 2G but since you have both, you could compare them.

 

[XiKeiyaZI]

Which one does the ECU read from? The Big sensor or the smaller sensor?

 

[fourgsixthree33]

The CTS for the ECU is the one in the bottom of the thermostat housing. It has two perpendicular spades. The other only has one. That is for the gauge in the dash. That's how it is in a 1G. 2G may be a little different. Like I said, I honestly don't know.

 

[XiKeiyaZI]

So basically, this? Taken from another thread... just trying to be positive.

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[1badpurple]

Yes thats it on a 2g.

 

[fourgsixthree33]

You should do a boost leak test before anything else after you swap the CTS out.

 

[spawn87]

check your wires and plugs if one is bad you will hit a cut like that. and since you say you have history of running lean i would double check the timing as well.

boost leak is the most likely the problem so as you pressurize the system also pay attention at your w/g for reactions. but check your plugs and wires anyways.

 

[XiKeiyaZI]

Everything has been addressed. It's the CTS.

I pulled the plug and bridged the connection. After fighting it not wanting to start, I got it to start and idle. It rev'd fine. I then cleaned the connections, plugged it back up.... revs fine now. About to drive it around the block and make sure that fixed it. For all I know it was a shitty connection to the CTS causing this...

 

[XiKeiyaZI]

Drove perfect.....In fact I think it's better than it was before the problem. Never felt the car pull so hard....... =___= turns out it was just a bad connection to the Coolant Temp Sensor....-facepalm- Damned DSMs keeping us on our toes, no doubt. If anyone else has this problem... poke the pins in the plug with a news-paper clip and your problems will be solved, apparently.

Thanks to everyone who helped with insight.

 

[fourgsixthree33]

Glad to hear you got her running again.