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High revving throws multiple misfires!!!

1K views 10 replies 3 participants last post by  dmdicks 
#1 · (Edited)
Alright guys I'm going to share what's going on and has been for the last week, so my car is an 03 GT SE 6-speed with 146000 miles. Mods are I/H/E - Stage 2 clutch/lightweight flywheel with a short throw shifter.

So okay, I started having problems with the angine while driving to work. It started off at first rough idle then would clear up after a few mins so I figured it was just a hiccup but then it started doing it while driving too (jerking and throttle would kill the engine) It started to happen more and more so I read up on NT and I ruled out it could be the CPS so before it died and completely left me stranded I replaced it, PITA btw due to it breaking off in the block but we got it. Come to find out that it wasn't the CPS and it was the FPR, it took a $hit on me and I was left stranded anyways. SO...I replaced the regulator and it ran rough for a few mins then smoothed out, thought all was good until I drove it later that day on a couple hour drive and when I went to accelerate and pass someone out of nowhere it sounds like the engine starts to misfire like crazy and has no power at all (Limp mode), I can drop it in neutral and rev it up a couple times and it goes away and when I drive normal it never happens but once I accelerate hard again it comes back. I had an autoparts store hook up to and and it's throwing misfire on all 6 cylinders (random misfire) and that's it nothing else is throwing code. So I'm so stumped, I have already ordered the TPS and the IAC in Hope of fixing it but as of now I've already started to chase sensors and I don't know what else to do. It doesn't have the power it used to either like something is choking it down, I cleaned the MAF too so yeah......can anyone try to give me an opinion on what else it could be? I would appreciate it so much and thanks guys.

Also I never unhooked the battery to reset the vehicle after installing the FPR and the CPS, do I need to? I figured the ECU would read after a couple minutes and set it's paramiters back to normal.
 
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#2 · (Edited)
Also I want to add that it's had all new plugs and wires (NGK) replaced, so that rules out the old stuff and wires were also gaped right. Also had the timing belt and water pump ect Replaced about 10,000 miles ago so that rules out a tooth skipping, I don't drive it hard at all hardly ever. I replaced the crank sensor with a genuine one, the fuel regulator wasn't genuine but I didn't think it mattered, I just now unplugged the battery and depressed the brake and let it sit for a couple hours to reset it again and nothing. Still going into limp mode when hard acceleration, just ordered a genuine MAF. this is driving me crazy!!!! Any suggestions?

Also here is the link to a video and an old poster on NT that had the same problem but never posted what problem/resolution was.

https://youtu.be/GKWiOYuSEf4
 
#3 ·
check for vaccum leaks. specially, around the accordion hose that goes to throttle body after MAF.
try disconnecting the MAF and see if idles better.

post the codes and freeze frame data if possible. does the misfire on cylinders changes or stays same? you can buy ELM327 bluetooth dongle and use torque app..

did the issue started after replacing something?
 
#5 · (Edited)
After it went into limp mode I tried disconnecting the MAF to see if it helped and it did nothing, when I disconnected the IAC and the TPS it tried to die so I assume those are good. I will have to inspect the bottom of the coil packs next, I've looked at them they look original so of I do replace them all do they have to be genuine also?

Yes, this started after I replaced the fuel regulator and the crank sensor but didn't have the limp mode problems until I put in a new regulator.

The random misfire code and all cylinders stays the same. No other codes.
 
#8 ·
I will have to inspect the bottom of the coil packs next, I've looked at them they look original so of I do replace them all do they have to be genuine also?
You can buy genuine part for less than price of aftermarket. Let me know if you need one.


Yes, this started after I replaced the fuel regulator and the crank sensor but didn't have the limp mode problems until I put in a new regulator.
There are two fuel pressure regulators, one in the fuel tank & one next to the fuel rails.
 
#6 ·
Here's the codes it's still throwing, the p1372 is for the crank sensor and I just replaced it with a genuine Hyundai sensor two days ago!?!?! Wtf!
 

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#7 ·
check the wires from CKS sensor connector onwards.
when you installed new oem CKS sensor (made by Siemens), was it fully seated and bolted (10mm bolt) properly? any visible damage to the reluctor ring behind it?
 
#10 · (Edited)
Okay so... I am going to say that we solved the issue hopefully.

The CPS wasn't seated fully against the block, which is crazy how centimeters between the block and sensor could cause multiple problems with engine due to the sensor not being able to read the crank distance correctly.

Reseated the sensor and no codes what so ever, still had a hiccup with a fuel issue (I think). Lugged it coming to a stop sign and it died and smelled of fuel very strongly and wouldn't start for like 10 mins then it ran great, all power back again. Maybe other pending problems, for another time guys.

Thank you both for the help it is appreciated very much, it always helps to have different minds when trying to figure out stuff like this, even tho diagnosis thru the internet can be difficult.

But I will say for future reference for everyone on NT, make sure the sensor is 100% fully seated against the block or you will have multiple problems, also use a little motor oil it helps with the tiny O-ring on the sensor to seat correctly, thanks!!! Drive safe guys!
 
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