Video of what my car is doing.

[bcracecar]

1993 GSX Eclipse cutting out in boost - YouTube

Not sure what is going on. It's idling high like there is a vacuum leak, but I couldn't find one. One of my lifters has a slight tick, could this be a knock sensor issue?

 

[Spoolin92GSX]

I noticed your coolant gauge dip when the revs dropped, that could definitely be causing problems if your sensor isn't working properly. That surging idle sounds more like a bad ISC, but could be related to the coolant sensor jumping around. How did you check for boost leaks?

 

[bcracecar]

I noticed your coolant gauge dip when the revs dropped, that could definitely be causing problems if your sensor isn't working properly. That surging idle sounds more like a bad ISC, but could be related to the coolant sensor jumping around. How did you check for boost leaks?

I noticed that gauge as well and wondered if there could be something linked into that. Maybe it isn't going into closed loop? Is there a separate CTS and sending unit on these cars? Or is it all linked to the CTS?

My buddy who drives an SRT-4 is actually the one who checked for boost leaks. I'm not sure how he tested, but he is a knowledgeable guy and I trust his work.

 

[Spoolin92GSX]

Closed loop wouldn't affect WOT, but coolant temp is used by the ECU for fuel enrichment. If the ECU is seeing wildly inaccurate coolant temps it would cause either lean or rich conditions that could cause a misfire. Our cars also hate a lean idle, so that could cause a surging idle if it's fighting between rich and lean. I would definitely test the ISC with a multimeter also.

 

[bcracecar]

Closed loop wouldn't affect WOT, but coolant temp is used by the ECU for fuel enrichment. If the ECU is seeing wildly inaccurate coolant temps it would cause either lean or rich conditions that could cause a misfire. Our cars also hate a lean idle, so that could cause a surging idle if it's fighting between rich and lean. I would definitely test the ISC with a multimeter also.

I'll check out the CTS when I get home. Part is cheap, maybe it is just a bad connection. Hopefully I can get this figured out. This car is becoming a big headache!

 

[pauleyman]

a datalogger would be very helpful here. Knowing what the ecu is doing, coolant temp, air temp, isc position, fuel trims etc will help point you in the right direction.

 

[bcracecar]

a datalogger would be very helpful here. Knowing what the ecu is doing, coolant temp, air temp, isc position, fuel trims etc will help point you in the right direction.

If only I had one

 

[pauleyman]

why don't you fill us in on what you've done so far. This is a no load miss. How does the car drive?

 

[trillatl]

Mine did this b4 I upgraded the fuel pump and injectors... Wouldn't rev part 5k... But my coolant gauge never moved like that...

Is your gas pedal kinda hard to push in?

 

[bcracecar]

why don't you fill us in on what you've done so far. This is a no load miss. How does the car drive?

The car does the same thing under load. May miss 500rpm less while under load. Ran a BLT and didn't find anything.

 

[pauleyman]

So you haven't done a basic tune up? Plug, wires etc? done any testing?

 

[bcracecar]

Changed plugs, wires, ran a BLT and didn't find anything. Just replaced the coolant temp sensor and the coolant temp sensor switch to no avail. Stumped. Any ideas? Starting to thing this is an ECU problem

 

[Spoolin92GSX]

Changed plugs, wires, ran a BLT and didn't find anything. Just replaced the coolant temp sensor and the coolant temp sensor switch to no avail. Stumped. Any ideas? Starting to thing this is an ECU problem

Test your ISC motor with a voltmeter, I believe there's a write-up on it on VFAQ. Is the coolant temp gauge still dipping/jumping? If so it's possible it could be ECU related. It wouldn't hurt to pull it for a quick visual check.

 

[bcracecar]

Test your ISC motor with a voltmeter, I believe there's a write-up on it on VFAQ. Is the coolant temp gauge still dipping/jumping? If so it's possible it could be ECU related. It wouldn't hurt to pull it for a quick visual check.

Temp gauge is still being erratic. I'll check the ISC, but wouldn't that only affect the car when it is idling? Would that cause that miss at higher RPM? There is an ECU for 100 bucks shipped on here that I think I'm going to grab while it is available for good measure.

 

[Spoolin92GSX]

Temp gauge is still being erratic. I'll check the ISC, but wouldn't that only affect the car when it is idling? Would that cause that miss at higher RPM? There is an ECU for 100 bucks shipped on here that I think I'm going to grab while it is available for good measure.

Generally, yes, that's right. I would still take a look at the ECU first just to make sure, but it definitely sounds like that's the issue.

 

[reallyslowfwd]

check your battery and alt. if voltage output is low it will mess with your gauges and make your car run like crap. could be why you see the temp gauge fluctuate with rpm.

 

[bcracecar]

Generally, yes, that's right. I would still take a look at the ECU first just to make sure, but it definitely sounds like that's the issue.

I bought the ECU from mustangmurdera today. Said he would ship it out today so hopefully I'll have it in the next couple days. I'll start from there and move on. What I really need help with right now is this stupid clutch adjustment

 

[Spoolin92GSX]

I bought the ECU from mustangmurdera today. Said he would ship it out today so hopefully I'll have it in the next couple days. I'll start from there and move on. What I really need help with right now is this stupid clutch adjustment

That's the easy part! Uncomfortable, but easy . Follow the clutch lever up to the shaft that goes to the clutch master cylinder, 12mm IIRC to loosen the jam nut and vice grips to adjust the rod one way or the other

 

[bcracecar]

That's the easy part! Uncomfortable, but easy . Follow the clutch lever up to the shaft that goes to the clutch master cylinder, 12mm IIRC to loosen the jam nut and vice grips to adjust the rod one way or the other

I tried... Posted a video, go to my thread about it!

 

[DSM1G90]

The pivot ball for the TOB fork could be worn. Pull the tranny and put a thin washer behind the pivot ball to extend the ball out a bit so more adjustment can be had. Goto http://vfaq.com on clutch adustments - there's a proper procedure to get the hydraulics adjusted right.

Did you check and reset the ISC, then adjust the BISS screw?

 

[bcracecar]

ECU should be in today. I'll swap it out and keep you guys posted on what happens. Really hoping this fixes the problem.

I changed out the ECU. Didn't fix a damn thing.
I'm starting to get extremely frustrated... I don't know where else to check.

Also, pulled the old ECU and it had a sticker on it with the name of a garage. Does this mean anything to any of you? Makes me curious.

http://i1146.photobucket.com/albums...-8199-6BB6D01CFF94-15565-000001AA20F28E6E.jpg

 

[DSM1G90]

Motoguys is an excellent ECU rebuild company - where I got my ECU back in '09.

Interesting that there are no tamper seals around the sides so if the case is split, it voids the warranty with them.

Still call it that your ISC unit isn't up to par... If you had vacuum leaks, thing would run super rough due to the idle mixture is being lean out where the motor would barely run.


Light ticking is a tired lifter - oughta think on a lifter kit sometime.

Good luck - DSM

 

[bcracecar]

Motoguys is an excellent ECU rebuild company - where I got my ECU back in '09.

Interesting that there are no tamper seals around the sides so if the case is split, it voids the warranty with them.

Still call it that your ISC unit isn't up to par... If you had vacuum leaks, thing would run super rough due to the idle mixture is being lean out where the motor would barely run.


Light ticking is a tired lifter - oughta think on a lifter kit sometime.

Good luck - DSM

Thank you for all of your input. I'm going to read up on the ISC as I have never messed with one before... I may unplug the knock sensor and try to run the car to see if that may be an issue. Wish me luck. Going in blind here!

 

[Spoolin92GSX]

I doubt it's the ISC, I've seen them go out and it's a very different behavior at idle and it doesn't affect much of anything once the throttle plate is open. Vacuum (boost) leaks have to be HUGE to actually make the car shut off. I had a capped 5/16" port on my intake manifold open up and I could still limp the car home with a little throttle control. Common sized boost leaks though, can absolutely cause headache inducing runability problems like you're having.
EDIT: Had to reread, saw you've done a boost leak test already.. At this point a data logger would be extremely helpful, I'm almost starting to suspect a TPS or MAF issue.

 

[sincitydru]

The up and down ldle leads me to believe the tps could be the problem. Had two different vehicles that had a bad tps, did the same thing. Do you still have an egr.? (This is just a guess) there is a temp sensor for the egr that has vacuum hoses coming out forgot what its called. Maybe the egr letting to much air in at times. I can't remember the exact symptom my buddies laser had but he needed one cause of his running condition. If anyone else can rule that one out. Just trying to help.